A Comparative Study of Surgical Approach, Patient Positioning and Cup Positioning Technique - Cup Orientation Using 2D/3D-matching Technique HipMatch in 349 Hips

A Comparative Study of Surgical Approach, Patient Positioning and Cup Positioning Technique - Cup Orientation Using 2D/3D-matching Technique HipMatch in 349 Hips | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article A Comparative Study of Surgical Approach, Patient Positioning and Cup Positioning Technique - Cup Orientation Using 2D/3D-matching Technique HipMatch in 349 Hips Corinne Andrea Zurmühle, Martin Beck, Guoyan Zheng, Joseph Michael Schwab, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7973490/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Introduction: Postoperative measurement of cup orientation on pelvic radiographs is prone to error, while CT scans are less practical in routine settings. The 2D/3D-matching technique allows measurement of cup orientation normalized to anterior pelvic plane using standard radiographs. This study aimed to determine the ( 1 ) precision and ( 2 ) percentage of outliers in cup orientation among three groups with different surgical approaches, patient positioning, and cup positioning techniques. Methods We retrospectively analyzed 322 patients (349 hips) who underwent total hip arthroplasty (THA) with three different approaches: the 'direct lateral' group (66 hips) using a lateral position and direct lateral approach; the 'supine anterior' group (128 hips) using a supine position and anterior approach; and the 'lateral anterior' group (155 hips) using a lateral position and anterior approach. Cup positioning was determined intraoperatively using a mechanical device in the ‘direct lateral’ and ‘lateral anterior’ groups and using fluoroscopy in the ‘supine anterior’ group. The 2D/3D-matching technique, HipMatch, was used to measure cup inclination and anteversion on postoperative radiographs normalized to the anterior pelvic plane. Precision was assessed using standard deviations (SDs), with outliers defined as orientations outside 2 SDs (31–56° inclination, 7–36° anteversion). Results ( 1 ) The ‘supine anterior’ group showed the highest precision for inclination (SD = 4.6°) compared to the ‘direct lateral’ (SD = 6.8°) and ‘lateral anterior’ (SD = 6.2°) groups (p < 0.001). Precision for anteversion did not differ significantly (p = 0.097). ( 2 ) The percentage of outliers did not significantly differ among the groups (p = 0.183 to 0.384). Conclusion Inclination and anteversion vary with surgical approach, patient positioning in this largest series of APP normalized cup position measurements. The highest precision for inclination was seen in the anterior approach in supine position with fluoroscopy but approach, positioning, and technique did not affect the percentage of outliers. Figures Figure 1 Figure 2 Figure 3 Figure 4 Introduction Cup orientation remains a critical determinant of long-term outcomes in total hip arthroplasty (THA) ( 1 – 3 ), albeit traditional safe zones such as the Lewinnek criteria are now considered outdated ( 4 , 5 ). The rise of less invasive surgical techniques for THA has led to reduced surgical exposure, potentially impacting cup positioning. However, there have been technical advancement in cup placement, including navigation and intraoperative fluoroscopy. The impact of surgical approach and patient positioning on cup orientation normalized to the anterior pelvic plane (APP) in THA has not been investigated in a large clinical series due to the lack of a technique to accurately determine correct cup orientation out of a postoperative pelvic radiograph. An alternative method involves assessing cup orientation using computed tomography (CT), which is associated with drawbacks such as unnecessary radiation exposure and increased costs, thereby limiting its application in evaluating a larger patient population. Multiple studies in the past have shown that assessing cup position using only plane pelvic radiographs is unreliable ( 6 – 8 ) compared with the CT scan as the ground truth. The 2D/3D-matching software HipMatch has been developed and validated with the goal to measure cup orientation based on a postoperative anterior posterior (AP) pelvic radiograph ( 9 – 12 ) and normalize it with the APP. Using statistical pelvic shape modelling, the cup orientation is calculated and referred to the APP comparable with the CT scan technique. This allows determining the exact cup orientation in a clinical routine setup but with the use of standard AP pelvic radiographs instead of CT scans. Using this validated technology for measurement of cup orientation, we compared the precision and outliers of cup orientation among three study groups. THA was performed either in the lateral decubitus position through the direct lateral approach (‘direct lateral’ group), in the supine position through the anterior approach (‘supine anterior’ group) and in the lateral decubitus position through the anterior approach (‘lateral anterior’ group). We asked whether the ( 1 ) precision and ( 2 ) the percentage of outliers of cup orientation (inclination and anteversion) differ among these three study groups? Material and Methods We performed one of the largest retrospective comparative study for APP normalized cup position measurement without CT including a total of 349 selected hips in 322 patients with primary total hip arthroplasty. The study was conducted according to local ethical guidelines and approved by local ethical committees. They were recruited from two different institutions of the authors. Inclusion criterion was the use of a radiolucent polyethylene cup (RM Pressfit or RM Pressfit vitamys cup, Mathys AG, Bettlach, Switzerland) for the socket. This cup was the acetabular implant of choice in both institutions at the time of study. It was chosen for this study since the radiolucency of the cup with the metal wire marking the cup opening facilitates the calculation of cup inclination and anteversion (Fig. 1 ). Exclusion criteria were the use of any other cup design (320 hips), different approaches other than the investigated direct anterior or direct lateral approach (46 hips) and congenital or posttraumatic pelvic deformities (5 hips; Fig. 1 ). An additional exclusion criterion was an insufficient image quality of the postoperative AP pelvic radiograph (26 hips; Fig. 2 ). Poor image contrast or missing anterior superior iliac spine on low-centered images were excluded due to inferior accuracy of cup orientation measurement using the 2D/3D-matching software ( 10 ). The three study groups were structured as follows: The 'direct lateral’ group comprised 66 patients (66 hips) who underwent THA in the lateral decubitus position via a direct lateral approach. This approach was considered standard for THA at one institution between February 2012 and December 2014 (Fig. 1 and Table 1 ). Simultaneously at the same institution, the supine anterior approach was introduced in February 2012, forming the ‘supine anterior’ group. A total of 118 patients (128 hips) underwent surgery between February 2012 and February 2015. The third study group, the ‘lateral anterior group’, included 138 patients (155 hips) operated on at another institution.( 13 ) These surgeries were performed through the direct anterior approach in the lateral decubitus position from September 2009 to July 2012. All surgeries were conducted in teaching hospitals and performed by various surgeons with differing levels of experience. The three study groups differed regarding the methods to control the cup orientation during surgery; in the ‘direct lateral’ group (direct lateral approach in lateral position) and the ‘lateral anterior’ group (anterior approach in lateral position) cup orientation was controlled during surgery by using a mechanical alignment guide. The guide was mounted to the impaction handle with two rods indicating 45° of inclination and 15° of cup anteversion. Verification of cup orientation during impaction was achieved by aligning these rods parallel to the table. In the last study group, THA was conducted through the anterior approach with the patient in the supine position (‘supine anterior’ group). In this group, fluoroscopy was applied to check intraoperative cup inclination and anteversion ( 14 ). During surgery the patient positioning was adjusted to achieve neutral rotation of the pelvis, indicated by alignment of the center of the sacrococcygeal joint and the symphysis. Additionally, pelvic inclination was monitored by tilting the C-arm until the shape of the obturator foramen resembled that observed on preoperative AP pelvic radiographs. Across all study groups, cup orientation was individually adjusted according to the specific anatomy of the acetabulum. Particularly in cases of dysplastic hips, adjustments were made for cup anteversion to align with the native acetabular version, aiming to prevent prominent anterior cup borders, which can irritate the psoas tendon. This adjustment often resulted in higher cup anteversion in dysplastic hips due to the deficient anterior acetabular rim. Postoperative radiographs were taken with the patient in the supine position, with internally rotated legs to counterbalance femoral antetorsion, and a film-focus distance of 1.2 m was maintained. The radiograph was centered low to ensure inclusion of the entire stem. Patients underwent radiographic follow-up immediately after surgery (either the same day or within two days), at 6 weeks post-surgery, and at the 1-year mark. For precise computerized measurement of cup orientation, accurate identification of the anterior superior iliac spines on the radiograph is essential ( 10 ). Therefore, images with overly deep centering were deemed unsuitable for evaluation and were either excluded from analysis or substituted with radiographs from later follow-up appointments. Radiographs for 2D/3D-matching analysis were conducted at an average follow-up interval of 4 ± 5 months (ranging from 0 to 37 months). Measurement of cup orientation was performed with a previously validated 2D/3D- matching software HipMatch ( 10 – 12 , 15 ). Using statistical shape modeling, the software creates a virtual 3D model of the pelvis with spatial information and, thus, allows to calculate anatomically referenced cup inclination and anteversion based on vectors (Fig. 1 ). As an anatomical reference system for cup orientation, the APP was used, defined by the anterior superior iliac spines and the pubic tubercles (Fig. 1 ). Computerized evaluation of cup orientation was performed semi-automatically by one of the authors (CAZ); the anatomical landmarks for the cup opening and APP on the radiograph had to be defined manually. The software then matched the outline of the 3D model of the pelvis with the contours of the pelvis on the radiograph to calculate cup orientation (Fig. 1 ). For both the cup inclination the radiographic definition and for cup anteversion the anatomical anteversion according to Murray ( 16 ) were used. The radiographic inclination is the vector defined by the longitudinal axis of the ellipse of the cup projected on to the coronal plane. ( 16 ) The anatomical anteversion is defined as the angle between the transverse axis and the acetabular axis when this is projected on to the transverse plane. ( 16 ) Accuracy of the software to calculate cup orientation was reported with a mean error of 0.4° ± 1.8° (− 2.6° to 3.3°) for inclination and 0.6° ± 1.5° (− 2.0° to 3.9°) for anteversion, with excellent reproducibility and reliability (intraclass correlation coefficient (ICC) of at least 0.95). [3] The precision of cup inclination and anteversion was evaluated across all study groups by comparing the standard deviation (SD) of these measurements. A smaller SD indicates a higher precision in cup orientation. Since traditional safe zones such as the one of Lewinnek are today considered outdated ( 4 , 5 , 17 ), outliers were defined when cup orientation was outside the range of two SDs of inclination and anteversion. For all the 349 hips, this range corresponds to 31–56° inclination and 7–36° of anteversion. Statistical analysis Normal distribution was tested with the Kolmogorov-Smirnov test. Differences in demographic data among the three study groups were tested using analysis of variance (ANOVA). If a difference among the three study groups existed, pairwise comparison between two study groups was done with the independent t-test and correction of the level of significance according to Bonferroni et al ( 18 – 20 ) (p = 0.057/3 = 0.017). The Fisher’s exact test was used to compare binominal demographic data among the three study groups. To evaluate precision of cup inclination and anteversion the SD among the three study groups were compared with the Levene F-test. Outliers for cup inclination and anteversion were compared with the Fisher’s exact test. Statistical analysis was performed with WinSTAT for Microsoft ® Excel Version 2012.1.0.96 (Robert K. Fitch Software, Bad Krozingen, Germany) and MedCalc for Windows, version 20.019 (MedCalc Software, Ostend, Belgium). Results For cup inclination, precision was increased in the ‘supine anterior’ group (SD = 4.6°) compared to the ‘direct lateral’ (SD = 6.8°) or ‘lateral anterior’ groups (SD = 6.2°; p < 0.001 for both; Table 2 and Fig. 3 ). The precision for anteversion did not differ among the three study groups (p = 0.097; Table 2 and Fig. 3 ). The mean inclination was decreased in the ‘lateral anterior’ group with 41° ± 6.2° (range, 18° – 55°) compared to the ‘direct lateral’ with 45° ± 6.8° (range, 31° – 61°; p < 0.001) or ‘supine anterior’ with 45° ± 4.6° (range, 32° – 58°; p < 0.001) groups (Table 2 and Fig. 3 ). The mean anteversion was highest in the ‘lateral anterior’ group with 23° ± 7.6° (2° – 42°) and lowest in the ‘direct lateral’ group with 18° ± 7.4° (2° – 37°; p < 0.001; Table 2 and Fig. 3 ). Within the ‘supine anterior’ and ‘lateral anterior’ study groups, the precision for inclination was increased compared to anteversion (indicated by lower SD of 4.6° vs. 6.4° and 6.2° vs 7.2° with p < 0.001 and p = 0.014, respectively; Table 2 and Fig. 3 ). The percentage of outliers did not differ among the three study groups (p ranging from 0.183 to 0.384; Table 2 , Fig. 4 ). Conclusion The 2D/3D-matching technique, HipMatch , enables evaluation of cup orientation normalized to the APP without requiring a postoperative CT scan. Therefore, evaluation of normalized cup orientation is for the first time possible in a routine clinical setup with large numbers of patients. Typically, studies employing postoperative CT measurement for cup orientation assessment tend to have a significantly smaller number of cases included (Table 3 ). The current study compares cup orientation across several groups with varying approaches, patient positioning, and cup placement techniques, making it the largest study to evaluate cup orientation normalized to the APP. This study has some limitations. Assessing the precision of cup orientation could not be conducted independently for each approach, patient position, or technique used for cup placement. However, a direct comparison between the anterior and direct lateral approaches was feasible (lateral anterior group vs. direct lateral group; Table 2 ), as both approaches involved patients in the lateral position and utilized a mechanical guide for cup placement. Another limitation was that only precision (how close measurements are to each other) could be calculated and not accuracy (how close a measurement is to the true value) since the final cup orientation was not recorded intraoperatively (e.g. with navigation ( 17 )). Most studies assessing cup orientation aimed to compare various techniques for cup placement, typically comparing