Factors Associated with Residual Pelvic Obliquity after Total Hip Arthroplasty for Dysplastic Hip Osteoarthritis: A Retrospective Observational Study

Factors Associated with Residual Pelvic Obliquity after Total Hip Arthroplasty for Dysplastic Hip Osteoarthritis: 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 Associated with Residual Pelvic Obliquity after Total Hip Arthroplasty for Dysplastic Hip Osteoarthritis: A Retrospective Observational Study Hiroyuki Yokoi, Yusuke Osawa, Yasuhiko Takegami, Hiroto Funahashi, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6975048/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Introduction: In patients with dysplastic hip osteoarthritis (DHOA), pelvic obliquity (PO) may present as either an upward tilt or a downward tilt on the affected side. Upward PO (U-PO) tends to persist more frequently after total hip arthroplasty (THA) than downward PO (D-PO), but the contributing factors remain unclear. This study aimed to identify factors associated with residual PO after THA, based on the preoperative direction of PO. Materials and Methods: This retrospective study included 116 patients (21 men, 95 women) who underwent unilateral THA for DHOA at a single institution between June 2018 and September 2023, and showed PO ≥2° on preoperative standing whole-spine radiographs. Based on the tilt direction, patients were categorized into the U-PO group (≥2° upward PO; n=35) or the D-PO group (≥2° downward PO; n=81). Pre-and postoperative radiographic parameters of the spine and lower limbs were analyzed to determine factors associated with residual PO. Results: In the U-PO group, PO improved to <2° in 14 patients and persisted in 21. In the D-PO group, PO improved in 50 and persisted in 31. Multivariate logistic regression identified limb lengthening (odds ratio [OR], 1.390; 95% confidence interval [CI], 1.010–1.910; P =0.045) as an independent factor associated with residual PO in the U-PO group. In the D-PO group, preoperative lumbar scoliosis angle (OR, 1.140; 95% CI, 1.010–1.290; P =0.039) and lumbar lateral bending mobility (OR, 0.680; 95% CI, 0.541–0.855; P <0.001) were independent predictors of residual PO. Conclusion: In the U-PO group, greater limb lengthening was associated with residual PO following THA. In contrast, in the D-PO group, a larger preoperative lumbar scoliosis angle and reduced lateral spinal flexibility contributed to residual PO. limb lengthening lumbar scoliosis pelvic obliquity spinal flexibility total hip arthroplasty Figures Figure 1 Figure 2 Figure 3 Figure 4 Introduction Pelvic obliquity (PO) is defined as an abnormal rotation of the pelvis in the coronal plane and is often referred to as pelvic asymmetry [ 1 – 3 ]. PO disrupts spinal balance, leading to secondary lumbar scoliosis, accelerated spinal degeneration, and gait abnormalities[ 4 ]. Multiple factors contribute to PO, including spinal deformities, such as scoliosis, abnormalities in pelvic bone morphology, hip contracture, and leg length discrepancy (LLD) [ 5 ]. Given these contributing factors, PO is frequently observed in patients with dysplastic hip osteoarthritis (DHOA). DHOA is characterized by hip subluxation, which not only causes severe acetabular deformities but also contributes to LLD, restricted hip range of motion (ROM), and spinal deformities. Consequently, DHOA often presents with marked PO due to its complex biomechanical mechanisms. PO in DHOA can manifest in two distinct directions: upward pelvic obliquity (U-PO), where the affected side of the pelvis tilts upward, and downward pelvic obliquity (D-PO), where the affected side tilts downward. Factors, such as LLD, hip adduction contracture, and reduced spinal flexibility, have been identified as contributors to PO in DHOA. Total hip arthroplasty (THA) is the standard treatment for DHOA; however, the rate of PO improvement following THA varies depending on the preoperative direction of PO [ 6 ]. As residual PO following THA can adversely affect adjacent joints and complicate optimal cup positioning [ 7 ], surgical planning should consider strategies for correcting PO. Nevertheless, the specific risk factors for residual PO in patients with U-PO and D-PO remain unclear. We aimed to identify the risk factors associated with residual PO after THA in patients with U-PO and D-PO. Based on previous research, we hypothesized that hip contracture, LLD, and spinal mobility would be associated with residual PO after THA. To test this hypothesis, we formulated the following clinical questions: Is postoperative joint contracture associated with residual PO after THA? Is the correction of LLD through THA associated with residual PO? Is spinal mobility associated with residual PO after THA? Materials and Methods Patients This retrospective observational study was conducted the approval of the institutional ethics committee. We reviewed 348 patients who underwent unilateral THA for DHOA at a single center between June 2018 and September 2023. The exclusion criteria were as follows: femoral head necrosis (n = 57), rapidly destructive coxarthrosis (n = 10), primary osteoarthritis (n = 44), THA performed for fractures (n = 7), rheumatoid arthritis (n = 2), contralateral THA performed within 1 year (n = 14), missing data (n = 9), contralateral end-stage hip osteoarthritis (n = 8), periprosthetic fractures (n = 2), periprosthetic joint infection (n = 1), and dislocation (n = 1). After applying these criteria, 193 patients were included. As PO in most healthy adults is < 2° [ 8 ], we set a cutoff value of 2° for this study and excluded 77 cases, leaving a final cohort of 116 patients. Patients were categorized into two groups based on PO direction: the U-PO group and the D-PO group (Fig. 1 ). Each group was further classified into patients whose PO improved to < 2° at 1 year postoperatively and those with persistent PO ≥ 2°, and comparisons were made between these subgroups. Clinical Assessment Baseline demographic data, including age, sex, height, weight, body mass index (BMI), condition of the contralateral hip, and disease duration, were extracted from medical records. Surgical data—including operative time, blood loss, cement usage, and bone grafting—were also collected. The Japanese Orthopaedic Association (JOA) score was used for clinical evaluation, and hip ROM was measured using a goniometer by a senior orthopedic surgeon. Evaluation of the Hip and Lower Limb Radiographic Parameters Radiographic analysis was performed using standardized anteroposterior pelvic images and full-length standing lower limb radiographs obtained preoperatively and 1 year postoperatively. The evaluated parameters included the Crowe index, acetabular offset, femoral offset, radiographic LLD (RLLD), and hip adduction angle (Fig. 2 ). The Crowe index quantified the degree of femoral head subluxation relative to the acetabulum [ 9 ]. Acetabular offset was defined as the horizontal distance from the center of the femoral head to a vertical reference line through the pubic symphysis. Femoral offset was measured as the perpendicular distance from the femoral head center to the anatomical axis of the femur [ 1 ]. RLLD was calculated as the difference in vertical height from the inter-teardrop line to the tip of the lesser trochanter between the operated and non-operated sides [ 10 ]; a positive value indicated a shorter operated limb. The hip adduction angle was measured as the angle between the femoral shaft axis and a vertical line drawn from the inferior border of the teardrop on the affected side [ 11 ], with positive values indicating adduction. Changes in these parameters were calculated by subtracting preoperative values from postoperative values. Evaluation of the Spinal Radiographic Parameters Spinal and pelvic alignment were assessed using standing full-spine anteroposterior radiographs obtained preoperatively and 1 year postoperatively. The parameters analyzed included PO, lumbar scoliosis angle, C7 coronal vertical axis (C7CVA), and lumber lateral bending mobility. PO was measured per Osebold et al. [ 12 ], as the angle between the horizontal plane and a line connecting the superior margins of the right and left iliac crests. To evaluate deviation from the horizontal plane within each group, PO was defined as positive when the affected side was elevated in the U-PO group, and positive when it was lower in the D-PO group. Absolute values were avoided to enable assessment of postoperative changes. C7CVA and lumbar scoliosis angle were measured following Nakashima et al. [ 13 ]. C7CVA was defined as the horizontal distance from the sacral center to the C7 vertebral body, with positive values indicating deviation toward the unaffected side. The lumbar scoliosis angle was defined as the angle between a vertical line from the L1 upper endplate and a line connecting the iliac crest margins; positive values indicated convexity toward the unaffected side. Lumbar lateral bending mobility was calculated as the sum of the maximum right and left lateral bending angles (Fig. 3 ). Changes in radiographic parameters were calculated by subtracting preoperative from postoperative values, consistent with standard practices in hip and lower limb assessments. Surgical Procedure Preoperative three-dimensional planning was conducted using ZedHip software (Lexi Co., Tokyo, Japan) to restore RLL and offset as closely as possible to the contralateral side [ 14 ]. Implant selection, positioning, and use of navigation were at the discretion of the operating surgeon. Cement was applied to the acetabular side when cementless cup fixation was unfeasible, and to the femoral side using a third-generation cementing technique when canal anatomy precluded cementless stem insertion. All surgeries were performed via a standard posterolateral approach with the patient in the lateral decubitus position by senior surgeons or junior surgeons under senior supervision. Postoperatively, all patients followed a standardized rehabilitation protocol including gait training, ROM exercises, and muscle strengthening. Data Analyses Statistical analyses included Student’s t -test for continuous variables and the Chi -square test for categorical variables. Factors associated with residual postoperative PO were evaluated using logistic regression analysis for variables with P < 0.05. All analyses were performed using EZR software (Saitama Medical Center, Jichi Medical University, Saitama, Japan), and P < 0.05 were considered statistically significant [ 15 ]. Results In the U-PO group (n=35), PO improved to <2° in 14 patients (40%) and persisted in 21 (60%). In the D-PO group (n=81), PO improved in 50 patients (62%) and persisted in 31 (38%). No significant differences in age, sex, height, weight, BMI, contralateral hip condition, or disease duration were found between the improved and non-improved groups. However, in the D-PO group, operative time was significantly longer in the non-improved group (113.9±32.7 min) compared to the improved group (91.7±25.4 min; P =0.001). Blood loss, cement use (cup or stem), and bone grafting did not differ significantly between groups (Table 1). In the U-PO group, hip JOA scores and ROM showed no significant differences between improved and non-improved patients. In contrast, the D-PO improved group had significantly greater preoperative internal rotation and postoperative external rotation ROM compared to the non-improved group (17.7°±8.7° vs. 10.5°±14.6°, P =0.044; 24.3°±11.2° vs. 17.8°±10.6°, P =0.015). In the U-PO group, the non-improved group had significantly lower preoperative lumbar lateral bending mobility (8.5±4.1°) than the improved group (17.1±6.4°, P <0.001), and significantly greater leg lengthening (15.6±6.8 vs. 6.6±4.6 mm, P <0.001). Postoperative lumbar scoliosis was more convex toward the unaffected side in the non-improved group (3.3±4.3° vs. 0.1±3.8°, P =0.029). In the D-PO group, the non-improved had a significantly higher Crowe index (30.7±22.9 vs. 17.5±17.2, P =0.004), greater preoperative RLLD (18.6±10.3 vs. 10.1±7.5 mm, P <0.001), and greater preoperative PO (5.6±2.7° vs. 3.3±1.3°, P <0.001). Moreover, they had significantly larger preoperative lumbar scoliosis angle (-6.5±8.0° vs. -0.5±5.8°, P <0.001) and lower lumbar lateral bending mobility (8.6±4.6° vs. 15.4±5.8°, P <0.001). Postoperatively, lumbar scoliosis was significantly more convex toward the unaffected side in the improved group (1.9±6.5°) than in the non-improved group (-2.4±10.7°, P =0.027). Leg lengthening remained significantly greater in the non-improved group (15.5±9.3 vs. 9.7±7.4 mm, P =0.002) (Table 2). Logistic regression was performed to identify predictors of persistent PO. In the U-PO group, variables included age, sex, BMI, preoperative lumbar scoliosis angle, preoperative lumbar lateral bending mobility, and leg lengthening. Only leg lengthening was a significant predictor of persistent PO (odds ratio [OR], 1.390; 95% confidence interval [CI], 1.010–1.910, P =0.045) (Table 3). In the D-PO group, predictors included age, sex, BMI, Crowe index, preoperative hip internal rotation, RLLD, PO, lumbar scoliosis angle, lumber lateral bending mobility, postoperative hip external rotation, and leg lengthening. Among these, preoperative lumbar scoliosis angle (OR, 1.230; 95% CI, 1.050–1.440, P =0.012) and lumbar lateral bending mobility (OR, 0.680; 95% CI, 0.541–0.855, P <0.001) were significant predictors of persistent PO (Table 4). Discussion This study assessed radiographic parameters based on the direction of preoperative PO in patients undergoing THA for DHOA and identified risk factors for residual PO. In the U-PO group, those with residual PO had reduced postoperative hip abduction ROM and tended to show greater hip adduction angles. Although postoperative RLLD was corrected in both groups, patients with residual PO experienced significantly more leg lengthening. Notably, in the U-PO group, increased leg lengthening independently predicted residual PO. Regarding spinal parameters, residual PO subgroups in both U-PO and D-PO groups showed significantly reduced preoperative lumbar lateral bending mobility and more persistent postoperative convex spinal deformities. In the D-PO group, a larger preoperative lumbar scoliosis angle and lower lumbar lateral bending mobility independently predicted residual PO. Hip contracture contributes to PO development in DHOA. Ozawa et al. reported that in severe DHOA, U-PO may result from a subluxated hip with a pronounced adduction angle [ 2 ]. Conversely, patients with D-PO generally have better hip ROM compared to those with U-PO, and preoperative adduction contracture is less common. In our study, though not statistically significant, the U-PO subgroup with residual PO tended to have larger postoperative hip adduction angles and reduced hip abduction ROM. While THA typically improves joint contracture, previous reports have indicated that contracture may persist for up to a year postoperatively in severe DHOA cases [ 16 ]. In addition, we have reported limited improvement in hip ROM in U-PO cases following THA [ 6 ]. Therefore, in patients with U-PO with persistent postoperative adduction contracture and limited ROM, residual PO may persist as a compensatory mechanism for maintaining coronal balance. In such cases, interventions, such as adductor tenotomy, removal of ROM-limiting osteophytes, and proactive perioperative rehabilitation, may help relieve the contracture. PO is considered a compensatory mechanism for LLD, with simulation studies showing that greater discrepancies are associated with larger pelvic tilt angles [ 17 , 18 ]. Thus, precise leg length control during THA is essential for improving postoperative quality of life. In patients with D-PO, LLD is a key contributor, and PO typically improves following correction via THA. Consistent with this, our study found that correcting LLD did not increase the risk of residual PO in the D-PO group. In contrast, the impact of leg length correction on postoperative PO in patients with U-PO remains unclear. Interestingly, our results demonstrated that in the U-PO group, greater leg lengthening was a significant risk factor for residual PO after surgery. Residual PO following THA has been linked to discrepancies between radiographic and perceived leg length [ 19 ]. As many patients with U-PO exhibit persistent postoperative hip adduction contracture, surgical planning should address both radiographic and perceived LLD, supported by comprehensive preoperative assessment. Previous studies have not reached a consensus on the link between spinal stiffness and residual PO after THA. Banno et al. reported a strong correlation between scoliosis and PO, suggesting that spinal flexibility influences PO in patients with hip osteoarthritis [ 20 ]. Similarly, Abe et al. found that THA cases involving leg lengthening showed greater PO improvement in patients with flexible scoliosis [ 4 ]. In our study, patients with residual PO had reduced lumbar lateral bending mobility, suggesting that limited spinal flexibility impedes PO correction. Specifically, in the D-PO group, both lumbar scoliosis angle and lumbar lateral bending mobility were independent predictors of residual PO. Even after correcting LLD, patients with rigid spines and limited coronal compensation due to scoliosis may remain prone to persistent PO. Although no statistically significant association was observed in the U-PO group, reduced spinal mobility appeared to contribute to residual PO. The smaller U-PO sample size and complex deformity patterns may have influenced this result. Nevertheless, in the U-PO and D-PO groups, surgical planning should consider the risk of poor PO improvement in patients with limited spinal flexibility following THA. This study has some limitations. First, it was a retrospective observational study conducted at a single institution with a relatively small sample size. A prospective multicenter study would be valuable in increasing case numbers and enhancing the generalizability of the findings. Second, the follow-up period was limited to 1 year, which may not capture long-term changes in PO and related clinical outcomes. In addition, as evaluations were based on anteroposterior radiographs, the influence of posture and pelvic rotation cannot be entirely excluded. However, we attempted to minimize these confounding factors by standardizing the radiographic acquisition protocol. A key strength of this study is that it is the first to evaluate risk factors for both U-PO and D-PO following THA in patients with DHOA. Residual PO following THA has been associated with implant positioning, adjacent joint disorders, and discrepancies in perceived leg length. Therefore, we believe our findings offer valuable guidance for hip surgeons in planning THA for patients with DHOA. In conclusion, in patients with U-PO, substantial leg lengthening may increase the risk of residual PO, especially in those with poor preoperative lumbar lateral bending mobility and persistent hip adduction contracture. Therefore, caution is advised when correcting leg length in these cases. In contrast, among patients with D-PO, no significant association was observed between residual PO and either hip contracture or leg lengthening, suggesting that leg length correction is generally recommended. Declarations Funding This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. Author Contribution H.Y and Yusuke.O. wrote the main manuscript text and Yuto. O and H. F. prepared figures. T. Y and S. I. are supervised manuscript. All authors reviewed the manuscript. References Ozawa Y, Osawa Y, Takegami Y, Iida H, Takemoto G, Imagama S (2024) Risk factors for residual pelvic obliquity one year after total hip arthroplasty. Eur J Orthop Surg Traumatol 34:3319–3327. https://doi.org/10.1007/s00590-024-04060-z Ozawa Y, Osawa Y, Takegami Y, Funahashi H, Tanaka S, Imagama S (2024) Characteristics of pelvic obliquity in dysplastic hip osteoarthritis. 