Vincent Justus Leopold

Aims: To determine the prevalence of MRI-confirmed ischiofemoral impingement (IFI) in young patients with nonarthritic hip pain, and to evaluate the associations of femoral, acetabular, pelvic, and spinopelvic parameters with IFI. Methods: We included 250 patients with nonarthritic hip pain who underwent standardized imaging (MRI and CT, lateral standing and deep-seated spinopelvic radiographs). IFI was diagnosed by quadratus femoris oedema/atrophy. IFI-positive/negative hips were compared for morphological and spinopelvic parameters. Underlying pathologies (e.g. femoroacetabular impingement, dysplasia) were documented. Multivariate regression identified independent predictors of IFI and determinants of quadratus femoris space (QFS). Results: IFI was identified in 14/250 patients (5.6%), all female. IFI cases had significantly reduced ischiofemoral space (24.8 mm (SD 6.7) vs 34.9 mm (SD 10.2); p < 0.001) and QFS (9.2 mm (SD 3.4) vs 20.7 mm (SD 7.0); p < 0.001). IFI cases demonstrated larger ischial angle (135.7° (SD 3.0°) vs 132.2° (SD 4.0°); p = 0.002), higher femoral version (16.5° (SD 10.3°) vs 10.4° (SD 12.3°); p = 0.031), and reduced femoral (34.2 mm (SD 5.6) vs 37.7 mm (SD 5.9); p = 0.016) and acetabular offset (29.4 mm (SD 3.5) vs 32.0 mm (SD 4.8); p = 0.036). In standing, IFI cases tended to have lower lumbar lordosis (LL) (55.31° (SD 7.95°) vs 59.91° (SD 10.50°); p = 0.077), higher pelvic tilt (15.68° (SD 4.73°) vs 12.39° (SD 6.20°); p = 0.047), and smaller mismatch between pelvic incidence and LL (–2.39° (SD 7.18°) vs –7.82° (SD 10.00°); p = 0.034). The change in LL across standing to deep-flexed sitting transition (ΔLL) was lower in IFI cases (50.31° (SD 10.89°) vs 56.89° (SD 10.64°); p = 0.020). Multivariate regression identified reduced QFS (odds ratio (OR) 1.92, 95% CI 1.30 to 2.89; p < 0.001) and greater LL (OR 1.16, 95% CI 1.00 to 1.33; p = 0.047) as independent predictors of IFI. Size of QFS was associated positively with femoral offset ( β = 0.35; p < 0.001) and mismatch between pelvic incidence and LL ( β = 0.18; p = 0.028), and negatively with ischial angle ( β = –0.34; p < 0.001), femoral version ( β = –0.14; p = 0.016), and standing pelvic tilt ( β = –0.16; p = 0.026). Conclusion: IFI occurred in 5.6% of patients and was characterized by a distinct morphometric and sagittal alignment profile, including increased femoral version, reduced offset, greater ischial angle, reduced LL, increased pelvic tilt, and diminished spinal motion. These findings support a multifactorial model in which hip morphology and spinopelvic alignment jointly influence posterior hip clearance in IFI. Cite this article: Bone Jt Open 2026;7(6):792–801.

