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Background: There is little known about translation of the hip and the relationship with hip rotation and morphology in asymptomatic patients., Hypotheses: (1) Femoral head would exhibit significant translations in asymptomatic hips, (2) femoral head translations would correlate to femoral rotations, and (3) range of femoral head translations would correlate to hip morphology., Study Design: Cross-sectional study; Level of evidence, 3., Methods: A total of 11 individuals (age, 23-47 years; 64% female) with asymptomatic hips underwent hip magnetic resonance imaging (MRI) in the following postures: neutral (supine), midflexion, maximum-flexion, internal rotation, internal rotation + midflexion, internal rotation + maximum-flexion, adduction, flexion-abduction-external rotation (FABER), extension, and lateral abduction. All rotations were passive. MRI-generated 3-dimensional hip models were used to quantify femoral rotations and translations. Femoral head diameter, acetabular diameter, lateral center-edge angle, alpha angle, femoral anteversion, acetabular version and inclination, and neck-shaft angle were measured from MRI. A t test was used if measured translations were statistically significant. Linear regression was used to assess the associations between translation and rotation. Pearson correlation was used to assess the relationships between hip anatomy and range of femoral head translations., Results: In all tested positions, the femoral head translated anteriorly by 2 ± 1 mm (maximum 5 mm, P  < .001), posteriorly by 1 ± 1 mm (maximum 6 mm, P  < .001), superiorly by 2 ± 2 mm (maximum 7 mm, P  < .001), inferiorly by 2 ± 2 mm (maximum 6 mm, P  < .001), laterally by 1 ± 1 mm (maximum 4 mm, P  < .001), and medially by 2 ± 1 mm (maximum 5 mm, P  < .001), relative to the rested supine position. Femoral flexion was associated with posterior translation of the femoral head ( P  = .038). Femoral abduction was associated with medial translation of the femoral head ( P  = .042). Higher femoral anteversion and smaller alpha angle were associated with a higher total magnitude of femoral head translation in the anterior-posterior direction ( P  < .04). Smaller femoral anteversion, higher acetabular inclination, smaller lateral center-edge angle, and lower neck-shaft angle were associated with a higher total magnitude of femoral head translation in the superior-inferior direction ( P ≤  .03)., Conclusion: Our study demonstrated that, during passive physiologic movement, asymptomatic hips on average translated up to 2 mm (with up to 7 mm maximum translation in some positions), which is potentially related to hip rotations and morphology. Further investigations are warranted to understand the normal and pathologic hip translations and their impact on hip function (ie, instability and impingement)., Competing Interests: One or more of the authors has declared the following potential conflict of interest or source of funding: This study received funding support from the Children's Hospital Orthopaedic Surgery Foundation and Boston Children's Hospital Faculty Council. A.M.K. is a paid consultant for Miach Orthopaedics, Inc, and maintained a conflict-of-interest management plan that was approved by Boston Children's Hospital and Harvard Medical School during the conduct of the trial, with oversight by both conflict-of-interest committees and the institutional review board of Boston Children's Hospital. Y.J.K holds stocks or stock options at Cytex and Imagen and is an unpaid consultant at Orthopediatrics. A.E. received education payments from Arthrex and CGG Medical. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto., (© The Author(s) 2024.)

To validate 3D methods for femoral version measurement, we asked: (1) Can a fully automated segmentation of the entire femur and 3D measurement of femoral version using a neck based method and a head-shaft based method be performed? (2) How do automatic 3D-based computed tomography (CT) measurements of femoral version compare to the most commonly used 2D-based measurements utilizing four different landmarks? Retrospective study (May 2017 to June 2018) evaluating 45 symptomatic patients (57 hips, mean age 18.7 ± 5.1 years) undergoing pelvic and femoral CT. Femoral version was assessed using four previously described methods (Lee, Reikeras, Tomczak, and Murphy). Fully-automated segmentation yielded 3D femur models used to measure femoral version via femoral neck- and head-shaft approaches. Mean femoral version with 95% confidence intervals, and intraclass correlation coefficients were calculated, and Bland-Altman analysis was performed. Automatic 3D segmentation was highly accurate, with mean dice coefficients of 0.98 ± 0.03 and 0.97 ± 0.02 for femur/pelvis, respectively. Mean difference between 3D head-shaft- (27.4 ± 16.6°) and 3D neck methods (12.9 ± 13.7°) was 14.5 ± 10.7° (p < 0.001). The 3D neck method was closer to the proximal Lee (-2.4 ± 5.9°, -4.4 to 0.5°, p = 0.009) and Reikeras (2 ± 5.6°, 95% CI: 0.2 to 3.8°, p = 0.03) methods. The 3D head-shaft method was closer to the distal Tomczak (-1.3 ± 7.5°, 95% CI: -3.8 to 1.1°, p = 0.57) and Murphy (1.5 ± 5.4°, -0.3 to 3.3°, p = 0.12) methods. Automatic 3D neck-based-/head-shaft methods yielded femoral version angles comparable to the proximal/distal 2D-based methods, when applying fully-automated segmentations., (© 2024 The Authors. Journal of Orthopaedic Research® published by Wiley Periodicals LLC on behalf of Orthopaedic Research Society.)

Background: The sphericity of the femoral head is a metric used to evaluate hip pathologies and is associated with the development of osteoarthritis and femoral-acetabular impingement., Aim: To analyze the three-dimensional asphericity of the femoral head of asymptomatic pediatric hips. We hypothesized that femoral head asphericity will vary significantly between male and female pediatric hips and increase with age in both sexes., Methods: Computed tomography scans were obtained on 158 children and adolescents from a single institution in the United States (8-18 years; 50% male) without hip pain. Proximal femoral measurements including the femoral head diameter, femoral head volume, residual volume, asphericity index, and local diameter difference were used to evaluate femoral head sphericity., Results: In both sexes, the residual volume increased by age ( P < 0.05). Despite significantly smaller femoral head size in older ages (> 13 years) in females, there were no sex-differences in residual volume and aspherity index. There were no age-related changes in mean diameter difference in both sexes ( P = 0.07) with no significant sex-differences across different age groups ( P = 0.06). In contrast, there were significant increases in local aspherity (maximum diameter difference) across whole surface of the femoral head and all quadrants except the inferior regions in males ( P = 0.03). There were no sex-differences in maximum diameter difference at any regions and age group ( P > 0.05). Increased alpha angle was only correlated to increased mean diameter difference across overall surface of the femoral head ( P = 0.024)., Conclusion: There is a substantial localized asphericity in asymptomatic hips which increases with age in. While 2D measured alpha angle can capture overall asphericity of the femoral head, it may not be sensitive enough to represent regional asphericity patterns., Competing Interests: Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article., (©The Author(s) 2024. Published by Baishideng Publishing Group Inc. All rights reserved.)