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J Neurosurg Spine 36:193–202. https://doi.org/10.3171/2021.4.SPINE21265 Tables Table1：patient demographics U-PO group P value D-PO group P value Improved PO (n=14) Residual PO (n=21) Improved PO (n=50) Residual PO (n=31) Demographics data Age, yrs (SD) 63.5 (10.3) 66.4 (12.4) 0.479 63.9 (10.3) 63.5 (10.6) 0.849 Sex (%) 0.192 1 Men 5 (35.7) 4 (19.0) 7 (14.0) 5 (16.1) Women 9 (64.3) 17 (81.0) 43 (86.0) 26 (83.9) Height, cm (SD) 157.8 (9.7) 155.3 (9.2) 0.436 154.9 (7.6) 154.3 (6.1) 0.748 Weight, kg (SD) 63.3 (15.1) 58.1 (12.2) 0.273 56.6 (11.0) 56.0 (9.8) 0.790 Body mass index, kg/m2 (SD) 25.3 (4.7) 24.1 (3.9) 0.411 23.6 (4.1) 23.4 (3.5) 0.855 Other side (healthy/ THA) 10/4 17/4 0.685 37/13 26/5 0.412 Duration of hip disorders, yrs (SD) 9.1 (9.8) 9.1 (9.6) 0.994 5.1 (4.6) 7.2 (11.3) 0.238 Surgical data Operative duration, min (SD) 113.8 (35.2) 116.9 (50.9) 0.848 91.7 (25.4) 113.9 (32.7) 0.001※ Blood loss, g (SD) 428.6 (275.4) 582.0 (487.0) 0.294 386.8 (200.1) 498.3 (430.9) 0.119 Cup (cement / cementless) 1/13 4/16 0.379 5/45 8/23 0.071 Stem (cement / cementless) 7/7 7/13 0.487 13/37 13/18 0.150 Bone implantation (none/ bulk bone/ tip bone) 11/2/1 15/5/0 0.393 40/5/5 20/8/3 0.163 *P＜0.05. U-PO, Pelvic obliquity with the affected side of the pelvis tilts upward; D-PO, Pelvic obliquity with the affected side of the pelvis tilts downward; THA, total hip arthroplasty; SD, standard deviation Table2: radiographic parameters U-PO group P value D-PO group P value Improve PO (n=14) Residual RO (n=21) Improve PO (n=50) Residual RO (n=31) Preoperative Crowe index (SD) 20.3 (27.1) 38.7 (36.7) 0.121 17.5 (17.2) 30.7 (22.9) 0.004* Acetabular offset (operative side), mm (SD) 107.5 (8.1) 109.2 (9.4) 0.596 106.7 (8.7) 108.2 (11.3) 0.516 Femoral offset (operative side), mm (SD) 36.3 (8.7) 33.1 (9.4) 0.328 34.6 (8.6) 33.1 (11.1) 0.496 Hip adduction angle, degree (SD) 8.4 (3.6) 9.5 (2.8) 0.316 5.2 (2.8) 5.1 (3.2) 0.879 RLLD, mm (SD) 9.1 (14.8) 15.4 (11.9) 0.175 10.1 (7.5) 18.6 (10.3) <0.001* PO, degree (SD) 3.6 (1.9) 4.4 (3.3) 0.423 3.3 (1.3) 5.6 (2.7) <0.001* LSA, degree (SD) 1.8 (4.4) 3.0 (6.1) 0.528 -0.5 (5.8) -6.5 (8.0) <0.001* C7CVA, mm (SD) 9.9 (12.5) 12.6 (25.3) 0.713 9.2 (16.4) 13.2 (17.8) 0.299 Lumbar lateral bending mobility, degree (SD) 17.1 (6.4) 8.5 (4.1) <0.001* 15.4 (5.8) 8.6 (4.6) <0.001* postoperative Acetabular offset (operative side), mm (SD) 10.3.5 (14.8) 100.9 (7.0) 0.494 100.7 (7.3) 98.1 (6.6) 0.115 Femoral offset (operative side), mm (SD) 42.7 (6.6) 41.8 (7.1) 0.730 41.6 (11.2) 41.5 (6.8) 0.950 Hip adduction angle, degree (SD) 6.8 (3.9) 8.4 (2.5) 0.061 5.5 (1.6) 4.7 (2.9) 0.130 Postoperative RLLD, mm (SD) 2.5 (14.8) -0.2 (7.6) 0.483 0.6 (4.9) 3.0 (8.0) 0.120 LSA, degree (SD) 0.1 (3.8) 3.3 (4.3) 0.029* 1.9 (6.5) -2.4 (10.7) 0.027* C7CVA, mm (SD) 6.1 (9.4) 9.2 (20.6) 0.600 7.2 (16.0) 6.1 (14.9) 0.750 Amount of limb lengthening, mm (SD) 6.6 (4.6) 15.6 (6.8) <0.001* 9.7 (7.4) 15.5 (9.3) 0.002* *P＜0.05. U-PO, Pelvic obliquity with the affected side of the pelvis tilts upward; D-PO, Pelvic obliquity with the affected side of the pelvis tilts downward; RLLD, radiographic leg length discrepancy; LSA, lumbar scoliosis angle; C7CVA, C7 coronal vertical axis; SD, standard deviation Table.3: Logistic regression model for predicting postoperative PO residual in U-PO group Odds ratio 95%CI P value Age, yrs 1.100 0.939-1.280 0.245 Sex (men) 2.090 0.111-39.20 0.622 Body mass index 0.794 0.518-1.220 0.290 Preoperative lumbar lateral bending mobility, degree 0.782 0.591-1.040 0.086 Postoperative LSA, degree 1.500 0.807-2.790 0.200 Amount of limb lengthening, mm 1.390 1.010-1.910 0.045* *P＜0.05. U-PO, Pelvic obliquity with the affected side of the pelvis tilts upward; LSA, lumbar scoliosis angle Table.4: Logistic regression model for predicting postoperative PO residual in D-PO group Odds ratio 95%CI P value Age, yrs 0.916 0.831-1.010 0.082 Sex (men) 0.882 0.049-15.90 0.932 Body mass index 0.988 0.772-1.260 0.922 Crowe index 0.857 0.002-336.0 0.959 Preoperative internal rotation 0.967 0.910-1.030 0.278 Preoperative RLLD, mm 1.070 0.926-1.240 0.346 Preoperative PO, degree 1.490 0.710-3.140 0.290 Preoperative LSA, degree 1.230 1.050-1.440 0.012* Preoperative lumbar lateral bending mobility, degree 0.671 0.521-0.863 0.002* Postoperative external rotation, degree 0.908 0.824-1.000 0.053 Amount of limb lengthening, mm 1.060 0.894-1.250 0.512 *P＜0.05. D-PO, Pelvic obliquity with the affected side of the pelvis tilts downward; RLLD, radiographic leg length discrepancy; LSA, lumbar scoliosis angle 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-6975048","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":476703833,"identity":"ac1418bf-2a20-45b6-a80f-d0fdc7ccfe0b","order_by":0,"name":"Hiroyuki Yokoi","email":"","orcid":"","institution":"Nagoya University","correspondingAuthor":false,"prefix":"","firstName":"Hiroyuki","middleName":"","lastName":"Yokoi","suffix":""},{"id":476703834,"identity":"fa6c2a91-e732-4b9b-a984-c2b3e0f9af26","order_by":1,"name":"Yusuke Osawa","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA3klEQVRIiWNgGAWjYFACNobDPyps5BgYeGAiBwhqYXzMcCbNmCQtzMaMLYcTGxBaCACD88fSpAsb0tI3HD978MEHBjs5Bsaz+K0xuJF2THrmDpvcDWfykg1nMCQDXXgugYAW9jYJ3jNpuRsO5JhJ8zAcALrwjAEBhx0Hamk7nG5w/g2xWg6kHTYGakkwuEGsLZI30hIfzjiTZjjzxhtjwxkGycZshPzCd/6YwYEPFTbyfOdzDB98qLCT45cgEGIKB1AYQCexSZzBq4NBvgGdwcDfg1/LKBgFo2AUjDgAALrfTzk5sYD0AAAAAElFTkSuQmCC","orcid":"","institution":"Nagoya University","correspondingAuthor":true,"prefix":"","firstName":"Yusuke","middleName":"","lastName":"Osawa","suffix":""},{"id":476703835,"identity":"037fe5aa-3324-4570-a3f8-8e515442fcfd","order_by":2,"name":"Yasuhiko Takegami","email":"","orcid":"","institution":"Nagoya University","correspondingAuthor":false,"prefix":"","firstName":"Yasuhiko","middleName":"","lastName":"Takegami","suffix":""},{"id":476703836,"identity":"3e686e31-ae8a-4bc7-bcbf-19cfd55afc35","order_by":3,"name":"Hiroto Funahashi","email":"","orcid":"","institution":"Nagoya University","correspondingAuthor":false,"prefix":"","firstName":"Hiroto","middleName":"","lastName":"Funahashi","suffix":""},{"id":476703837,"identity":"6bbbb703-b982-4fce-ab69-b5fb290157b4","order_by":4,"name":"Yuto Ozawa","email":"","orcid":"","institution":"Nagoya University","correspondingAuthor":false,"prefix":"","firstName":"Yuto","middleName":"","lastName":"Ozawa","suffix":""},{"id":476703838,"identity":"5ea0e0f6-7c6b-4e18-8fcf-f315fdf13973","order_by":5,"name":"Shiro Imagama","email":"","orcid":"","institution":"Nagoya University","correspondingAuthor":false,"prefix":"","firstName":"Shiro","middleName":"","lastName":"Imagama","suffix":""}],"badges":[],"createdAt":"2025-06-25 13:08:16","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6975048/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6975048/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":85619714,"identity":"1e0f2a2e-caaa-4d11-b063-843182d032c0","added_by":"auto","created_at":"2025-06-29 15:03:00","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":63283,"visible":true,"origin":"","legend":"\u003cp\u003eInclusion criteria for this study. Patients with affected-side downward tilt \u0026gt;2° are categorized into the D-PO group. Patients with affected-side upward tilt \u0026gt;2° are categorized into the U-PO group\u003c/p\u003e\n\u003cp\u003eTHA, Total hip arthroplasty; DHOA, Developmental hip osteoarthritis; PO, Pelvic obliquity; U-PO, Pelvic obliquity with the affected side of the pelvis tilts upward; D-PO, Pelvic obliquity with the affected side of the pelvis tilts downward\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-6975048/v1/993792bcee3c66f70e7d895f.png"},{"id":85619718,"identity":"e0f2cdd7-a6c9-4167-bfee-c2f89c69e832","added_by":"auto","created_at":"2025-06-29 15:03:00","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":293535,"visible":true,"origin":"","legend":"\u003cp\u003eRadiographic evaluation of the lower limbs. (a) Clowe index: 5A/B*100. (b) Radiographic leg-length discrepancy: A-B. (c) Acetabular offset: A, femoral offset: B. (d) Hip adduction angle\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-6975048/v1/4f71e108977cdf7f79aa4c3a.png"},{"id":85620389,"identity":"ce3626df-e8d6-48d5-84ce-4372d561f3e1","added_by":"auto","created_at":"2025-06-29 15:19:00","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":436178,"visible":true,"origin":"","legend":"\u003cp\u003eRadiographic evaluation of spinal parameters. (a) Pelvic obliquity. (b) C7 coronal vertical axis. (c) Lumbar scoliosis angle. (d) Lumbar lateral bending mobility: A+B.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-6975048/v1/d8b07497ace592b57a7cbbdf.png"},{"id":85619717,"identity":"8541d14a-267c-422f-b751-441c0fc8a19b","added_by":"auto","created_at":"2025-06-29 15:03:00","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":388094,"visible":true,"origin":"","legend":"\u003cp\u003eRepresentative cases\u003c/p\u003e\n\u003cp\u003eA 53-year-old female underwent hybrid total hip arthroplasty (THA) for right dysplastic hip osteoarthritis (DHOA). Preoperative parameters were upward pelvic obliquity (PO) 10.5° (1-a), radiographic length discrepancies (RLLD) 20 mm, lumbar scoliosis angle (LSA) 4.1° (1-b), and lumbar lateral bending mobility 13° (1-c), (1-d). Postoperative parameters included PO 9.2°, RLLD 0 mm, and amount of limb lengthening 20 mm (1-e).\u003c/p\u003e\n\u003cp\u003eA 59-year-old female underwent cementless THA for right DHOA. Preoperative parameters were downward PO 7.8° (2-a), RLLD 17 mm, LSA -9.7° (2-b), and lumbar lateral bending mobility 5.2° (2-c), (2-d). Postoperative parameters included PO 5.8°, RLLD 4 mm, and amount of limb lengthening 13 mm (2-e).\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-6975048/v1/335ab0f09ecfef55777e8b18.png"},{"id":90375631,"identity":"99ebb6b5-816a-4d67-88e7-e5f4e1040835","added_by":"auto","created_at":"2025-09-02 05:46:49","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2015559,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6975048/v1/de534718-8090-4424-865b-44b00a64bd2a.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Factors Associated with Residual Pelvic Obliquity after Total Hip Arthroplasty for Dysplastic Hip Osteoarthritis: A Retrospective Observational Study","fulltext":[{"header":"Introduction","content":"\u003cp\u003ePelvic obliquity (PO) is defined as an abnormal rotation of the pelvis in the coronal plane and is often referred to as pelvic asymmetry [\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. PO disrupts spinal balance, leading to secondary lumbar scoliosis, accelerated spinal degeneration, and gait abnormalities[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Multiple factors contribute to PO, including spinal deformities, such as scoliosis, abnormalities in pelvic bone morphology, hip contracture, and leg length discrepancy (LLD) [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Given these contributing factors, PO is frequently observed in patients with dysplastic hip osteoarthritis (DHOA). DHOA is characterized by hip subluxation, which not only causes severe acetabular deformities but also contributes to LLD, restricted hip range of motion (ROM), and spinal deformities. Consequently, DHOA often presents with marked PO due to its complex biomechanical mechanisms.\u003c/p\u003e \u003cp\u003ePO in DHOA can manifest in two distinct directions: upward pelvic obliquity (U-PO), where the affected side of the pelvis tilts upward, and downward pelvic obliquity (D-PO), where the affected side tilts downward. Factors, such as LLD, hip adduction contracture, and reduced spinal flexibility, have been identified as contributors to PO in DHOA. Total hip arthroplasty (THA) is the standard treatment for DHOA; however, the rate of PO improvement following THA varies depending on the preoperative direction of PO [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. As residual PO following THA can adversely affect adjacent joints and complicate optimal cup positioning [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e], surgical planning should consider strategies for correcting PO. Nevertheless, the specific risk factors for residual PO in patients with U-PO and D-PO remain unclear.