navigation with conventional cup placement (Table 3 ). Only a few studies assessed cup orientation depending on different surgical approaches or patient positioning (Table 3 ) ( 21 – 23 ). These studies did not reveal any differences in precision of cup inclination and anteversion for different approaches ( 21 , 22 ) or patient positioning ( 22 , 24 ) (Table 3 ). Consistent with this literature (Table 3 ), in the current study cup anteversion did not differ depending on patient position or approach (Table 2 , Fig. 3 ). In contrast, cup inclination demonstrated increased precision in hips with the anterior approach in supine position (Fig. 3 ). This could be attributed to notable smaller study series in the literature (Table 3 ) or the fact that, in the current study different techniques of cup positioning were applied (e.g. mechanical positioning device or fluoroscopy). In addition, the current study showed a higher precision for inclination compared to anteversion (Table 2 , Fig. 3 ), which is consistent with most studies in literature (Table 3 ). This fact can be attributed to the surgeons’ discretion and anatomical adjustments of cup anteversion during surgery to avoid psoas tendon irritation which results in a wider range of cup anteversion. We found no difference in the prevalence of outliers for inclination or anteversion compared among the three study groups. Traditional metrics like the Lewinnek safe zones, which have long guided cup placement, are increasingly seen as inadequate due to their limitations in accounting for individual patient anatomy and variability in pelvic orientation. Therefore we used a statistical approach to define outliers consistent with previously reported methods in the literature ( 4 , 5 , 17 ). In conclusion, the anterior supine approach demonstrated comparable or improved precision in cup orientation compared to the traditional direct lateral approach. The use of intraoperative fluoroscopy appears to offer a more consistent means of controlling cup inclination during surgery ( 17 , 25 , 26 ). A wider range of cup anteversion across all approaches may reflect a greater need for patient-specific cup anteversion. Declarations Conflict of interest: The authors declare no conflict of interest. Declaration of Generative AI and AI-assisted technologies in the writing process: During the preparation of this work, the authors used AI tools to correct grammar and enhance sentence variety. After using these tools, the authors—including a native English speaker—carefully reviewed and edited the content as needed and take full responsibility for the final version of the publication. Funding: This study was support by Mathys Research grant, RMS Foundation, Bettlach, Switzerland. Project: “Conventional versus less-invasive Anterior Total Hip Arthroplasty: “Anatomical-referenced Accuracy of the RM-Pressfit Cup Orientation” Availability of data and materials: The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request Authors contribution: Conceptualization – CAZ, MB, MT, SDS, JMS, GZ; Data curation – CAZ, SDS, GZ; Formal analysis CAZ, SDS; Funding acquisition CAZ, MB, MT, SDS; Investigation CZ, SDS; Methodology CAZ, MB, MT, SDS; Project administration CAZ, SDS, JMS; Resources; Software GZ; Supervision SDS, MT; Visualization – CAZ, SDS; Roles/Writing - original draft CAZ, SDS, JMS; and Writing - review & editing CAZ, MB, MT, SDS, JMS. We confirm that all authors contributed substantially to the current submission. Human Ethics and Consent to Participate declarations We hereby confirm that the study was conducted according to Swiss ethical guidelines and approved by local ethical committees (KEK Bern 22-12-13 and EK Luzern 893). Consent for anonymous use of x-ray data and consent to participate: Patients at our institution are asked to give their general consent for the anonymous use of their data for general research purposes. Patients who have refused to allow the anonymous use of their data have been excluded. References Elkins JM, Callaghan JJ, Brown TD. The 2014 Frank Stinchfield Award: The landing zone for wear and stability in total hip arthroplasty is smaller than we thought: a computational analysis. Clin Orthop Relat Res. 2015;473(2):441–52. Schmalzried TP, Guttmann D, Grecula M, Amstutz HC. l. The relationship between the design, position, and articular wear of acetabular components inserted without cement and the development of pelvic osteolysis. J Bone Joint Surg Am. 1994;76(5):677–88. Tian J, Sun L, Hu R, Han W, Tian X. Long-term Results of Primary Hip Arthroplasty with Cup Inclination Angle Bigger than Fifty Degrees. J Clin Orthop Trauma. 2018;9(2):133–6. Abdel MP, Von Roth P, Jennings MT, Hanssen AD, Pagnano MW. What Safe Zone? The Vast Majority of Dislocated THAs Are Within the Lewinnek Safe Zone for Acetabular Component Position. Clin Orthop Relat Res. 2016;474(2):386–91. Dorr LD, Callaghan JJ. Death of the Lewinnek Safe Zone. J Arthroplast. 2019;34(1):1–2. Kalteis T, Handel M, Herold T, Perlick L, Paetzel C, Grifka J. Position of the acetabular cup—accuracy of radiographic calculation compared to CT-based measurement. Eur J Radiol. 2006;58(2):294–300. Penney GP, Edwards PJ, Hipwell JH, Slomczykowski M, Revie I, Hawkes DJ. Postoperative Calculation of Acetabular Cup Position Using 2-D–3-D Registration. IEEE Trans Biomed Eng. 2007;54(7):1342–8. Tannast M, Langlotz U, Siebenrock KA, Wiese M, Bernsmann K, Langlotz F. Anatomic referencing of cup orientation in total hip arthroplasty. Clin Orthop Relat Res. 2005;(436):144–50. Craiovan B, Renkawitz T, Weber M, Grifka J, Nolte L, Zheng G. Is the acetabular cup orientation after total hip arthroplasty on a two dimension or three dimension model accurate? Int Orthop. 2014;38(10):2009–15. Steppacher SD, Tannast M, Zheng G, Zhang X, Kowal J, Murphy SB. HipMatch: a 2D/3D matching software; accurate and reliabel. J Bone Joint Surg. 2010;(92-B(SUPP I)):109–109. Zheng G, von Recum J, Nolte LP, Grützner PA, Steppacher SD, Franke J. Validation of a statistical shape model-based 2D/3D reconstruction method for determination of cup orientation after THA. Int J Comput Assist Radiol Surg. 2012;7(2):225–31. Zheng G, Zhang X, Steppacher SD, Murphy SB, Siebenrock KA, Tannast M. HipMatch: an object-oriented cross-platform program for accurate determination of cup orientation using 2D-3D registration of single standard X-ray radiograph and a CT volume. Comput Methods Programs Biomed. 2009;95(3):236–48. Camenzind RS, Stoffel K, Lash NJ, Beck M. Direct anterior approach to the hip joint in the lateral decubitus position for joint replacement. Oper Orthop Traumatol. 2018;30(4):276–85. Matta JM, Shahrdar C, Ferguson T. Single-incision anterior approach for total hip arthroplasty on an orthopaedic table. Clin Orthop Relat Res. 2005;441:115–24. Steppacher SD, Tannast M, Zheng G, Zhang X, Kowal J, Anderson SE, et al. Validation of a new method for determination of cup orientation in THA. J Orthop Res. 2009;27(12):1583–8. Murray DW. The definition and measurement of acetabular orientation. J Bone Joint Surg Br. 1993;75(2):228–32. Zurmühle CA, Zickmantel B, Christen M, Christen B, Zheng G, Schwab JM, et al. Image-Less THA Cup Navigation in Clinical Routine Setup: Individual Adjustments, Accuracy, Precision, and Robustness. Medicina. 2022;58(6):832. Abdi H. Bonferroni and Sidak corrections for multiple comparisons. In: Encyclopedia of Measurement and Statistics [Internet]. Sage, Oaks T. CA; 2007. pp. 103–7. Available from: https://www.bibsonomy.org/bibtex/2ab68b97b46031a8c94414e0d64dea6be/lran022 Bonferroni C. Teoria statistica delle classi e calcolo delle probabilita. Pubblicazioni del R Istituto Superiore di Scienze Economiche e Commericiali di Firenze. 1936;8:3–62. Bland JM, Altman DG. Multiple significance tests: the Bonferroni method. BMJ. 1995;310(6973):170. Hananouchi T, Takao M, Nishii T, Miki H, Iwana D, Yoshikawa H, et al. Comparison of navigation accuracy in THA between the mini-anterior and -posterior approaches. Int J Med Robot. 2009;5(1):20–5. Maeda Y, Sugano N, Nakamura N, Hamawaki M. The Accuracy of a Mechanical Cup Alignment Guide in Total Hip Arthroplasty (THA) Through Direct Anterior and Posterior Approaches Measured with CT-Based Navigation. J Arthroplast. 2015;30(9):1561–4. Zhao W, Li S, Yin Y, Wang Z, Sun G, Peng X, et al. Direct Anterior Approach in Lateral Decubitus Position Versus Supine Position for Unilateral Total Hip Arthroplasty: A Comparative Study. Orthop Surg. 2021;13(3):786–90. Zhao W, Li S, Yin Y, Wang Z, Sun G, Peng X, et al. Direct Anterior Approach in Lateral Decubitus Position Versus Supine Position for Unilateral Total Hip Arthroplasty: A Comparative Study. Orthop Surg. 2021;13(3):786–90. Hasart O, Poepplau B, Asbach P, Perka C, Wassilew C. Ultrasound-based navigation and 3D CT compared in acetabular cup position. Orthopedics. 2009;32(10 Suppl):6–10. Takada R, Jinno T, Miyatake K, Hirao M, Yoshii T, Okawa A. Portable imageless navigation system and surgeon’s estimate for accurate evaluation of acetabular cup orientation during total hip arthroplasty in supine position. Eur J Orthop Surg Traumatol. 2020;30(4):707–12. Grützner PA, Zheng G, Langlotz U, von Recum J, Nolte LP, Wentzensen A, et al. C-arm based navigation in total hip arthroplasty-background and clinical experience. Injury. 2004;35(Suppl 1):S–A90. Blendea S, Eckman K, Jaramaz B, Levison T, Digioia A. Measurements of acetabular cup position and pelvic spatial orientation after total hip arthroplasty using computed tomography/radiography matching. Comput Aided Surg. 2005;10(1):37–43. Kim T, Lee S, Yang J, Oh K. Computed tomography assessment of image-free navigation-assisted cup placement in THA in an Asian population. Orthopedics. 2012;35(10 Suppl):13–7. Kalteis T, Handel M, Herold T, Perlick L, Paetzel C, Grifka J. Position of the acetabular cup -- accuracy of radiographic calculation compared to CT-based measurement. Eur J Radiol. 2006;58(2):294–300. Fukunishi S, Fukui T, Imamura F, Nishio S. Assessment of accuracy of acetabular cup orientation in CT-free navigated total hip arthroplasty. Orthopedics. 2008;31(10): orthosupersite.com/view.asp?rID = 31515 Carcangiu A, D’Arrigo C, Topa D, Alonzo R, Speranza A, De Sanctis S, et al. Reliability of cup position in navigated THA in the lateral decubitus position using the flip technique. Hip Int. 2011;21(6):700–5. Saxler G, Marx A, Vandevelde D, Langlotz U, Tannast M, Wiese M, et al. The accuracy of free-hand cup positioning–a CT based measurement of cup placement in 105 total hip arthroplasties. Int Orthop. 2004;28(4):198–201. Haaker R, Tiedjen K, Ottersbach A, Rubenthaler F, Stockheim M, Stiehl J. Comparison of conventional versus computer-navigated acetabular component insertion. J Arthroplasty. 2007;22(2):151–9. Parratte S, Argenson JN, Flecher X, Aubaniac JM. [Computer-assisted surgery for acetabular cup positioning in total hip arthroplasty: comparative prospective randomized study]. Rev Chir Orthop Reparatrice Appar Mot. 2007;93(3):238–46. Jenny J, Boeri C, Dosch J, Uscatu M, Ciobanu E. Navigated non-image-based positioning of the acetabulum during total hip replacement. Int Orthop. 2009;33(1):83–7. Craiovan B, Weber M, Worlicek M, Schneider M, Springorum H, Zeman F, et al. Measuring Acetabular Cup Orientation on Antero-Posterior Radiographs of the Hip after Total Hip Arthroplasty with a Vector Arithmetic Radiological Method. Is It Valid and Verified for Daily Clinical Practice? Rofo. 2016;188(6):574–81. Woerner M, Sendtner E, Springorum R, Craiovan B, Worlicek M, Renkawitz T, et al. Visual intraoperative estimation of cup and stem position is not reliable in minimally invasive hip arthroplasty. Acta Orthop. 2016;87(3):225–30. Hayashi S, Hashimoto S, Kuroda Y, Nakano N, Matsumoto T, Ishida K, et al. Accuracy of cup position following robot-assisted total hip arthroplasty may be associated with surgical approach and pelvic tilt. Sci Rep. 2021;11(1):7578. Sariali E, Boukhelifa N, Catonne Y, Pascal Moussellard H. Comparison of Three-Dimensional Planning-Assisted and Conventional Acetabular Cup Positioning in Total Hip Arthroplasty: A Randomized Controlled Trial. J Bone Joint Surg Am. 2016;98(2):108–16. Steppacher S, Kowal J, Murphy S. Improving cup positioning using a mechanical navigation instrument. Clin Orthop Relat Res. 2011;469(2):423–8. Lu M, Zhou Y, Du H, Zhang J, Liu J. Reliability and validity of measuring acetabular component orientation by plain anteroposterior radiographs. Clin Orthop Relat Res. 2013;471(9):2987–94. McMahon SJ, Christmas MUSI, Pierrepont J, McMahon J, McMahon R. The Accuracy of Acetabular Cup Positioning Using Patient-Specific 3D Orientation Guidance in Total Hip Arthroplasty. Surg Technol Int. 2020;36:426–31. Tables Table 1 Demographic and surgery related data of the three study groups: THA performed with a direct lateral approach in lateral position (‘direct lateral’ group), anterior approach in supine position (‘supine anterior’ group) and anterior approach in lateral position (‘lateral anterior’ group). Parameter Direct lateral Supine anterior Lateral anterior p-value global p-value* Direct lateral vs supine anterior p-value* Direct lateral vs lateral anterior p-value* Supine vs lateral anterior Approach Direct lateral Anterior Anterior - - - - Patient positioning Lateral Supine Lateral - - - - Techique of cup positioning Mechanical Fluroscopy Mechanical - - - - Number of patients 66 118 138 - - - - Number of hips 66 128 155 - - - - Age at operation (years) 66 ± 12 (26–89) 61 ± 13 (25–90) 68 ± 9 (41–88) < 0.005 0.016 0.312 < 0.005 Gender (percent male of all hips) 53 59 51 0.402 - - - Weight (kg) 83 ± 27 (44–170) 80 ± 18 (47–156) 77 ± 15 (46–116) 0.082 - - Height (m) 1.70 ± 0.10 (1.50–1.89) 1.70 ± 0.10 (1.40–1.90) 1.68 ± 0.09 (1.42–1.92) 0.342 - - - BMI (m/kg 2 ) 29 ± 10 (17–57) 27 ± 5 (18–47) 27 ± 4 ( 17 – 43 ) 0.148 - - - Side (percent right of all hips) 42 52 47 0.399 - - - Indications for THA (number of hips [percentage]) - Primary osteoarthritis - Hip fracture - Avascular necrosis - Posttraumatic 44 (66%) 13 (20%) 3 (5%) 6 (9%) 99 (77%) 14 (11%) 15 (12%) 0 (0%) 148 (96%) 0 (0%) 7 (4%) 0 (0%) < 0.001 0.107 < 0.001 < 0.001 Values are expressed as mean ± standard deviation with range in parentheses; THA = total hip arthroplasty; BMI = body mass index; *the level of significance for pairwise comparison was adjusted according to Bonferroni et al ( 9 ) and was p = 0.05/3 = 0.017 Table 2 Results of cup inclination, anteversion and outliers of the three study groups Parameter Direct lateral Supine anterior Lateral anterior Comparison of Means Precision* (n = 66 hips) (n = 128 hips) (n = 155 hips) p-value global p-value † Direct lateral vs supine anterior p-value † Direct lateral vs lateral anterior p-value † Supine vs lateral anterior p-value global p-value † Direct lateral vs supine anterior p-value † Direct lateral vs lateral anterior p-value † Supine vs lateral anterior Inclination (degrees) 45 ± 6.8 (31–61) 45 ± 4.6 (32–58) 41 ± 6.2 (18–55) < 0.001 0.835 < 0.001 < 0.001 0.003 < 0.001 0.397 < 0.001 Anteversion (degrees) 18 ± 7.4 ( 2 – 37 ) 21 ± 6.4 ( 6 – 37 ) 23 ± 7.6 ( 2 – 42 ) < 0.001 0.035 < 0.001 < 0.001 0.097 - - - Comparison of Precision* - p-value Inclination vs anteversion 0.447 < 0.001 0.014 - Outlier ‡ (number of hips [percentage]) Inclination Anteversion All 4 ( 6 ) 5 ( 8 ) 8 ( 12 ) 3 ( 2 ) 4 ( 3 ) 7 ( 5 ) 9 ( 6 ) 8 ( 5 ) 17 ( 11 ) 0.312 0.384 0.183 Values are expressed as mean ± standard deviation with range in parentheses; *precision was calculated by comparing the standard deviation using the Levene F-Test; † the level of significance for pairwise comparison was adjusted according to Bonferroni et al ( 9 ) and was p = 0.05/3 = 0.017; ‡ outliers were defined as a cup orientation outside an inclination of 31–56° and/or an