Aims: Occupational outcomes after periacetabular osteotomy (PAO) remain underexplored. The aims were to: 1) to determine rate and duration to return to work (RTW) after PAO; 2) to analyze frequency and reasons for occupational change; and 3) assess career trajectories of students undergoing PAO. Methods: We retrospectively analyzed 117 patients who underwent PAO between January 2015 and June 2017, with a mean follow-up of 63.2 months (SD 10.2). A total of 90 patients were employed; 27 were students. Work-related outcomes were assessed via questionnaire, including RTW status, duration of work absence, occupational change, and whether PAO was considered reason for job change. Preoperative workload was assessed by the Reich Committee for Working Time Determination (REFA) classification. Returnees and non-returnees were compared, and predictors of occupational change were assessed with logistic regression. Results: Among 90 employed patients, 58 (64.4%) returned to their preoperative occupation, while 32 (35.6%) changed jobs. Overall, 14 patients (15.6% of all employed patients) reported that the hip that had undergone PAO was the reason for occupational change. Non-returnees reported higher preoperative pain (Numeric Rating Scale for pain 7.9 vs 7.0, p = 0.027), worse Hip disability and Osteoarthritis Outcome Score (HOOS)-Symptoms (42.3 vs 55.6, p = 0.038) and HOOS-Activities in daily living (44.1 vs 60.5, p = 0.015), higher workload-grades (0 (0 to 1) vs 2 (1 to 3), p < 0.001), and longer work absence (33.4 vs 26.7 weeks, p = 0.024). Logistic regression identified workload as the only independent predictor of occupational change (odds ratio up to 13.1 for heavier workload). The median time to job change was 86 weeks (IQR 10 to 208). Most changes occurred between one and two years postoperatively. Among students, 87.5% were employed at follow-up, most in sedentary (50%) or light (43%) occupations. Only one reported that PAO had influenced career choice. Conclusion: PAO enables the majority of young adults to RTW, but more than one third adapt their occupation in the mid-term, with higher preoperative workload being the key determinant. Despite improved hip function, occupational adaptations remained common, while long-term career trajectories in students were largely unaffected. Cite this article: Bone Jt Open 2026;7(6):704–712.

Aims: Periacetabular osteotomy (PAO) is the gold-standard treatment for symptomatic hip dysplasia. While long-term joint preservation and functional improvement are documented, early postoperative recovery trajectories and predictors of meaningful improvement remain unclear. Methods: This prospective multicentre cohort study is a secondary analysis of a randomized trial including 218 patients (mean age 27.1 years (SD 7.7); 83.2% female (181/218)) undergoing PAO with or without hip arthroscopy. We aimed to 1) determine the timing and proportion of patients achieving minimal clinically important difference (MCID, + 26), substantial clinical benefit (SCB, + 42), and patient-acceptable symptom state (PASS, ≥ 65) on the 33-item International Hip Outcome Tool (iHOT-33) within 24 months; and 2) identify predictors of threshold achievement. Correction was assessed by lateral centre-edge angle (LCEA) and acetabular index. Logistic regression evaluated patient- and surgery-specific factors. Results: Radiological parameters improved significantly (mean LCEA 18.7° (SD 8.4°) to 32.2° (SD 5.7°); acetabular index 12.8° (SD 7.6°) to 1.6 (SD 6.3°), both p < 0.001). iHOT-33 improved from 34.2 (SD 16.4) preoperatively to 61.4 (SD 24.0) at six months, 72.8 (SD 22.0) at 12 months, and 78.0 (SD 21.0) at 24 months (p < 0.001). At six, 12, and 24 months, MCID was achieved by 70.2%, 71.5%, and 80.3% of patients; SCB by 52.8%, 64.6%, and 74.6%; and PASS by 56.3%, 73.5%, and 79.6%. Most recovery occurred within the first year, with continued gains thereafter. Multivariable analysis identified higher BMI as negative predictor for MCID, SCB, and PASS at 12 months (OR 0.88 to 0.89; p = 0.015 to 0.019). Residual undercorrection, reflected by higher postoperative acetabular index, reduced odds of MCID at 12 months (OR ~ 0.80 (95% CI 0.67 to 0.95); p = 0.011). Older age lowered the likelihood of PASS (OR 0.94 (95% CI 0.89 to 0.999); p = 0.047). Labral repair was negatively associated with PASS at six months (OR 0.27 (95% CI 0.09 to 0.89); p = 0.031), but not thereafter. Conclusion: Most patients achieve clinically meaningful improvement within the first postoperative year, with further recovery into the second. Elevated BMI, older age, and residual undercorrection reduce the likelihood of reaching thresholds, while concomitant labral repair may temporarily delay early symptom acceptability. Cite this article: Bone Joint J 2026;108-B(5):607–615.