\u003c/p\u003e \u003cp\u003eWe aimed to identify the risk factors associated with residual PO after THA in patients with U-PO and D-PO. Based on previous research, we hypothesized that hip contracture, LLD, and spinal mobility would be associated with residual PO after THA. To test this hypothesis, we formulated the following clinical questions: Is postoperative joint contracture associated with residual PO after THA? Is the correction of LLD through THA associated with residual PO? Is spinal mobility associated with residual PO after THA?\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003ePatients\u003c/h2\u003e \u003cp\u003e This retrospective observational study was conducted the approval of the institutional ethics committee. We reviewed 348 patients who underwent unilateral THA for DHOA at a single center between June 2018 and September 2023. The exclusion criteria were as follows: femoral head necrosis (n\u0026thinsp;=\u0026thinsp;57), rapidly destructive coxarthrosis (n\u0026thinsp;=\u0026thinsp;10), primary osteoarthritis (n\u0026thinsp;=\u0026thinsp;44), THA performed for fractures (n\u0026thinsp;=\u0026thinsp;7), rheumatoid arthritis (n\u0026thinsp;=\u0026thinsp;2), contralateral THA performed within 1 year (n\u0026thinsp;=\u0026thinsp;14), missing data (n\u0026thinsp;=\u0026thinsp;9), contralateral end-stage hip osteoarthritis (n\u0026thinsp;=\u0026thinsp;8), periprosthetic fractures (n\u0026thinsp;=\u0026thinsp;2), periprosthetic joint infection (n\u0026thinsp;=\u0026thinsp;1), and dislocation (n\u0026thinsp;=\u0026thinsp;1). After applying these criteria, 193 patients were included. As PO in most healthy adults is \u0026lt;\u0026thinsp;2\u0026deg; [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e], we set a cutoff value of 2\u0026deg; for this study and excluded 77 cases, leaving a final cohort of 116 patients. Patients were categorized into two groups based on PO direction: the U-PO group and the D-PO group (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Each group was further classified into patients whose PO improved to \u0026lt;\u0026thinsp;2\u0026deg; at 1 year postoperatively and those with persistent PO\u0026thinsp;\u0026ge;\u0026thinsp;2\u0026deg;, and comparisons were made between these subgroups.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eClinical Assessment\u003c/h3\u003e\n\u003cp\u003eBaseline demographic data, including age, sex, height, weight, body mass index (BMI), condition of the contralateral hip, and disease duration, were extracted from medical records. Surgical data\u0026mdash;including operative time, blood loss, cement usage, and bone grafting\u0026mdash;were also collected. The Japanese Orthopaedic Association (JOA) score was used for clinical evaluation, and hip ROM was measured using a goniometer by a senior orthopedic surgeon.\u003c/p\u003e\n\u003ch3\u003eEvaluation of the Hip and Lower Limb Radiographic Parameters\u003c/h3\u003e\n\u003cp\u003eRadiographic analysis was performed using standardized anteroposterior pelvic images and full-length standing lower limb radiographs obtained preoperatively and 1 year postoperatively. The evaluated parameters included the Crowe index, acetabular offset, femoral offset, radiographic LLD (RLLD), and hip adduction angle (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e2\u003c/span\u003e). The Crowe index quantified the degree of femoral head subluxation relative to the acetabulum [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Acetabular offset was defined as the horizontal distance from the center of the femoral head to a vertical reference line through the pubic symphysis. Femoral offset was measured as the perpendicular distance from the femoral head center to the anatomical axis of the femur [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. RLLD was calculated as the difference in vertical height from the inter-teardrop line to the tip of the lesser trochanter between the operated and non-operated sides [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]; a positive value indicated a shorter operated limb. The hip adduction angle was measured as the angle between the femoral shaft axis and a vertical line drawn from the inferior border of the teardrop on the affected side [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e], with positive values indicating adduction. Changes in these parameters were calculated by subtracting preoperative values from postoperative values.\u003c/p\u003e\n\u003ch3\u003eEvaluation of the Spinal Radiographic Parameters\u003c/h3\u003e\n\u003cp\u003eSpinal and pelvic alignment were assessed using standing full-spine anteroposterior radiographs obtained preoperatively and 1 year postoperatively. The parameters analyzed included PO, lumbar scoliosis angle, C7 coronal vertical axis (C7CVA), and lumber lateral bending mobility. PO was measured per Osebold et al. [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e], as the angle between the horizontal plane and a line connecting the superior margins of the right and left iliac crests. To evaluate deviation from the horizontal plane within each group, PO was defined as positive when the affected side was elevated in the U-PO group, and positive when it was lower in the D-PO group. Absolute values were avoided to enable assessment of postoperative changes. C7CVA and lumbar scoliosis angle were measured following Nakashima et al. [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. C7CVA was defined as the horizontal distance from the sacral center to the C7 vertebral body, with positive values indicating deviation toward the unaffected side. The lumbar scoliosis angle was defined as the angle between a vertical line from the L1 upper endplate and a line connecting the iliac crest margins; positive values indicated convexity toward the unaffected side. Lumbar lateral bending mobility was calculated as the sum of the maximum right and left lateral bending angles (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e3\u003c/span\u003e). Changes in radiographic parameters were calculated by subtracting preoperative from postoperative values, consistent with standard practices in hip and lower limb assessments.\u003c/p\u003e\n\u003ch3\u003eSurgical Procedure\u003c/h3\u003e\n\u003cp\u003ePreoperative three-dimensional planning was conducted using ZedHip software (Lexi Co., Tokyo, Japan) to restore RLL and offset as closely as possible to the contralateral side [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. Implant selection, positioning, and use of navigation were at the discretion of the operating surgeon. Cement was applied to the acetabular side when cementless cup fixation was unfeasible, and to the femoral side using a third-generation cementing technique when canal anatomy precluded cementless stem insertion. All surgeries were performed via a standard posterolateral approach with the patient in the lateral decubitus position by senior surgeons or junior surgeons under senior supervision. Postoperatively, all patients followed a standardized rehabilitation protocol including gait training, ROM exercises, and muscle strengthening.\u003c/p\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eData Analyses\u003c/h2\u003e \u003cp\u003eStatistical analyses included Student\u0026rsquo;s \u003cem\u003et\u003c/em\u003e-test for continuous variables and the \u003cem\u003eChi\u003c/em\u003e-square test for categorical variables. Factors associated with residual postoperative PO were evaluated using logistic regression analysis for variables with \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05. All analyses were performed using EZR software (Saitama Medical Center, Jichi Medical University, Saitama, Japan), and \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05 were considered statistically significant [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eIn the U-PO group (n=35), PO improved to \u0026lt;2° in 14 patients (40%) and persisted in 21 (60%). In the D-PO group (n=81), PO improved in 50 patients (62%) and persisted in 31 (38%). No significant differences in age, sex, height, weight, BMI, contralateral hip condition, or disease duration were found between the improved and non-improved groups. However, in the D-PO group, operative time was significantly longer in the non-improved group (113.9±32.7 min) compared to the improved group (91.7±25.4 min; \u003cem\u003eP\u003c/em\u003e=0.001). Blood loss, cement use (cup or stem), and bone grafting did not differ significantly between groups (Table 1).\u003c/p\u003e\n\u003cp\u003eIn the U-PO group, hip JOA scores and ROM showed no significant differences between improved and non-improved patients. In contrast, the D-PO improved group had significantly greater preoperative internal rotation and postoperative external rotation ROM compared to the non-improved group (17.7°±8.7° vs. 10.5°±14.6°, \u003cem\u003eP\u003c/em\u003e=0.044; 24.3°±11.2° vs. 17.8°±10.6°, \u003cem\u003eP\u003c/em\u003e=0.015).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eIn the U-PO group, the non-improved group had significantly lower preoperative lumbar lateral bending mobility (8.5±4.1°) than the improved group (17.1±6.4°, \u003cem\u003eP\u003c/em\u003e\u0026lt;0.001), and significantly greater leg lengthening (15.6±6.8 vs. 6.6±4.6 mm, \u003cem\u003eP\u003c/em\u003e\u0026lt;0.001). Postoperative lumbar scoliosis was more convex toward the unaffected side in the non-improved group (3.3±4.3° vs. 0.1±3.8°, \u003cem\u003eP\u003c/em\u003e=0.029). In the D-PO group, the non-improved had a significantly higher Crowe index (30.7±22.9 vs. 17.5±17.2, \u003cem\u003eP\u003c/em\u003e=0.004), greater preoperative RLLD (18.6±10.3 vs. 10.1±7.5 mm, \u003cem\u003eP\u003c/em\u003e\u0026lt;0.001), and greater preoperative PO (5.6±2.7° vs. 3.3±1.3°, \u003cem\u003eP\u003c/em\u003e\u0026lt;0.001). Moreover, they had significantly larger preoperative lumbar scoliosis angle (-6.5±8.0° vs. -0.5±5.8°, \u003cem\u003eP\u003c/em\u003e\u0026lt;0.001) and lower lumbar lateral bending mobility (8.6±4.6° vs. 15.4±5.8°, \u003cem\u003eP\u003c/em\u003e\u0026lt;0.001). Postoperatively, lumbar scoliosis was significantly more convex toward the unaffected side in the improved group (1.9±6.5°) than in the non-improved group (-2.4±10.7°, \u003cem\u003eP\u003c/em\u003e=0.027). Leg lengthening remained significantly greater in the non-improved group (15.5±9.3 vs. 9.7±7.4 mm, \u003cem\u003eP\u003c/em\u003e=0.002) (Table 2).