anteversion 7–36° (these limits were defined as ± 2 standard deviation of mean inclination or anteversion of the entire series of 349 evaluated hips); continuous data were compared with the Kruskall Wallis-test and the Mann Whitney U-test for pairwise comparison; binominal data were compared with the Fisher’s exact test; differences in standard deviation were tested with the Levene F-test. Table 3 Selected literature about 3-dimensional cup orientation of THA evaluated using CT or specific software HipMatch ( 10 ) Author Number of Hips Modality Refe-rence Approach Patient Positioning Technique of Cup Positioning Inclination (°) Anteversion (°) Results* Grützner et al ( 27 ), 2004 50 CT APP N/A Supine C-arm navigated 42 ± 4 (36–49) 21 ± 4 ( 10 – 28 ) Accuracy of inclination 1.5° ± 1.1° and anteversion 2.4° ± 1.3° (target 40° inclination and 20° inclination) Blendea et al ( 28 ), 2005 38 CT APP N/A N/A CT-based navigation 52 ± 5 (43–59) 18 ± 7 (0–29) Navigation study for validation of 2D/3D-matching software Xalign Kim et al ( 29 ), 2012 81 CT APP N/A Supine Image less navigated 41 (30–57) 21 ( 1 – 37 ) Validation of image less navigation. Increased accuracy for navigated cup orientation. Tannast et al ( 8 ), 2005 I: 13 II: 13 CT APP Direct lateral Lateral I: C-arm navigated II: Conventional I: 39 ± 3 (35–47) II: 41 ± 8 (29–56) I: 8 ± 6 (-3–17) II: 33 ± 6 (23–45) Cadaver study. Increased precision with navigation for inclination (p = 0.001) but not anteversion (p = 0.79) Kalteis et al ( 30 ), 2006 I: 30 II: 30 III: 30 CT APP Direct lateral Supine I: CT-based navigation II: Image less navigation III: Conventional I: 42 ± 4 (34–53) II: 43 ± 4 (33–50) III: 44 ± 7 (29–57) I: 11 ± 5 ( 1 – 23 ) II: 15 ± 6 ( 5 – 25 ) III: 22 ± 14 (1–53) Increased precision for both inclination and anteversion for image less or CT-based navigation compared to conventional Fukunishi et al ( 31 ), 2008 79 CT APP Direct lateral Lateral Image less navigation 41 ± 4 (30–49) 21 ± 5 ( 9 – 32 ) Validation study for image less navigation Carcangiu et al ( 32 ), 2011 24 CT APP Direct lateral Lateral Image less navigation 43 ± 5 (35–56) 14 ± 5 ( 5 – 28 ) Validation study for image less navigation Saxler et al ( 33 ), 2004 I: 80 II: 105 CT APP Anterolateral Supine I: CT-based navigation II: Conventional I: 43 ± 4 (35–53) II: 46 ± 10 (23–72) I: 26 ± 7 ( 12 – 38 ) II: 27 ± 15 (-24–59) Precision for inclination and anteversion higher in navigated compared to conventional THA (both p < 0.001) Haaker et al ( 34 ), 2007 I: 98 II: 69 CT APP Anterolateral N/A I: Navigated II: Conventional I: 43 ± 5 (30–58) II: 46 ± 9 (26–64) I: 22 ± 7 ( 5 – 38 ) II: 29 ± 10 (9–53) Precision for inclination and anteversion higher in navigated compared to conventional THA (both p < 0.001) Parratte et al ( 35 ), 2007 I: 30 II: 30 CT APP Anterolateral Supine I: Image less navigation II: Conventional I: 34 ± 6 (25–45) II: 34 ± 8 (24–50) I: 14 ± 5 ( 7 – 25 ) II: 16 ± 10 ( 2 – 35 ) Precision for inclination and anteversion higher in navigated compared to conventional THA (p from < 0.001 to 0.028) Hasart et al ( 25 ), 2009 25 CT APP Anterolateral Supine Image less navigation 45 ± 4 (37–52) 26 ± 4 ( 16 – 35 ) Validation of ultrasound based navigation Jenny et al ( 36 ), 2009 50 CT APP Anterolateral Supine Image less navigation 44 ± 5 (30–57) 19 ± 7 ( 2 – 32 ) Validation study for image less navigation Craiovan et al ( 37 ), 2016 123 CT APP Anterolateral Lateral Navigated and conventional 44 ± 7 (26–66) 21 ± 11 (-15–50) Validation study for vector arithmetic cup orientation Woerner et al ( 38 ), 2016 65 CT APP Anterolateral Lateral Conventional 39 ± 6 (23–54) 23 ± 12 (-6–54) Precision of conventional cup placement Takada et al ( 26 ), 2020 30 CT APP Anterolateral Supine HipAlign portable navigation system versus manual goniometer 38 ± 4 (32–46) 18 ± 4 ( 10 – 25 ) No difference between navigation tool and surgeon’s estimate with goniometer Zurmühle et al ( 17 ), 2022 367 Radio-graph and HipMatch APP Anterolateral Supine Image-less navigation 40 ± 4 (26–50) 25 ± 6 (0–41) Accuracy, precision and robustness of image less navigation validated with HipMatch Hayashi et al ( 39 ), 2021 115 CT APP Anterolateral or posterior Supine or lateral CT based navigation and robot-assisted 40 ± 3 19 ± 3 Accuracy of robot-assisted total hip arthroplasty Sariali et al ( 40 ), 2016 I: 28 II: 28 CT APP Anterior Supine I: 3D planning II: Conventional I: 38 ± 6 ( 35 – 40 ) II: 44 ± 8 (41–47) I: 13 ± 6 ( 10 – 15 ) II: 25 ± 7 ( 22 – 28 ) Accuracy of cup inclination and anteversion with 3D planning increased (p = 0.003 and < 0.001) Zhao et al ( 23 ), 2021 I: 46 II: 43 CT N/A Anterior I: Lateral II: Supine Conventional I: 43 ± 3 II: 44 ± 4 I: 16 ± 5 II: 17 ± 4 No mean difference in cup inclination and anteversion compared to lateral and supine position Hananouchi et al ( 21 ), 2009 I: 20 II: 20 CT N/A I: Anterior II: Posterior Lateral I and II: CT based navigation I: 39 ± 3 (35–44) II: 37 ± 4 (32–48) I: 15 ± 3 ( 10 – 20 ) II: 16 ± 4 ( 8 – 25 ) Accuracy and precision between different approaches did not differ for inclination and anteversion (p ranging from 0.18 to 0.73) Maeda et al ( 22 ), 2015 I: 34 II: 47 III: 35 CT APP I: Anterior II: Anterior III: Posterior I: Supine II: Lateral III: Lateral CT-based navigation system and mechanical guide I: 48 ± 5 (33–60) II: 49 ± 4 (39–62) III: 48 ± 5 (38–56) I: 21 ± 7 ( 11 – 37 ) II: 18 ± 8 (0–37) III: 8 ± 6 ( 2 – 24 ) Validation of mechanical guide. No difference in precision compared to CT-based navigation. Mean anteversion with posterior approach lower. Steppacher et al ( 41 ), 2011 I: 70 II: 146 Radio-graph and HipMatch APP I: Posterior II: Posterior Lateral I: Mechanical guide II: CT based navigation I: 42 ± 0 ( 39 – 42 ) II: 41 ± 1 (38–45) I: 23 ± 0 ( 23 – 25 ) II: 31 ± 3 ( 23 – 37 ) Increased accuracy for mechanical navigation compared to CT based navigation (p < 0.001 and 0.003) Lu et al ( 42 ), 2013 60 CT Coro-nal plane Posterior Lateral Conventional 37 ± 6 (23–58) 17 ± 8 ( 1 – 33 ) Comparison of cup orientation measurement in plain radiographs and CT McMahon et al ( 43 ), 2020 60 CT APP Posterior Lateral Patient specific 3D guide and laser beam 43 (33–58) 29 ( 16 – 41 ) Validation of patient specific 3D guide. Lower accuracy for anteversion compared to inclination. Zurmühle et al (current study) 349 Radio-graph and HipMatch APP I: Direct lateral II: Anterior III:Anterior I: Lateral II: Supine III: Lateral I: mechanical guide II: fluoroscopy III: mechanical guide I: 45 ± 7 (31–61) II: 45 ± 5 (32–58) III: 41 ± 6 (18–55) I: 18 ± 7 ( 2 – 37 ) II: 21 ± 6 ( 6 – 37 ) III: 23 ± 8 ( 2 – 42 ) Comparison of cup orientation among different approaches, patient positioning and techniques of cup positioning; highest precision for anterior approach in supine position APP = anterior pelvic plane, defined by the two anterior superior iliac spines and the two pubic tubercules. N/A = not available. FPP = functional pelvic plane. * A difference in precision was defined by a significant difference in standard deviation for cup inclination or anteversion. Gray background: studies comparing different patient positioning or surgical approaches. Additional Declarations No competing interests reported. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7973490","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":545189608,"identity":"5405a025-94f5-4d2d-8966-5b5ba5a294c6","order_by":0,"name":"Corinne Andrea 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10:08:20","extension":"html","order_by":12,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":161738,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-7973490/v1/d09760161910e330bb9ffbb5.html"},{"id":96652438,"identity":"8c9a2753-cb7c-41b7-a1a2-e10691894916","added_by":"auto","created_at":"2025-11-24 16:34:28","extension":"jpeg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":758143,"visible":true,"origin":"","legend":"\u003cp\u003e(A) AP pelvic radiograph with the radiolucent polyethylene cup (RM Pressfit or RM Pressfit vitamys cup, Mathys AG, Bettlach, Switzerland). (B) The cup orientation was calculated using a postoperative AP pelvic radiograph and validated 2D/3D-matching software (\u003cem\u003eHipMatch\u003c/em\u003e, Institute for Surgical Technology and Biomechanics ISTB, University of Bern, Bern, Switzerland) with a statistical shape model of the pelvis. (C) Cup inclination and anteversion were measured according to the anatomy of the pelvis with reference to the anterior pelvic plane (defined by the anterior superior iliac spines and pubic tubercles).\u003c/p\u003e","description":"","filename":"floatimage1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7973490/v1/229839ca20c6384ca9bda652.jpeg"},{"id":96652439,"identity":"f334c27e-99a3-4385-b780-863abb7e0783","added_by":"auto","created_at":"2025-11-24 16:34:29","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":292651,"visible":true,"origin":"","legend":"\u003cp\u003ePatient selection for the three study groups from the two authors’ institutions\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-7973490/v1/f69e418cb1347946caa6453a.png"},{"id":96652441,"identity":"e1d4780c-07b7-4556-82c8-d8e43bab8f4c","added_by":"auto","created_at":"2025-11-24 16:34:29","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":413187,"visible":true,"origin":"","legend":"\u003cp\u003ePrecision for (A) inclination was increased in the ‘supine anterior’ group (SD = 4.6°), indicated by a narrower Gaussian distribution, compared to the ‘direct lateral’ (Standard deviation [SD] = 6.8°) or ‘lateral anterior’ groups (SD = 6.2°; p \u0026lt; 0.001 for both; Table 2). Precision for (B) anteversion did not differ among the three study groups (p = 0.097). In the ‘lateral anterior’ group, the mean inclination was lower and the mean anteversion higher compared to the other study groups (both p \u0026lt;0.001; Table 2). Within the ‘supine anterior’ and ‘lateral anterior’ study groups, the precision for inclination was increased compared to anteversion (indicated by narrower Gaussian distribution; Table 2).\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-7973490/v1/76bff279bc1c6b9971e88f12.png"},{"id":96652446,"identity":"44510023-214a-4346-84e5-23d2cd17361d","added_by":"auto","created_at":"2025-11-24 16:34:29","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":310087,"visible":true,"origin":"","legend":"\u003cp\u003eResults for cup inclination and anteversion for the three study groups with different approaches and patient positioning; ‘direct lateral’ group (direct lateral approach in lateral position), ‘supine anterior’ group (anterior approach in supine position) and ‘lateral anterior’ group (anterior approach in lateral position).\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-7973490/v1/1745a1a1295459fbdc28b06e.png"},{"id":98431679,"identity":"48d645ae-2a76-4b19-bca6-1a8b1b544561","added_by":"auto","created_at":"2025-12-17 16:48:08","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2591253,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7973490/v1/77a0b575-6fdb-433e-816d-dd8f7f26a2a6.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"\u003cp\u003eA Comparative Study of Surgical Approach, Patient Positioning and Cup Positioning Technique - Cup Orientation Using 2D/3D-matching Technique HipMatch in 349 Hips\u003c/p\u003e","fulltext":[{"header":"Introduction","content":"\u003cp\u003eCup orientation remains a critical determinant of long-term outcomes in total hip arthroplasty (THA) (\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e), albeit traditional safe zones such as the Lewinnek criteria are now considered outdated (\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e). The rise of less invasive surgical techniques for THA has led to reduced surgical exposure, potentially impacting cup positioning. However, there have been technical advancement in cup placement, including navigation and intraoperative fluoroscopy. The impact of surgical approach and patient positioning on cup orientation normalized to the anterior pelvic plane (APP) in THA has not been investigated in a large clinical series due to the lack of a technique to accurately determine correct cup orientation out of a postoperative pelvic radiograph. An alternative method involves assessing cup orientation using computed tomography (CT), which is associated with drawbacks such as unnecessary radiation exposure and increased costs, thereby limiting its application in evaluating a larger patient population.\u003c/p\u003e\u003cp\u003eMultiple studies in the past have shown that assessing cup position using only plane pelvic radiographs is unreliable (\u003cspan additionalcitationids=\"CR7\" citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e) compared with the CT scan as the ground truth. The 2D/3D-matching software \u003cem\u003eHipMatch\u003c/em\u003e has been developed and validated with the goal to measure cup orientation based on a postoperative anterior posterior (AP) pelvic radiograph (\u003cspan additionalcitationids=\"CR10 CR11\" citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e) and normalize it with the APP. Using statistical pelvic shape modelling, the cup orientation is calculated and referred to the APP comparable with the CT scan technique. This allows determining the exact cup orientation in a clinical routine setup but with the use of standard AP pelvic radiographs instead of CT scans.\u003c/p\u003e\u003cp\u003eUsing this validated technology for measurement of cup orientation, we compared the precision and outliers of cup orientation among three study groups. THA was performed either in the lateral decubitus position through the direct lateral approach (\u0026lsquo;direct lateral\u0026rsquo; group), in the supine position through the anterior approach (\u0026lsquo;supine anterior\u0026rsquo; group) and in the lateral decubitus position through the anterior approach (\u0026lsquo;lateral anterior\u0026rsquo; group). We asked whether the (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e) precision and (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e) the percentage of outliers of cup orientation (inclination and anteversion) differ among these three study groups?\u003c/p\u003e"},{"header":"Material and Methods","content":"\u003cp\u003eWe performed one of the largest retrospective comparative study for APP normalized cup position measurement without CT including a total of 349 selected hips in 322 patients with primary total hip arthroplasty. The study was conducted according to local ethical guidelines and approved by local ethical committees. They were recruited from two different institutions of the authors. Inclusion criterion was the use of a radiolucent polyethylene cup (RM Pressfit or RM Pressfit vitamys cup, Mathys AG, Bettlach, Switzerland) for the socket. This cup was the acetabular implant of choice in both institutions at the time of study. It was chosen for this study since the radiolucency of the cup with the metal wire marking the cup opening facilitates the calculation of cup inclination and anteversion (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Exclusion criteria were the use of any other cup design (320 hips), different approaches other than the investigated direct anterior or direct lateral approach (46 hips) and congenital or posttraumatic pelvic deformities (5 hips; Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). An additional exclusion criterion was an insufficient image quality of the postoperative AP pelvic radiograph (26 hips; Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). Poor image contrast or missing anterior superior iliac spine on low-centered images were excluded due to inferior accuracy of cup orientation measurement using the 2D/3D-matching software (\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eThe three study groups were structured as follows: The 'direct lateral\u0026rsquo; group comprised 66 patients (66 hips) who underwent THA in the lateral decubitus position via a direct lateral approach. This approach was considered standard for THA at one institution between February 2012 and December 2014 (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e and Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Simultaneously at the same institution, the supine anterior approach was introduced in February 2012, forming the \u0026lsquo;supine anterior\u0026rsquo; group. A total of 118 patients (128 hips) underwent surgery between February 2012 and February 2015. The third study group, the \u0026lsquo;lateral anterior group\u0026rsquo;, included 138 patients (155 hips) operated on at another institution.