Background: There is limited evidence supporting the value of morphological parameters on post-reduction magnetic resonance imaging (MRI) to predict long-term residual acetabular dysplasia (RAD) after closed or open reduction for the treatment of developmental dysplasia of the hip (DDH)., Methods: We performed a retrospective study of 42 patients (47 hips) undergoing open or closed reduction with a minimum 10 years of follow-up; 39 (83%) of the hips were in female patients, and the median age at reduction was 6.3 months (interquartile range [IQR], 3.3 to 8.9 months). RAD was defined as additional surgery with an acetabular index >2 standard deviations above the age- and sex-specific population-based mean value or Severin classification grade of >2 at last follow-up. Acetabular version and depth-width ratio, coronal and axial femoroacetabular distance, cartilaginous and osseous acetabular indices, transverse ligament thickness, and the thickness of the medial and lateral (limbus) acetabular cartilage were measured on post-reduction MRI., Results: At the time of final follow-up, 24 (51%) of the hips had no RAD; 23 (49%) reached a failure end point at a median of 11.4 years (IQR, 7.6 to 15.4 years). Most post-reduction MRI measurements, with the exception of the cartilaginous acetabular index, revealed a significant distinction between the group with RAD and the group with no RAD when mean values were compared. The coronal femoroacetabular distance (area under the receiver operating characteristic curve [AUC], 0.95; 95% confidence interval [CI], 0.90 to 1.00), with a 5-mm cutoff, and limbus thickness (AUC, 0.91; 95% CI, 0.83 to 0.99), with a 4-mm cutoff, had the highest discriminatory ability. A 5-mm cutoff for the coronal femoroacetabular distance produced 96% sensitivity (95% CI, 78% to 100%), 83% specificity (95% CI, 63% to 95%), 85% positive predictive value (95% CI, 65% to 96%), and 95% negative predictive value (95% CI, 76% to 100%). A 4-mm cutoff for limbus thickness had 96% sensitivity (95% CI, 78% to 100%), 63% specificity (95% CI, 41% to 81%), 71% positive predictive value (95% CI, 52% to 86%), and 94% negative predictive value (95% CI, 70% to 100%)., Conclusions: Coronal femoroacetabular distance, a quantitative metric assessing a reduction's concentricity, and limbus thickness, a quantitative metric assessing the acetabulum's cartilaginous component, help to predict hips that will have RAD in the long term after closed or open reduction., Level of Evidence: Diagnostic Level IV . See Instructions for Authors for a complete description of levels of evidence., Competing Interests: Disclosure: This work was funded in part by the Swiss National Science Foundation Grant no. 181643. The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article ( http://links.lww.com/JBJS/H781 )., (Copyright © 2023 by The Journal of Bone and Joint Surgery, Incorporated.)

Background: Extensive literature documents the adverse sequelae of delayed diagnosis of slipped capital femoral epiphysis (SCFE), including worsening deformity and surgical complications. Less is known about predictors of delayed diagnosis of SCFE, particularly the effects of social determinants of health. The purpose of this study was to evaluate the impact of insurance type, family structure, and neighborhood-level socioeconomic vulnerability on the delay of SCFE diagnosis., Methods: We reviewed medical records of patients who underwent surgical fixation for stable SCFE at a tertiary pediatric hospital from 2002 to 2021. We abstracted data on demographic characteristics, insurance status, family structure, home address, and symptom duration. We measured diagnostic delay in weeks from the date of symptom onset to diagnosis. We then geocoded patient addresses to determine their Census tract-level U.S. Centers for Disease Control and Prevention (CDC) and Agency for Toxic Substances and Disease Registry (ATSDR) Social Vulnerability Index (SVI), using U.S. Census and American Community Survey data. We performed 3 separate logistic regression models to examine the effects of (1) insurance status, (2) family structure, and (3) SVI on a delay of ≥12 weeks (reference, <12 weeks). We adjusted for age, sex, weight status, number of siblings, and calendar year., Results: We identified 351 patients with SCFE; 37% (129) had a diagnostic delay of ≥12 weeks. In multivariable logistic regression models, patients with public insurance were more likely to have a delay of ≥12 weeks than patients with private insurance (adjusted odds ratio [OR], 1.83 [95% confidence interval (CI), 1.12 to 2.97]; p = 0.015) and patients from single-guardian households were more likely to have a delay of ≥12 weeks than patients from multiguardian households (adjusted OR, 1.95 [95% CI, 1.11 to 3.45]; p = 0.021). We did not observe a significant increase in the odds of delay among patients in the highest quartile of overall SVI compared with patients from the lower 3 quartiles, in both the U.S. comparison (adjusted OR, 1.43 [95% CI, 0.79 to 2.58]; p = 0.24) and the Massachusetts comparison (adjusted OR, 1.45 [95% CI, 0.79 to 2.66]; p = 0.23)., Conclusions: The delay in diagnosis of SCFE remains a concern, with 37% of patients with SCFE presenting with delay of ≥12 weeks. Public insurance and single-guardian households emerged as independent risk factors for diagnostic delay. Interventions to reduce delay may consider focusing on publicly insured patients and those from single-guardian households., Level of Evidence: Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence., Competing Interests: Disclosure: The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article ( http://links.lww.com/JBJS/H707 )., (Copyright © 2023 by The Journal of Bone and Joint Surgery, Incorporated.)

Background: Treating patients with symptomatic hips after healed Legg-Calvé-Perthes disease (LCPD) is challenging, mainly because of the complexity of the deformity. We performed a retrospective study to evaluate clinical and radiographic outcomes, measure the survival rate, and identify predictors of failure following a surgical hip dislocation (SHD) with femoral-head reshaping and relative femoral-neck lengthening for the treatment of symptomatic residual hip deformity after healed LCPD., Methods: We identified 60 patients undergoing SHD for the treatment of symptomatic residual LCPD deformity. Fifty-one (85%) of the patients (mean age, 16.3 ± 4.7 years; 21 male patients [41%]), were followed ≥4 years after surgery. We defined surgical failure as conversion to, or recommendation for, total hip arthroplasty (THA) or a Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain score of ≥10 at the most recent follow-up. We used a multivariable Cox proportional hazards model to identify factors that were predictive of failure. The rate of survival free from failure was estimated using a Kaplan-Meier curve., Results: Twenty (39%) of the patients met 1 of the end-point criteria for surgical failure, while the hips of the remaining 31 (61%) of the patients were successfully preserved at a median follow-up of 10.2 years (interquartile range, 5.7 to 12.9 years). The estimated survival was 80% (95% confidence interval [CI] = 70% to 92%) at 5 years and 66% (95% CI = 53% to 81%) at 10 years. Independent factors associated with surgical failure were the severity of preoperative pain as assessed by the WOMAC pain score (hazard ratio [HR] = 1.16; 95% CI = 1.03 to 1.30; p = 0.01) and the severity of the deformity as assessed by the anteroposterior alpha angle (HR = 1.06; 95% CI = 1.01 to 1.11; p = 0.01)., Conclusions: We found that SHD with relative femoral-neck lengthening and osteochondroplasty of the femoral head-neck junction was associated with improved deformity as assessed radiographically and decreased pain and symptoms of stiffness among patients with symptomatic residual LCPD deformity. Preoperative pain and deformity were identified as predictors of surgical failure. Further research is needed to establish the role of SHD and other procedures in preserving the hip over the long term., Level of Evidence: Therapeutic L evel IV . See Instructions for Authors for a complete description of levels of evidence., Competing Interests: Disclosure: The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article ( http://links.lww.com/JBJS/H636 )., (Copyright © 2023 by The Journal of Bone and Joint Surgery, Incorporated.)

Ehlers-Danlos Syndrome (EDS) is a rare disease affecting the skin, joints, vasculature, and internal organs. Approximately 85% of those affected are categorized as the hypermobile type (hEDS), which is associated with numerous medical and psychiatric comorbidities, including chronic pain. Additionally, approximately 71% of patients with hEDS undergo at least one surgical procedure; however, indicators for surgery and pain outcomes after surgery are poorly understood. This preliminary study used a medical chart review to identify the frequency and nature of comorbidities in a cohort of adolescents and young adult patients with hEDS and a surgical history compared to those without a surgical history. Results showed that patients diagnosed with hEDS who underwent surgery reported significantly more comorbidities (e.g., CRPS, IBS, Fibromyalgia, POTS, hypothyroidism, etc.) than those who did not have surgery. Seventy percent of individuals who presented for surgery fell within the categories of orthopedic, gastrointestinal, or laparoscopic/endometriosis-related surgeries. Identifying patients with hEDS who are at risk for needing surgery will help identify the mechanisms contributing to risk factors for poor surgical outcomes. The results of this study may be instructive in the management and care of hEDS patients undergoing surgery.

