Factors Influencing Postoperative Sliding Distance in Elderly Patients with Intertrochanteric Fractures Treated with PFNA-II: A Retrospective Observational Study

Factors Influencing Postoperative Sliding Distance in Elderly Patients with Intertrochanteric Fractures Treated with PFNA-II: A Retrospective Observational Study | 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 Factors Influencing Postoperative Sliding Distance in Elderly Patients with Intertrochanteric Fractures Treated with PFNA-II: A Retrospective Observational Study Dongwei Wu, Haichuan Guo, Jingqiao Li, Chengsi Li, Tianyu Wang, and 5 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4989761/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 Purpose Excessive sliding of intramedullary nails following surgical treatment of intertrochanteric fracture has been strongly associated with the development of mechanical complications and unfavorable results. This study aims to investigate the factors that influence the postoperative sliding distance in elderly patients treated with PFNA-II device for intertrochanteric fracture fixation. Methods A retrospective analysis of patients over 65 years old with intertrochanteric fractures using PFNA-II device in a university teaching hospital was performed between January 2020 and December 2021. Data on sociodemographics, comorbidities, operative procedure and postoperative radiographic sliding distance were collected. The Youden index was used to determine the threshold for excessive sliding, and the risk of mechanical complication in relation with excessive sliding was calculated using multivariate regression analysis. Also, potential factors influencing the slinding distance as a continuous outcome variable were investigated using univariate and multivariate linear regression analysis. Result Among the 507 eligible patients, the mean postoperative sliding distance was 4.45 mm (SD, 5.39 mm; range, 0-31.67 mm). The threshold for excessive sliding was determined as 6.75 mm, and 103 patients (20.3%) had excessive sliding, among whom 18 (17.5%) developed mechanical complications. The risk of postoperative mechanical complications was significantly higher in the excessive sliding group (adjusted OR = 14.714, 95% CI: 4.270–50.710, P < 0.001) than in non-excessive sliding group. Multiple linear regression analysis revealed that older age (B = 0.061, 95% CI: 0.007–0.114, P = 0.026), poor reduction quality (B = 4.736, 95% CI: 1.236–8.235, P = 0.008), and subtype P in lateral view (B = 11.193, 95% CI: 6.836–15.549, P < 0.001) were positively correlated with postoperative sliding distance. Conclusions Age, reduction quality and LAT reduction mode are important predictors of helical blade sliding distance after intertrochanteric fracture surgery. Surgeons should pay close attention to these factors during preoperative planning and postoperative rehabilitation protocols. Intertrochanteric fractures Sliding distance Implant fixations Postoperative mechanical complications Figures Figure 1 Figure 2 Introduction Intertrochanteric fractures account for approximately 50% of hip fractures and pose a substantial burden on hip function and quality of daily living, with even a 1-year mortality rate of 11–27% [1, 2]. The current treatment with sliding hip screws or intramedullary nails with sliding screws or helical blade has been the treatment of choice [3–6]. Take PFNA for example, during postoperative weight-bearing, the proximal fragment slides along the helical blade and the distal fragment comes into direct contact, thus improving stability and healing at the fracture site[7]. However, excessive increase in sliding distance clearly increases the risk of mechanical complications, ie, nail breakage and cut-out by sevenfold, and leads to reduced hip function and independence in walking [7–9]. Therefore, identification of relevant risk factors that affect the sliding distance is of critical importance for prevention of these potentially devastating mechanical complications. Several previous studies have made multiple efforts to address the risk factors associated with excessive sliding distance. In 2014, Liu et al. retrospectively analyzed 223 patients treated with TFN and concluded that calcar reduction and fracture stability were independent risk factors for excessive sliding (exceeding 10 mm)[10]. However, this study did not include physiological factors such as BMI and did not adjust for bias due to large differences in surgeon experience. In 2021, a retrospective multicenter study by Kenta et al., which included 115 patients, concluded that females, unstable fracture type, larger TAD, and poor reduction in one plane were associated with excessive postoperative sliding (exceeding 8 mm)[11]. In 2023, Li et al.'s retrospective case-control study of 369 patients treated with PFNA-II suggested that low medullary filling and negative fracture reduction pattern in lateral view were independent risk factors for excessive sliding (exceeding 10 mm)[12]. However, these studies may have been limited by small sample sizes, underadjustment for covariates or confounders, an arbitrary threshold set for defining excessive sliding distance, and short follow-up periods. The purpose of this study was to characteristize the sliding distance observed with intertrochanteric fractures treated using the PFNA-II and to identify the factors that predict sliding distance and their association with mechanical complications. Materials and Methods This study received approval from the Ethics Committee and adhered to the international ethical guidelines outlined in the Declaration of Helsinki for research involving human subjects. Data Source and Study Population We conducted a retrospective cohort study involving patients with intertrochanteric fractures (ITF) at our tertiary care referral hospital from January 2021 to December 2022. Inclusion criteria are as follows: (1) intertrochanteric fracture, (2) surgery performed within two weeks of the fracture, and (3) closed reduction internal fixation surgery. Exclusion criteria are as follows: (1) age < 65 years, (2) high-energy trauma fractures, (3) comorbid primary tumors, (4) multiple or open fractures, (5) pathological fractures, (6) previous fracture in the same femur, and (7) incomplete follow-up data. The treatments used the Proximal Femoral Nail Antirotation II device (PFNA II) (Synthes GmbH, Oberdorf, Switzerland). Patient data, including age, sex, body mass index (BMI), side of injury, American Society of Anesthesiologists (ASA) score, and intramedullary nail lengths, were extracted from the hospital database. Radiographic evaluations used a picture archiving and communication system (PACS) for immediate preoperative and postoperative evaluations, including anteroposterior projections of the pelvis and affected hip joints in axial projection, as well as anteroposterior and lateral radiographs. Follow-up evaluations were conducted at one, three, six, nine, and twelve months post-discharge, with radiographs taken at each visit for comparison. Measurements of the tip-apex distance (TAD) and calcar-referenced tip-apex distance (Cal-TAD) were taken from postoperative photographs. Radiological evaluations included preoperative considerations such as fracture classification (AO / OTA 2007), stability, and the presence of a combined posterolateral wall fracture. Postoperative evaluations focused on TAD, Cal-TAD, Parker ratio, distal locking mode, Cleveland-Bosworth quadrant, reduction quality, and classification of reduction in AP and LAT view. The postoperatively mechanical complications at one year were included as follows: (1) cut-out, breakage, and lateral displacement of the helical blade or distal locking nail, (2) periprosthetic fracture, (3) malunion, delayed union, nonunion, (4) hip varus deformity (assessed by the neck-shaft angle variation). All these findings could be identified on orthopantomograms during the follow-up review[13]. Definition and measurements of parameters The TAD defined by Baumgaertner is the sum of the distances from the tip of the screw to the apex of the femoral head in anteroposterior and lateral views[14]. Cal-TAD defined by Kuzyk, is the sum of the distances from the tip of the helical blade to the intersection of the femoral head and the medial femoral neck cortical tangent on the AP view and from the tip of the helical blade to the apex of the femoral head on the Lat view[15]. Parker’s ratio is defined as the distance from the helical blade to the inferior and posterior margins of the femoral neck in the AP or Lat views[16]. According to Cleveland’s initial report, the femoral head is divided into nine zones on postoperative frontal and lateral views[17]. The quality of reduction (poor, acceptable, good) is based on postoperative radiographic evaluation according to Baumgaertner's criteria[14]. Fracture gapping was measured according to the method described by Ciufor et al., with the measured distance corrected using the known diameter of the lag screw[18]. Extramedullary fractures had the inner cortex of the proximal bone fragment outside the medial cortex of the distal fragment. Anatomical fractures had continuous medial cortices of the proximal and distal fragments. Intramedullary fractures had the medial cortex of the proximal fragment inside the distal fragment. Using a lateral view, reductions were classified as subtype A, N, or P. Subtype A had the anterior anterior cortex of the proximal fragment and on top of the anterior cortex of the distal fragment. Subtype N had continuous anterior cortices of the proximal and distal fragments. Subtype P had the anterior cortex of the proximal fragment that entered the medullary cavity of the distal fragment[19, 20]. The sliding distance of the helical blade was determined from the AP view taken immediately after surgery and at the final follow-up. Measurements were performed by senior physicians. The length of the lag screw (AB) and the distance (AC) from the tip of the lag screw (A) to the intersection point (C) of lines drawn between the lag screw axis and the contact point with the external sides of the nails and screws were measured at 2 weeks, 4 weeks, 3 months and 6 months postoperatively. Each measurement at the final follow-up was defined as AC’ or AB’, and the sliding distance between the nail and the lag screw was calculated as AC – AC’ (AB/AB’) (Fig. 1 .). Surgical procedure All operations were carried out by a group of four hip surgeons, each with more than five years of surgical expertise. Operations occurred on a radiolucent fracture table, managed by a senior chief surgeon with professional training, under the direction of general anesthesia and fluoroscopy. The surgeries were performed within 2–6 days of patient admission, using general and spinal anesthesia. No intraoperative complications were encountered. Postoperative management Each patient was given antithrombotic prophylaxis using low molecular weight heparin (enoxaparin) and antibiotic prophylaxis with a