(\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e) These surgeries were performed through the direct anterior approach in the lateral decubitus position from September 2009 to July 2012. All surgeries were conducted in teaching hospitals and performed by various surgeons with differing levels of experience.\u003c/p\u003e\u003cp\u003eThe three study groups differed regarding the methods to control the cup orientation during surgery; in the \u0026lsquo;direct lateral\u0026rsquo; group (direct lateral approach in lateral position) and the \u0026lsquo;lateral anterior\u0026rsquo; group (anterior approach in lateral position) cup orientation was controlled during surgery by using a mechanical alignment guide. The guide was mounted to the impaction handle with two rods indicating 45\u0026deg; of inclination and 15\u0026deg; of cup anteversion. Verification of cup orientation during impaction was achieved by aligning these rods parallel to the table. In the last study group, THA was conducted through the anterior approach with the patient in the supine position (\u0026lsquo;supine anterior\u0026rsquo; group). In this group, fluoroscopy was applied to check intraoperative cup inclination and anteversion (\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e). During surgery the patient positioning was adjusted to achieve neutral rotation of the pelvis, indicated by alignment of the center of the sacrococcygeal joint and the symphysis. Additionally, pelvic inclination was monitored by tilting the C-arm until the shape of the obturator foramen resembled that observed on preoperative AP pelvic radiographs. Across all study groups, cup orientation was individually adjusted according to the specific anatomy of the acetabulum. Particularly in cases of dysplastic hips, adjustments were made for cup anteversion to align with the native acetabular version, aiming to prevent prominent anterior cup borders, which can irritate the psoas tendon. This adjustment often resulted in higher cup anteversion in dysplastic hips due to the deficient anterior acetabular rim.\u003c/p\u003e\u003cp\u003ePostoperative radiographs were taken with the patient in the supine position, with internally rotated legs to counterbalance femoral antetorsion, and a film-focus distance of 1.2 m was maintained. The radiograph was centered low to ensure inclusion of the entire stem. Patients underwent radiographic follow-up immediately after surgery (either the same day or within two days), at 6 weeks post-surgery, and at the 1-year mark. For precise computerized measurement of cup orientation, accurate identification of the anterior superior iliac spines on the radiograph is essential (\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e). Therefore, images with overly deep centering were deemed unsuitable for evaluation and were either excluded from analysis or substituted with radiographs from later follow-up appointments. Radiographs for 2D/3D-matching analysis were conducted at an average follow-up interval of 4\u0026thinsp;\u0026plusmn;\u0026thinsp;5 months (ranging from 0 to 37 months).\u003c/p\u003e\u003cp\u003eMeasurement of cup orientation was performed with a previously validated 2D/3D- matching software \u003cem\u003eHipMatch\u003c/em\u003e (\u003cspan additionalcitationids=\"CR11\" citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e). Using statistical shape modeling, the software creates a virtual 3D model of the pelvis with spatial information and, thus, allows to calculate anatomically referenced cup inclination and anteversion based on vectors (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). As an anatomical reference system for cup orientation, the APP was used, defined by the anterior superior iliac spines and the pubic tubercles (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Computerized evaluation of cup orientation was performed semi-automatically by one of the authors (CAZ); the anatomical landmarks for the cup opening and APP on the radiograph had to be defined manually. The software then matched the outline of the 3D model of the pelvis with the contours of the pelvis on the radiograph to calculate cup orientation (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). For both the cup inclination the radiographic definition and for cup anteversion the anatomical anteversion according to Murray (\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e) were used. The radiographic inclination is the vector defined by the longitudinal axis of the ellipse of the cup projected on to the coronal plane. (\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e) The anatomical anteversion is defined as the angle between the transverse axis and the acetabular axis when this is projected on to the transverse plane. (\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e) Accuracy of the software to calculate cup orientation was reported with a mean error of 0.4\u0026deg; \u0026plusmn; 1.8\u0026deg; (\u0026minus;\u0026thinsp;2.6\u0026deg; to 3.3\u0026deg;) for inclination and 0.6\u0026deg; \u0026plusmn; 1.5\u0026deg; (\u0026minus;\u0026thinsp;2.0\u0026deg; to 3.9\u0026deg;) for anteversion, with excellent reproducibility and reliability (intraclass correlation coefficient (ICC) of at least 0.95). [3]\u003c/p\u003e\u003cp\u003eThe precision of cup inclination and anteversion was evaluated across all study groups by comparing the standard deviation (SD) of these measurements. A smaller SD indicates a higher precision in cup orientation. Since traditional safe zones such as the one of Lewinnek are today considered outdated (\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e), outliers were defined when cup orientation was outside the range of two SDs of inclination and anteversion. For all the 349 hips, this range corresponds to 31\u0026ndash;56\u0026deg; inclination and 7\u0026ndash;36\u0026deg; of anteversion.\u003c/p\u003e\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003eStatistical analysis\u003c/h2\u003e\u003cp\u003eNormal distribution was tested with the Kolmogorov-Smirnov test. Differences in demographic data among the three study groups were tested using analysis of variance (ANOVA). If a difference among the three study groups existed, pairwise comparison between two study groups was done with the independent t-test and correction of the level of significance according to Bonferroni et al (\u003cspan additionalcitationids=\"CR19\" citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e) (p\u0026thinsp;=\u0026thinsp;0.057/3\u0026thinsp;=\u0026thinsp;0.017). The Fisher\u0026rsquo;s exact test was used to compare binominal demographic data among the three study groups. To evaluate precision of cup inclination and anteversion the SD among the three study groups were compared with the Levene F-test. Outliers for cup inclination and anteversion were compared with the Fisher\u0026rsquo;s exact test. Statistical analysis was performed with WinSTAT for Microsoft \u0026reg; Excel Version 2012.1.0.96 (Robert K. Fitch Software, Bad Krozingen, Germany) and MedCalc for Windows, version 20.019 (MedCalc Software, Ostend, Belgium).\u003c/p\u003e\u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eFor cup inclination, precision was increased in the \u0026lsquo;supine anterior\u0026rsquo; group (SD\u0026thinsp;=\u0026thinsp;4.6\u0026deg;) compared to the \u0026lsquo;direct lateral\u0026rsquo; (SD\u0026thinsp;=\u0026thinsp;6.8\u0026deg;) or \u0026lsquo;lateral anterior\u0026rsquo; groups (SD\u0026thinsp;=\u0026thinsp;6.2\u0026deg;; p\u0026thinsp;\u0026lt;\u0026thinsp;0.001 for both; Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e and Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). The precision for anteversion did not differ among the three study groups (p\u0026thinsp;=\u0026thinsp;0.097; Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e and Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). The mean inclination was decreased in the \u0026lsquo;lateral anterior\u0026rsquo; group with 41\u0026deg; \u0026plusmn; 6.2\u0026deg; (range, 18\u0026deg; \u0026ndash; 55\u0026deg;) compared to the \u0026lsquo;direct lateral\u0026rsquo; with 45\u0026deg; \u0026plusmn; 6.8\u0026deg; (range, 31\u0026deg; \u0026ndash; 61\u0026deg;; p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) or \u0026lsquo;supine anterior\u0026rsquo; with 45\u0026deg; \u0026plusmn; 4.6\u0026deg; (range, 32\u0026deg; \u0026ndash; 58\u0026deg;; p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) groups (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e and Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). The mean anteversion was highest in the \u0026lsquo;lateral anterior\u0026rsquo; group with 23\u0026deg; \u0026plusmn; 7.6\u0026deg; (2\u0026deg; \u0026ndash; 42\u0026deg;) and lowest in the \u0026lsquo;direct lateral\u0026rsquo; group with 18\u0026deg; \u0026plusmn; 7.4\u0026deg; (2\u0026deg; \u0026ndash; 37\u0026deg;; p\u0026thinsp;\u0026lt;\u0026thinsp;0.001; Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e and Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). Within the \u0026lsquo;supine anterior\u0026rsquo; and \u0026lsquo;lateral anterior\u0026rsquo; study groups, the precision for inclination was increased compared to anteversion (indicated by lower SD of 4.6\u0026deg; vs. 6.4\u0026deg; and 6.2\u0026deg; vs 7.2\u0026deg; with p\u0026thinsp;\u0026lt;\u0026thinsp;0.001 and p\u0026thinsp;=\u0026thinsp;0.014, respectively; Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e and Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eThe percentage of outliers did not differ among the three study groups (p ranging from 0.183 to 0.384; Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThe 2D/3D-matching technique, \u003cem\u003eHipMatch\u003c/em\u003e, enables evaluation of cup orientation normalized to the APP without requiring a postoperative CT scan. Therefore, evaluation of normalized cup orientation is for the first time possible in a routine clinical setup with large numbers of patients. Typically, studies employing postoperative CT measurement for cup orientation assessment tend to have a significantly smaller number of cases included (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). The current study compares cup orientation across several groups with varying approaches, patient positioning, and cup placement techniques, making it the largest study to evaluate cup orientation normalized to the APP.\u003c/p\u003e\u003cp\u003eThis study has some limitations. Assessing the precision of cup orientation could not be conducted independently for each approach, patient position, or technique used for cup placement. However, a direct comparison between the anterior and direct lateral approaches was feasible (lateral anterior group vs. direct lateral group; Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e), as both approaches involved patients in the lateral position and utilized a mechanical guide for cup placement. Another limitation was that only precision (how close measurements are to each other) could be calculated and not accuracy (how close a measurement is to the true value) since the final cup orientation was not recorded intraoperatively (e.g. with navigation (\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e)).\u003c/p\u003e\u003cp\u003eMost studies assessing cup orientation aimed to compare various techniques for cup placement, typically comparing navigation with conventional cup placement (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). Only a few studies assessed cup orientation depending on different surgical approaches or patient positioning (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e) (\u003cspan additionalcitationids=\"CR22\" citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e). These studies did not reveal any differences in precision of cup inclination and anteversion for different approaches (\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e) or patient positioning (\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e) (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). Consistent with this literature (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e), in the current study cup anteversion did not differ depending on patient position or approach (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). In contrast, cup inclination demonstrated increased precision in hips with the anterior approach in supine position (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). This could be attributed to notable smaller study series in the literature (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e) or the fact that, in the current study different techniques of cup positioning were applied (e.g. mechanical positioning device or fluoroscopy). In addition, the current study showed a higher precision for inclination compared to anteversion (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e), which is consistent with most studies in literature (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). This fact can be attributed to the surgeons\u0026rsquo; discretion and anatomical adjustments of cup anteversion during surgery to avoid psoas tendon irritation which results in a wider range of cup anteversion.\u003c/p\u003e\u003cp\u003eWe found no difference in the prevalence of outliers for inclination or anteversion compared among the three study groups. Traditional metrics like the Lewinnek safe zones, which have long guided cup placement, are increasingly seen as inadequate due to their limitations in accounting for individual patient anatomy and variability in pelvic orientation. Therefore we used a statistical approach to define outliers consistent with previously reported methods in the literature (\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eIn conclusion, the anterior supine approach demonstrated comparable or improved precision in cup orientation compared to the traditional direct lateral approach. The use of intraoperative fluoroscopy appears to offer a more consistent means of controlling cup inclination during surgery (\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e). A wider range of cup anteversion across all approaches may reflect a greater need for patient-specific cup anteversion.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eConflict of interest:\u003c/strong\u003e The authors declare no conflict of interest.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDeclaration of Generative AI and AI-assisted technologies in the writing process:\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eDuring the preparation of this work, the authors used AI tools to correct grammar and enhance sentence variety. After using these tools, the authors—including a native English speaker—carefully reviewed and edited the content as needed and take full responsibility for the final version of the publication.