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eLogistic regression was performed to identify predictors of persistent PO. In the U-PO group, variables included age, sex, BMI, preoperative lumbar scoliosis angle, preoperative lumbar lateral bending mobility, and leg lengthening. Only leg lengthening was a significant predictor of persistent PO (odds ratio [OR], 1.390; 95% confidence interval [CI], 1.010–1.910, \u003cem\u003eP\u003c/em\u003e=0.045) (Table 3). In the D-PO group, predictors included age, sex, BMI, Crowe index, preoperative hip internal rotation, RLLD, PO, lumbar scoliosis angle, lumber lateral bending mobility, postoperative hip external rotation, and leg lengthening. Among these, preoperative lumbar scoliosis angle (OR, 1.230; 95% CI, 1.050–1.440, \u003cem\u003eP\u003c/em\u003e=0.012) and lumbar lateral bending mobility (OR, 0.680; 95% CI, 0.541–0.855, \u003cem\u003eP\u003c/em\u003e\u0026lt;0.001) were significant predictors of persistent PO (Table 4).\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThis study assessed radiographic parameters based on the direction of preoperative PO in patients undergoing THA for DHOA and identified risk factors for residual PO. In the U-PO group, those with residual PO had reduced postoperative hip abduction ROM and tended to show greater hip adduction angles. Although postoperative RLLD was corrected in both groups, patients with residual PO experienced significantly more leg lengthening. Notably, in the U-PO group, increased leg lengthening independently predicted residual PO. Regarding spinal parameters, residual PO subgroups in both U-PO and D-PO groups showed significantly reduced preoperative lumbar lateral bending mobility and more persistent postoperative convex spinal deformities. In the D-PO group, a larger preoperative lumbar scoliosis angle and lower lumbar lateral bending mobility independently predicted residual PO.\u003c/p\u003e \u003cp\u003eHip contracture contributes to PO development in DHOA. Ozawa et al. reported that in severe DHOA, U-PO may result from a subluxated hip with a pronounced adduction angle [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Conversely, patients with D-PO generally have better hip ROM compared to those with U-PO, and preoperative adduction contracture is less common. In our study, though not statistically significant, the U-PO subgroup with residual PO tended to have larger postoperative hip adduction angles and reduced hip abduction ROM. While THA typically improves joint contracture, previous reports have indicated that contracture may persist for up to a year postoperatively in severe DHOA cases [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. In addition, we have reported limited improvement in hip ROM in U-PO cases following THA [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Therefore, in patients with U-PO with persistent postoperative adduction contracture and limited ROM, residual PO may persist as a compensatory mechanism for maintaining coronal balance. In such cases, interventions, such as adductor tenotomy, removal of ROM-limiting osteophytes, and proactive perioperative rehabilitation, may help relieve the contracture.\u003c/p\u003e \u003cp\u003ePO is considered a compensatory mechanism for LLD, with simulation studies showing that greater discrepancies are associated with larger pelvic tilt angles [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. Thus, precise leg length control during THA is essential for improving postoperative quality of life. In patients with D-PO, LLD is a key contributor, and PO typically improves following correction via THA. Consistent with this, our study found that correcting LLD did not increase the risk of residual PO in the D-PO group. In contrast, the impact of leg length correction on postoperative PO in patients with U-PO remains unclear. Interestingly, our results demonstrated that in the U-PO group, greater leg lengthening was a significant risk factor for residual PO after surgery. Residual PO following THA has been linked to discrepancies between radiographic and perceived leg length [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. As many patients with U-PO exhibit persistent postoperative hip adduction contracture, surgical planning should address both radiographic and perceived LLD, supported by comprehensive preoperative assessment.\u003c/p\u003e \u003cp\u003ePrevious studies have not reached a consensus on the link between spinal stiffness and residual PO after THA. Banno et al. reported a strong correlation between scoliosis and PO, suggesting that spinal flexibility influences PO in patients with hip osteoarthritis [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. Similarly, Abe et al. found that THA cases involving leg lengthening showed greater PO improvement in patients with flexible scoliosis [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. In our study, patients with residual PO had reduced lumbar lateral bending mobility, suggesting that limited spinal flexibility impedes PO correction. Specifically, in the D-PO group, both lumbar scoliosis angle and lumbar lateral bending mobility were independent predictors of residual PO. Even after correcting LLD, patients with rigid spines and limited coronal compensation due to scoliosis may remain prone to persistent PO. Although no statistically significant association was observed in the U-PO group, reduced spinal mobility appeared to contribute to residual PO. The smaller U-PO sample size and complex deformity patterns may have influenced this result. Nevertheless, in the U-PO and D-PO groups, surgical planning should consider the risk of poor PO improvement in patients with limited spinal flexibility following THA.\u003c/p\u003e \u003cp\u003eThis study has some limitations. First, it was a retrospective observational study conducted at a single institution with a relatively small sample size. A prospective multicenter study would be valuable in increasing case numbers and enhancing the generalizability of the findings. Second, the follow-up period was limited to 1 year, which may not capture long-term changes in PO and related clinical outcomes. In addition, as evaluations were based on anteroposterior radiographs, the influence of posture and pelvic rotation cannot be entirely excluded. However, we attempted to minimize these confounding factors by standardizing the radiographic acquisition protocol.\u003c/p\u003e \u003cp\u003eA key strength of this study is that it is the first to evaluate risk factors for both U-PO and D-PO following THA in patients with DHOA. Residual PO following THA has been associated with implant positioning, adjacent joint disorders, and discrepancies in perceived leg length. Therefore, we believe our findings offer valuable guidance for hip surgeons in planning THA for patients with DHOA.\u003c/p\u003e \u003cp\u003eIn conclusion, in patients with U-PO, substantial leg lengthening may increase the risk of residual PO, especially in those with poor preoperative lumbar lateral bending mobility and persistent hip adduction contracture. Therefore, caution is advised when correcting leg length in these cases. In contrast, among patients with D-PO, no significant association was observed between residual PO and either hip contracture or leg lengthening, suggesting that leg length correction is generally recommended.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eFunding\u003c/h2\u003e \u003cp\u003eThis research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eH.Y and Yusuke.O. wrote the main manuscript text and Yuto. O and H. F. prepared figures. T. Y and S. I. are supervised manuscript. All authors reviewed the manuscript.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eOzawa Y, Osawa Y, Takegami Y, Iida H, Takemoto G, Imagama S (2024) Risk factors for residual pelvic obliquity one year after total hip arthroplasty. Eur J Orthop Surg Traumatol 34:3319\u0026ndash;3327. https://doi.org/10.1007/s00590-024-04060-z\u003c/li\u003e\n \u003cli\u003eOzawa Y, Osawa Y, Takegami Y, Funahashi H, Tanaka S, Imagama S (2024) Characteristics of pelvic obliquity in dysplastic hip osteoarthritis. Arch Orthop Trauma Surg 144:3813\u0026ndash;3821. https://doi.org/10.1007/s00402-024-05476-2\u003c/li\u003e\n \u003cli\u003eMoharrami A, Mirghaderi SP, Hoseini-Zare N, Kaseb MH, Moazen-Jamshidi SMM, Mansour AK, Mortazavi SMJ (2022) Restoring femoral medial offset could reduce pelvic obliquity following primary total hip arthroplasty, an observational study. Int Orthop 46:2765\u0026ndash;2774. https://doi.org/10.1007/s00264-022-05506-x\u003c/li\u003e\n \u003cli\u003eAbe Y, Sato S, Abe S, Masuda T, Yamada K (2015) The impact of the leg-lengthening total hip arthroplasty on the coronal alignment of the spine. Scoliosis 10:S4. https://doi.org/10.1186/1748-7161-10-S2-S4\u003c/li\u003e\n \u003cli\u003eWinter RB, Pinto WC (1986) Pelvic obliquity. Its causes and its treatment. Spine (Phila Pa 1976) 11:225\u0026ndash;234.\u003c/li\u003e\n \u003cli\u003eYokoi H, Osawa Y, Takegami Y, Ozawa Y, Funahashi H, Imagama S (2025) Direction of pelvic obliquity after total hip arthroplasty for dysplastic hip osteoarthritis: a retrospective observational study. Arch Orthop Trauma Surg 145:195. https://doi.org/10.1007/s00402-025-05829-5\u003c/li\u003e\n \u003cli\u003eZhou X, Wang Q, Zhang X, Chen Y, Shen H, Jiang Y (2012) Effect of pelvic obliquity on the orientation of the acetabular component in total hip arthroplasty. J Arthroplasty 27:299\u0026ndash;304. https://doi.org/10.1016/j.arth.2011.09.022\u003c/li\u003e\n \u003cli\u003eMoharrami A, Mirghaderi P, Hoseini Zare N, Moazen-Jamshidi MM, Ebrahimian M, Mortazavi SMJ (2023) Slight pelvic obliquity is normal in a healthy population: a cross-sectional study. J Exp Orthop 10:57. https://doi.org/10.1186/s40634-023-00613-z\u003c/li\u003e\n \u003cli\u003eOkuzu Y, Goto K, Kawata T, So K, Kuroda Y, Matsuda S (2017) The relationship between subluxation percentage of the femoroacetabular joint and acetabular width in Asian women with developmental dysplasia of the hip. J Bone Joint Surg Am 99:e31. https://doi.org/10.2106/JBJS.16.00444\u003c/li\u003e\n \u003cli\u003eWoolson ST, Harris WH (1985) A method of intraoperative limb length measurement in total hip arthroplasty. Clin Orthop Relat Res\u0026nbsp;207\u0026ndash;210.