Introduction: The deleterious influence of increased mechanical forces on capital femoral epiphysis development is well established; however, the growth of the physis in the absence of such forces remains unclear. The hips of non-ambulatory cerebral palsy (CP) patients provide a weight-restricted (partial weightbearing) model which can elucidate the influence of decreased mechanical forces on the development of physis morphology, including features related to development of slipped capital femoral epiphysis (SCFE). Here we used 3D image analysis to compare the physis morphology of children with non-ambulatory CP, as a model for abnormal hip loading, with age-matched native hips., Materials and Methods: CT images of 98 non-ambulatory CP hips (8-15 years) and 80 age-matched native control hips were used to measure height, width, and length of the tubercle, depth, width, and length of the metaphyseal fossa, and cupping height across different epiphyseal regions. The impact of age on morphology was assessed using Pearson correlations. Mixed linear model was used to compare the quantified morphological features between partial weightbearing hips and full weightbearing controls., Results: In partial weightbearing hips, tubercle height and length along with fossa depth and length significantly decreased with age, while peripheral cupping height increased with age (r > 0.2, P < 0.04). Compared to normally loaded (full weightbearing) hips and across all age groups, partially weightbearing hips' epiphyseal tubercle height and length were smaller (P < .05), metaphyseal fossa depth was larger (P < .01), and posterior, inferior, and anterior peripheral cupping heights were smaller (P < .01)., Conclusions: Smaller epiphyseal tubercle and peripheral cupping with greater metaphyseal fossa size in partial weightbearing hips suggests that the growing capital femoral epiphysis requires mechanical stimulus to adequately develop epiphyseal stabilizers. Deposit low prevalence and relevance of SCFE in CP, these findings highlight both the role of normal joint loading in proper physis development and how chronic abnormal loading may contribute to various pathomorphological changes of the proximal femur (i.e., capital femoral epiphysis)., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Recent investigations suggest that physeal morphologic features have a major role in the capital femoral epiphysis stability and slipped capital femoral epiphysis (SCFE) pathology, with a smaller epiphyseal tubercle and larger peripheral cupping of the femoral epiphysis being present in hips with progressive SCFE compared to healthy controls. Yet, little is known on the causal versus remodeling nature of these associations. This study aimed to use preoperative magnetic resonance imaging (MRI) of patients with unilateral SCFE to perform a comparison of the morphology of the epiphyseal tubercle, metaphyseal fossa, and peripheral cupping in hips with SCFE versus the contralateral uninvolved hips. Preoperative MRIs from 22 unilateral SCFE patients were used to quantify the morphological features of the epiphyseal tubercle (height, width, and length), metaphyseal fossa (depth, width, and length), and peripheral cupping height in three dimension. The quantified anatomical features were compared between hips with SCFE and the contralateral uninvolved side across the whole cohort and within SCFE severity subgroups using paired t-test. We found significantly smaller epiphyseal tubercle heights (p < 0.001) across all severities of SCFE when compared to their uninvolved contralateral side. There was a marginally smaller metaphyseal fossa length (p = 0.05) in SCFE hips compared to their contralateral uninvolved hips, with mild SCFE hips specifically having smaller fossa and epiphyseal lengths (p < 0.05) than their contralateral uninvolved side. There were no side-to-side differences in any other features of the epiphyseal tubercle, metaphyseal fossa and peripheral cupping across all severities (p > 0.05). These findings suggest a potential causal role of epiphyseal tubercle in SCFE pathogenesis., (© 2023 Orthopaedic Research Society. Published by Wiley Periodicals LLC.)

Introduction: In situ pinning is an accepted treatment for stable slipped capital femoral epiphysis. However, residual deformity of severe slipped capital femoral epiphysis can cause femoroacetabular impingement and forced external rotation., Purpose/questions: The aim of this study was to evaluate the (1) hip external rotation and internal rotation in flexion, (2) hip impingement location, and (3) impingement frequency in early flexion in severe slipped capital femoral epiphysis patients after in situ pinning using three-dimensional computed tomography., Patients and Methods: A retrospective Institutional Review Board-approved study evaluating 22 patients (26 hips) with severe slipped capital femoral epiphysis (slip angle > 60°) using postoperative three-dimensional computed tomography after in situ pinning was performed. Mean age at slipped capital femoral epiphysis diagnosis was 13 ± 2 years (58% male, four patients bilateral, 23% unstable, 85% chronic). Patients were compared to contralateral asymptomatic hips (15 hips) with unilateral slipped capital femoral epiphysis (control group). Pelvic three-dimensional computed tomography after in situ pinning was used to generate three-dimensional models. Specific software was used to determine range of motion and impingement location (equidistant method). And 22 hips (85%) underwent subsequent surgery., Results: (1) Severe slipped capital femoral epiphysis patients had significantly (p < 0.001) decreased hip flexion (43 ± 40°) and internal rotation in 90° of flexion (-16 ± 21°, IRF-90°) compared to control group (122 ± 9° and 36 ± 11°). (2) Femoral impingement in maximal flexion was located anterior to anterior-superior (27% on 3 o'clock and 27% on 1 o'clock) of severe slipped capital femoral epiphysis patients and located anterior to anterior-inferior (38% on 3 o'clock and 35% on 4 o'clock) in IRF-90°. (3) However, 21 hips (81%) had flexion < 90° and 22 hips (85%) had < 10° of IRF-90° due to hip impingement and 21 hips (81%) had forced external rotation in 90° of flexion (< 0° of IRF-90°)., Conclusion: After in situ pinning, patient-specific three-dimensional models showed restricted flexion and IRF-90° and forced external rotation in 90° of flexion due to early hip impingement and residual deformity in most of the severe slipped capital femoral epiphysis patients. This could help to plan subsequent hip preservation surgery, such as hip arthroscopy or femoral (derotation) osteotomy., Competing Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (© The Author(s) 2023.)

Background: The Bernese periacetabular osteotomy (PAO) is controversial as a treatment for symptomatic acetabular dysplasia in patients ≥40 years of age. We conducted a retrospective study to evaluate the outcomes, measure the survival rate, and identify factors associated with PAO failure in patients ≥40 years of age., Methods: We performed a retrospective study of patients ≥40 years of age undergoing PAO. Study eligibility criteria were met by 166 patients (149 women; mean age, 44 ± 3 years), and 145 (87%) were followed for ≥4 years after PAO. We used a Kaplan-Meier curve with right-censoring to calculate survivorship, with "failure" defined as either conversion to or recommendation for total hip arthroplasty or a Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain score of ≥10 at the most recent follow-up. We used simple logistic regression models to determine whether any preoperative characteristics were significantly associated with PAO failure., Results: The median follow-up time was 9.6 years (range, 4.2 to 22.5 years). Sixty-one of 145 hips (42%, 95% confidence interval [CI] = 34% to 51%) experienced PAO failure during follow-up. The median survival time was 15.5 years (95% CI = 13.4 to 22.1 years). The median survival time was longer for hips with no or mild preoperative osteoarthritis: 17.0 years for Tönnis grade 0, 14.6 years for grade 1, and 12.9 years for grade 2. Higher preoperative Tönnis arthritis grades (p = 0.03) and worse WOMAC function scores (p < 0.001) were associated with an increased likelihood of failure., Conclusions: PAO is usually effective at improving function and is effective at preserving the hip in patients ≥40 years of age provided that they have good preoperative function and no or mild preoperative osteoarthritis (Tönnis grade 0 or 1). Patients who are ≥40 years old with advanced preoperative osteoarthritis (Tönnis grade 2) and those with poor preoperative dysfunction have a high risk of therapeutic failure after PAO., Level of Evidence: Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence., Competing Interests: Disclosure: The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article ( http://links.lww.com/JBJS/H561 )., (Copyright © 2023 by The Journal of Bone and Joint Surgery, Incorporated.)