second-generation cephalosporin (cefazolin). All individuals followed a standardized rehabilitation protocol. Postoperative functional exercises were strongly recommended. On the first day, isometric quadriceps and ankle pump exercises were initiated, followed by weight-bearing as tolerated starting 4 weeks after surgery. Full weight bearing was limited until bone union, typically 3–5 months. At each follow-up appointment, ortho- and lateral X-rays were taken to monitor healing progress. Internal criteria to assess fracture healing included the absence of localized pain and abnormal activity, radiographs showing a blurred fracture line, and continuous trabeculae. Statistical analysis Continuous variables were expressed as means with standard deviations (SD), while categorical variables were expressed as frequencies with percentages. Continuous data was analyzed using t-tests, Mann-Whitney U tests, or ANOVA. The Youden index identified the optimal cut-off for sliding distance where postoperative mechanical complications occurred. Significant variables from univariate analyzes were included in linear regression models. Logistic regression assessed the relationship between excessive sliding distance and postoperative mechanical complications. We constructed three models that were adjusted for different covariates. Model 1 adjusted for baseline characteristics such as age, sex, BMI, and ASA score. Model 2 was additionally adjusted for intertrochanteric fracture-related covariates along with those of Model 1. The final model was further adjusted for surgery-related covariates in addition to the variables in Model 2. A P-value < 0.05 was considered statistically significant, and all tests were two-sided. SPSS version 26.0 (IBM Corp, Armonk, NY, USA) was used for data analysis. Result A total of 507 patients with intertrochanteric fractures were included in this retrospective study. The mean age was 77.60 ± 7.59 years. 208 patients were male and 299 patients were female. According to the AO/OTA classification system, 277 fractures were considered stable and 230 fractures were considered unstable. Long nails were used in 120 patients and short nails in 387 patients. The mean follow-up time was 13.4 months (12–56 months). The mean TAD was 22.79 mm (SD, 7.78MM; median: 21.63 mm; range: 2.22–47.22 mm). Postoperative mechanical complications occurred in 33 (6.5%) patients included. The mean sliding distance was 4.45 mm (SD, 5.39 mm; range: 0-31.67 mm). 27 (5.32%) patients had a sliding distance between 8 mm and 10 mm, 38 (7.50%) patients had a sliding distance between 10 mm and 20 mm, and 19 (3.75%) patients had a sliding distance greater than 20 mm. 126 (24.85%) patients sliding less than 1 mm and the maximum sliding amount was 31.67 mm. The mean sliding distance of each fracture classification was 3.03 mm (0-20.74 mm) in A1, 4.61 mm (0-31.67) in A2, and 5.28 mm (0.41–20.73 mm) in A3. The mean sliding distance of individual reduction patterns in the AP view was 4.68 mm (0-14.41 mm) in the anatomical type, 5.25 mm (0-14.3 mm) in the extramedullary type, and 3.72 mm (0-31.67 mm) in the intramedullary type. The mean sliding distance of the individual reduction patterns in the lateral view was 3.73 mm (0-18.25 mm) in subtype A, 4.04 mm (0-21.2 mm) in subtype N, and 14.71 mm (3.21–31.67 mm) in subtype P. Based on the analysis of the threshold value of the ROC curve for postoperative mechanical complications, the optimal threshold for the sliding distance was 6.75 mm to balance sensitivity and specificity (Fig. 2 .). Excessive sliding distances increase the incidence of postoperative mechanical complications twelve-fold(OR = 12.133, 95%CI: 4.605–31.968, P<0.001). To examine the independent prognostic value of excessive sliding, we adjusted for potential confounders. In the fully adjusted model, which accounts for 15 potential confounders, the risk of postoperative mechanical complications was significantly higher in the excessive sliding group (OR = 14.714, 95% CI: 4.270–50.710) compared to the normal sliding group (Table 2 ). Table 1 Univariate analysis of variables Variables Overall(n=507) Average nail sliding distance P value AGE, years 77.60 ±·7.59 0.013* < 77 328 (64.7%) 1.99 (0.65, 4.88) ≥ 77 179 (35.3%) 3.87 (1.71, 7.11) SEX, n 0.232 Male 208 (41.0%) 2.24 (1.01, 4.25) Female 299 (59.0%) 3.37 (0.95, 6.34) BMI, kg/m² 24.55±3.73 0.216 ≤ 23.9 210 (41.4%) 2.33 (0.91, 4.32) 24-27.9 227 (44.8%) 2.65 (0.73, 6.34) ≥ 28.0 63 (12.4%) 3.86 (1.41, 8.07) ASA score, n 0.540 1-2 272 2.29 (1.01, 5.47) 3-4 235 3.21 (0.95, 7.35) Lateral, n 0.494 Left 275 2.38 (0.63, 5.42) Right 232 2.81 (1.21, 5.79) Classification, n 0.260 31A1 106 3.03 (0.52, 3.66) 31A2 305 4.61 (0.85, 5.76) 31A3 96 5.28 (2.25, 7.36) Fracture Type, n 0.112 Stable 277 1.91 (0.67, 5.18) Unstable 230 3.72 (1.07, 6.75) Doctor Evidence, years 0.872 15 294 4.07 (0.95, 5.42) Nail length, n 0.943 Short 387 2.65 (1.10, 5.49) Long 120 2.66 (0.99, 5.72) Reduction, n 0.001* Good 362 2.62 (0.70, 4.89) Acceptable 132 2.25 (0.91, 4.76) Poor 13 9.44 (6.62, 15.92) Lateral femoral wall, n 0.025* Intact 411 2.09 (0.83, 5.41) Fracture 96 3.87 (2.25, 7.35) TAD, mm 22.79±7.78 0.363 Cal-TAD, mm 24.97±6.91 0.033* APparker, % 39.84±9.17 0.241 LATparker, % 54.44±11.49 0.885 Blade position, n AP 0.531 Central 274 3.21 (1.29, 5.47) Superior 52 1.92 (0.56, 7.01) Inferior 181 3.80 (0.91, 5.75) LAT 0.325 Central 302 2.91 (1.26, 5.59) Anterior 159 3.61 (0.66, 6.00) Posterior 46 1.13 (0.10, 2.20) Distal locking mode, n 0.449 Static locking 286 2.87 (1.13, 5.72) Dynamic locking 221 2.25 (0.55, 5.34) AP reduction, n 0.546 Intramedullary type 51 4.61, (2.35, 7.67) Anatomical type 303 2.60, (1.00, 6.00) Extramedullary type 153 2.15, (0.91, 4.62) LAT reduction, n 0.009* Subtype A 111 1.31, (0.54, 6.01) Subtype N 373 2.63, (1.16, 5.40) Subtype P 23 12.17, (4.79, 25.74) *P < 0.05 was considered statistically significant. Abbreviations: M: male; F: female; BMI: Body mass index; ASA: American Society of Anesthesiologists; TAD: tip-apex distance; Cal-TAD: calcar-referenced tip-apex distance; AP: anterior; LAT: lateral Table 2 The logistic regression analysis Variable β OR/Adjusted OR Crude OR/ Adjusted OR 95%CI P value Sliding 2.294 12.133 4.605–31.968 < 0.001 Model 1* 2.491 12.072 4.182–34.849 < 0.001 Model 2† 2.523 12.471 4.210-36.911 < 0.001 Model 3‡ 2.689 14.714 4.270–50.710 < 0.001 CI confidence interval, OR odds ratio, Postoperative mechanical complications were a composite of cut out, nail withdrawal, varus deformity, periprosthetic fracture, nonunion, and nail breakage. *Adjusted for age, sex, body mass index, and ASA score † Adjusted for age, sex, body mass index, ASA score, fracture type, fracture lateral, fracture stability, and integrity of the lateral femoral wall ‡ Adjusted for age, sex, body mass index, ASA score, fracture type, fracture lateral, fracture stability, and integrity of the lateral femoral wall, TAD, Cal-TAD, AP parker ratio, LAT parker ratio, blade position, nail length and nail locking mode In terms of baseline characteristics, the sliding distance was positively correlated with age (r = 0.182, P = 0.036) and did not show statistically significant differences with gender (P = 0.491), BMI (r = 0.068, P = 0.436) and ASA score (P = 0.540). In terms of perioperative variables, the sliding distance with respect to the fracture lateral (P = 0.494), fracture classification (P = 0.260), fracture stability (P = 0.112), surgeon's experience (P = 0.872), nail length (P = 0.943), TAD (r = -0.056, P = 0.363), AP parker ratio (r = 0.070, P = 0.241), LAT parker ratio (r = 0.006, P = 0.885), helical blade in AP position (P = 0.531), helical blade in LAT position (P = 0.325), distal locking mode (P = 0.449), and AP reduction mode (P = 0.546) were not statistically significant differences. The statistically significant difference in the quality of fracture reduction (P = 0.001), integrity of lateral femoral wall (P = 0.025), LAT reduction mode (P = 0.009), and negative correlation with Cal-TAD (r=-0.185, P = 0.033). The results of the univariate analysis are listed in Table 1 . Analysis using multiple linear regression showed that the regression equation was significant (F = 5.158, p < 0.0001) and that older age, poor reduction quality, and subtype P in lateral view significantly and positively predicted the longer sliding distance of helical blade. The AP reduction mode, integrity of lateral femoral wall, fracture stability, and Cal-TAD did not predict the sliding distance. Together, these variables explained 31.9% of the variance in sliding distance (Table 3 ). Table 3 Linear regression analysis for factors of sliding distance. B β t p F Adjusted R² Age 0.061 0.182 2.251 0.026* 5.158 0.319 Reduction Acceptable-Good -0.736 -0.067 -0.778 0.438 Poor-Good 4.736 0.233 2.679 0.008* LAT reduction Subgroup N-A 0.790 0.065 0.737 0.463 Subgroup P-A 11.193 0.433 5.086 < 0.001* AP reduction Extramedullary-Anatomical -0.290 -0.025 -0.295 0.768 Intramedullary- Anatomical -0.756 -0.043 -0.532 0.596 Lateral Fracture -0.450 -0.036 -0.370 0.712 Stable 1.025 0.095 0.949 0.345 Cal-TAD -0.077 -0.102 -1.298 0.197 Constant -2.612 *P < 0.05 was considered statistically significant. Discussion This retrospective observational study provides evidence of an association in sliding distance with age, reduction quality, and LAT reduction mode. Patients with elder age, poor reduction quality, and subtype P in lateral view would have a longer sliding distance. These results highlight the importance of focusing on the quality of reduction in older patients with intertrochanteric fractures. Moreover, the rate of complication is higher when the patient's sliding distance is too long. Several articles have demonstrated that the use of intramedullary nails with sliding devices improves bony apposition and compression, reestablishing medial cortical contact, increases fracture site stability, induces osseointegration, and reduces the incidence of postoperative complications in the treatment of intertrochanteric fractures[21, 22]. However, as the sliding distance increases, there is no medial support at the base of the femoral neck to prevent fragment collapse. The lower medial cortex of the femoral neck slips into the medullary canal while the proximal lateral portion of the base of the femoral neck abuts the greater trochanter resulting in collapse. The femoral stem is displaced medially and the medial cortex is unsupported. The risk of failure of the reduction increases, leading to complications such as lateral thigh pain, impaired walking, intramedullary nail breakage, helical blade cuts, and bone nonunion[23]. The threshold at which the sliding distance causes postoperative mechanical complications remains controversial, Elizabeth et al. suggests that a shortening threshold of 8mm affects gait by altering the relationship between adductor length and tension, leading to adductor weakness and the development of a Trendelenburg gait[24]. However, Liu et al.'s study indicated that t et al.his threshold