\u003c/li\u003e\n \u003cli\u003eKobayashi T, Morimoto T, Hirata H, Yoshihara T, Tsukamoto M, Sonohata M, Mawatari M (2023) Changes of the coronal lumbar-pelvic-femoral alignment after conversion total hip arthroplasty in patients with unilateral ankylosed hip. Sci Rep 13:5541. https://doi.org/10.1038/s41598-023-32672-8\u003c/li\u003e\n \u003cli\u003eOsebold WR, Mayfield JK, Winter RB, Moe JH (1982) Surgical treatment of paralytic scoliosis associated with myelomeningocele. J Bone Joint Surg Am 64:841\u0026ndash;856\u003c/li\u003e\n \u003cli\u003eNakashima H, Kawakami N, Ohara T, Saito T, Tauchi R, Imagama S (2021) A new global spinal balance classification based on individual pelvic anatomical measurements in patients with adult spinal deformity. spine (Phila Pa 1976) 46:223\u0026ndash;231. https://doi.org/10.1097/BRS.0000000000003780\u003c/li\u003e\n \u003cli\u003eImai N, Takubo R, Suzuki H, Shimada H, Miyasaka D, Tsuchiya K, Endo N (2019) Accuracy of acetabular cup placement using CT-based navigation in total hip arthroplasty: Comparison between obese and non-obese patients. J Orthop Sci 24:482\u0026ndash;487. https://doi.org/10.1016/j.jos.2018.11.007\u003c/li\u003e\n \u003cli\u003eKanda Y (2013) Investigation of the freely available easy-to-use software \u0026apos;EZR\u0026apos; for medical statistics. Bone Marrow Transplant 48:452\u0026ndash;458. https://doi.org/10.1038/bmt.2012.244\u003c/li\u003e\n \u003cli\u003eLi T, Li Y, Gao J, Ma R, Zhang Q, Wang W (2024) Effects of lower limb length discrepancy on spinopelvic compensation following total hip arthroplasty in patients with developmental dysplasia of the hip. J Orthop Surg Res 19:337. https://doi.org/10.1186/s13018-024-04816-7\u003c/li\u003e\n \u003cli\u003eCummings G, Scholz JP, Barnes K (1993) The effect of imposed leg length difference on pelvic bone symmetry. Spine (Phila Pa 1976) 18:368\u0026ndash;373. https://doi.org/10.1097/00007632-199303000-00012\u003c/li\u003e\n \u003cli\u003eSiebers HL, Eschweiler J, Quack VM, Tingart M, Betsch M (2021) Inertial measurement units for the detection of the effects of simulated leg length inequalities. J Orthop Surg Res 16:142. https://doi.org/10.1186/s13018-021-02212-z\u003c/li\u003e\n \u003cli\u003eTakemoto G, Osawa Y, Seki T, Takegami Y, Ochiai S, Kato D, Imagama S (2022) Factors influencing inconsistent leg length discrepancy in dysplastic hip osteoarthritis: a retrospective study. BMC Musculoskelet Disord 23:381. https://doi.org/10.1186/s12891-022-05348-z\u003c/li\u003e\n \u003cli\u003eBanno T, Yamato Y, Oba H et al (2022) Preoperative pelvic obliquity: possible relation to postoperative coronal decompensation in thoracolumbar/lumbar adolescent idiopathic scoliosis. J Neurosurg Spine 36:193\u0026ndash;202. https://doi.org/10.3171/2021.4.SPINE21265\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003eTable1：patient demographics\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"567\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" style=\"width: 132px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 180px;\"\u003e\n \u003cp\u003eU-PO group\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" style=\"width: 57px;\"\u003e\n \u003cp\u003eP value\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 151px;\"\u003e\n \u003cp\u003eD-PO group\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" style=\"width: 47px;\"\u003e\n \u003cp\u003eP value\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp\u003eImproved PO (n=14)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003eResidual PO (n=21)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003eImproved PO (n=50)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003eResidual PO (n=31)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003eDemographics data\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 94px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e\u0026nbsp;Age, yrs (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp\u003e63.5 (10.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e66.4 (12.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\n \u003cp\u003e0.479\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e63.9 (10.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e63.5 (10.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e0.849\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e\u0026nbsp;Sex (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\n \u003cp\u003e0.192\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e\u0026nbsp; Men\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp\u003e5 (35.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e4 (19.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e7 (14.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e5 (16.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e\u0026nbsp; Women\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp\u003e9 (64.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e17 (81.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e43 (86.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e26 (83.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e\u0026nbsp;Height, cm (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp\u003e157.8 (9.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e155.3 (9.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\n \u003cp\u003e0.436\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e154.9 (7.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e154.3 (6.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e0.748\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e\u0026nbsp;Weight, kg (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp\u003e63.3 (15.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e58.1 (12.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\n \u003cp\u003e0.273\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e56.6 (11.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e56.0 (9.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e0.790\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e\u0026nbsp;Body mass index, kg/m2 (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp\u003e25.3 (4.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e24.1 (3.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\n \u003cp\u003e0.411\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e23.6 (4.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e23.4 (3.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e0.855\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e\u0026nbsp;Other side (healthy/ THA)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp\u003e10/4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e17/4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\n \u003cp\u003e0.685\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e37/13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e26/5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e0.412\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e\u0026nbsp;Duration of hip disorders, yrs (SD)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp\u003e9.1 (9.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e9.1 (9.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\n \u003cp\u003e0.994\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e5.1 (4.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e7.2 (11.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e0.238\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003eSurgical data\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 94px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e\u0026nbsp;Operative duration, min (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp\u003e113.8 (35.2)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e116.9 (50.9)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\n \u003cp\u003e0.848\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e91.7 (25.4)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e113.9 (32.7)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e0.001※\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e\u0026nbsp;Blood loss, g (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp\u003e428.6 (275.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e582.0 (487.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\n \u003cp\u003e0.294\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e386.8 (200.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e498.3 (430.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e0.119\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e\u0026nbsp;Cup (cement / cementless)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp\u003e1/13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e4/16\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\n \u003cp\u003e0.379\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e5/45\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e8/23\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e0.071\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e\u0026nbsp;Stem (cement / cementless)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp\u003e7/7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e7/13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\n \u003cp\u003e0.487\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e13/37\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e13/18\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e0.150\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e\u0026nbsp;Bone implantation (none/ bulk bone/ tip bone)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp\u003e11/2/1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e15/5/0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\n \u003cp\u003e0.393\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e40/5/5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e20/8/3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e0.163\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e*P＜0.05.