Background: The diagnosis of hip instability remains challenging because of its multifactorial etiology and the variability of imaging practices across institutions. Hip instability refers to a clinical condition of insufficient osseous and/or soft tissue constraint with abnormal femoral head motion and symptoms, which may occur along a morphologic spectrum that overlaps with—but is not synonymous with—developmental dysplasia of the hip. Although numerous imaging modalities and imaging parameters have been proposed, there is limited consensus on which are most relevant, how they should be measured, and what diagnostic thresholds best correlate with instability. To address this gap, a Delphi consensus study with an international panel of experts to establish standardized clinical statements for the diagnostic criteria of hip instability was conducted. Questions/purposes: (1) What are the imaging modalities and protocols for investigating hip instability? (2) Which imaging parameters are most strongly associated with clinical hip instability? (3) What are the quantitative imaging thresholds for diagnosing hip instability? Methods: A consensus study using a modified Delphi technique was conducted in accordance with the Accurate Consensus Reporting Document (ACCORD) guideline. Following a scoping review, 27 statements addressing imaging modalities and protocols (question 1), imaging parameters associated with hip instability (question 2), and quantitative imaging thresholds (question 3) were developed. These statements were evaluated by a multidisciplinary international expert panel during a structured consensus meeting, with two rounds of anonymous voting and consensus defined a priori as ≥ 75% agreement. Consensus was achieved for 81% (22 of 27) of statements. Results: There was strong agreement that radiography (AP pelvis, false-profile, Dunn view) and MRI and CT constitute the foundational imaging modalities for the assessment of hip instability, whereas cartilage mapping techniques and dynamic ultrasound were considered adjunctive modalities with a more limited and evolving role. Radiographic measurements such as lateral center-edge angle (LCEA), anterior wall index (AWI), posterior wall index, and Tönnis angle reached consensus as key morphologic indicators. Several quantitative thresholds were endorsed. An LCEA of < 20° was considered diagnostic for hip dysplasia, a condition in which clinical hip instability is highly prevalent, whereas values between 20° and 25° were considered concerning for possible clinical hip instability. Additional thresholds included an AWI of < 0.30, PWI of < 0.8, and acetabular version < 5° or > 30°. In contrast, no consensus was reached for less-established imaging metrics such as the FEAR index, crescent sign, anterior capsule thickness, and dynamic femoral head translation. Conclusion: This international Delphi consensus defined core imaging approaches and threshold values for the evaluation of hip instability. Although agreement was reached on key morphometric parameters and diagnostic thresholds, a lack of consensus exists around newer soft tissue and dynamic measures, highlighting important areas for future research. Clinical Relevance: In patients with suspected clinical hip instability, standard radiography should be used as the first-line imaging modality, followed by targeted use of CT and MRI to evaluate three-dimensional bony morphology and soft tissue stabilizers. Imaging findings should be interpreted within a stepwise, algorithmic framework that integrates clinical assessment with multiple complementary imaging parameters rather than relying on isolated measurements. Ultimately, accurate diagnosis of hip instability depends on the integration of findings from multiple modalities. Additionally, it must be recognized that hip instability may exist even in the absence of characteristic radiologic signs.

Aims: This systematic review aimed to synthesize current evidence on postoperative rehabilitation strategies, particularly weight-bearing restrictions after periacetabular osteotomy (PAO). Methods: A systematic review was conducted following PRISMA 2020 guidelines. PubMed, Web of Science, and Embase were searched until January 12, 2025. After duplicate removal, studies were screened by title, abstract, and full text using predefined criteria. Studies were included if they reported postoperative weight-bearing protocols after isolated PAO; studies with additional procedures, non-human data, or lacking mobilization details were excluded. Primary endpoints included postoperative weight-bearing instructions, duration of partial weight-bearing, and brace use. Secondary endpoints included hip function, return to sports, and complications. Data extraction was performed independently by two reviewers. Bias was assessed using the MINORS tool. Results: The majority of studies recommended partial weight-bearing immediately postoperatively, commonly initiated on postoperative day one (18% of studies), typically lasting six (21%) to eight (18%) weeks. Variations included toe-touch, tip-touch, touch-down, flat-foot, protected, or restricted weight-bearing. Crutches were frequently recommended (48%). Bracing was infrequently reported (5%), with limited details provided. Return to sporting activities varied widely, typically recommended between six and twelve months postoperatively. Complication rates were diverse, with delayed weight-bearing showing a lower incidence of pelvic fractures compared to immediate full weight-bearing. Conclusion: This review highlights substantial variability and imprecise terminology in existing PAO mobilization protocols and a lack of standardization. Future research should prioritize prospective comparative studies to clarify safe, effective postoperative mobilization strategies. Establishing standardized, evidence-based rehabilitation guidelines could enhance patient outcomes, reduce complications, and decrease practice variability following PAO.