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding:\u003c/strong\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThis study was support by Mathys Research grant, RMS Foundation, Bettlach, Switzerland. Project: “Conventional versus less-invasive Anterior Total Hip Arthroplasty: “Anatomical-referenced Accuracy of the RM-Pressfit Cup Orientation”\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials:\u003c/strong\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe datasets used and/or analysed during the current study are available from the corresponding author on reasonable request\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors contribution:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eConceptualization – CAZ, MB, MT, SDS, JMS, GZ; Data curation – CAZ, SDS, GZ; Formal analysis CAZ, SDS; Funding acquisition CAZ, MB, MT, SDS; Investigation CZ, SDS; Methodology CAZ, MB, MT, SDS; Project administration CAZ, SDS, JMS; Resources; Software GZ; Supervision SDS, MT; Visualization – CAZ, SDS; Roles/Writing - original draft CAZ, SDS, JMS; and Writing - review \u0026amp; editing CAZ, MB, MT, SDS, JMS.\u003c/p\u003e\n\u003cp\u003eWe confirm that all authors contributed substantially to the current submission.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eHuman Ethics and Consent to Participate declarations\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe hereby confirm that the study was conducted according to Swiss ethical guidelines and approved by local ethical committees (KEK Bern 22-12-13 and EK Luzern 893).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for anonymous use of x-ray data and consent to participate:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003ePatients at our institution are asked to give their general consent for the anonymous use of their data for general research purposes. Patients who have refused to allow the anonymous use of their data have been excluded.\u0026nbsp;\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eElkins JM, Callaghan JJ, Brown TD. The 2014 Frank Stinchfield Award: The landing zone for wear and stability in total hip arthroplasty is smaller than we thought: a computational analysis. Clin Orthop Relat Res. 2015;473(2):441\u0026ndash;52.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSchmalzried TP, Guttmann D, Grecula M, Amstutz HC. l. The relationship between the design, position, and articular wear of acetabular components inserted without cement and the development of pelvic osteolysis. J Bone Joint Surg Am. 1994;76(5):677\u0026ndash;88.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eTian J, Sun L, Hu R, Han W, Tian X. Long-term Results of Primary Hip Arthroplasty with Cup Inclination Angle Bigger than Fifty Degrees. J Clin Orthop Trauma. 2018;9(2):133\u0026ndash;6.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eAbdel MP, Von Roth P, Jennings MT, Hanssen AD, Pagnano MW. What Safe Zone? The Vast Majority of Dislocated THAs Are Within the Lewinnek Safe Zone for Acetabular Component Position. Clin Orthop Relat Res. 2016;474(2):386\u0026ndash;91.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eDorr LD, Callaghan JJ. Death of the Lewinnek Safe Zone. J Arthroplast. 2019;34(1):1\u0026ndash;2.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eKalteis T, Handel M, Herold T, Perlick L, Paetzel C, Grifka J. Position of the acetabular cup\u0026mdash;accuracy of radiographic calculation compared to CT-based measurement. Eur J Radiol. 2006;58(2):294\u0026ndash;300.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003ePenney GP, Edwards PJ, Hipwell JH, Slomczykowski M, Revie I, Hawkes DJ. Postoperative Calculation of Acetabular Cup Position Using 2-D\u0026ndash;3-D Registration. IEEE Trans Biomed Eng. 2007;54(7):1342\u0026ndash;8.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eTannast M, Langlotz U, Siebenrock KA, Wiese M, Bernsmann K, Langlotz F. Anatomic referencing of cup orientation in total hip arthroplasty. Clin Orthop Relat Res. 2005;(436):144\u0026ndash;50.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eCraiovan B, Renkawitz T, Weber M, Grifka J, Nolte L, Zheng G. Is the acetabular cup orientation after total hip arthroplasty on a two dimension or three dimension model accurate? Int Orthop. 2014;38(10):2009\u0026ndash;15.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSteppacher SD, Tannast M, Zheng G, Zhang X, Kowal J, Murphy SB. HipMatch: a 2D/3D matching software; accurate and reliabel. J Bone Joint Surg. 2010;(92-B(SUPP I)):109\u0026ndash;109.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eZheng G, von Recum J, Nolte LP, Gr\u0026uuml;tzner PA, Steppacher SD, Franke J. Validation of a statistical shape model-based 2D/3D reconstruction method for determination of cup orientation after THA. Int J Comput Assist Radiol Surg. 2012;7(2):225\u0026ndash;31.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eZheng G, Zhang X, Steppacher SD, Murphy SB, Siebenrock KA, Tannast M. HipMatch: an object-oriented cross-platform program for accurate determination of cup orientation using 2D-3D registration of single standard X-ray radiograph and a CT volume. Comput Methods Programs Biomed. 2009;95(3):236\u0026ndash;48.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eCamenzind RS, Stoffel K, Lash NJ, Beck M. Direct anterior approach to the hip joint in the lateral decubitus position for joint replacement. Oper Orthop Traumatol. 2018;30(4):276\u0026ndash;85.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMatta JM, Shahrdar C, Ferguson T. Single-incision anterior approach for total hip arthroplasty on an orthopaedic table. Clin Orthop Relat Res. 2005;441:115\u0026ndash;24.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSteppacher SD, Tannast M, Zheng G, Zhang X, Kowal J, Anderson SE, et al. Validation of a new method for determination of cup orientation in THA. J Orthop Res. 2009;27(12):1583\u0026ndash;8.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMurray DW. The definition and measurement of acetabular orientation. J Bone Joint Surg Br. 1993;75(2):228\u0026ndash;32.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eZurm\u0026uuml;hle CA, Zickmantel B, Christen M, Christen B, Zheng G, Schwab JM, et al. Image-Less THA Cup Navigation in Clinical Routine Setup: Individual Adjustments, Accuracy, Precision, and Robustness. Medicina. 2022;58(6):832.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eAbdi H. Bonferroni and Sidak corrections for multiple comparisons. In: Encyclopedia of Measurement and Statistics [Internet]. Sage, Oaks T. CA; 2007. pp. 103\u0026ndash;7. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.bibsonomy.org/bibtex/2ab68b97b46031a8c94414e0d64dea6be/lran022\u003c/span\u003e\u003cspan address=\"https://www.bibsonomy.org/bibtex/2ab68b97b46031a8c94414e0d64dea6be/lran022\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eBonferroni C. Teoria statistica delle classi e calcolo delle probabilita. Pubblicazioni del R Istituto Superiore di Scienze Economiche e Commericiali di Firenze. 1936;8:3\u0026ndash;62.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eBland JM, Altman DG. Multiple significance tests: the Bonferroni method. BMJ. 1995;310(6973):170.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eHananouchi T, Takao M, Nishii T, Miki H, Iwana D, Yoshikawa H, et al. Comparison of navigation accuracy in THA between the mini-anterior and -posterior approaches. Int J Med Robot. 2009;5(1):20\u0026ndash;5.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMaeda Y, Sugano N, Nakamura N, Hamawaki M. The Accuracy of a Mechanical Cup Alignment Guide in Total Hip Arthroplasty (THA) Through Direct Anterior and Posterior Approaches Measured with CT-Based Navigation. J Arthroplast. 2015;30(9):1561\u0026ndash;4.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eZhao W, Li S, Yin Y, Wang Z, Sun G, Peng X, et al. Direct Anterior Approach in Lateral Decubitus Position Versus Supine Position for Unilateral Total Hip Arthroplasty: A Comparative Study. Orthop Surg. 2021;13(3):786\u0026ndash;90.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eZhao W, Li S, Yin Y, Wang Z, Sun G, Peng X, et al. Direct Anterior Approach in Lateral Decubitus Position Versus Supine Position for Unilateral Total Hip Arthroplasty: A Comparative Study. Orthop Surg. 2021;13(3):786\u0026ndash;90.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eHasart O, Poepplau B, Asbach P, Perka C, Wassilew C. Ultrasound-based navigation and 3D CT compared in acetabular cup position. Orthopedics. 2009;32(10 Suppl):6\u0026ndash;10.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eTakada R, Jinno T, Miyatake K, Hirao M, Yoshii T, Okawa A. Portable imageless navigation system and surgeon\u0026rsquo;s estimate for accurate evaluation of acetabular cup orientation during total hip arthroplasty in supine position. Eur J Orthop Surg Traumatol. 2020;30(4):707\u0026ndash;12.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eGr\u0026uuml;tzner PA, Zheng G, Langlotz U, von Recum J, Nolte LP, Wentzensen A, et al. C-arm based navigation in total hip arthroplasty-background and clinical experience. Injury. 2004;35(Suppl 1):S\u0026ndash;A90.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eBlendea S, Eckman K, Jaramaz B, Levison T, Digioia A. Measurements of acetabular cup position and pelvic spatial orientation after total hip arthroplasty using computed tomography/radiography matching. Comput Aided Surg. 2005;10(1):37\u0026ndash;43.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eKim T, Lee S, Yang J, Oh K. Computed tomography assessment of image-free navigation-assisted cup placement in THA in an Asian population. Orthopedics. 2012;35(10 Suppl):13\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eKalteis T, Handel M, Herold T, Perlick L, Paetzel C, Grifka J. Position of the acetabular cup -- accuracy of radiographic calculation compared to CT-based measurement. Eur J Radiol. 2006;58(2):294\u0026ndash;300.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eFukunishi S, Fukui T, Imamura F, Nishio S. Assessment of accuracy of acetabular cup orientation in CT-free navigated total hip arthroplasty. Orthopedics. 2008;31(10):\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003eorthosupersite.com/view.asp?rID\u0026thinsp;=\u0026thinsp;31515\u003c/span\u003e\u003cspan address=\"http://orthosupersite.com/view.asp?rID\u0026thinsp;=\u0026thinsp;31515\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eCarcangiu A, D\u0026rsquo;Arrigo C, Topa D, Alonzo R, Speranza A, De Sanctis S, et al. Reliability of cup position in navigated THA in the lateral decubitus position using the flip technique. Hip Int. 2011;21(6):700\u0026ndash;5.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSaxler G, Marx A, Vandevelde D, Langlotz U, Tannast M, Wiese M, et al. The accuracy of free-hand cup positioning\u0026ndash;a CT based measurement of cup placement in 105 total hip arthroplasties. Int Orthop. 2004;28(4):198\u0026ndash;201.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eHaaker R, Tiedjen K, Ottersbach A, Rubenthaler F, Stockheim M, Stiehl J. Comparison of conventional versus computer-navigated acetabular component insertion. J Arthroplasty. 2007;22(2):151\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eParratte S, Argenson JN, Flecher X, Aubaniac JM. [Computer-assisted surgery for acetabular cup positioning in total hip arthroplasty: comparative prospective randomized study]. Rev Chir Orthop Reparatrice Appar Mot. 2007;93(3):238\u0026ndash;46.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eJenny J, Boeri C, Dosch J, Uscatu M, Ciobanu E. Navigated non-image-based positioning of the acetabulum during total hip replacement. Int Orthop. 2009;33(1):83\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eCraiovan B, Weber M, Worlicek M, Schneider M, Springorum H, Zeman F, et al. Measuring Acetabular Cup Orientation on Antero-Posterior Radiographs of the Hip after Total Hip Arthroplasty with a Vector Arithmetic Radiological Method. Is It Valid and Verified for Daily Clinical Practice? Rofo. 2016;188(6):574\u0026ndash;81.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eWoerner M, Sendtner E, Springorum R, Craiovan B, Worlicek M, Renkawitz T, et al. Visual intraoperative estimation of cup and stem position is not reliable in minimally invasive hip arthroplasty. Acta Orthop. 2016;87(3):225\u0026ndash;30.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eHayashi S, Hashimoto S, Kuroda Y, Nakano N, Matsumoto T, Ishida K, et al. Accuracy of cup position following robot-assisted total hip arthroplasty may be associated with surgical approach and pelvic tilt. Sci Rep. 2021;11(1):7578.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSariali E, Boukhelifa N, Catonne Y, Pascal Moussellard H. Comparison of Three-Dimensional Planning-Assisted and Conventional Acetabular Cup Positioning in Total Hip Arthroplasty: A Randomized Controlled Trial. J Bone Joint Surg Am. 2016;98(2):108\u0026ndash;16.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSteppacher S, Kowal J, Murphy S. Improving cup positioning using a mechanical navigation instrument. Clin Orthop Relat Res. 2011;469(2):423\u0026ndash;8.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLu M, Zhou Y, Du H, Zhang J, Liu J. Reliability and validity of measuring acetabular component orientation by plain anteroposterior radiographs. Clin Orthop Relat Res. 2013;471(9):2987\u0026ndash;94.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMcMahon SJ, Christmas MUSI, Pierrepont J, McMahon J, McMahon R. The Accuracy of Acetabular Cup Positioning Using Patient-Specific 3D Orientation Guidance in Total Hip Arthroplasty. Surg Technol Int. 2020;36:426\u0026ndash;31.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eDemographic and surgery related data of the three study groups: THA performed with a direct lateral approach in lateral position (\u0026lsquo;direct lateral\u0026rsquo; group), anterior approach in supine position (\u0026lsquo;supine anterior\u0026rsquo; group) and anterior approach in lateral position (\u0026lsquo;lateral anterior\u0026rsquo; group).