Background: Full-thickness acetabular cartilage lesions are common findings during primary surgical treatment of femoroacetabular impingement (FAI)., Purpose: To evaluate clinical outcomes after acetabular microfracture performed during FAI surgery in a prospective, multicenter cohort., Study Design: Cohort Study; Level of evidence, 3., Methods: Patients with FAI who had failed nonoperative management were prospectively enrolled in a multicenter cohort. Preoperative and postoperative (mean follow-up, 4.3 years) patient-reported outcome measures were obtained with a follow-up rate of 81.6% (621/761 hips), including 54 patients who underwent acetabular microfracture. Patient characteristics, radiographic parameters, intraoperative disease severity, and operative procedures were analyzed. Propensity matching using linear regression was used to match 54 hips with microfracture to 162 control hips (1:3) to control for confounding variables. Subanalyses of hips ≤35 and >35 years of age with propensity matching were also performed., Results: Patients who underwent acetabular microfracture were more likely to be male (81.8% vs 40.9%; P < .001), be older in age (35.0 vs 29.9 years; P = .001), have a higher body mass index (27.2 vs 25.0; P = .001), and have a greater alpha angle (69.6° vs 62.3°; P < .001) compared with the nonmicrofracture cohort (n = 533). After propensity matching to control for covariates, patients treated with microfracture displayed no differences in the modified Harris Hip Score or Hip Disability and Osteoarthritis Outcome Score ( P = .22-.95) but were more likely to undergo total hip arthroplasty (THA) (13% [7/54] compared with 4% [6/162] in the control group; P = .002), and age >35 years was associated with conversion to THA after microfracture. Microfracture performed at or before 35 years of age portended good outcomes with no significant risk of conversion to THA at the most recent follow-up., Conclusion: Microfracture of acetabular cartilage defects appears to be safe and associated with reliably improved short- to mid-term results in younger patients; modified expectations should be realized when full-thickness chondral lesions are identified in patients >35 years of age.

Case: An adolescent female dancer with excessive femoral anteversion presented with posterior and anterior hip pain aggravated by poses that required extension and external rotation. Imaging revealed an atypical cam deformity of the posterior head-neck junction. During surgery, the posterior head-neck junction was observed to impinge on the posterior acetabulum with anterior subluxation of the hip. After a derotational femoral osteotomy, the patient experienced resolution of her symptoms., Conclusion: Excessive femoral anteversion can lead to reactive cam deformity, posterior intra-articular impingement, and anterior hip instability in patients who require repetitive hip extension and external rotation, such as ballet dancers., Competing Interests: Disclosure: The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article (http://links.lww.com/JBJSCC/C128)., (Copyright © 2023 by The Journal of Bone and Joint Surgery, Incorporated.)

Background: Severe slipped capital femoral epiphysis (SCFE) leads to femoroacetabular impingement and restricted hip motion. We investigated the improvement of impingement-free flexion and internal rotation (IR) in 90 degrees of flexion following a simulated osteochondroplasty, a derotation osteotomy, and a combined flexion-derotation osteotomy in severe SCFE patients using 3D-CT-based collision detection software., Methods: Preoperative pelvic CT of 18 untreated patients (21 hips) with severe SCFE (slip-angle>60 degrees) was used to generate patient-specific 3D models. The contralateral hips of the 15 patients with unilateral SCFE served as the control group. There were 14 male hips (mean age 13±2 y). No treatment was performed before CT. Specific collision detection software was used for the calculation of impingement-free flexion and IR in 90 degrees of flexion and simulation of osteochondroplasty, derotation osteotomy, and combined flexion-derotation osteotomy., Results: Osteochondroplasty alone improved impingement-free motion but compared with the uninvolved contralateral control group, severe SCFE hips had persistently significantly decreased motion (mean flexion 59±32 degrees vs. 122±9 degrees, P <0.001; mean IR in 90 degrees of flexion -5±14 degrees vs. 36±11 degrees, P <0.001). Similarly, the impingement-free motion was improved after derotation osteotomy, and impingement-free flexion after a 30 degrees derotation was equivalent to the control group (113± 42 degrees vs. 122±9 degrees, P =0.052). However, even after the 30 degrees derotation, the impingement-free IR in 90 degrees of flexion persisted lower (13±15 degrees vs. 36±11 degrees, P <0.001). Following the simulation of flexion-derotation osteotomy, mean impingement-free flexion and IR in 90 degrees of flexion increased for combined correction of 20 degrees (20 degrees flexion and 20 degrees derotation) and 30 degrees (30 degrees flexion and 30 degrees derotation). Although mean flexion was equivalent to the control group for both (20 degrees and 30 degrees) combined correction, the mean IR in 90 degrees of flexion persisted decreased, even after the 30 degrees combined flexion-derotation (22±22 degrees vs. 36 degrees±11, P =0.009)., Conclusions: Simulation of derotation-osteotomy (30 degrees correction) and flexion-derotation-osteotomy (20 degrees correction) normalized hip flexion for severe SCFE patients, but IR in 90 degrees of flexion persisted slightly lower despite significant improvement. Not all SCFE patients had improved hip motion with the performed simulations; therefore, some patients may need a higher degree of correction or combined treatment with osteotomy and cam-resection, although not directly investigated in this study. Patient-specific 3D-models could help individual preoperative planning for severe SCFE patients to normalize the hip motion., Level of Evidence: III, case-control study., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc.)

The purpose of this study was to review the current literature on perioperative pain management in hip arthroscopy, periacetabular osteotomy and surgical hip dislocation. A systematic review of the literature published from January 2000 to December 2022 was performed. Selection criteria included published randomized controlled trials, prospective reviews and retrospective reviews of all human subjects undergoing hip preservation surgery. Exclusion criteria included case reports, animal studies and studies not reporting perioperative pain control protocols. Thirty-four studies included hip arthroscopy in which peripheral nerve blocks were associated with a significant reduction in pain score ( P  = 0.037) compared with general anesthesia alone. However, no pain control modality was associated with a significant difference in postanesthesia care unit opioid use ( P  = 0.127) or length of stay ( P  = 0.251) compared with general anesthesia alone. Falls were the most common complication reported, accounting for 37% of all complications. Five studies included periacetabular osteotomy and surgical hip dislocation in which peripheral nerve blocks were associated with an 18% reduction in pain on postoperative Day 2, a 48% reduction in cumulative opioid use on postoperative Day 2 and a 40% reduction in hospital stay. Due to the low sample size of the periacetabular osteotomy and surgical hip dislocation studies, we were unable to determine the significant difference between the means. Due to significant between-study heterogeneity, additional studies with congruent outcome measures need to be conducted to determine the efficacy of regional anesthesia in hip arthroscopy, periacetabular osteotomy and surgical hip dislocation., Competing Interests: None declared., (© The Author(s) 2023. Published by Oxford University Press.)