\u003c/p\u003e\n\u003cp\u003eU-PO, Pelvic obliquity with the affected side of the pelvis tilts upward; D-PO, Pelvic obliquity with the affected side of the pelvis tilts downward; THA, total hip arthroplasty; SD, standard deviation\u0026nbsp;\u003cbr\u003e\u0026nbsp;Table2: radiographic parameters\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"98%\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" style=\"width: 20px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 33px;\"\u003e\n \u003cp\u003eU-PO group\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" style=\"width: 8px;\"\u003e\n \u003cp\u003eP value\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 30px;\"\u003e\n \u003cp\u003eD-PO group\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" style=\"width: 6px;\"\u003e\n \u003cp\u003eP value\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 16px;\"\u003e\n \u003cp\u003eImprove PO (n=14)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 16px;\"\u003e\n \u003cp\u003eResidual RO (n=21)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003eImprove PO (n=50)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003eResidual RO (n=31)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 20px;\"\u003e\n \u003cp\u003ePreoperative\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 16px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 16px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 8px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 20px;\"\u003e\n \u003cp\u003e\u0026nbsp;Crowe index (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 16px;\"\u003e\n \u003cp\u003e20.3 (27.1)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 16px;\"\u003e\n \u003cp\u003e38.7 (36.7)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 8px;\"\u003e\n \u003cp\u003e0.121\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e17.5 (17.2)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e30.7 (22.9)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6px;\"\u003e\n \u003cp\u003e0.004*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 20px;\"\u003e\n \u003cp\u003e\u0026nbsp;Acetabular offset (operative side), mm (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 16px;\"\u003e\n \u003cp\u003e107.5 (8.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 16px;\"\u003e\n \u003cp\u003e109.2 (9.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 8px;\"\u003e\n \u003cp\u003e0.596\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e106.7 (8.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e108.2 (11.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6px;\"\u003e\n \u003cp\u003e0.516\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 20px;\"\u003e\n \u003cp\u003e\u0026nbsp;Femoral offset (operative side), mm (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 16px;\"\u003e\n \u003cp\u003e36.3 (8.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 16px;\"\u003e\n \u003cp\u003e33.1 (9.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 8px;\"\u003e\n \u003cp\u003e0.328\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e34.6 (8.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e33.1 (11.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6px;\"\u003e\n \u003cp\u003e0.496\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 20px;\"\u003e\n \u003cp\u003e\u0026nbsp;Hip adduction angle, degree (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 16px;\"\u003e\n \u003cp\u003e8.4 (3.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 16px;\"\u003e\n \u003cp\u003e9.5 (2.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 8px;\"\u003e\n \u003cp\u003e0.316\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e5.2 (2.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e5.1 (3.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6px;\"\u003e\n \u003cp\u003e0.879\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 20px;\"\u003e\n \u003cp\u003e\u0026nbsp;RLLD, mm (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 16px;\"\u003e\n \u003cp\u003e9.1 (14.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 16px;\"\u003e\n \u003cp\u003e15.4 (11.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 8px;\"\u003e\n \u003cp\u003e0.175\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e10.1 (7.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e18.6 (10.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6px;\"\u003e\n \u003cp\u003e\u0026lt;0.001*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 20px;\"\u003e\n \u003cp\u003e\u0026nbsp;PO, degree (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 16px;\"\u003e\n \u003cp\u003e3.6 (1.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 16px;\"\u003e\n \u003cp\u003e4.4 (3.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 8px;\"\u003e\n \u003cp\u003e0.423\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e3.3 (1.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e5.6 (2.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6px;\"\u003e\n \u003cp\u003e\u0026lt;0.001*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 20px;\"\u003e\n \u003cp\u003e\u0026nbsp;LSA, degree (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 16px;\"\u003e\n \u003cp\u003e1.8 (4.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 16px;\"\u003e\n \u003cp\u003e3.0 (6.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 8px;\"\u003e\n \u003cp\u003e0.528\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e-0.5 (5.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e-6.5 (8.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6px;\"\u003e\n \u003cp\u003e\u0026lt;0.001*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 20px;\"\u003e\n \u003cp\u003e\u0026nbsp;C7CVA, mm (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 16px;\"\u003e\n \u003cp\u003e9.9 (12.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 16px;\"\u003e\n \u003cp\u003e12.6 (25.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 8px;\"\u003e\n \u003cp\u003e0.713\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e9.2 (16.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e13.2 (17.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6px;\"\u003e\n \u003cp\u003e0.299\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 20px;\"\u003e\n \u003cp\u003eLumbar lateral bending mobility, degree (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 16px;\"\u003e\n \u003cp\u003e17.1 (6.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 16px;\"\u003e\n \u003cp\u003e8.5 (4.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 8px;\"\u003e\n \u003cp\u003e\u0026lt;0.001*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e15.4 (5.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e8.6 (4.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6px;\"\u003e\n \u003cp\u003e\u0026lt;0.001*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 20px;\"\u003e\n \u003cp\u003e\u0026nbsp;postoperative\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 16px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 16px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 8px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 20px;\"\u003e\n \u003cp\u003e\u0026nbsp;Acetabular offset (operative side), mm (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 16px;\"\u003e\n \u003cp\u003e10.3.5 (14.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 16px;\"\u003e\n \u003cp\u003e100.9 (7.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 8px;\"\u003e\n \u003cp\u003e0.494\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e100.7 (7.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e98.1 (6.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6px;\"\u003e\n \u003cp\u003e0.115\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 20px;\"\u003e\n \u003cp\u003e\u0026nbsp;Femoral offset (operative side), mm (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 16px;\"\u003e\n \u003cp\u003e42.7 (6.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 16px;\"\u003e\n \u003cp\u003e41.8 (7.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 8px;\"\u003e\n \u003cp\u003e0.730\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e41.6 (11.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e41.5 (6.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6px;\"\u003e\n \u003cp\u003e0.950\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 20px;\"\u003e\n \u003cp\u003e\u0026nbsp;Hip adduction angle, degree (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 16px;\"\u003e\n \u003cp\u003e6.8 (3.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 16px;\"\u003e\n \u003cp\u003e8.4 (2.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 8px;\"\u003e\n \u003cp\u003e0.061\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e5.5 (1.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e4.7 (2.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6px;\"\u003e\n \u003cp\u003e0.130\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 20px;\"\u003e\n \u003cp\u003e\u0026nbsp;Postoperative RLLD, mm (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 16px;\"\u003e\n \u003cp\u003e2.5 (14.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 16px;\"\u003e\n \u003cp\u003e-0.2 (7.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 8px;\"\u003e\n \u003cp\u003e0.483\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e0.6 (4.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e3.0 (8.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6px;\"\u003e\n \u003cp\u003e0.120\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 20px;\"\u003e\n \u003cp\u003e\u0026nbsp;LSA, degree (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 16px;\"\u003e\n \u003cp\u003e0.1 (3.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 16px;\"\u003e\n \u003cp\u003e3.3 (4.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 8px;\"\u003e\n \u003cp\u003e0.029*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e1.9 (6.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e-2.4 (10.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6px;\"\u003e\n \u003cp\u003e0.027*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 20px;\"\u003e\n \u003cp\u003e\u0026nbsp;C7CVA, mm (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 16px;\"\u003e\n \u003cp\u003e6.1 (9.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 16px;\"\u003e\n \u003cp\u003e9.2 (20.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 8px;\"\u003e\n \u003cp\u003e0.600\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e7.2 (16.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e6.1 (14.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6px;\"\u003e\n \u003cp\u003e0.750\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 20px;\"\u003e\n \u003cp\u003e\u0026nbsp;Amount of limb lengthening, mm (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 16px;\"\u003e\n \u003cp\u003e6.6 (4.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 16px;\"\u003e\n \u003cp\u003e15.6 (6.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 8px;\"\u003e\n \u003cp\u003e\u0026lt;0.001*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e9.7 (7.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e15.5 (9.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6px;\"\u003e\n \u003cp\u003e0.002*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e*P＜0.05.