\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"8\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eParameter\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eDirect lateral\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eSupine anterior\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eLateral anterior\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003ep-value\u003c/p\u003e\u003cp\u003eglobal\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003ep-value*\u003c/p\u003e\u003cp\u003eDirect lateral vs\u003c/p\u003e\u003cp\u003esupine anterior\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003ep-value*\u003c/p\u003e\u003cp\u003eDirect lateral vs\u003c/p\u003e\u003cp\u003elateral anterior\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c8\"\u003e\u003cp\u003ep-value*\u003c/p\u003e\u003cp\u003eSupine vs\u003c/p\u003e\u003cp\u003elateral anterior\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eApproach\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eDirect lateral\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eAnterior\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eAnterior\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePatient positioning\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eLateral\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eSupine\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eLateral\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTechique of cup positioning\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eMechanical\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eFluroscopy\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eMechanical\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNumber of patients\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e66\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e118\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e138\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNumber of hips\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e66\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e128\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e155\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAge at operation (years)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e66\u0026thinsp;\u0026plusmn;\u0026thinsp;12\u003c/p\u003e\u003cp\u003e(26\u0026ndash;89)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e61\u0026thinsp;\u0026plusmn;\u0026thinsp;13\u003c/p\u003e\u003cp\u003e(25\u0026ndash;90)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e68\u0026thinsp;\u0026plusmn;\u0026thinsp;9\u003c/p\u003e\u003cp\u003e(41\u0026ndash;88)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.005\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.016\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e0.312\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.005\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eGender (percent male of all hips)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e53\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e59\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e51\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.402\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e-\u003c/p\u003e \u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eWeight (kg)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e83\u0026thinsp;\u0026plusmn;\u0026thinsp;27\u003c/p\u003e\u003cp\u003e(44\u0026ndash;170)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e80\u0026thinsp;\u0026plusmn;\u0026thinsp;18\u003c/p\u003e\u003cp\u003e(47\u0026ndash;156)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e77\u0026thinsp;\u0026plusmn;\u0026thinsp;15\u003c/p\u003e\u003cp\u003e(46\u0026ndash;116)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.082\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eHeight (m)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1.70\u0026thinsp;\u0026plusmn;\u0026thinsp;0.10\u003c/p\u003e\u003cp\u003e(1.50\u0026ndash;1.89)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1.70\u0026thinsp;\u0026plusmn;\u0026thinsp;0.10\u003c/p\u003e\u003cp\u003e(1.40\u0026ndash;1.90)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.68\u0026thinsp;\u0026plusmn;\u0026thinsp;0.09\u003c/p\u003e\u003cp\u003e(1.42\u0026ndash;1.92)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.342\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eBMI (m/kg\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e29\u0026thinsp;\u0026plusmn;\u0026thinsp;10\u003c/p\u003e\u003cp\u003e(17\u0026ndash;57)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e27\u0026thinsp;\u0026plusmn;\u0026thinsp;5\u003c/p\u003e\u003cp\u003e(18\u0026ndash;47)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e27\u0026thinsp;\u0026plusmn;\u0026thinsp;4\u003c/p\u003e\u003cp\u003e(\u003cspan additionalcitationids=\"CR18 CR19 CR20 CR21 CR22 CR23 CR24 CR25 CR26 CR27 CR28 CR29 CR30 CR31 CR32 CR33 CR34 CR35 CR36 CR37 CR38 CR39 CR40 CR41 CR42\" citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.148\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSide (percent right of all hips)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e42\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e52\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e47\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.399\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eIndications for THA (number of hips [percentage])\u003c/p\u003e\u003cp\u003e- Primary osteoarthritis\u003c/p\u003e\u003cp\u003e- Hip fracture\u003c/p\u003e\u003cp\u003e- Avascular necrosis\u003c/p\u003e\u003cp\u003e- Posttraumatic\u003c/p\u003e \u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e44 (66%)\u003c/p\u003e\u003cp\u003e13 (20%)\u003c/p\u003e\u003cp\u003e3 (5%)\u003c/p\u003e\u003cp\u003e6 (9%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e99 (77%)\u003c/p\u003e\u003cp\u003e14 (11%)\u003c/p\u003e\u003cp\u003e15 (12%)\u003c/p\u003e\u003cp\u003e0 (0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e148 (96%)\u003c/p\u003e\u003cp\u003e0 (0%)\u003c/p\u003e\u003cp\u003e7 (4%)\u003c/p\u003e\u003cp\u003e0 (0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.107\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"8\"\u003eValues are expressed as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation with range in parentheses; THA\u0026thinsp;=\u0026thinsp;total hip arthroplasty; BMI\u0026thinsp;=\u0026thinsp;body mass index; *the level of significance for pairwise comparison was adjusted according to Bonferroni et al (\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e) and was p\u0026thinsp;=\u0026thinsp;0.05/3\u0026thinsp;=\u0026thinsp;0.017\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eResults of cup inclination, anteversion and outliers of the three study groups\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"12\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c11\" colnum=\"11\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c12\" colnum=\"12\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eParameter\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eDirect lateral\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eSupine anterior\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eLateral anterior\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"4\" nameend=\"c8\" namest=\"c5\"\u003e\u003cp\u003eComparison of Means\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"4\" nameend=\"c12\" namest=\"c9\"\u003e\u003cp\u003ePrecision*\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e(n\u0026thinsp;=\u0026thinsp;66 hips)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e(n\u0026thinsp;=\u0026thinsp;128 hips)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e(n\u0026thinsp;=\u0026thinsp;155 hips)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u003cb\u003ep-value\u003c/b\u003e\u003c/p\u003e\u003cp\u003eglobal\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e\u003cb\u003ep-value\u003c/b\u003e\u003csup\u003e\u0026dagger;\u003c/sup\u003e\u003c/p\u003e\u003cp\u003eDirect lateral vs supine anterior\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e\u003cb\u003ep-value\u003c/b\u003e\u003csup\u003e\u0026dagger;\u003c/sup\u003e\u003c/p\u003e\u003cp\u003eDirect lateral vs\u003c/p\u003e\u003cp\u003elateral anterior\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e\u003cb\u003ep-value\u003c/b\u003e\u003csup\u003e\u0026dagger;\u003c/sup\u003e\u003c/p\u003e\u003cp\u003eSupine vs lateral anterior\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e\u003cb\u003ep-value\u003c/b\u003e\u003c/p\u003e\u003cp\u003eglobal\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e\u003cb\u003ep-value\u003c/b\u003e\u003csup\u003e\u0026dagger;\u003c/sup\u003e\u003c/p\u003e\u003cp\u003eDirect lateral vs supine anterior\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e\u003cb\u003ep-value\u003c/b\u003e\u003csup\u003e\u0026dagger;\u003c/sup\u003e\u003c/p\u003e\u003cp\u003eDirect lateral vs\u003c/p\u003e\u003cp\u003elateral anterior\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u003cp\u003e\u003cb\u003ep-value\u003c/b\u003e\u003csup\u003e\u0026dagger;\u003c/sup\u003e\u003c/p\u003e\u003cp\u003eSupine vs lateral anterior\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eInclination (degrees)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e45\u0026thinsp;\u0026plusmn;\u0026thinsp;6.8\u003c/p\u003e\u003cp\u003e(31\u0026ndash;61)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e45\u0026thinsp;\u0026plusmn;\u0026thinsp;4.6\u003c/p\u003e\u003cp\u003e(32\u0026ndash;58)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e41\u0026thinsp;\u0026plusmn;\u0026thinsp;6.2\u003c/p\u003e\u003cp\u003e(18\u0026ndash;55)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.835\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e0.003\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e0.397\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAnteversion (degrees)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e18\u0026thinsp;\u0026plusmn;\u0026thinsp;7.4\u003c/p\u003e\u003cp\u003e(\u003cspan additionalcitationids=\"CR3 CR4 CR5 CR6 CR7 CR8 CR9 CR10 CR11 CR12 CR13 CR14 CR15 CR16 CR17 CR18 CR19 CR20 CR21 CR22 CR23 CR24 CR25 CR26 CR27 CR28 CR29 CR30 CR31 CR32 CR33 CR34 CR35 CR36\" citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e21\u0026thinsp;\u0026plusmn;\u0026thinsp;6.4\u003c/p\u003e\u003cp\u003e(\u003cspan additionalcitationids=\"CR7 CR8 CR9 CR10 CR11 CR12 CR13 CR14 CR15 CR16 CR17 CR18 CR19 CR20 CR21 CR22 CR23 CR24 CR25 CR26 CR27 CR28 CR29 CR30 CR31 CR32 CR33 CR34 CR35 CR36\" citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e23\u0026thinsp;\u0026plusmn;\u0026thinsp;7.6\u003c/p\u003e\u003cp\u003e(\u003cspan additionalcitationids=\"CR3 CR4 CR5 CR6 CR7 CR8 CR9 CR10 CR11 CR12 CR13 CR14 CR15 CR16 CR17 CR18 CR19 CR20 CR21 CR22 CR23 CR24 CR25 CR26 CR27 CR28 CR29 CR30 CR31 CR32 CR33 CR34 CR35 CR36 CR37 CR38 CR39 CR40 CR41\" citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.035\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e0.097\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eComparison of Precision*\u003c/p\u003e\u003cp\u003e- p-value Inclination vs anteversion\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.447\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.014\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eOutlier\u003csup\u003e\u0026Dagger;\u003c/sup\u003e (number of hips [percentage])\u003c/p\u003e\u003cp\u003eInclination\u003c/p\u003e\u003cp\u003eAnteversion\u003c/p\u003e\u003cp\u003eAll\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e4 (\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e)\u003c/p\u003e\u003cp\u003e5 (\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e)\u003c/p\u003e\u003cp\u003e8 (\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3 (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e)\u003c/p\u003e\u003cp\u003e4 (\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e)\u003c/p\u003e\u003cp\u003e7 (\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e9 (\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e)\u003c/p\u003e\u003cp\u003e8 (\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e)\u003c/p\u003e\u003cp\u003e17 (\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.312\u003c/p\u003e\u003cp\u003e0.384\u003c/p\u003e\u003cp\u003e0.183\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eValues are expressed as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation with range in parentheses; *precision was calculated by comparing the standard deviation using the Levene F-Test; \u003csup\u003e\u0026dagger;\u003c/sup\u003ethe level of significance for pairwise comparison was adjusted according to Bonferroni et al (\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e) and was p\u0026thinsp;=\u0026thinsp;0.05/3\u0026thinsp;=\u0026thinsp;0.017; \u003csup\u003e\u0026Dagger;\u003c/sup\u003eoutliers were defined as a cup orientation outside an inclination of 31\u0026ndash;56\u0026deg; and/or an anteversion 7\u0026ndash;36\u0026deg; (these limits were defined as \u0026plusmn;\u0026thinsp;2 standard deviation of mean inclination or anteversion of the entire series of 349 evaluated hips); continuous data were compared with the Kruskall Wallis-test and the Mann Whitney U-test for pairwise comparison; binominal data were compared with the Fisher\u0026rsquo;s exact test; differences in standard deviation were tested with the Levene F-test.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eSelected literature about 3-dimensional cup orientation of THA evaluated using CT or specific software \u003cem\u003eHipMatch\u003c/em\u003e (\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e)\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"10\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAuthor\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eNumber of Hips\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eModality\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eRefe-rence\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eApproach\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003ePatient Positioning\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003eTechnique of Cup Positioning\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c8\"\u003e\u003cp\u003eInclination (\u0026deg;)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c9\"\u003e\u003cp\u003eAnteversion (\u0026deg;)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c10\"\u003e\u003cp\u003eResults*\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eGr\u0026uuml;tzner et al (\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e), 2004\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eCT\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eAPP\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eN/A\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eSupine\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eC-arm navigated\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e42\u0026thinsp;\u0026plusmn;\u0026thinsp;4 (36\u0026ndash;49)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e21\u0026thinsp;\u0026plusmn;\u0026thinsp;4 (\u003cspan additionalcitationids=\"CR11 CR12 CR13 CR14 CR15 CR16 CR17 CR18 CR19 CR20 CR21 CR22 CR23 CR24 CR25 CR26 CR27\" citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003eAccuracy of inclination 1.5\u0026deg; \u0026plusmn; 1.1\u0026deg; and anteversion 2.4\u0026deg; \u0026plusmn; 1.3\u0026deg; (target 40\u0026deg; inclination and 20\u0026deg; inclination)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eBlendea et al (\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e), 2005\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e38\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eCT\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eAPP\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eN/A\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eN/A\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eCT-based navigation\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e52\u0026thinsp;\u0026plusmn;\u0026thinsp;5 (43\u0026ndash;59)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e18\u0026thinsp;\u0026plusmn;\u0026thinsp;7 (0\u0026ndash;29)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003eNavigation study for validation of 2D/3D-matching software \u003cem\u003eXalign\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eKim et al (\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e), 2012\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e81\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eCT\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eAPP\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eN/A\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eSupine\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eImage less navigated\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e41 (30\u0026ndash;57)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e21 (\u003cspan additionalcitationids=\"CR2 CR3 CR4 CR5 CR6 CR7 CR8 CR9 CR10 CR11 CR12 CR13 CR14 CR15 CR16 CR17 CR18 CR19 CR20 CR21 CR22 CR23 CR24 CR25 CR26 CR27 CR28 CR29 CR30 CR31 CR32 CR33 CR34 CR35 CR36\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003eValidation of image less navigation. Increased accuracy for navigated cup orientation.