Background: Apophyseal avulsion fractures of the pelvis and hip are common injuries in adolescent athletes. However, high volume comparative studies elucidating the spectrum of injuries are largely absent from the literature. The current study provides a comprehensive analysis of demographic, anatomic, pathophysiological, clinical, and athletic-related variables associated with such injuries in an extensive population of affected adolescents., Methods: A retrospective review was performed of records of patients presenting to a single tertiary care pediatric hospital between January 1, 2005, and July 31, 2020, collecting variables including patient sex, age, body mass index, fracture location, injury mechanism, sport at the time of injury, and duration of prodromal symptoms., Results: Seven hundred nineteen fractures were identified in 709 patients. The average patient age was 14.6, and 78% of the fractures occurred in male patients. The anterior inferior iliac spine (33.4%), anterior superior iliac spine (30.5%), and ischial tuberosity (19.4%) were the most common fracture sites. The most common injury mechanisms were running (27.8%), kicking (26.7%), and falls (8.8%). The most common sports at the time of injury were soccer (38.1%), football (11.2%), and baseball (10.5%). Fracture site was significantly associated with patient sex, age, body mass index, laterality, mechanism, sport, time from injury, and presence of prodromal symptoms. The annual volume of pelvic avulsion fractures treated at the institution increased significantly from n=17 in 2005 to n=75 in 2019., Conclusions: Adolescent pelvic and hip avulsion fractures occur during a narrow window of age and skeletal maturation and are frequently sustained during sporting activities. Each fracture location is associated with certain demographic, mechanistic, and patient-specific characteristics. The associations between fracture site and patient-specific or injury-specific variables offer insights into the pathophysiology and possible underlying biomechanical risk factors that contribute to these injuries., Level of Evidence: This is a level III retrospective study., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Posterior femoroacetabular impingement (FAI) is poorly understood. Patients with increased femoral anteversion (FV) exhibit posterior hip pain., Purpose: To correlate hip impingement area with FV and with combined version and to investigate frequency of limited external rotation (ER) and hip extension (<40°, <20°, and <0°) due to posterior extra-articular ischiofemoral impingement., Study Design: Cross-sectional study; Level of evidence, 3., Methods: Osseous patient-specific three-dimensional (3D) models based on 3D computed tomography scans were generated of 37 female patients (50 hips) with positive posterior impingement test (100%) and increased FV >35° (Murphy method). Surgery was performed in 50% of patients (mean age, 30 years; 100% female). FV and acetabular version (AV) were added to calculate combined version. Subgroups of patients (24 hips) with increased combined version >70° and patients (9 valgus hips) with increased combined version >50° were analyzed. The control group (20 hips) had normal FV, normal AV, and no valgus. Bone segmentation was performed to generate 3D models of every patient. Validated 3D collision detection software was used for simulation of impingement-free hip motion (equidistant method). Impingement area was evaluated in combined 20° of ER and 20° of extension., Results: Posterior extra-articular ischiofemoral impingement occurred between the ischium and the lesser trochanter in 92% of patients with FV >35° in combined 20° of ER and 20° of extension. Impingement area in combined 20° of ER and 20° of extension was larger with increasing FV and with higher combined version; correlation was significant ( P < .001, r = 0.57, and r = 0.65). Impingement area was significantly ( P = .001) larger (681 vs 296 mm 2 ) for patients with combined version >70° (vs <70°, respectively) in combined 20° of ER and 20° of extension. All symptomatic patients with increased FV >35° (100%) had limited ER <40°, and most (88%) had limited extension <40°. The frequency of posterior intra- and extra-articular hip impingement of symptomatic patients (100% and 88%, respectively) was significantly ( P < .001) higher compared with the control group (10% and 10%, respectively). The frequency of patients with increased FV >35° with limited extension <20° (70%) and patients with limited ER <20° (54%) was significantly ( P < .001) higher compared with the control group (0% and 0%, respectively). The frequency of completely limited extension <0° (no extension) and ER <0° (no ER in extension) was significantly ( P < .001) higher for valgus hips (44%) with combined version >50° compared with patients with FV >35° (0%)., Conclusion: All patients with increased FV >35° had limited ER <40°, and most of them had limited extension <20° due to posterior intra- or extra-articular hip impingement. This is important for patient counselling, for physical therapy, and for planning of hip-preservation surgery (eg, hip arthroscopy). This finding has implications and could limit daily activities (long-stride walking), sexual activity, ballet dancing, and sports (eg, yoga or skiing), although not studied directly. Good correlation between impingement area and combined version supports evaluation of combined version in female patients with positive posterior impingement test or posterior hip pain.

Purpose: Slipped capital femoral epiphysis is a common pediatric hip disease and was associated with femoral retroversion, but femoral version was rarely measured. Therefore, mean femoral version, mean femoral neck version, and prevalence of femoral retroversion were analyzed for slipped capital femoral epiphysis patients., Methods: A retrospective observational study evaluating preoperative hip magnetic resonance imaging of 27 patients (49 hips) was performed. Twenty-seven untreated slipped capital femoral epiphysis patients (28 slipped capital femoral epiphysis hips and 21 contralateral hips, age 10-16 years) were evaluated (79% stable slipped capital femoral epiphysis, 22 patients; 43% severe slipped capital femoral epiphysis, 12 patients). Femoral version was measured using Murphy method on magnetic resonance imaging (January 2014-December 2021, rapid bilateral 3-dimensional T1 water-only Dixon-based images of pelvis and knee). All slipped capital femoral epiphysis patients underwent surgery after magnetic resonance imaging., Results: Mean femoral version of slipped capital femoral epiphysis patients (-1° ± 15°) was significantly (p < 0.001) lower compared to contralateral side (15° ± 14°). Femoral version of slipped capital femoral epiphysis patients had significantly (p < 0.001) wider range from -42° to 35° (range 77°) compared to contralateral side (-5° to 44°, range 49°). Mean femoral neck version of slipped capital femoral epiphysis patients (6° ± 15°) was lower compared to contralateral side (11° ± 12°). Fifteen slipped capital femoral epiphysis patients (54%) had absolute femoral retroversion (femoral version < 0°). Six of the 12 hips (50%) with severe slips and 4 of the 8 hips (50%) with mild slips had absolute femoral retroversion (femoral version < 0°). Ten slipped capital femoral epiphysis patients (40%) had absolute femoral neck retroversion (femoral neck version < 0°)., Conclusion: Although slipped capital femoral epiphysis patients showed asymmetrically lower femoral version compared to contralateral side, there was a wide range of femoral version, underlining the importance of patient-specific femoral version analysis on preoperative magnetic resonance imaging. Absolute femoral retroversion was prevalent in half of slipped capital femoral epiphysis patients, in half of severe slipped capital femoral epiphysis patients, and in half of mild slipped capital femoral epiphysis patients. This has implications for anterior hip impingement and for surgical treatment with in situ pinning or femoral osteotomy (e.g. proximal femoral derotation osteotomy) or other hip preservation surgery., Competing Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (© The Author(s) 2023.)

Aims: Femoroacetabular impingement (FAI) patients report exacerbation of hip pain in deep flexion. However, the exact impingement location in deep flexion is unknown. The aim was to investigate impingement-free maximal flexion, impingement location, and if cam deformity causes hip impingement in flexion in FAI patients., Methods: A retrospective study involving 24 patients (37 hips) with FAI and femoral retroversion (femoral version (FV) < 5° per Murphy method) was performed. All patients were symptomatic (mean age 28 years (SD 9)) and had anterior hip/groin pain and a positive anterior impingement test. Cam- and pincer-type subgroups were analyzed. Patients were compared to an asymptomatic control group (26 hips). All patients underwent pelvic CT scans to generate personalized CT-based 3D models and validated software for patient-specific impingement simulation (equidistant method)., Results: Mean impingement-free flexion of patients with mixed-type FAI (110° (SD 8°)) and patients with pincer-type FAI (112° (SD 8°)) was significantly (p < 0.001) lower compared to the control group (125° (SD 13°)). The frequency of extra-articular subspine impingement was significantly (p < 0.001) increased in patients with pincer-type FAI (57%) compared to cam-type FAI (22%) in 125° flexion. Bony impingement in maximal flexion was located anterior-inferior at femoral four and five o'clock position in patients with cam-type FAI (63% (10 of 16 hips) and 37% (6 of 10 hips)), and did not involve the cam deformity. The cam deformity did not cause impingement in maximal flexion., Conclusion: Femoral impingement in maximal flexion was located anterior-inferior distal to the cam deformity. This differs to previous studies, a finding which could be important for FAI patients in order to avoid exacerbation of hip pain in deep flexion (e.g. during squats) and for hip arthroscopy (hip-preservation surgery) for planning of bone resection. Hip impingement in flexion has implications for daily activities (e.g. putting on shoes), sports, and sex.Cite this article: Bone Joint Res  2023;12(1):22-32.