was 10mm[10]. Steinberg et al. reported that sliding 15 mm or more resulted in increased failure rates[25]. Kim et al. observed leg shortening and femoral pain in patients who slid 20 mm or more[26]. Therefore, it is important to determine the postoperative threshold for complications due to the sliding distance and explore the risk factors for the increased sliding distance. In our study, the sliding distance was positively correlated with age, increasing by 0.061 mm per year of age. This finding aligns with a prospective cohort study by Fang et al. involving 319 patients, which showed that older patients experienced more severe collapse, with 86-year-olds having a collapse of up to 20 mm[27]. The literature confirms that as age increases, the neck-shaft angle decreases and the anterior inclination angle increases[28, 29]. These changes lead to greater weight-bearing eccentricity, which increases the force of the transverse shear component and decreases the longitudinal axis compression component force, impairing the lever arm of the hip adductors and affecting the length-tension relationship of the adductors. Additionally, the increased concentration of stress at the junction of the helical blade and the main nail decreases the overall stability of the internal fixation, leading to an increased sliding displacement of the intramedullary nail[13, 30, 31]. Retrospective studies by Gun and Rha also demonstrated that excessive sliding is more likely to occur in older patients. However, the definition of excessive sliding varied in these studies[32, 33]. Our further analysis concluded that a sliding distance of more than 6.75 mm increased the incidence of postoperative mechanical complications by a factor of 12.133. The quality of fracture reduction is one of the five factors that influence the outcome of the treatment of intertrochanteric fractures, as suggested by Professor Kaufer in 1980[34]. Chang et al.'s 2019 system review of intertrochanteric fracture treatment in Asia concluded that good fracture reduction is the primary and critical component of treatment[3]. In our study, patients with poor reduction had a mean sliding distance of 9.44 mm, significantly higher than that of patients with good or acceptable reduction quality. These results are in accordance with Liu et al.'s series, where patients with poor reduction had a mean sliding distance of 7.6 mm, along with a 2.585-fold higher risk of excessive sliding than patients with good reduction[10, 35]. When the gap between the fracture fragments is too large and stable bone contact is lacking, the iliopsoas and adductor muscles exert strong traction and internal rotation on the distal fragment. This ultimately leads to a conflict between osseointegration (resulting in fragment impingement and shortening) and mechanical loading (resulting in implant failure) when all forces are transmitted through the main nail of the endoprosthesis instead of through the bone[36]. The end of the helical blade is diamond shaped, which connects to the femoral head and neck of the femoral after insertion, effectively reducing loosening and withdrawal due to the rotation of the internal fixation. However, the design of intramedullary nails does not provide absolute control over the helical blade. Bonnarie et al. demonstrated that when bone density is less than 0.6 g/cm³, there is insufficient purchase to control the helical blade, resulting in loosening and withdrawal[37]. A three-dimensional finite element analysis revealed that early weight bearing should be avoided after surgery to prevent helical blade loosening and withdrawal[38]. During weight-bearing exercises, pressure is transmitted to the distal end through the femoral neck through the helical blade, with stress concentrated in the weight-bearing area of the femoral neck. If the patient lifts weights too early, and the fracture scab has not yet formed, or the patient has severe osteoporosis, the anchoring force of the helical blade and the surrounding bone will be weakened, resulting in the loosening of the helical blade and ultimately the sliding of the blade. To the best of our knowledge, this is the largest sample size of articles to date examining postoperative helical blade sliding distances. However, the following limitations of this study should be noted, the first of which is that the article has the limitations of a retrospective study. Second, we focused solely on fracture healing outcomes and complications, neglecting the inclusion of clinical criteria or functional rating scales. This deliberate choice was made to evaluate the efficacy and reliability of internal fixation, prioritizing objective measures over subjective assessments. Lastly, our statistical analysis relied on single-center data, which required caution in generalizing our conclusions. To enhance the robustness of our findings, we recommend further validation and optimization through multicenter, large-sample randomized controlled trials with extended follow-up periods and a more comprehensive biomechanical analysis in future research. Conclusion In conclusion, our study found that elder age, reduction quality, and the subtype P in lateral view were associated with a longer sliding distance of the helical blade in the postoperative period. Therefore, attention to the quality of intertrochanteric fracture reduction and the extension of postoperative weight-bearing time in elderly patients with risk factors are important to achieve a satisfactory outcome. Declarations Conflict of Interest The authors declare that they have no conflict of interest. Funding This research was supported by the Xinjiang Uygur Autonomous Region Major Science and Technology Projects (No. 2022A03011) Availability of data and material All data in this study can be obtained from the authors based on reasonable demand. Consent for publication The authors have seen the manuscript and approved to submit it to your journal. Code availability Not applicable Ethical approval Our institutional ethics committee accepted this study. Informed Consent All subjects were informed and anonymized. Authors’ contributions YZZ, and SAZ designed the study; DWW, HCG, and JQL searched for relevant studies and abstracted the data; DWW, TYW, ZBY, XQC, CSL, and YBZ analyzed and interpreted the data; DWW wrote the manuscript; YZZ and SAZ approved the final version of the manuscript. All authors reviewed the manuscript before submitting it. Acknowledgments We sincerely thank all the patients for their participation in this study. References Lichtblau S: The unstable intertrochanteric hip fracture . Orthopedics 2008, 31 (8):792-797. Tawari AA, Kempegowda H, Suk M, Horwitz DS: What makes an intertrochanteric fracture unstable in 2015? Does the lateral wall play a role in the decision matrix? J Orthop Trauma 2015, 29 Suppl 4 :S4-9. Chang SM, Hou ZY, Hu SJ, Du SC: Intertrochanteric Femur Fracture Treatment in Asia: What We Know and What the World Can Learn . Orthop Clin North Am 2020, 51 (2):189-205. 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Li SJ, Chen SY, Chang SM, Du SC, Hu SJ: Insufficient proximal medullary filling of cephalomedullary nails in intertrochanteric femur fractures predicts excessive postoperative sliding: a case-control study . BMC Musculoskelet Disord 2023, 24 (1):156. Klima ML: Mechanical Complications After Intramedullary Fixation of Extracapsular Hip Fractures . J Am Acad Orthop Surg 2022, 30 (24):e1550-e1562. Baumgaertner MR, Curtin SL, Lindskog DM, Keggi JM: The value of the tip-apex distance in predicting failure of fixation of peritrochanteric fractures of the hip . J Bone Joint Surg Am 1995, 77 (7):1058-1064. Kuzyk PR, Zdero R, Shah S, Olsen M, Waddell JP, Schemitsch EH: Femoral head lag screw position for cephalomedullary nails: a biomechanical analysis . J Orthop Trauma 2012, 26 (7):414-421. Parker MJ: Cutting-out of the dynamic hip screw related to its position . J Bone Joint Surg Br 1992, 74 (4):625. Cleveland M, Bosworth DM, Thompson FR, Wilson HJ, Jr., Ishizuka T: A ten-year analysis of intertrochanteric fractures of the femur . J Bone Joint Surg Am 1959, 41-A :1399-1408. Ciufo DJ, Zaruta DA, Lipof JS, Judd KT, Gorczyca JT, Ketz JP: Risk Factors Associated With Cephalomedullary Nail Cutout in the Treatment of Trochanteric Hip Fractures . J Orthop Trauma 2017, 31 (11):583-588. Inui T, Watanabe Y, Suzuki T, Matsui K, Kurata Y, Ishii K, Kurozumi T, Kawano H: Anterior Malreduction is Associated With Lag Screw Cutout After Internal Fixation of Intertrochanteric Fractures . Clin Orthop Relat Res 2024, 482 (3):536-545. Itou J, Kuramitsu Y, Hatta S, Okazaki K: AP3xML3 reduction quality classification for femoral trochanteric fractures: validation for reliability focusing on positive medial cortical support . J Orthop Surg Res 2023, 18 (1):64. Hoffmann MF, Khoriaty JD, Sietsema DL, Jones CB: Outcome of intramedullary nailing treatment for intertrochanteric femoral fractures . J Orthop Surg Res 2019, 14 (1):360. Yang F, Li X, Zhao L, Yang Q: Dual-screw versus single-screw cephalomedullary nails for intertrochanteric femoral fractures: a systematic review and meta-analysis . J Orthop Surg Res 2023, 18 (1):607. Goto K, Murakami T, Saku I: Postoperative subtype P as a risk factor for excessive postoperative sliding of cephalomedullary nail in femoral trochanteric fractures in old patients: A case series of 263 patients using computed tomography analysis . Injury 2022, 53 (6):2163-2171. Gausden EB, Sin D, Levack AE, Wessel LE, Moloney G, Lane JM, Lorich DG: Gait Analysis After Intertrochanteric Hip Fracture: Does Shortening Result in Gait Impairment? J Orthop Trauma 2018, 32 (11):554-558. Steinberg GG, Desai SS, Kornwitz NA, Sullivan TJ: The intertrochanteric hip fracture. A retrospective analysis . Orthopedics 1988, 11 (2):265-273. Kim WY, Han CH, Park JI, Kim JY: Failure of intertrochanteric fracture fixation with a dynamic hip screw in relation to pre-operative fracture stability and osteoporosis . Int Orthop 2001, 25 (6):360-362. Fang C, Gudushauri P, Wong TM, Lau TW, Pun T, Leung F: Increased Fracture Collapse after Intertrochanteric Fractures Treated by the Dynamic Hip Screw Adversely Affects Walking Ability but Not Survival . Biomed Res Int 2016, 2016 :4175092. Jiang N, Peng L, Al-Qwbani M, Xie GP, Yang QM, Chai Y, Zhang Q, Yu B: Femoral version, neck-shaft angle, and acetabular anteversion in Chinese Han population: a retrospective analysis of 466 healthy adults . Medicine (Baltimore) 2015, 94 (21):e891. Yin Y, Zhang R, Jin L, Li S, Hou Z, Zhang Y: The Hip Morphology Changes with Ageing in Asian Population . Biomed Res Int 2018, 2018 :1507979. Zlowodzki M, Brink O, Switzer J, Wingerter S, Woodall J, Jr., Petrisor BA, Kregor PJ, Bruinsma DR, Bhandari M: The effect of shortening and varus collapse of the femoral neck on function after fixation of intracapsular fracture of the hip: a multi-centre cohort study . J Bone Joint Surg Br 2008, 90 (11):1487-1494. McGrory BJ, Morrey BF, Cahalan TD, An KN, Cabanela ME: Effect of femoral offset on range of motion and abductor muscle strength after total hip arthroplasty . J Bone Joint Surg Br 1995, 77 (6):865-869. Im GI, Shin YW, Song YJ: Potentially unstable intertrochanteric fractures . J Orthop Trauma 2005, 19 (1):5-9. Rha JD, Kim YH, Yoon SI, Park TS, Lee MH: Factors affecting sliding of the lag screw in intertrochanteric fractures . Int Orthop 1993, 17 (5):320-324. Kaufer H: Mechanics of the treatment of hip injuries . Clin Orthop Relat Res 1980(146):53-61. Liu W, Zhou D, Liu F, Weaver MJ, Vrahas MS: Mechanical complications of intertrochanteric hip fractures treated with trochanteric femoral nails . J Trauma Acute Care Surg 2013, 75 (2):304-310. Li J, Zhang L, Zhang H, Yin P, Lei M, Wang G, Wang S, Tang P: Effect of reduction quality on post-operative outcomes in 31-A2 intertrochanteric fractures following intramedullary fixation: a retrospective study based on computerised tomography findings . Int Orthop 2019, 43 (8):1951-1959. Bonnaire F, Weber A, Bosl O, Eckhardt C, Schwieger K, Linke B: ["Cutting out" in pertrochanteric fractures--problem of osteoporosis?] . Unfallchirurg 2007, 110 (5):425-432. Li SJ, Huang HJ, Li CT, Hu GJ, Yu F, Liu YB: Mechanical effect of changed femoral neck ante-version angles on the stability of an intertrochanteric fracture fixed with PFNA: A finite element analysis . Heliyon 2024, 10 (10):e31480. 