\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTannast et al (\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e), 2005\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eI: 13\u003c/p\u003e\u003cp\u003eII: 13\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eCT\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eAPP\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eDirect lateral\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eLateral\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eI: C-arm navigated\u003c/p\u003e\u003cp\u003eII: Conventional\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003eI: 39\u0026thinsp;\u0026plusmn;\u0026thinsp;3 (35\u0026ndash;47)\u003c/p\u003e\u003cp\u003eII: 41\u0026thinsp;\u0026plusmn;\u0026thinsp;8 (29\u0026ndash;56)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003eI: 8\u0026thinsp;\u0026plusmn;\u0026thinsp;6 (-3\u0026ndash;17)\u003c/p\u003e\u003cp\u003eII: 33\u0026thinsp;\u0026plusmn;\u0026thinsp;6 (23\u0026ndash;45)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003eCadaver study. Increased precision with navigation for inclination (p\u0026thinsp;=\u0026thinsp;0.001) but not anteversion (p\u0026thinsp;=\u0026thinsp;0.79)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eKalteis et al (\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e), 2006\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eI: 30\u003c/p\u003e\u003cp\u003eII: 30\u003c/p\u003e\u003cp\u003eIII: 30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eCT\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eAPP\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eDirect lateral\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eSupine\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eI: CT-based navigation\u003c/p\u003e\u003cp\u003eII: Image less navigation\u003c/p\u003e\u003cp\u003eIII: Conventional\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003eI: 42\u0026thinsp;\u0026plusmn;\u0026thinsp;4 (34\u0026ndash;53)\u003c/p\u003e\u003cp\u003eII: 43\u0026thinsp;\u0026plusmn;\u0026thinsp;4 (33\u0026ndash;50)\u003c/p\u003e\u003cp\u003eIII: 44\u0026thinsp;\u0026plusmn;\u0026thinsp;7 (29\u0026ndash;57)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003eI: 11\u0026thinsp;\u0026plusmn;\u0026thinsp;5 (\u003cspan additionalcitationids=\"CR2 CR3 CR4 CR5 CR6 CR7 CR8 CR9 CR10 CR11 CR12 CR13 CR14 CR15 CR16 CR17 CR18 CR19 CR20 CR21 CR22\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e)\u003c/p\u003e\u003cp\u003eII: 15\u0026thinsp;\u0026plusmn;\u0026thinsp;6 (\u003cspan additionalcitationids=\"CR6 CR7 CR8 CR9 CR10 CR11 CR12 CR13 CR14 CR15 CR16 CR17 CR18 CR19 CR20 CR21 CR22 CR23 CR24\" citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e)\u003c/p\u003e\u003cp\u003eIII: 22\u0026thinsp;\u0026plusmn;\u0026thinsp;14 (1\u0026ndash;53)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003eIncreased precision for both inclination and anteversion for image less or CT-based navigation compared to conventional\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eFukunishi et al (\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e), 2008\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e79\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eCT\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eAPP\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eDirect lateral\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eLateral\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eImage less navigation\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e41\u0026thinsp;\u0026plusmn;\u0026thinsp;4 (30\u0026ndash;49)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e21\u0026thinsp;\u0026plusmn;\u0026thinsp;5 (\u003cspan additionalcitationids=\"CR10 CR11 CR12 CR13 CR14 CR15 CR16 CR17 CR18 CR19 CR20 CR21 CR22 CR23 CR24 CR25 CR26 CR27 CR28 CR29 CR30 CR31\" citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003eValidation study for image less navigation\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCarcangiu et al (\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e), 2011\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e24\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eCT\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eAPP\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eDirect lateral\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eLateral\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eImage less navigation\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e43\u0026thinsp;\u0026plusmn;\u0026thinsp;5 (35\u0026ndash;56)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e14\u0026thinsp;\u0026plusmn;\u0026thinsp;5 (\u003cspan additionalcitationids=\"CR6 CR7 CR8 CR9 CR10 CR11 CR12 CR13 CR14 CR15 CR16 CR17 CR18 CR19 CR20 CR21 CR22 CR23 CR24 CR25 CR26 CR27\" citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003eValidation study for image less navigation\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSaxler et al (\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e), 2004\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eI: 80\u003c/p\u003e\u003cp\u003eII: 105\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eCT\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eAPP\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eAnterolateral\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eSupine\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eI: CT-based navigation\u003c/p\u003e\u003cp\u003eII: Conventional\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003eI: 43\u0026thinsp;\u0026plusmn;\u0026thinsp;4 (35\u0026ndash;53)\u003c/p\u003e\u003cp\u003eII: 46\u0026thinsp;\u0026plusmn;\u0026thinsp;10 (23\u0026ndash;72)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003eI: 26\u0026thinsp;\u0026plusmn;\u0026thinsp;7 (\u003cspan additionalcitationids=\"CR13 CR14 CR15 CR16 CR17 CR18 CR19 CR20 CR21 CR22 CR23 CR24 CR25 CR26 CR27 CR28 CR29 CR30 CR31 CR32 CR33 CR34 CR35 CR36 CR37\" citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e)\u003c/p\u003e\u003cp\u003eII: 27\u0026thinsp;\u0026plusmn;\u0026thinsp;15 (-24\u0026ndash;59)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003ePrecision for inclination and anteversion higher in navigated compared to conventional THA (both p\u0026thinsp;\u0026lt;\u0026thinsp;0.001)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eHaaker et al (\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e), 2007\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eI: 98\u003c/p\u003e\u003cp\u003eII: 69\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eCT\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eAPP\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eAnterolateral\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eN/A\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eI: Navigated\u003c/p\u003e\u003cp\u003eII: Conventional\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003eI: 43\u0026thinsp;\u0026plusmn;\u0026thinsp;5 (30\u0026ndash;58)\u003c/p\u003e\u003cp\u003eII: 46\u0026thinsp;\u0026plusmn;\u0026thinsp;9 (26\u0026ndash;64)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003eI: 22\u0026thinsp;\u0026plusmn;\u0026thinsp;7 (\u003cspan additionalcitationids=\"CR6 CR7 CR8 CR9 CR10 CR11 CR12 CR13 CR14 CR15 CR16 CR17 CR18 CR19 CR20 CR21 CR22 CR23 CR24 CR25 CR26 CR27 CR28 CR29 CR30 CR31 CR32 CR33 CR34 CR35 CR36 CR37\" citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e)\u003c/p\u003e\u003cp\u003eII: 29\u0026thinsp;\u0026plusmn;\u0026thinsp;10 (9\u0026ndash;53)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003ePrecision for inclination and anteversion higher in navigated compared to conventional THA (both p\u0026thinsp;\u0026lt;\u0026thinsp;0.001)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eParratte et al (\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e), 2007\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eI: 30\u003c/p\u003e\u003cp\u003eII: 30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eCT\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eAPP\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eAnterolateral\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eSupine\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eI: Image less navigation\u003c/p\u003e\u003cp\u003eII: Conventional\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003eI: 34\u0026thinsp;\u0026plusmn;\u0026thinsp;6 (25\u0026ndash;45)\u003c/p\u003e\u003cp\u003eII: 34\u0026thinsp;\u0026plusmn;\u0026thinsp;8 (24\u0026ndash;50)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003eI: 14\u0026thinsp;\u0026plusmn;\u0026thinsp;5 (\u003cspan additionalcitationids=\"CR8 CR9 CR10 CR11 CR12 CR13 CR14 CR15 CR16 CR17 CR18 CR19 CR20 CR21 CR22 CR23 CR24\" citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e)\u003c/p\u003e\u003cp\u003eII: 16\u0026thinsp;\u0026plusmn;\u0026thinsp;10 (\u003cspan additionalcitationids=\"CR3 CR4 CR5 CR6 CR7 CR8 CR9 CR10 CR11 CR12 CR13 CR14 CR15 CR16 CR17 CR18 CR19 CR20 CR21 CR22 CR23 CR24 CR25 CR26 CR27 CR28 CR29 CR30 CR31 CR32 CR33 CR34\" citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003ePrecision for inclination and anteversion higher in navigated compared to conventional THA (p from \u0026lt;\u0026thinsp;0.001 to 0.028)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eHasart et al (\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e), 2009\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e25\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eCT\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eAPP\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eAnterolateral\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eSupine\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eImage less navigation\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e45\u0026thinsp;\u0026plusmn;\u0026thinsp;4 (37\u0026ndash;52)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e26\u0026thinsp;\u0026plusmn;\u0026thinsp;4 (\u003cspan additionalcitationids=\"CR17 CR18 CR19 CR20 CR21 CR22 CR23 CR24 CR25 CR26 CR27 CR28 CR29 CR30 CR31 CR32 CR33 CR34\" citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003eValidation of ultrasound based navigation\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eJenny et al (\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e), 2009\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eCT\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eAPP\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eAnterolateral\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eSupine\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eImage less navigation\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e44\u0026thinsp;\u0026plusmn;\u0026thinsp;5 (30\u0026ndash;57)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e19\u0026thinsp;\u0026plusmn;\u0026thinsp;7 (\u003cspan additionalcitationids=\"CR3 CR4 CR5 CR6 CR7 CR8 CR9 CR10 CR11 CR12 CR13 CR14 CR15 CR16 CR17 CR18 CR19 CR20 CR21 CR22 CR23 CR24 CR25 CR26 CR27 CR28 CR29 CR30 CR31\" citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003eValidation study for image less navigation\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCraiovan et al (\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e), 2016\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e123\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eCT\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eAPP\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eAnterolateral\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eLateral\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eNavigated and conventional\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e44\u0026thinsp;\u0026plusmn;\u0026thinsp;7 (26\u0026ndash;66)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e21\u0026thinsp;\u0026plusmn;\u0026thinsp;11 (-15\u0026ndash;50)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003eValidation study for vector arithmetic cup orientation\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eWoerner et al (\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e), 2016\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e65\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eCT\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eAPP\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eAnterolateral\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eLateral\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eConventional\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e39\u0026thinsp;\u0026plusmn;\u0026thinsp;6 (23\u0026ndash;54)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e23\u0026thinsp;\u0026plusmn;\u0026thinsp;12 (-6\u0026ndash;54)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003ePrecision of conventional cup placement\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTakada et al (\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e), 2020\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eCT\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eAPP\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eAnterolateral\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eSupine\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eHipAlign portable navigation system\u003c/p\u003e\u003cp\u003eversus manual goniometer\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e38\u0026thinsp;\u0026plusmn;\u0026thinsp;4 (32\u0026ndash;46)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e18\u0026thinsp;\u0026plusmn;\u0026thinsp;4 (\u003cspan additionalcitationids=\"CR11 CR12 CR13 CR14 CR15 CR16 CR17 CR18 CR19 CR20 CR21 CR22 CR23 CR24\" citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003eNo difference between navigation tool and surgeon\u0026rsquo;s estimate with goniometer\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eZurm\u0026uuml;hle et al (\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e), 2022\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e367\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eRadio-graph and \u003cem\u003eHipMatch\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eAPP\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eAnterolateral\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eSupine\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eImage-less navigation\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e40\u0026thinsp;\u0026plusmn;\u0026thinsp;4 (26\u0026ndash;50)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e25\u0026thinsp;\u0026plusmn;\u0026thinsp;6 (0\u0026ndash;41)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003eAccuracy, precision and robustness of image less navigation validated with \u003cem\u003eHipMatch\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eHayashi et al (\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e), 2021\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e115\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eCT\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eAPP\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eAnterolateral or posterior\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eSupine or lateral\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eCT based navigation and robot-assisted\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e40\u0026thinsp;\u0026plusmn;\u0026thinsp;3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e19\u0026thinsp;\u0026plusmn;\u0026thinsp;3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003eAccuracy of robot-assisted total hip arthroplasty\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSariali et al (\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e), 