Aims: Frequency of abnormal femoral and acetabular version (AV) and combinations are unclear in patients with developmental dysplasia of the hip (DDH). This study aimed to investigate femoral version (FV), the proportion of increased FV and femoral retroversion, and combined-version (CV, FV+AV) in DDH patients and acetabular-retroversion (AR)., Patients and Methods: A retrospective IRB-approved observational study was performed with 78 symptomatic DDH patients (90 hips) and 65 patients with femoroacetabular-impingement (FAI) due to AR (77 hips, diagnosis on AP radiographs). CT/MRI-based measurement of FV (Murphy method) and central AV were compared. Frequency of increased FV(FV > 25°), severely increased FV (FV > 35°) and excessive FV (FV > 45°) and of decreased FV (FV < 10°) and CV (McKibbin-index/COTAV-index) was analysed., Results: Mean FV and CV was significantly (p < 0.001) increased of DDH patients (mean ± SD of 25 ± 11° and 47 ± 18°) compared to AR (16 ± 11° and 28 ± 13°). Mean FV of female DDH patients (27 ± 16°) and AR (19 ± 12°) was significantly (p < 0.001) increased compared to male DDH patients (18 ± 13°) and AR (13 ± 8°). Frequency of increased FV (>25°) was 47% and of severely increased FV (>35°) was 23% for DDH patients. Proportion of femoral retroversion (FV < 10°) was significantly (p < 0.001) higher in patients AR (31%) compared to DDH patients (17%). 18% of DDH patients had AV > 25° combined with FV > 25°. Of patients with AR, 12% had FV < 10° combined with AV < 10°., Conclusion: Patients with DDH and AR have remarkable sex-related differences of FV and CV. Frequency of severely increased FV > 35° (23%) is considerable for patients with DDH, but 17% exhibited decreased FV, that could influence management. The different combinations underline the importance of patient-specific evaluation before open hip preservation surgery (periacetabular osteotomy and femoral derotation osteotomy) and hip-arthroscopy., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.)

Purpose: The purpose of the study was to compare the post-reduction magnetic resonance imaging morphology for hips that developed residual acetabular dysplasia, hips without residual dysplasia, and uninvolved contralateral hips in patients with unilateral developmental dysplasia of the hip undergoing closed or open reduction and had a minimum 10-year follow-up., Methods: Retrospective study of patients with unilateral dysplasia of the hip who underwent open/closed hip reduction followed by post-reduction magnetic resonance imaging. Twenty-eight patients with a mean follow-up of 13 ± 3 years were included. In the treated hips, residual dysplasia was defined as subsequent surgery for residual acetabular dysplasia or for Severin grade > 2 at latest follow-up. On post-reduction, magnetic resonance imaging measurements were performed by two readers and compared between the hips with/without residual dysplasia and the contralateral uninvolved side. Magnetic resonance imaging measurements included acetabular version, coronal/ axial femoroacetabular distance, acetabular depth-width ratio, osseous/cartilaginous acetabular indices, and medial/lateral (limbus) cartilage thickness., Results: Fifteen (54%) and 13 (46%) hips were allocated to the "no residual dysplasia" group and to the "residual dysplasia" group, respectively. All eight magnetic resonance imaging parameters differed between hips with residual dysplasia and contralateral uninvolved hips (all p < 0.05). Six of eight parameters differed (all p < 0.05) between hips with and without residual dysplasia. Among these, increased limbus thickness had the largest effect (odds ratio = 12.5; p < 0.001) for increased likelihood of residual dysplasia., Conclusions: We identified acetabular morphology and reduction quality parameters that can be reliably measured on the post-reduction magnetic resonance imaging to facilitate the differentiation between hips that develop with/without residual acetabular dysplasia at 10 years postoperatively., Level of Evidence: level III, prognostic case-control study., Competing Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (© The Author(s) 2022.)

Introduction: Slipped capital femoral epiphysis (SCFE) is the most common hip disorder in adolescent patients that can result in complex 3 dimensional (3D)-deformity and hip preservation surgery (eg, in situ pinning or proximal femoral osteotomy) is often performed. But there is little information about location of impingement.Purpose/Questions: The purpose of this study was to evaluate (1) impingement-free hip flexion and internal rotation (IR), (2) frequency of impingement in early flexion (30 to 60 degrees), and (3) location of acetabular and femoral impingement in IR in 90 degrees of flexion (IRF-90 degrees) and in maximal flexion for patients with untreated severe SCFE using preoperative 3D-computed tomography (CT) for impingement simulation., Methods: A retrospective study involving 3D-CT scans of 18 patients (21 hips) with untreated severe SCFE (slip angle>60 degrees) was performed. Preoperative CT scans were used for bone segmentation of preoperative patient-specific 3D models. Three patients (15%) had bilateral SCFE. Mean age was 13±2 (10 to 16) years and 67% were male patients (86% unstable slip, 81% chronic slip). The contralateral hips of 15 patients with unilateral SCFE were evaluated (control group). Validated software was used for 3D impingement simulation (equidistant method)., Results: (1) Impingement-free flexion (46±32 degrees) and IRF-90 degrees (-17±18 degrees) were significantly ( P <0.001) decreased in untreated severe SCFE patients compared with contralateral side (122±9 and 36±11 degrees).(2) Frequency of impingement was significantly ( P <0.001) higher in 30 and 60 degrees flexion (48% and 71%) of patients with severe SCFE compared with control group (0%).(3) Acetabular impingement conflict was located anterior-superior (SCFE patients), mostly 12 o'clock (50%) in IRF-90 degrees (70% on 2 o'clock for maximal flexion). Femoral impingement was located on anterior-superior to anterior-inferior femoral metaphysis (between 2 and 6 o'clock, 40% on 3 o'clock and 40% on 5 o'clock) in IRF-90 degrees and on anterior metaphysis (40% on 3 o'clock) in maximal flexion and frequency was significantly ( P <0.001) different compared with control group., Conclusion: Severe SCFE patients have limited hip flexion and IR due to early hip impingement using patient-specific preoperative 3D models. Because of the large variety of hip motion, individual evaluation is recommended to plan the osseous correction for severe SCFE patients., Level of Evidence: Level III., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2022 The Author(s). Published by Wolters Kluwer Health, Inc.)

Aims: To evaluate how abnormal proximal femoral anatomy affects different femoral version measurements in young patients with hip pain., Methods: First, femoral version was measured in 50 hips of symptomatic consecutively selected patients with hip pain (mean age 20 years (SD 6), 60% (n = 25) females) on preoperative CT scans using different measurement methods: Lee et al, Reikerås et al, Tomczak et al, and Murphy et al. Neck-shaft angle (NSA) and α angle were measured on coronal and radial CT images. Second, CT scans from three patients with femoral retroversion, normal femoral version, and anteversion were used to create 3D femur models, which were manipulated to generate models with different NSAs and different cam lesions, resulting in eight models per patient. Femoral version measurements were repeated on manipulated femora., Results: Comparing the different measurement methods for femoral version resulted in a maximum mean difference of 18° (95% CI 16 to 20) between the most proximal (Lee et al) and most distal (Murphy et al) methods. Higher differences in proximal and distal femoral version measurement techniques were seen in femora with greater femoral version ( r > 0.46; p < 0.001) and greater NSA ( r > 0.37; p = 0.008) between all measurement methods. In the parametric 3D manipulation analysis, differences in femoral version increased 11° and 9° in patients with high and normal femoral version, respectively, with increasing NSA (110° to 150°)., Conclusion: Measurement of femoral version angles differ depending on the method used to almost 20°, which is in the range of the aimed surgical correction in derotational femoral osteotomy and thus can be considered clinically relevant. Differences between proximal and distal measurement methods further increase by increasing femoral version and NSA. Measurement methods that take the entire proximal femur into account by using distal landmarks may produce more sensitive measurements of these differences.Cite this article: Bone Jt Open  2022;3(10):759-766.