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-4989761","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":357947795,"identity":"bca1d3ad-bb92-4ab1-8e74-64febcd37841","order_by":0,"name":"Dongwei Wu","email":"","orcid":"","institution":"Hebei Medical University Third Hospital","correspondingAuthor":false,"prefix":"","firstName":"Dongwei","middleName":"","lastName":"Wu","suffix":""},{"id":357947796,"identity":"920c7f1d-ba44-4f0f-9c3c-b57cabf0621a","order_by":1,"name":"Haichuan Guo","email":"","orcid":"","institution":"Hebei Medical University Third Hospital","correspondingAuthor":false,"prefix":"","firstName":"Haichuan","middleName":"","lastName":"Guo","suffix":""},{"id":357947797,"identity":"ee27c7f6-f11c-4b0b-aca5-c4efdd21f18f","order_by":2,"name":"Jingqiao Li","email":"","orcid":"","institution":"Hebei Jing-Xing Xian Hospital","correspondingAuthor":false,"prefix":"","firstName":"Jingqiao","middleName":"","lastName":"Li","suffix":""},{"id":357947798,"identity":"223e6895-21f7-4ed6-9d68-c6a5fbc23915","order_by":3,"name":"Chengsi Li","email":"","orcid":"","institution":"Hebei Medical University Third Hospital","correspondingAuthor":false,"prefix":"","firstName":"Chengsi","middleName":"","lastName":"Li","suffix":""},{"id":357947799,"identity":"2c9f7953-e16f-4f0c-8f12-fc8584d703a8","order_by":4,"name":"Tianyu Wang","email":"","orcid":"","institution":"Hebei Medical University Third Hospital","correspondingAuthor":false,"prefix":"","firstName":"Tianyu","middleName":"","lastName":"Wang","suffix":""},{"id":357947800,"identity":"b04fd5ad-b919-4b83-94ab-67652bb5c818","order_by":5,"name":"Zhenbang Yang","email":"","orcid":"","institution":"Hebei Medical University Third Hospital","correspondingAuthor":false,"prefix":"","firstName":"Zhenbang","middleName":"","lastName":"Yang","suffix":""},{"id":357947801,"identity":"13a7420f-fca0-4154-ac8b-0c6040bc3572","order_by":6,"name":"Xinqun Cheng","email":"","orcid":"","institution":"Hebei Medical University Third Hospital","correspondingAuthor":false,"prefix":"","firstName":"Xinqun","middleName":"","lastName":"Cheng","suffix":""},{"id":357947802,"identity":"79e22b8d-7770-4e9d-9037-b65d9b95cb11","order_by":7,"name":"Yanbin Zhu","email":"","orcid":"","institution":"Hebei Medical University Third Hospital","correspondingAuthor":false,"prefix":"","firstName":"Yanbin","middleName":"","lastName":"Zhu","suffix":""},{"id":357947803,"identity":"11ed8b94-52f8-4d9c-9339-784902de7a5a","order_by":8,"name":"Yingze Zhang","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA0UlEQVRIiWNgGAWjYFAC5oYDQFKGjYH5wIEPP4jSwgjWwsPGwJZ4cGYPkVpAJA8QGR/mYCNCg8H5g42HC34x8PBJ5Hw4DNQpzy92gICWAwcbDs/sAzpMInfD4QILBsOZsxMIaDnY2HCYtweqZQYPQ4LBbUJaDjPCtOQ8OAwMBCK0HANq4fkB1sJAnBbJMyBbGoBaeJ4ZAANZgrBf+M4fPvyZ5w+DnHx78uMPH37YyPNLE9CicABIMLb9h/El8CsHAfkGEPmHsMJRMApGwSgYwQAAaqdFe9BlnY0AAAAASUVORK5CYII=","orcid":"","institution":"Hebei Medical University Third Hospital","correspondingAuthor":true,"prefix":"","firstName":"Yingze","middleName":"","lastName":"Zhang","suffix":""},{"id":357947804,"identity":"53e4bce8-cb71-46aa-a4f3-486541a2290d","order_by":9,"name":"Shian Zhang","email":"","orcid":"","institution":"The Chinese University of Hong Kong","correspondingAuthor":false,"prefix":"","firstName":"Shian","middleName":"","lastName":"Zhang","suffix":""}],"badges":[],"createdAt":"2024-08-28 09:12:38","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4989761/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4989761/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":66870424,"identity":"6bc23d3a-6d81-4397-9e87-7049d571ab6a","added_by":"auto","created_at":"2024-10-17 09:39:34","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":1042434,"visible":true,"origin":"","legend":"\u003cp\u003eMeasurement protocol The sliding distance = AC - AC’( AB/AB’)\u003c/p\u003e","description":"","filename":"Figure118.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4989761/v1/4f417f40e1449b59538fe82e.jpg"},{"id":66869285,"identity":"802f6ed0-ea8c-45e5-8470-b2bcd9c5fa1b","added_by":"auto","created_at":"2024-10-17 09:31:33","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":29125,"visible":true,"origin":"","legend":"\u003cp\u003eThe receiver operating characteristic curve (ROC) of the logistic regression.\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-4989761/v1/fdcfe731b834ce4d1925aa99.png"},{"id":66872596,"identity":"38d30343-96b0-4ce8-80f7-0620bfba1093","added_by":"auto","created_at":"2024-10-17 09:55:37","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2793260,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4989761/v1/c72565ea-4d26-4602-8634-59f648e76a0e.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Factors Influencing Postoperative Sliding Distance in Elderly Patients with Intertrochanteric Fractures Treated with PFNA-II: A Retrospective Observational Study","fulltext":[{"header":"Introduction","content":"\u003cp\u003eIntertrochanteric fractures account for approximately 50% of hip fractures and pose a substantial burden on hip function and quality of daily living, with even a 1-year mortality rate of 11\u0026ndash;27% [1, 2]. The current treatment with sliding hip screws or intramedullary nails with sliding screws or helical blade has been the treatment of choice [3\u0026ndash;6]. Take PFNA for example, during postoperative weight-bearing, the proximal fragment slides along the helical blade and the distal fragment comes into direct contact, thus improving stability and healing at the fracture site[7]. However, excessive increase in sliding distance clearly increases the risk of mechanical complications, ie, nail breakage and cut-out by sevenfold, and leads to reduced hip function and independence in walking [7\u0026ndash;9]. Therefore, identification of relevant risk factors that affect the sliding distance is of critical importance for prevention of these potentially devastating mechanical complications.\u003c/p\u003e \u003cp\u003eSeveral previous studies have made multiple efforts to address the risk factors associated with excessive sliding distance. In 2014, Liu et al. retrospectively analyzed 223 patients treated with TFN and concluded that calcar reduction and fracture stability were independent risk factors for excessive sliding (exceeding 10 mm)[10]. However, this study did not include physiological factors such as BMI and did not adjust for bias due to large differences in surgeon experience. In 2021, a retrospective multicenter study by Kenta et al., which included 115 patients, concluded that females, unstable fracture type, larger TAD, and poor reduction in one plane were associated with excessive postoperative sliding (exceeding 8 mm)[11]. In 2023, Li et al.'s retrospective case-control study of 369 patients treated with PFNA-II suggested that low medullary filling and negative fracture reduction pattern in lateral view were independent risk factors for excessive sliding (exceeding 10 mm)[12]. However, these studies may have been limited by small sample sizes, underadjustment for covariates or confounders, an arbitrary threshold set for defining excessive sliding distance, and short follow-up periods.\u003c/p\u003e \u003cp\u003eThe purpose of this study was to characteristize the sliding distance observed with intertrochanteric fractures treated using the PFNA-II and to identify the factors that predict sliding distance and their association with mechanical complications.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cp\u003e This study received approval from the Ethics Committee and adhered to the international ethical guidelines outlined in the Declaration of Helsinki for research involving human subjects.\u003c/p\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eData Source and Study Population\u003c/h2\u003e \u003cp\u003e We conducted a retrospective cohort study involving patients with intertrochanteric fractures (ITF) at our tertiary care referral hospital from January 2021 to December 2022.\u003c/p\u003e \u003cp\u003eInclusion criteria are as follows: (1) intertrochanteric fracture, (2) surgery performed within two weeks of the fracture, and (3) closed reduction internal fixation surgery. Exclusion criteria are as follows: (1) age\u0026thinsp;\u0026lt;\u0026thinsp;65 years, (2) high-energy trauma fractures, (3) comorbid primary tumors, (4) multiple or open fractures, (5) pathological fractures, (6) previous fracture in the same femur, and (7) incomplete follow-up data.\u003c/p\u003e \u003cp\u003eThe treatments used the Proximal Femoral Nail Antirotation II device (PFNA II) (Synthes GmbH, Oberdorf, Switzerland). Patient data, including age, sex, body mass index (BMI), side of injury, American Society of Anesthesiologists (ASA) score, and intramedullary nail lengths, were extracted from the hospital database. Radiographic evaluations used a picture archiving and communication system (PACS) for immediate preoperative and postoperative evaluations, including anteroposterior projections of the pelvis and affected hip joints in axial projection, as well as anteroposterior and lateral radiographs. Follow-up evaluations were conducted at one, three, six, nine, and twelve months post-discharge, with radiographs taken at each visit for comparison. Measurements of the tip-apex distance (TAD) and calcar-referenced tip-apex distance (Cal-TAD) were taken from postoperative photographs. Radiological evaluations included preoperative considerations such as fracture classification (AO / OTA 2007), stability, and the presence of a combined posterolateral wall fracture. Postoperative evaluations focused on TAD, Cal-TAD, Parker ratio, distal locking mode, Cleveland-Bosworth quadrant, reduction quality, and classification of reduction in AP and LAT view.