This study evaluates the quality and readability of responses given by ChatGPT 4 relating to common patient queries on Developmental Dysplasia of the Hip (DDH) and Periacetabular Osteotomy (PAO). Frequently asked questions on DDH and PAO were selected from online Patient Education Materials and posed to ChatGPT 4. The responses were evaluated by four high-volume PAO surgeons using a well-established evidence-based rating system, categorizing responses from ‘excellent response not requiring clarification’ to ‘unsatisfactory requiring substantial clarification’. Readability assessments were subsequently conducted to determine the required literacy level to understand the content provided. Responses from ChatGPT 4 varied significantly between preoperative and postoperative queries. In the postoperative category, 50% of responses were rated as ‘excellent’, showing no need for further clarification, while the preoperative responses frequently required minimal to moderate clarification. The overall median response rating was ‘satisfactory requiring minimal clarification’. Readability tests showed that the average Reading Grade Level was 13.44, considerably higher than the recommended sixth-grade level for patient education materials, indicating a substantial barrier to comprehension for the general public. While ChatGPT delivers generally reliable information, the complexity of its language is a major barrier to widespread utilization as a tool for patient education. Future iterations of ChatGPT should aim to utilize more simplistic language, as such enhancing accessibility without compromising content quality.

Aims: Developmental dysplasia of the hip (DDH) often leads to early osteoarthritis, causing pain and functional limitations that may impair sexual function. This study investigates the impact of periacetabular osteotomy (PAO) on sexual function in DDH patients, assessing changes from preoperative impairments to postoperative improvements.Methods: This retrospective study analyzed data from DDH patients treated with PAO between January 2015 and June 2017 at a single orthopaedic university centre. Data included radiological parameters and patient-reported outcome measures: International Hip Outcome Tool (iHOT-12), Subjective Hip Value, Hip disability and Osteoarthritis Outcome Score (HOOS) and its sub-scores, and Numeric Pain Scale. Sexual function was specifically assessed using iHOT-12 item nine, asking, “How much trouble do you have with sexual activity because of your hip?”Results: The study included 120 hips in 107 patients, predominantly female (85.1%). Radiological improvements post PAO were significant, with increases in the lateral centre-edge angle (LCEA) (16.6° (SD 6.0°) to 29.4° (SD 5.8°); p < 0.001) and reductions in the Tönnis angle (13.3° (SD 6.7°) to 1.2° (SD 7.4°); p < 0.001). Patient-reported outcomes demonstrated significant improvements postoperatively. Specifically, the iHOT-12 sexual function item showed substantial improvement from a mean preoperative score of 54.3 (SD 33.7) to a postoperative score of 75.0 (SD 27.1) (p < 0.001). Females reported significant enhancements in sexual function (p < 0.001), whereas improvements in males did not reach statistical significance (p = 0.181). Cases of under-correction (LCEA < 25°) demonstrated significantly higher impairments in sexual function postoperatively compared with adequately corrected cases, indicating the importance of achieving optimal anatomical correction.Conclusion: PAO significantly enhances sexual function and overall hip-related quality of life in patients with symptomatic DDH. The findings underscore the necessity of precise surgical techniques and highlight that outcomes may vary by sex, suggesting a need for a sex-sensitive approach in both clinical practice and research.Cite this article: Bone Jt Open 2025;6(4):440–445.