Background: Symptomatic patients with femoroacetabular impingement (FAI) have limitations in daily activities and sports and report the exacerbation of hip pain in deep flexion. Yet, the exact impingement location in deep flexion and the effect of femoral version (FV) are unclear., Purpose: To investigate the acetabular and femoral locations of intra- or extra-articular hip impingement in flexion in patients with FAI with and without femoral retroversion., Study Design: Cross-sectional study; Level of evidence, 3., Methods: An institutional review board-approved retrospective study involving 84 hips (68 participants) was performed. Of these, symptomatic patients (37 hips) with anterior FAI and femoral retroversion (FV <5°) were compared with symptomatic patients (21 hips) with anterior FAI (normal FV) and with a control group (26 asymptomatic hips without FAI and normal FV). All patients were symptomatic, had anterior hip pain, and had positive anterior impingement test findings. Most of the patients had hip/groin pain in maximal flexion or deep flexion or during sports. All 84 hips underwent pelvic computed tomography (CT) to measure FV as well as validated dynamic impingement simulation with patient-specific CT-based 3-dimensional models using the equidistant method., Results: In maximal hip flexion, femoral impingement was located anterior-inferior at 4 o'clock (57%) and 5 o'clock (32%) in patients with femoral retroversion and mostly at 5 o'clock in patients without femoral retroversion (69%) and in asymptomatic controls (76%). Acetabular intra-articular impingement was located anterior-superior (2 o'clock) in all 3 groups. In 125° of flexion, patients with femoral retroversion had a significantly ( P < .001) higher prevalence of anterior extra-articular subspine impingement (54%) and anterior intra-articular impingement (89%) compared with the control group (29% and 62%, respectively)., Conclusion: Knowing the exact location of hip impingement in deep flexion has implications for surgical treatment, sports, and physical therapy and confirms previous recommendations: Deep flexion (eg, during squats/lunges) should be avoided in patients with FAI and even more in patients with femoral retroversion. Patients with femoral retroversion may benefit and have less pain when avoiding deep flexion. For these patients, the femoral location of the impingement conflict in flexion was different (anterior-inferior) and distal to the cam deformity compared with the location during the anterior impingement test (anterior-superior). This could be important for preoperative planning and bone resection (cam resection or acetabular rim trimming) during hip arthroscopy or open hip preservation surgery to ensure that the region of impingement is appropriately identified before treatment.

Aims: The aims of this study were to characterize the incidence and risk factors associated with stress fractures following periacetabular osteotomy, and to determine their effect on osteotomy union., Methods: We retrospectively reviewed all periacetabular osteotomies (PAOs) performed for developmental dysplasia of the hip (DDH) at one institution over a six-year period between 2012 and 2017. Perioperative factors were recorded, and included demographic and surgical data. Postoperatively, patients were followed for a minimum of one year with anteroposterior and false profile radiographs of the pelvis to monitor for evidence of stress fracture and union of osteotomies. We characterized the incidence and locations of stress fractures, and used univariate and multivariable analysis to identify factors predictive of stress fracture and the association of stress fracture on osteotomy union., Results: A total of 331 patients underwent PAO during the study period with 56 (15.4%) stress fractures: 46 fractures of the retroacetabular posterior column, five cases of ischiopubic stress fracture, and five cases of concurrent ischiopubic and retroacetabular stress fractures. Overall, 86% (48/56) healed without intervention. Univariate analysis revealed that stress fractures occurred more frequently in females (p = 0.040), older patients (mean age 27.6 years (SD 8.4) vs 23.8 (SD 9.0); p = 0.003), and most often with the use of the broad Mast chisel (28.5%; p < 0.001). Multivariable analysis revealed that increasing age (odds ratio (OR) 1.04; 95% CI 1.01 to 1.07; p = 0.028) and use of the broad Mast chisel (OR 5.1 (95% CI 1.3 to 19.0) compared to narrow Ganz chisel; p = 0.038) and surgeon (p = 0.043) were associated with increased risk of stress fracture. Patients with stress fractures were less likely to have healed osteotomies after one-year follow-up (76% vs 96%; p < 0.001)., Conclusion: Stress fracture of the posterior column may be an under-recognized complication following PAO, and the rate may be influenced by surgical technique. Consideration should be given to using a narrow chisel during the ischial cut to reduce the risk of stress propagation through the posterior column.Cite this article: Bone Joint J  2022;104-B(9):1017-1024.

Objectives: To investigate ultrasound (US) femoroacetabular translation measurements in female athlete patients., Methods: A prospective cross-sectional study was conducted in female athlete patients <50 years. Demographic data, Beighton score/hypermobility status, and sport participation were collected. Hip dysplasia was determined using radiographic measurements (lateral center edge angle, anterior center edge angle, Tönnis angle); femoral version angles were measured with CT or MR. Femoroacetabular translation US measures included neutral (N), neutral flexed (NF), extension external rotation/apprehension (EER) positions. Maximal difference (delta) between US measures was calculated., Results: 206/349 female hips were analyzed (median age 21.2 years [range, 12-49.5]). The primary sport group was performing arts (45%, 92/206). Mean Beighton score was 5.2 (SD, 2.5) with 61% (129/206) of hips exhibiting hypermobility (Beighton score ≥5). For each additional unit of Beighton score, N US measurement increased by 0.7 mm (β = 0.7; 95% confidence interval [CI] = 0.22-1.25; P < .001), NF by 1 mm ( β = 0.9; 95% CI = 0.3-1.43; P = .002) and EER by 0.8 mm ( β = 0.8; 95% CI = 0.27-1.37; P < .001) when adjusting for age and dysplasia status. A positive correlation was detected between NF (r = 0.19; 95% CI = 0.05-0.33; P = .007) and EER (r = 0.19; 95% CI = 0.05-0.32; P = .01) with Tönnis angle and a negative correlation between the delta and femoral version (r = -0.20; 95% CI = -0.35 to 0.03; P = .02). No difference in US measures was detected across sport groups (N [P = .24], NF [P = .51], EER [P = .20], delta [P = .07])., Conclusion: Beighton score was independently associated with dynamic US measures in female athlete patients who are not hypermobile when controlling for other factors., (© 2021 American Institute of Ultrasound in Medicine.)

Aims: The frequency of severe femoral retroversion is unclear in patients with femoroacetabular impingement (FAI). This study aimed to investigate mean femoral version (FV), the frequency of absolute femoral retroversion, and the combination of decreased FV and acetabular retroversion (AR) in symptomatic patients with FAI subtypes., Methods: A retrospective institutional review board-approved observational study was performed with 333 symptomatic patients (384 hips) with hip pain due to FAI evaluated for hip preservation surgery. Overall, 142 patients (165 hips) had cam-type FAI, while 118 patients (137 hips) had mixed-type FAI. The allocation to each subgroup was based on reference values calculated on anteroposterior radiographs. CT/MRI-based measurement of FV (Murphy method) and AV were retrospectively compared among five FAI subgroups. Frequency of decreased FV < 10°, severely decreased FV < 5°, and absolute femoral retroversion (FV < 0°) was analyzed., Results: A significantly (p < 0.001) lower mean FV was found in patients with cam-type FAI (15° (SD 10°)), and in patients with mixed-type FAI (17° (SD 11°)) compared to severe over-coverage (20° (SD 12°). Frequency of decreased FV < 10° was significantly (p < 0.001) higher in patients with cam-type FAI (28%, 46 hips) and in patients with over-coverage (29%, 11 hips) compared to severe over-coverage (12%, 5 hips). Absolute femoral retroversion (FV < 0°) was found in 13% (5 hips) of patients with over-coverage, 6% (10 hips) of patients with cam-type FAI, and 5% (7 hips) of patients with mixed-type FAI. The frequency of decreased FV< 10° combined with acetabular retroversion (AV < 10°) was 6% (8 hips) in patients with mixed-type FAI and 5% (20 hips) in all FAI patients. Of patients with over-coverage, 11% (4 hips) had decreased FV < 10° combined with acetabular retroversion (AV < 10°)., Conclusion: Patients with cam-type FAI had a considerable proportion (28%) of decreased FV < 10° and 6% had absolute femoral retroversion (FV < 0°), even more for patients with pincer-type FAI due to over-coverage (29% and 13%). This could be important for patients evaluated for open hip preservation surgery or hip arthroscopy, and each patient requires careful personalized evaluation. Cite this article: Bone Jt Open  2022;3(7):557-565.