\u003c/p\u003e \u003cp\u003eThe postoperatively mechanical complications at one year were included as follows: (1) cut-out, breakage, and lateral displacement of the helical blade or distal locking nail, (2) periprosthetic fracture, (3) malunion, delayed union, nonunion, (4) hip varus deformity (assessed by the neck-shaft angle variation). All these findings could be identified on orthopantomograms during the follow-up review[13].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003eDefinition and measurements of parameters\u003c/h2\u003e \u003cp\u003eThe TAD defined by Baumgaertner is the sum of the distances from the tip of the screw to the apex of the femoral head in anteroposterior and lateral views[14]. Cal-TAD defined by Kuzyk, is the sum of the distances from the tip of the helical blade to the intersection of the femoral head and the medial femoral neck cortical tangent on the AP view and from the tip of the helical blade to the apex of the femoral head on the Lat view[15]. Parker\u0026rsquo;s ratio is defined as the distance from the helical blade to the inferior and posterior margins of the femoral neck in the AP or Lat views[16]. According to Cleveland\u0026rsquo;s initial report, the femoral head is divided into nine zones on postoperative frontal and lateral views[17]. The quality of reduction (poor, acceptable, good) is based on postoperative radiographic evaluation according to Baumgaertner's criteria[14]. Fracture gapping was measured according to the method described by Ciufor et al., with the measured distance corrected using the known diameter of the lag screw[18]. Extramedullary fractures had the inner cortex of the proximal bone fragment outside the medial cortex of the distal fragment. Anatomical fractures had continuous medial cortices of the proximal and distal fragments. Intramedullary fractures had the medial cortex of the proximal fragment inside the distal fragment. Using a lateral view, reductions were classified as subtype A, N, or P. Subtype A had the anterior anterior cortex of the proximal fragment and on top of the anterior cortex of the distal fragment. Subtype N had continuous anterior cortices of the proximal and distal fragments. Subtype P had the anterior cortex of the proximal fragment that entered the medullary cavity of the distal fragment[19, 20].\u003c/p\u003e \u003cp\u003eThe sliding distance of the helical blade was determined from the AP view taken immediately after surgery and at the final follow-up. Measurements were performed by senior physicians. The length of the lag screw (AB) and the distance (AC) from the tip of the lag screw (A) to the intersection point (C) of lines drawn between the lag screw axis and the contact point with the external sides of the nails and screws were measured at 2 weeks, 4 weeks, 3 months and 6 months postoperatively. Each measurement at the final follow-up was defined as AC\u0026rsquo; or AB\u0026rsquo;, and the sliding distance between the nail and the lag screw was calculated as AC \u0026ndash; AC\u0026rsquo; (AB/AB\u0026rsquo;) (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eSurgical procedure\u003c/h2\u003e \u003cp\u003eAll operations were carried out by a group of four hip surgeons, each with more than five years of surgical expertise. Operations occurred on a radiolucent fracture table, managed by a senior chief surgeon with professional training, under the direction of general anesthesia and fluoroscopy. The surgeries were performed within 2\u0026ndash;6 days of patient admission, using general and spinal anesthesia. No intraoperative complications were encountered.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003ePostoperative management\u003c/h2\u003e \u003cp\u003eEach patient was given antithrombotic prophylaxis using low molecular weight heparin (enoxaparin) and antibiotic prophylaxis with a second-generation cephalosporin (cefazolin). All individuals followed a standardized rehabilitation protocol. Postoperative functional exercises were strongly recommended. On the first day, isometric quadriceps and ankle pump exercises were initiated, followed by weight-bearing as tolerated starting 4 weeks after surgery. Full weight bearing was limited until bone union, typically 3\u0026ndash;5 months. At each follow-up appointment, ortho- and lateral X-rays were taken to monitor healing progress. Internal criteria to assess fracture healing included the absence of localized pain and abnormal activity, radiographs showing a blurred fracture line, and continuous trabeculae.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003eStatistical analysis\u003c/h2\u003e \u003cp\u003eContinuous variables were expressed as means with standard deviations (SD), while categorical variables were expressed as frequencies with percentages. Continuous data was analyzed using t-tests, Mann-Whitney U tests, or ANOVA. The Youden index identified the optimal cut-off for sliding distance where postoperative mechanical complications occurred. Significant variables from univariate analyzes were included in linear regression models. Logistic regression assessed the relationship between excessive sliding distance and postoperative mechanical complications. We constructed three models that were adjusted for different covariates. Model 1 adjusted for baseline characteristics such as age, sex, BMI, and ASA score. Model 2 was additionally adjusted for intertrochanteric fracture-related covariates along with those of Model 1. The final model was further adjusted for surgery-related covariates in addition to the variables in Model 2. A P-value\u0026thinsp;\u0026lt;\u0026thinsp;0.05 was considered statistically significant, and all tests were two-sided. SPSS version 26.0 (IBM Corp, Armonk, NY, USA) was used for data analysis.\u003c/p\u003e \u003c/div\u003e"},{"header":"Result","content":"\u003cp\u003eA total of 507 patients with intertrochanteric fractures were included in this retrospective study. The mean age was 77.60\u0026thinsp;\u0026plusmn;\u0026thinsp;7.59 years. 208 patients were male and 299 patients were female. According to the AO/OTA classification system, 277 fractures were considered stable and 230 fractures were considered unstable. Long nails were used in 120 patients and short nails in 387 patients. The mean follow-up time was 13.4 months (12\u0026ndash;56 months). The mean TAD was 22.79 mm (SD, 7.78MM; median: 21.63 mm; range: 2.22\u0026ndash;47.22 mm). Postoperative mechanical complications occurred in 33 (6.5%) patients included.\u003c/p\u003e \u003cp\u003eThe mean sliding distance was 4.45 mm (SD, 5.39 mm; range: 0-31.67 mm). 27 (5.32%) patients had a sliding distance between 8 mm and 10 mm, 38 (7.50%) patients had a sliding distance between 10 mm and 20 mm, and 19 (3.75%) patients had a sliding distance greater than 20 mm. 126 (24.85%) patients sliding less than 1 mm and the maximum sliding amount was 31.67 mm. The mean sliding distance of each fracture classification was 3.03 mm (0-20.74 mm) in A1, 4.61 mm (0-31.67) in A2, and 5.28 mm (0.41\u0026ndash;20.73 mm) in A3.\u003c/p\u003e \u003cp\u003eThe mean sliding distance of individual reduction patterns in the AP view was 4.68 mm (0-14.41 mm) in the anatomical type, 5.25 mm (0-14.3 mm) in the extramedullary type, and 3.72 mm (0-31.67 mm) in the intramedullary type. The mean sliding distance of the individual reduction patterns in the lateral view was 3.73 mm (0-18.25 mm) in subtype A, 4.04 mm (0-21.2 mm) in subtype N, and 14.71 mm (3.21\u0026ndash;31.67 mm) in subtype P.\u003c/p\u003e \u003cp\u003eBased on the analysis of the threshold value of the ROC curve for postoperative mechanical complications, the optimal threshold for the sliding distance was 6.75 mm to balance sensitivity and specificity (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e.). Excessive sliding distances increase the incidence of postoperative mechanical complications twelve-fold(OR\u0026thinsp;=\u0026thinsp;12.133, 95%CI: 4.605\u0026ndash;31.968, P\u0026lt;0.001). To examine the independent prognostic value of excessive sliding, we adjusted for potential confounders. In the fully adjusted model, which accounts for 15 potential confounders, the risk of postoperative mechanical complications was significantly higher in the excessive sliding group (OR\u0026thinsp;=\u0026thinsp;14.714, 95% CI: 4.270\u0026ndash;50.710) compared to the normal sliding group (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e\u003cstrong\u003eTable 1\u0026nbsp;\u003c/strong\u003eUnivariate analysis of variables\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eVariables\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eOverall(n=507)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eAverage nail sliding distance\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eP value\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eAGE, years\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e77.60 \u0026plusmn;\u0026middot;7.59\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e0.013*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u0026lt;\u0026nbsp;77\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e328 (64.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e1.99 (0.65, 4.88)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u0026ge; 77\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e179 (35.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e3.87 (1.71, 7.11)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSEX, n\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e0.232\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u0026nbsp;Male\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e208 (41.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e2.24 (1.01, 4.25)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u0026nbsp;Female\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e299 (59.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e3.37 (0.95, 6.34)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eBMI, kg/m\u0026sup2;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e24.55\u0026plusmn;3.73\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e0.216\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u0026le; 23.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e210 (41.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e2.33 (0.91, 4.32)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u0026nbsp;24-27.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e227 (44.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e2.65 (0.73, 6.34)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u0026ge; 28.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e63 (12.