Background: The optimal surgical approach in patients with borderline hip dysplasia (BHD) remains controversial. Both hip arthroscopy and periacetabular osteotomy (PAO) are commonly employed in this patient population. Those who participate in sports want to resume and maintain sports activities after surgery, and the ability to do so plays an important role in the choice of a treatment method. To our knowledge, no previous study has assessed return-to-sports rates and activity levels in patients with BHD after PAO. Purpose: To assess return-to-sports rates and postoperative activity levels as measured by the University of California, Los Angeles (UCLA), activity scale as well as patient-reported outcome measures. Also to assess changes in sports activity both qualitatively and quantitatively as well as underlying reasons for these changes. Study Design: Case series; Level of evidence, 4. Methods: We conducted a retrospective analysis of prospectively collected data from 55 hips in 52 patients with BHD who underwent PAO between January 2015 and June 2017. Return-to-sports rates, UCLA activity scores, International Hip Outcome Tool–12 scores, Subjective Hip Value scores, Hip disability and Osteoarthritis Outcome Score subscores, sports practiced, frequency and duration of sports activity, and postoperative changes as well as underlying reasons were recorded. Results: The mean follow-up was 62.8 ± 9.0 months. The return-to-sports rate among preoperatively active patients was 92.5%. Most patients resumed sports activity after 6 months (50%) or after 3 to 6 months (37.5%). The UCLA activity score improved significantly (from 5.2 ± 2.4 to 7.0 ± 1.8; P < .001). The International Hip Outcome Tool-12, Subjective Hip Value, and Hip disability and Osteoarthritis Outcome Score scores also improved significantly (all, P < .001). Changes in sports activity occurred in 34.5% of cases after PAO. Significantly more patients engaged in low-impact sports postoperatively. Participation in high-impact sports did not decrease significantly. Reasons for changes were both hip related and non–hip related. Quantitatively, patients were able to significantly increase both the frequency ( P = .007) and duration ( P = .007) of sports activity. Conclusion: The return-to-sports rate in patients with BHD after PAO was high at over 92%. Most patients returned to sports after a period of 6 months or 3 to 6 months. Overall, activity levels and hip function improved after PAO. A number of patients adjusted their sports activity after PAO. Although more patients engaged in low-impact sports, participation in high-impact sports was maintained postoperatively. The results of this study may help both patients and orthopaedic surgeons in deciding on the best surgical procedure in the setting of BHD.

Background: Conflicting evidence exists regarding outcomes in middle-aged patients undergoing periacetabular osteotomy (PAO) for symptomatic developmental dysplasia of the hip (DDH). Aims: To compare patient reported outcomes (PROMs) of middle-aged PAO patients with younger patient groups. Methods: Retrospective analysis of prospectively collected data of PAO patients between 01/2015 and 06/2017 at a single orthopedic university center with a primary diagnosis of symptomatic DDH. The cohort was divided into four age groups and compared: < 20, 20–30, 30–40 and > 40 years. Joint function was assessed using iHOT-12, mHHS and SHV. Activity level was assessed using UCLA Activity score. Patient satisfaction and pain were assessed on the numerical rating scale 0–10. Conversion rates to THA were assessed. Results: Out of 202 PAOs, 120 cases with complete data were included. Mean follow-up was 63 months (range 47–81 months). Eighteen patients were < 20 years old, 54 were 20–30 years, 37 were 30–40 years, 11 patients were older than 40. No significant differences were observed for preoperative or postoperative iHOT-12 (p = 0.898; p = 0.087), mHHS (p = 0.878; p = 0.103), SHV (p = 0.602; p = 0.352) or UCLA (p = 0.539; p = 0.978) between groups. Improvement deltas were also not significantly different for all PROMs. Postoperative patient satisfaction was similar between groups (p = 0.783). Conclusion: Patients with symptomatic DDH may benefit from PAO even at middle age with similar outcomes and pre- to postoperative improvements as younger age groups. Indication should be based on biological age and preoperative joint condition rather than age.