\u003c/p\u003e\n\u003cp\u003eU-PO, Pelvic obliquity with the affected side of the pelvis tilts upward; D-PO, Pelvic obliquity with the affected side of the pelvis tilts downward; RLLD, radiographic leg length discrepancy; LSA, lumbar scoliosis angle; C7CVA, C7 coronal vertical axis; SD, standard deviation\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eTable.3: Logistic regression model for predicting postoperative PO residual in U-PO group\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"100%\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 20px;\"\u003e\n \u003cp\u003eOdds ratio\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 22px;\"\u003e\n \u003cp\u003e95%CI\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 10px;\"\u003e\n \u003cp\u003eP value\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003eAge, yrs\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 20px;\"\u003e\n \u003cp\u003e1.100\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 22px;\"\u003e\n \u003cp\u003e0.939-1.280\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 10px;\"\u003e\n \u003cp\u003e0.245\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003eSex (men)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 20px;\"\u003e\n \u003cp\u003e2.090\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 22px;\"\u003e\n \u003cp\u003e0.111-39.20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 10px;\"\u003e\n \u003cp\u003e0.622\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003eBody mass index\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 20px;\"\u003e\n \u003cp\u003e0.794\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 22px;\"\u003e\n \u003cp\u003e0.518-1.220\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 10px;\"\u003e\n \u003cp\u003e0.290\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003ePreoperative lumbar lateral bending mobility, degree\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 20px;\"\u003e\n \u003cp\u003e0.782\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 22px;\"\u003e\n \u003cp\u003e0.591-1.040\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 10px;\"\u003e\n \u003cp\u003e0.086\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003ePostoperative LSA, degree\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 20px;\"\u003e\n \u003cp\u003e1.500\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 22px;\"\u003e\n \u003cp\u003e0.807-2.790\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 10px;\"\u003e\n \u003cp\u003e0.200\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003eAmount of limb lengthening, mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 20px;\"\u003e\n \u003cp\u003e1.390\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 22px;\"\u003e\n \u003cp\u003e1.010-1.910\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 10px;\"\u003e\n \u003cp\u003e0.045*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e*P＜0.05.\u003c/p\u003e\n\u003cp\u003eU-PO, Pelvic obliquity with the affected side of the pelvis tilts upward; LSA, lumbar scoliosis angle\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eTable.4: Logistic regression model for predicting postoperative PO residual in D-PO group\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"100%\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 20px;\"\u003e\n \u003cp\u003eOdds ratio\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 22px;\"\u003e\n \u003cp\u003e95%CI\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 10px;\"\u003e\n \u003cp\u003eP value\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003eAge, yrs\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 20px;\"\u003e\n \u003cp\u003e0.916\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 22px;\"\u003e\n \u003cp\u003e0.831-1.010\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 10px;\"\u003e\n \u003cp\u003e0.082\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003eSex (men)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 20px;\"\u003e\n \u003cp\u003e0.882\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 22px;\"\u003e\n \u003cp\u003e0.049-15.90\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 10px;\"\u003e\n \u003cp\u003e0.932\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003eBody mass index\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 20px;\"\u003e\n \u003cp\u003e0.988\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 22px;\"\u003e\n \u003cp\u003e0.772-1.260\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 10px;\"\u003e\n \u003cp\u003e0.922\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003eCrowe index\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 20px;\"\u003e\n \u003cp\u003e0.857\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 22px;\"\u003e\n \u003cp\u003e0.002-336.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 10px;\"\u003e\n \u003cp\u003e0.959\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003ePreoperative internal rotation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 20px;\"\u003e\n \u003cp\u003e0.967\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 22px;\"\u003e\n \u003cp\u003e0.910-1.030\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 10px;\"\u003e\n \u003cp\u003e0.278\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003ePreoperative RLLD, mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 20px;\"\u003e\n \u003cp\u003e1.070\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 22px;\"\u003e\n \u003cp\u003e0.926-1.240\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 10px;\"\u003e\n \u003cp\u003e0.346\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003ePreoperative PO, degree\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 20px;\"\u003e\n \u003cp\u003e1.490\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 22px;\"\u003e\n \u003cp\u003e0.710-3.140\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 10px;\"\u003e\n \u003cp\u003e0.290\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003ePreoperative LSA, degree\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 20px;\"\u003e\n \u003cp\u003e1.230\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 22px;\"\u003e\n \u003cp\u003e1.050-1.440\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 10px;\"\u003e\n \u003cp\u003e0.012*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003ePreoperative lumbar lateral bending mobility, degree\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 20px;\"\u003e\n \u003cp\u003e0.671\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 22px;\"\u003e\n \u003cp\u003e0.521-0.863\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 10px;\"\u003e\n \u003cp\u003e0.002*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003ePostoperative external rotation, degree\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 20px;\"\u003e\n \u003cp\u003e0.908\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 22px;\"\u003e\n \u003cp\u003e0.824-1.000\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 10px;\"\u003e\n \u003cp\u003e0.053\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003eAmount of limb lengthening, mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 20px;\"\u003e\n \u003cp\u003e1.060\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 22px;\"\u003e\n \u003cp\u003e0.894-1.250\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 10px;\"\u003e\n \u003cp\u003e0.512\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e*P＜0.05.\u003c/p\u003e\n\u003cp\u003eD-PO, Pelvic obliquity with the affected side of the pelvis tilts downward; RLLD, radiographic leg length discrepancy; LSA, lumbar scoliosis angle\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"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":"limb lengthening, lumbar scoliosis, pelvic obliquity, spinal flexibility, total hip arthroplasty","lastPublishedDoi":"10.21203/rs.3.rs-6975048/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6975048/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eIntroduction:\u003c/strong\u003e In patients with dysplastic hip osteoarthritis (DHOA), pelvic obliquity (PO) may present as either an upward tilt or a downward tilt on the affected side. Upward PO (U-PO) tends to persist more frequently after total hip arthroplasty (THA) than downward PO (D-PO), but the contributing factors remain unclear. This study aimed to identify factors associated with residual PO after THA, based on the preoperative direction of PO.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMaterials and Methods:\u003c/strong\u003e This retrospective study included 116 patients (21 men, 95 women) who underwent unilateral THA for DHOA at a single institution between June 2018 and September 2023, and showed PO ≥2° on preoperative standing whole-spine radiographs. Based on the tilt direction, patients were categorized into the U-PO group (≥2° upward PO; n=35) or the D-PO group (≥2° downward PO; n=81). Pre-and postoperative radiographic parameters of the spine and lower limbs were analyzed to determine factors associated with residual PO.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults:\u003c/strong\u003e In the U-PO group, PO improved to \u0026lt;2° in 14 patients and persisted in 21. In the D-PO group, PO improved in 50 and persisted in 31. Multivariate logistic regression identified limb lengthening (odds ratio [OR], 1.390; 95% confidence interval [CI], 1.010–1.910; \u003cem\u003eP\u003c/em\u003e=0.045) as an independent factor associated with residual PO in the U-PO group. In the D-PO group, preoperative lumbar scoliosis angle (OR, 1.140; 95% CI, 1.010–1.290; \u003cem\u003eP\u003c/em\u003e=0.039) and lumbar lateral bending mobility (OR, 0.680; 95% CI, 0.541–0.855; \u003cem\u003eP\u003c/em\u003e\u0026lt;0.001) were independent predictors of residual PO.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion:\u003c/strong\u003e In the U-PO group, greater limb lengthening was associated with residual PO following THA. In contrast, in the D-PO group, a larger preoperative lumbar scoliosis angle and reduced lateral spinal flexibility contributed to residual PO.\u003c/p\u003e","manuscriptTitle":"Factors Associated with Residual Pelvic Obliquity after Total Hip Arthroplasty for Dysplastic Hip Osteoarthritis: A Retrospective Observational Study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-06-29 15:02:56","doi":"10.21203/rs.3.rs-6975048/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":"13652b8a-40a4-4f4e-bfd9-2fa489e3f5ab","owner":[],"postedDate":"June 29th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-09-02T05:38:39+00:00","versionOfRecord":[],"versionCreatedAt":"2025-06-29 15:02:56","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6975048","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6975048","identity":"rs-6975048","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}