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e3.86 (1.41, 8.07)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eASA score, n\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e0.540\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u0026nbsp;1-2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e272\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e2.29 (1.01, 5.47)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u0026nbsp;3-4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e235\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e3.21 (0.95, 7.35)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eLateral, n\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e0.494\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u0026nbsp;Left\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e275\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e2.38 (0.63, 5.42)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u0026nbsp;Right\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e232\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e2.81 (1.21, 5.79)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eClassification, n\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e0.260\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u0026nbsp;31A1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e106\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e3.03 (0.52, 3.66)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u0026nbsp;31A2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e305\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e4.61 (0.85, 5.76)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u0026nbsp;31A3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e96\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e5.28 (2.25, 7.36)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eFracture Type, n\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e0.112\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u0026nbsp;Stable\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e277\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e1.91 (0.67, 5.18)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u0026nbsp;Unstable\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e230\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e3.72 (1.07, 6.75)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eDoctor Evidence, years\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e0.872\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u0026lt; 10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e81\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e4.81 (1.30, 5.42)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u0026nbsp;10-15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e132\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e4.43 (0.91, 5.84)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u0026gt; 15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e294\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e4.07 (0.95, 5.42)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eNail length, n\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e0.943\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u0026nbsp;Short\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e387\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e2.65 (1.10, 5.49)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u0026nbsp;Long\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e120\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e2.66 (0.99, 5.72)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eReduction, n\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e0.001*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u0026nbsp;Good\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e362\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e2.62 (0.70, 4.89)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u0026nbsp;Acceptable\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e132\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e2.25 (0.91, 4.76)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u0026nbsp;Poor\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e9.44 (6.62, 15.92)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eLateral femoral wall, n\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e0.025*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u0026nbsp;Intact\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e411\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e2.09 (0.83, 5.41)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u0026nbsp;Fracture\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e96\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e3.87 (2.25, 7.35)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eTAD, mm\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e22.79\u0026plusmn;7.78\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e0.363\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eCal-TAD, mm\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e24.97\u0026plusmn;6.91\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e0.033*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eAPparker, %\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e39.84\u0026plusmn;9.17\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e0.241\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eLATparker, %\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e54.44\u0026plusmn;11.49\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e0.885\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eBlade position, n\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003eAP\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e0.531\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u0026nbsp; Central\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e274\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e3.21 (1.29, 5.47)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u0026nbsp; Superior\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e52\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e1.92 (0.56, 7.01)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u0026nbsp; Inferior\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e181\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e3.80 (0.91, 5.75)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u0026nbsp;LAT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e0.325\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u0026nbsp; Central\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e302\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e2.91 (1.26, 5.59)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u0026nbsp; Anterior\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e159\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e3.61 (0.66, 6.00)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u0026nbsp; Posterior\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e46\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e1.13 (0.10, 2.20)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eDistal locking mode, n\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e0.449\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u0026nbsp;Static locking\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e286\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e2.87 (1.13, 5.72)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u0026nbsp;Dynamic locking\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e221\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e2.25 (0.55, 5.34)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eAP reduction, n\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e0.546\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u0026nbsp;Intramedullary\u0026nbsp;type\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e51\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e4.61, (2.35, 7.67)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u0026nbsp;Anatomical\u0026nbsp;type\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e303\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e2.60, (1.00, 6.00)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u0026nbsp;Extramedullary type\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e153\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e2.15, (0.91, 4.62)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eLAT reduction, n\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e0.009*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u0026nbsp;Subtype A\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e111\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e1.31, (0.54, 6.01)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u0026nbsp;Subtype N\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e373\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e2.63, (1.16, 5.40)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30.7971%;\"\u003e\n \u003cp\u003e\u0026nbsp;Subtype P\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19.2029%;\"\u003e\n \u003cp\u003e23\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 37.1377%;\"\u003e\n \u003cp\u003e12.17, (4.79, 25.74)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8623%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e*P \u0026lt; 0.05 was considered statistically significant.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAbbreviations:\u0026nbsp;\u003c/strong\u003eM: male; F: female; BMI: Body mass index; ASA: American Society of Anesthesiologists; TAD: tip-apex distance; Cal-TAD: calcar-referenced tip-apex distance; AP: anterior; LAT: lateral\u0026nbsp;\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eThe logistic regression analysis\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVariable\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eβ\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eOR/Adjusted OR\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eCrude OR/ Adjusted OR 95%CI\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eP value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSliding\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2.294\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e12.133\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e4.605\u0026ndash;31.968\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\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\u003eModel 1*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2.491\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e12.072\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e4.182\u0026ndash;34.849\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\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\u003eModel 2\u0026dagger;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2.523\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e12.471\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e4.210-36.911\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\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\u003eModel 3\u0026Dagger;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2.689\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e14.714\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e4.270\u0026ndash;50.710\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\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=\"5\"\u003eCI confidence interval, OR odds ratio,\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"5\"\u003ePostoperative mechanical complications were a composite of cut out, nail withdrawal, varus deformity, periprosthetic fracture, nonunion, and nail breakage.