2016\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eI: 28\u003c/p\u003e\u003cp\u003eII: 28\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eCT\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eAPP\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eAnterior\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eSupine\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eI: 3D planning\u003c/p\u003e\u003cp\u003eII: Conventional\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003eI: 38\u0026thinsp;\u0026plusmn;\u0026thinsp;6 (\u003cspan additionalcitationids=\"CR36 CR37 CR38 CR39\" citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e)\u003c/p\u003e\u003cp\u003eII: 44\u0026thinsp;\u0026plusmn;\u0026thinsp;8 (41\u0026ndash;47)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003eI: 13\u0026thinsp;\u0026plusmn;\u0026thinsp;6 (\u003cspan additionalcitationids=\"CR11 CR12 CR13 CR14\" citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e)\u003c/p\u003e\u003cp\u003eII: 25\u0026thinsp;\u0026plusmn;\u0026thinsp;7 (\u003cspan additionalcitationids=\"CR23 CR24 CR25 CR26 CR27\" citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003eAccuracy of cup inclination and anteversion with 3D planning increased (p\u0026thinsp;=\u0026thinsp;0.003 and \u0026lt;\u0026thinsp;0.001)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eZhao et al (\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e), 2021\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eI: 46\u003c/p\u003e\u003cp\u003eII: 43\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eCT\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eN/A\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eAnterior\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eI: Lateral\u003c/p\u003e\u003cp\u003eII: Supine\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eConventional\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003eI: 43\u0026thinsp;\u0026plusmn;\u0026thinsp;3\u003c/p\u003e\u003cp\u003eII: 44\u0026thinsp;\u0026plusmn;\u0026thinsp;4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003eI: 16\u0026thinsp;\u0026plusmn;\u0026thinsp;5\u003c/p\u003e\u003cp\u003eII: 17\u0026thinsp;\u0026plusmn;\u0026thinsp;4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003eNo mean difference in cup inclination and anteversion compared to lateral and supine position\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eHananouchi et al (\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e), 2009\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eI: 20\u003c/p\u003e\u003cp\u003eII: 20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eCT\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eN/A\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eI: Anterior\u003c/p\u003e\u003cp\u003eII: Posterior\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eLateral\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eI and II: CT based navigation\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003eI: 39\u0026thinsp;\u0026plusmn;\u0026thinsp;3 (35\u0026ndash;44)\u003c/p\u003e\u003cp\u003eII: 37\u0026thinsp;\u0026plusmn;\u0026thinsp;4 (32\u0026ndash;48)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003eI: 15\u0026thinsp;\u0026plusmn;\u0026thinsp;3 (\u003cspan additionalcitationids=\"CR11 CR12 CR13 CR14 CR15 CR16 CR17 CR18 CR19\" citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e)\u003c/p\u003e\u003cp\u003eII: 16\u0026thinsp;\u0026plusmn;\u0026thinsp;4 (\u003cspan additionalcitationids=\"CR9 CR10 CR11 CR12 CR13 CR14 CR15 CR16 CR17 CR18 CR19 CR20 CR21 CR22 CR23 CR24\" citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003eAccuracy and precision between different approaches did not differ for inclination and anteversion (p ranging from 0.18 to 0.73)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMaeda et al (\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e), 2015\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eI: 34\u003c/p\u003e\u003cp\u003eII: 47\u003c/p\u003e\u003cp\u003eIII: 35\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eCT\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eAPP\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eI: Anterior\u003c/p\u003e\u003cp\u003eII: Anterior\u003c/p\u003e\u003cp\u003eIII: Posterior\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eI: Supine\u003c/p\u003e\u003cp\u003eII: Lateral\u003c/p\u003e\u003cp\u003eIII: Lateral\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eCT-based navigation system and mechanical guide\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003eI: 48\u0026thinsp;\u0026plusmn;\u0026thinsp;5 (33\u0026ndash;60)\u003c/p\u003e\u003cp\u003eII: 49\u0026thinsp;\u0026plusmn;\u0026thinsp;4 (39\u0026ndash;62)\u003c/p\u003e\u003cp\u003eIII: 48\u0026thinsp;\u0026plusmn;\u0026thinsp;5 (38\u0026ndash;56)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003eI: 21\u0026thinsp;\u0026plusmn;\u0026thinsp;7 (\u003cspan additionalcitationids=\"CR12 CR13 CR14 CR15 CR16 CR17 CR18 CR19 CR20 CR21 CR22 CR23 CR24 CR25 CR26 CR27 CR28 CR29 CR30 CR31 CR32 CR33 CR34 CR35 CR36\" citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e)\u003c/p\u003e\u003cp\u003eII: 18\u0026thinsp;\u0026plusmn;\u0026thinsp;8 (0\u0026ndash;37)\u003c/p\u003e\u003cp\u003eIII: 8\u0026thinsp;\u0026plusmn;\u0026thinsp;6 (\u003cspan additionalcitationids=\"CR3 CR4 CR5 CR6 CR7 CR8 CR9 CR10 CR11 CR12 CR13 CR14 CR15 CR16 CR17 CR18 CR19 CR20 CR21 CR22 CR23\" citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003eValidation of mechanical guide. No difference in precision compared to CT-based navigation. Mean anteversion with posterior approach lower.\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSteppacher et al (\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e), 2011\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eI: 70\u003c/p\u003e\u003cp\u003eII: 146\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eRadio-graph and \u003cem\u003eHipMatch\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eAPP\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eI: Posterior\u003c/p\u003e\u003cp\u003eII: Posterior\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eLateral\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eI: Mechanical guide\u003c/p\u003e\u003cp\u003eII: CT based navigation\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003eI: 42\u0026thinsp;\u0026plusmn;\u0026thinsp;0 (\u003cspan additionalcitationids=\"CR40 CR41\" citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e)\u003c/p\u003e\u003cp\u003eII: 41\u0026thinsp;\u0026plusmn;\u0026thinsp;1 (38\u0026ndash;45)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003eI: 23\u0026thinsp;\u0026plusmn;\u0026thinsp;0 (\u003cspan additionalcitationids=\"CR24\" citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e)\u003c/p\u003e\u003cp\u003eII: 31\u0026thinsp;\u0026plusmn;\u0026thinsp;3 (\u003cspan additionalcitationids=\"CR24 CR25 CR26 CR27 CR28 CR29 CR30 CR31 CR32 CR33 CR34 CR35 CR36\" citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003eIncreased accuracy for mechanical navigation compared to CT based navigation (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001 and 0.003)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eLu et al (\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e), 2013\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e60\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eCT\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eCoro-nal plane\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003ePosterior\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eLateral\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eConventional\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e37\u0026thinsp;\u0026plusmn;\u0026thinsp;6 (23\u0026ndash;58)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e17\u0026thinsp;\u0026plusmn;\u0026thinsp;8 (\u003cspan additionalcitationids=\"CR2 CR3 CR4 CR5 CR6 CR7 CR8 CR9 CR10 CR11 CR12 CR13 CR14 CR15 CR16 CR17 CR18 CR19 CR20 CR21 CR22 CR23 CR24 CR25 CR26 CR27 CR28 CR29 CR30 CR31 CR32\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003eComparison of cup orientation measurement in plain radiographs and CT\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMcMahon et al (\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e), 2020\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e60\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eCT\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eAPP\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003ePosterior\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eLateral\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003ePatient specific 3D guide and laser beam\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e43 (33\u0026ndash;58)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e29 (\u003cspan additionalcitationids=\"CR17 CR18 CR19 CR20 CR21 CR22 CR23 CR24 CR25 CR26 CR27 CR28 CR29 CR30 CR31 CR32 CR33 CR34 CR35 CR36 CR37 CR38 CR39 CR40\" citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003eValidation of patient specific 3D guide. Lower accuracy for anteversion compared to inclination.\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eZurm\u0026uuml;hle et al (current study)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e349\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eRadio-graph and \u003cem\u003eHipMatch\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eAPP\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eI: Direct lateral\u003c/p\u003e\u003cp\u003eII: Anterior\u003c/p\u003e\u003cp\u003eIII:Anterior\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eI: Lateral\u003c/p\u003e\u003cp\u003eII: Supine\u003c/p\u003e\u003cp\u003eIII: Lateral\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eI: mechanical guide\u003c/p\u003e\u003cp\u003eII: fluoroscopy\u003c/p\u003e\u003cp\u003eIII: mechanical guide\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003eI: 45\u0026thinsp;\u0026plusmn;\u0026thinsp;7 (31\u0026ndash;61)\u003c/p\u003e\u003cp\u003eII: 45\u0026thinsp;\u0026plusmn;\u0026thinsp;5 (32\u0026ndash;58)\u003c/p\u003e\u003cp\u003eIII: 41\u0026thinsp;\u0026plusmn;\u0026thinsp;6 (18\u0026ndash;55)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003eI: 18\u0026thinsp;\u0026plusmn;\u0026thinsp;7 (\u003cspan additionalcitationids=\"CR3 CR4 CR5 CR6 CR7 CR8 CR9 CR10 CR11 CR12 CR13 CR14 CR15 CR16 CR17 CR18 CR19 CR20 CR21 CR22 CR23 CR24 CR25 CR26 CR27 CR28 CR29 CR30 CR31 CR32 CR33 CR34 CR35 CR36\" citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e)\u003c/p\u003e\u003cp\u003eII: 21\u0026thinsp;\u0026plusmn;\u0026thinsp;6 (\u003cspan additionalcitationids=\"CR7 CR8 CR9 CR10 CR11 CR12 CR13 CR14 CR15 CR16 CR17 CR18 CR19 CR20 CR21 CR22 CR23 CR24 CR25 CR26 CR27 CR28 CR29 CR30 CR31 CR32 CR33 CR34 CR35 CR36\" citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e)\u003c/p\u003e\u003cp\u003eIII: 23\u0026thinsp;\u0026plusmn;\u0026thinsp;8 (\u003cspan additionalcitationids=\"CR3 CR4 CR5 CR6 CR7 CR8 CR9 CR10 CR11 CR12 CR13 CR14 CR15 CR16 CR17 CR18 CR19 CR20 CR21 CR22 CR23 CR24 CR25 CR26 CR27 CR28 CR29 CR30 CR31 CR32 CR33 CR34 CR35 CR36 CR37 CR38 CR39 CR40 CR41\" citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003eComparison of cup orientation among different approaches, patient positioning and techniques of cup positioning; highest precision for anterior approach in supine position\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eAPP\u0026thinsp;=\u0026thinsp;anterior pelvic plane, defined by the two anterior superior iliac spines and the two pubic tubercules. N/A\u0026thinsp;=\u0026thinsp;not available. FPP\u0026thinsp;=\u0026thinsp;functional pelvic plane. * A difference in precision was defined by a significant difference in standard deviation for cup inclination or anteversion. Gray background: studies comparing different patient positioning or surgical approaches.\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-7973490/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7973490/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eIntroduction:\u003c/h2\u003e\u003cp\u003ePostoperative measurement of cup orientation on pelvic radiographs is prone to error, while CT scans are less practical in routine settings. The 2D/3D-matching technique allows measurement of cup orientation normalized to anterior pelvic plane using standard radiographs. This study aimed to determine the (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e) precision and (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e) percentage of outliers in cup orientation among three groups with different surgical approaches, patient positioning, and cup positioning techniques.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e\u003cp\u003eWe retrospectively analyzed 322 patients (349 hips) who underwent total hip arthroplasty (THA) with three different approaches: the 'direct lateral' group (66 hips) using a lateral position and direct lateral approach; the 'supine anterior' group (128 hips) using a supine position and anterior approach; and the 'lateral anterior' group (155 hips) using a lateral position and anterior approach. Cup positioning was determined intraoperatively using a mechanical device in the \u0026lsquo;direct lateral\u0026rsquo; and \u0026lsquo;lateral anterior\u0026rsquo; groups and using fluoroscopy in the \u0026lsquo;supine anterior\u0026rsquo; group. The 2D/3D-matching technique, HipMatch, was used to measure cup inclination and anteversion on postoperative radiographs normalized to the anterior pelvic plane. Precision was assessed using standard deviations (SDs), with outliers defined as orientations outside 2 SDs (31\u0026ndash;56\u0026deg; inclination, 7\u0026ndash;36\u0026deg; anteversion).\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e\u003cp\u003e(\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e) The \u0026lsquo;supine anterior\u0026rsquo; group showed the highest precision for inclination (SD\u0026thinsp;=\u0026thinsp;4.6\u0026deg;) compared to the \u0026lsquo;direct lateral\u0026rsquo; (SD\u0026thinsp;=\u0026thinsp;6.8\u0026deg;) and \u0026lsquo;lateral anterior\u0026rsquo; (SD\u0026thinsp;=\u0026thinsp;6.2\u0026deg;) groups (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Precision for anteversion did not differ significantly (p\u0026thinsp;=\u0026thinsp;0.097). (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e) The percentage of outliers did not significantly differ among the groups (p\u0026thinsp;=\u0026thinsp;0.183 to 0.384).\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e\u003cp\u003eInclination and anteversion vary with surgical approach, patient positioning in this largest series of APP normalized cup position measurements. The highest precision for inclination was seen in the anterior approach in supine position with fluoroscopy but approach, positioning, and technique did not affect the percentage of outliers.\u003c/p\u003e","manuscriptTitle":"A Comparative Study of Surgical Approach, Patient Positioning and Cup Positioning Technique - Cup Orientation Using 2D/3D-matching Technique HipMatch in 349 Hips","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-11-24 16:34:24","doi":"10.21203/rs.3.rs-7973490/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"0a57e300-2561-4399-90b2-711ae4856211","owner":[],"postedDate":"November 24th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-12-15T10:24:08+00:00","versionOfRecord":[],"versionCreatedAt":"2025-11-24 16:34:24","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7973490","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7973490","identity":"rs-7973490","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}