\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"5\"\u003e*Adjusted for age, sex, body mass index, and ASA score\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"5\"\u003e\u0026dagger; Adjusted for age, sex, body mass index, ASA score, fracture type, fracture lateral, fracture stability, and integrity of the lateral femoral wall\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"5\"\u003e\u0026Dagger; Adjusted for age, sex, body mass index, ASA score, fracture type, fracture lateral, fracture stability, and integrity of the lateral femoral wall, TAD, Cal-TAD, AP parker ratio, LAT parker ratio, blade position, nail length and nail locking mode\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eIn terms of baseline characteristics, the sliding distance was positively correlated with age (r\u0026thinsp;=\u0026thinsp;0.182, P\u0026thinsp;=\u0026thinsp;0.036) and did not show statistically significant differences with gender (P\u0026thinsp;=\u0026thinsp;0.491), BMI (r\u0026thinsp;=\u0026thinsp;0.068, P\u0026thinsp;=\u0026thinsp;0.436) and ASA score (P\u0026thinsp;=\u0026thinsp;0.540). In terms of perioperative variables, the sliding distance with respect to the fracture lateral (P\u0026thinsp;=\u0026thinsp;0.494), fracture classification (P\u0026thinsp;=\u0026thinsp;0.260), fracture stability (P\u0026thinsp;=\u0026thinsp;0.112), surgeon's experience (P\u0026thinsp;=\u0026thinsp;0.872), nail length (P\u0026thinsp;=\u0026thinsp;0.943), TAD (r = -0.056, P\u0026thinsp;=\u0026thinsp;0.363), AP parker ratio (r\u0026thinsp;=\u0026thinsp;0.070, P\u0026thinsp;=\u0026thinsp;0.241), LAT parker ratio (r\u0026thinsp;=\u0026thinsp;0.006, P\u0026thinsp;=\u0026thinsp;0.885), helical blade in AP position (P\u0026thinsp;=\u0026thinsp;0.531), helical blade in LAT position (P\u0026thinsp;=\u0026thinsp;0.325), distal locking mode (P\u0026thinsp;=\u0026thinsp;0.449), and AP reduction mode (P\u0026thinsp;=\u0026thinsp;0.546) were not statistically significant differences. The statistically significant difference in the quality of fracture reduction (P\u0026thinsp;=\u0026thinsp;0.001), integrity of lateral femoral wall (P\u0026thinsp;=\u0026thinsp;0.025), LAT reduction mode (P\u0026thinsp;=\u0026thinsp;0.009), and negative correlation with Cal-TAD (r=-0.185, P\u0026thinsp;=\u0026thinsp;0.033). The results of the univariate analysis are listed in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e \u003cp\u003eAnalysis using multiple linear regression showed that the regression equation was significant (F\u0026thinsp;=\u0026thinsp;5.158, p\u0026thinsp;\u0026lt;\u0026thinsp;0.0001) and that older age, poor reduction quality, and subtype P in lateral view significantly and positively predicted the longer sliding distance of helical blade. The AP reduction mode, integrity of lateral femoral wall, fracture stability, and Cal-TAD did not predict the sliding distance. Together, these variables explained 31.9% of the variance in sliding distance (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e3\u003c/span\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 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eLinear regression analysis for factors of sliding distance.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"7\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eB\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eβ\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003et\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003ep\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eAdjusted R\u0026sup2;\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.061\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.182\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e2.251\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e0.026*\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e5.158\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0.319\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eReduction\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAcceptable-Good\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e-0.736\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e-0.067\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e-0.778\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.438\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 \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePoor-Good\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e4.736\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.233\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e2.679\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e0.008*\u003c/b\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 \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLAT reduction\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSubgroup N-A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.790\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.065\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.737\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.463\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 \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSubgroup P-A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e11.193\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.433\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e5.086\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;\u003cb\u003e0.001*\u003c/b\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 \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAP reduction\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eExtramedullary-Anatomical\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e-0.290\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e-0.025\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e-0.295\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.768\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 \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIntramedullary- Anatomical\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e-0.756\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e-0.043\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e-0.532\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.596\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 \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLateral Fracture\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e-0.450\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e-0.036\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e-0.370\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.712\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 \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eStable\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1.025\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.095\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.949\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.345\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 \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCal-TAD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e-0.077\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e-0.102\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e-1.298\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.197\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 \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eConstant\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e-2.612\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"7\"\u003e*P\u0026thinsp;\u0026lt;\u0026thinsp;0.05 was considered statistically significant.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThis retrospective observational study provides evidence of an association in sliding distance with age, reduction quality, and LAT reduction mode. Patients with elder age, poor reduction quality, and subtype P in lateral view would have a longer sliding distance. These results highlight the importance of focusing on the quality of reduction in older patients with intertrochanteric fractures. Moreover, the rate of complication is higher when the patient's sliding distance is too long.\u003c/p\u003e \u003cp\u003eSeveral articles have demonstrated that the use of intramedullary nails with sliding devices improves bony apposition and compression, reestablishing medial cortical contact, increases fracture site stability, induces osseointegration, and reduces the incidence of postoperative complications in the treatment of intertrochanteric fractures[21, 22]. However, as the sliding distance increases, there is no medial support at the base of the femoral neck to prevent fragment collapse. The lower medial cortex of the femoral neck slips into the medullary canal while the proximal lateral portion of the base of the femoral neck abuts the greater trochanter resulting in collapse. The femoral stem is displaced medially and the medial cortex is unsupported. The risk of failure of the reduction increases, leading to complications such as lateral thigh pain, impaired walking, intramedullary nail breakage, helical blade cuts, and bone nonunion[23]. The threshold at which the sliding distance causes postoperative mechanical complications remains controversial, Elizabeth et al. suggests that a shortening threshold of 8mm affects gait by altering the relationship between adductor length and tension, leading to adductor weakness and the development of a Trendelenburg gait[24]. However, Liu et al.'s study indicated that t et al.his threshold was 10mm[10]. Steinberg et al. reported that sliding 15 mm or more resulted in increased failure rates[25]. Kim et al. observed leg shortening and femoral pain in patients who slid 20 mm or more[26]. Therefore, it is important to determine the postoperative threshold for complications due to the sliding distance and explore the risk factors for the increased sliding distance.\u003c/p\u003e \u003cp\u003eIn our study, the sliding distance was positively correlated with age, increasing by 0.061 mm per year of age. This finding aligns with a prospective cohort study by Fang et al. involving 319 patients, which showed that older patients experienced more severe collapse, with 86-year-olds having a collapse of up to 20 mm[27]. The literature confirms that as age increases, the neck-shaft angle decreases and the anterior inclination angle increases[28, 29]. These changes lead to greater weight-bearing eccentricity, which increases the force of the transverse shear component and decreases the longitudinal axis compression component force, impairing the lever arm of the hip adductors and affecting the length-tension relationship of the adductors. Additionally, the increased concentration of stress at the junction of the helical blade and the main nail decreases the overall stability of the internal fixation, leading to an increased sliding displacement of the intramedullary nail[13, 30, 31]. Retrospective studies by Gun and Rha also demonstrated that excessive sliding is more likely to occur in older patients. However, the definition of excessive sliding varied in these studies[32, 33]. Our further analysis concluded that a sliding distance of more than 6.75 mm increased the incidence of postoperative mechanical complications by a factor of 12.133.\u003c/p\u003e \u003cp\u003eThe quality of fracture reduction is one of the five factors that influence the outcome of the treatment of intertrochanteric fractures, as suggested by Professor Kaufer in 1980[34]. Chang et al.'s 2019 system review of intertrochanteric fracture treatment in Asia concluded that good fracture reduction is the primary and critical component of treatment[3]. In our study, patients with poor reduction had a mean sliding distance of 9.44 mm, significantly higher than that of patients with good or acceptable reduction quality. These results are in accordance with Liu et al.'s series, where patients with poor reduction had a mean sliding distance of 7.6 mm, along with a 2.585-fold higher risk of excessive sliding than patients with good reduction[10, 35]. When the gap between the fracture fragments is too large and stable bone contact is lacking, the iliopsoas and adductor muscles exert strong traction and internal rotation on the distal fragment. This ultimately leads to a conflict between osseointegration (resulting in fragment impingement and shortening) and mechanical loading (resulting in implant failure) when all forces are transmitted through the main nail of the endoprosthesis instead of through the bone[36].\u003c/p\u003e \u003cp\u003eThe end of the helical blade is diamond shaped, which connects to the femoral head and neck of the femoral after insertion, effectively reducing loosening and withdrawal due to the rotation of the internal fixation. However, the design of intramedullary nails does not provide absolute control over the helical blade. Bonnarie et al. demonstrated that when bone density is less than 0.6 g/cm\u0026sup3;, there is insufficient purchase to control the helical blade, resulting in loosening and withdrawal[37]. A three-dimensional finite element analysis revealed that early weight bearing should be avoided after surgery to prevent helical blade loosening and withdrawal[38]. During weight-bearing exercises, pressure is transmitted to the distal end through the femoral neck through the helical blade, with stress concentrated in the weight-bearing area of the femoral neck. If the patient lifts weights too early, and the fracture scab has not yet formed, or the patient has severe osteoporosis, the anchoring force of the helical blade and the surrounding bone will be weakened, resulting in the loosening of the helical blade and ultimately the sliding of the blade.\u003c/p\u003e \u003cp\u003eTo the best of our knowledge, this is the largest sample size of articles to date examining postoperative helical blade sliding distances. However, the following limitations of this study should be noted, the first of which is that the article has the limitations of a retrospective study. Second, we focused solely on fracture healing outcomes and complications, neglecting the inclusion of clinical criteria or functional rating scales. This deliberate choice was made to evaluate the efficacy and reliability of internal fixation, prioritizing objective measures over subjective assessments. Lastly, our statistical analysis relied on single-center data, which required caution in generalizing our conclusions. To enhance the robustness of our findings, we recommend further validation and optimization through multicenter, large-sample randomized controlled trials with extended follow-up periods and a more comprehensive biomechanical analysis in future research.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eIn conclusion, our study found that elder age, reduction quality, and the subtype P in lateral view were associated with a longer sliding distance of the helical blade in the postoperative period. Therefore, attention to the quality of intertrochanteric fracture reduction and the extension of postoperative weight-bearing time in elderly patients with risk factors are important to achieve a satisfactory outcome.\u003c/p\u003e "},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eConflict of Interest\u0026nbsp;\u003c/strong\u003eThe authors declare that they have no conflict of interest.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u0026nbsp;\u003c/strong\u003eThis research was supported by the Xinjiang Uygur Autonomous Region Major Science and Technology Projects (No. 2022A03011)\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and material\u0026nbsp;\u003c/strong\u003eAll data in this study can be obtained from the authors based on reasonable demand.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u0026nbsp;\u003c/strong\u003eThe authors have seen the manuscript and approved to submit it to your journal.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCode availability\u0026nbsp;\u003c/strong\u003eNot applicable\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthical approval\u0026nbsp;\u003c/strong\u003eOur institutional ethics committee accepted this study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eInformed Consent\u003c/strong\u003e All subjects were informed and anonymized.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026rsquo; contributions\u003c/strong\u003e YZZ, and SAZ designed the study; DWW, HCG, and JQL searched for relevant studies and abstracted the data; DWW, TYW, ZBY, XQC, CSL, and YBZ analyzed and interpreted the data; DWW wrote the manuscript; YZZ and SAZ approved the final version of the manuscript. All authors reviewed the manuscript before submitting it.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgments\u0026nbsp;\u003c/strong\u003eWe sincerely thank all the patients for their participation in this study.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eLichtblau S: \u003cstrong\u003eThe unstable intertrochanteric hip fracture\u003c/strong\u003e. \u003cem\u003eOrthopedics\u0026nbsp;\u003c/em\u003e2008, \u003cstrong\u003e31\u003c/strong\u003e(8):792-797.\u003c/li\u003e\n \u003cli\u003eTawari AA, Kempegowda H, Suk M, Horwitz DS: \u003cstrong\u003eWhat makes an intertrochanteric fracture unstable in 2015? 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in pertrochanteric fractures--problem of osteoporosis?]\u003c/strong\u003e. \u003cem\u003eUnfallchirurg\u0026nbsp;\u003c/em\u003e2007, \u003cstrong\u003e110\u003c/strong\u003e(5):425-432.\u003c/li\u003e\n \u003cli\u003eLi SJ, Huang HJ, Li CT, Hu GJ, Yu F, Liu YB: \u003cstrong\u003eMechanical effect of changed femoral neck ante-version angles on the stability of an intertrochanteric fracture fixed with PFNA: A finite element analysis\u003c/strong\u003e. \u003cem\u003eHeliyon\u0026nbsp;\u003c/em\u003e2024, \u003cstrong\u003e10\u003c/strong\u003e(10):e31480.\u003c/li\u003e\n\u003c/ol\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":"Intertrochanteric fractures, Sliding distance, Implant fixations, Postoperative mechanical complications","lastPublishedDoi":"10.21203/rs.3.rs-4989761/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4989761/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003ePurpose\u003c/h2\u003e \u003cp\u003eExcessive sliding of intramedullary nails following surgical treatment of intertrochanteric fracture has been strongly associated with the development of mechanical complications and unfavorable results. This study aims to investigate the factors that influence the postoperative sliding distance in elderly patients treated with PFNA-II device for intertrochanteric fracture fixation.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eA retrospective analysis of patients over 65 years old with intertrochanteric fractures using PFNA-II device in a university teaching hospital was performed between January 2020 and December 2021. Data on sociodemographics, comorbidities, operative procedure and postoperative radiographic sliding distance were collected. The Youden index was used to determine the threshold for excessive sliding, and the risk of mechanical complication in relation with excessive sliding was calculated using multivariate regression analysis. Also, potential factors influencing the slinding distance as a continuous outcome variable were investigated using univariate and multivariate linear regression analysis.\u003c/p\u003e\u003ch2\u003eResult\u003c/h2\u003e \u003cp\u003eAmong the 507 eligible patients, the mean postoperative sliding distance was 4.45 mm (SD, 5.39 mm; range, 0-31.67 mm). The threshold for excessive sliding was determined as 6.75 mm, and 103 patients (20.3%) had excessive sliding, among whom 18 (17.5%) developed mechanical complications. The risk of postoperative mechanical complications was significantly higher in the excessive sliding group (adjusted OR\u0026thinsp;=\u0026thinsp;14.714, 95% CI: 4.270\u0026ndash;50.710, P\u0026thinsp;\u0026lt;\u0026thinsp;0.001) than in non-excessive sliding group. Multiple linear regression analysis revealed that older age (B\u0026thinsp;=\u0026thinsp;0.061, 95% CI: 0.007\u0026ndash;0.114, P\u0026thinsp;=\u0026thinsp;0.026), poor reduction quality (B\u0026thinsp;=\u0026thinsp;4.736, 95% CI: 1.236\u0026ndash;8.235, P\u0026thinsp;=\u0026thinsp;0.008), and subtype P in lateral view (B\u0026thinsp;=\u0026thinsp;11.193, 95% CI: 6.836\u0026ndash;15.549, P\u0026thinsp;\u0026lt;\u0026thinsp;0.001) were positively correlated with postoperative sliding distance.\u003c/p\u003e\u003ch2\u003eConclusions\u003c/h2\u003e \u003cp\u003eAge, reduction quality and LAT reduction mode are important predictors of helical blade sliding distance after intertrochanteric fracture surgery. Surgeons should pay close attention to these factors during preoperative planning and postoperative rehabilitation protocols.\u003c/p\u003e","manuscriptTitle":"Factors Influencing Postoperative Sliding Distance in Elderly Patients with Intertrochanteric Fractures Treated with PFNA-II: A Retrospective Observational Study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-10-17 09:31:29","doi":"10.21203/rs.3.rs-4989761/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":"c597d016-44ce-4930-91b7-e7d2c247d06c","owner":[],"postedDate":"October 17th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2024-10-17T09:31:31+00:00","versionOfRecord":[],"versionCreatedAt":"2024-10-17 09:31:29","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4989761","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4989761","identity":"rs-4989761","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}