Case: Wiedemann-Steiner syndrome (WDSTS) is a rare autosomal dominant disorder with many phenotypic characteristics, including multiple orthopaedic manifestations. Of these, symptomatic significant hip dysplasia has been variably noted. Nonetheless, few reports detail surgical treatment for these patients, including hip preservation for those with hip dysplasia., Conclusion: Periacetabular osteotomy allows for the correction of severe hip dysplasia in patients with WDSTS. With proper recognition and timely intervention, adequate care may be provided for these patients., Competing Interests: Disclosure: The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article (http://links.lww.com/JBJSCC/B778)., (Copyright © 2022 by The Journal of Bone and Joint Surgery, Incorporated.)

Purpose: To determine and stratify femoral version in Legg-Calvé-Perthes disease (LCPD), and to compare the femoral version between the LCPD hip and the contralateral unaffected hip., Methods: We performed a retrospective review of 45 patients with unilateral LCPD who had available CT scan through the hips and knees between January 2000 and June 2017. There were 34 (76%) male cases with a mean age of 14 years (sd 4.69). Two independent readers measured femoral version on the affected and the unaffected contralateral femur. Femoral version was classified as follows: severely decreased version (< 10°); moderately decreased (10° to 14°); normal femoral version range (15° to 20°); moderately increased (21° to 25°); and severely increased version (> 25°)., Results: LCPD hips had predominantly increased femoral version (38% severely increased anteversion, 24% moderately increased anteversion), while 51% of the contralateral unaffected hips had normal femoral version (p < 0.001). LCPD hips had higher mean femoral version than the contralateral, unaffected side (mean difference = 13 o ; 95% confidence iterval 10 o to 16 o ; p < 0.001). As the version of the affected hip increased, so did the discrepancy between sides. No effect of sex on the LCPD femoral version was detected (p = 0.34)., Conclusion: This study included a selected group of patients with unilateral LCPD and available CT scans obtained for surgical planning. The femoral version was asymmetric, with a high proportion of excessive anteversion observed at later stages of disease in the affected hips. Future studies will be necessary to determine the pathogenesis of increased femoral version associated with LCPD., Level of Evidence: Level IV, retrospective study., (Copyright © 2021, The author(s).)

Introduction: This paper aims to review the indications criteria for the surgical treatment of adolescents with hip osteoarthritis and summarize the contemporary techniques that orthopaedic surgeons can apply for hip reconstruction., Discussion: Hip osteoarthritis remains a concerning burden to North American society. While the rate of total hip replacement (THR) in younger patients has increased in the last decades, younger patients may have a higher risk of revision hip replacement because of their increased level of activity and expected patient longevity compared with the elderly. Increased demand for multiple revision surgeries is a concern for the adolescent patient. Although in general THR has been increasingly recommended for the treatment of end-stage osteoarthritis secondary to pediatric hip disorders, hip arthrodesis remains a beneficial alternative for the treatment of severe hip disease secondary to infection and for patients who desire to engage in a very active lifestyle. Hip preservation procedures are ideally performed in the prearthritic stage or in hips with minimal degeneration to preserve the joint and achieve the most optimal outcomes. However, adolescents and young adults with moderate and rarely advanced arthritis may benefit from surgical treatment using hip preservation techniques., Conclusions: Treatment of adolescents with pain and dysfunction because of end-stage hip disease is challenging and controversial. THR and arthrodesis are the 2 principal alternatives. However, in particular circumstances, hip reconstruction may be recommended., Competing Interests: The author declares no conflicts of interest., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Background: The epiphyseal tubercle, the corresponding metaphyseal fossa, and peripheral cupping are key stabilizers of the femoral head-neck junction. Abnormal development of these features in the setting of supraphysiologic physeal stress under high forces (for example, forces that occur during sports activity) may result in a cam morphology. Although most previous studies on cam-type femoroacetabular impingement (FAI) have mainly focused on overgrowth of the peripheral cupping, little is known about detailed morphologic changes of the epiphyseal and metaphyseal bony surfaces in patients with cam morphology., Questions/purposes: (1) Does the CT-based bony morphology of the peripheral epiphyseal cupping differ between patients with a cam-type morphology and asymptomatic controls (individuals who did not have hip pain)? (2) Does the CT-based bony morphology of the epiphyseal tubercle differ between patients with a cam-type morphology and asymptomatic controls? (3) Does the CT-based bony morphology of the metaphyseal fossa differ between patients with a cam-type morphology and asymptomatic controls?, Methods: After obtaining institutional review board approval for this study, we retrospectively searched our institutional database for patients aged 8 to 15 years with a diagnosis of an idiopathic cam morphology who underwent a preoperative CT evaluation of the affected hip between 2005 and 2018 (n = 152). We excluded 96 patients with unavailable CT scans and 40 patients with prior joint diseases other than cam-type FAI. Our search resulted in 16 patients, including nine males. Six of 16 patients had a diagnosis of bilateral FAI, for whom we randomly selected one side for the analysis. Three-dimensional (3-D) models of the proximal femur were generated to quantify the size of the peripheral cupping (peripheral growth of the epiphysis around the metaphysis), epiphyseal tubercle (a beak-like prominence in the posterosuperior aspect of the epiphysis), and metaphyseal fossa (a groove on the metaphyseal surface corresponding to the epiphyseal tubercle). A general linear model was used to compare the quantified anatomic features between the FAI cohort and 80 asymptomatic hips (aged 8 to 15 years; 50% male) after adjusting for age and sex. A secondary analysis using the Wilcoxon matched-pairs signed rank test was performed to assess side-to-side differences in quantified morphological features in 10 patients with unilateral FAI., Results: After adjusting for age and sex, we found that patients with FAI had larger peripheral cupping in the anterior, posterior, superior, and inferior regions than control patients who did not have hip symptoms or radiographic signs of FAI (by 1.3- to 1.7-fold; p < 0.01 for all comparisons). The epiphyseal tubercle height and length were smaller in patients with FAI than in controls (by 0.3- to 0.6-fold; p < 0.02 for all comparisons). There was no difference in tubercle width between the groups. Metaphyseal fossa depth, width, and length were larger in patients with FAI than in controls (by 1.8- to 2.3-fold; p < 0.001 for all comparisons). For patients with unilateral FAI, we saw similar peripheral cupping but smaller epiphyseal tubercle (height and length) along with larger metaphyseal fossa (depth) in the FAI side compared with the uninvolved contralateral side., Conclusion: Consistent with prior studies, we observed more peripheral cupping in patients with cam-type FAI than control patients without hip symptoms or radiographic signs of FAI. Interestingly, the epiphyseal tubercle height and length were smaller and the metaphyseal fossa was larger in hips with cam-type FAI, suggesting varying inner bone surface morphology of the growth plate. The docking mechanism between the epiphyseal tubercle and the metaphyseal fossa is important for epiphyseal stability, particularly at early ages when the peripheral cupping is not fully developed. An underdeveloped tubercle and a large fossa could be associated with a reduction in stability, while excessive peripheral cupping growth would be a factor related to improved physeal stability. This is further supported by observed side-to-side differences in tubercle and fossa morphology in patients with unilateral FAI. Further longitudinal studies would be worthwhile to study the causality and compensatory mechanisms related to epiphyseal and metaphyseal bony morphology in pathogenesis cam-type FAI. Such information will lay the foundation for developing imaging biomarkers to predict the risk of FAI or to monitor its progress, which are critical in clinical care planning., Level of Evidence: Level III, prognostic study., Competing Interests: All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research® editors and board members are on file with the publication and can be viewed on request. Each author certifies that neither he nor she, nor any member of his or her immediate family, has funding or commercial associations (consultancies, stock ownership, equity interest, patent/licensing arrangements, etc.) that might pose a conflict of interest in connection with the submitted article., (Copyright © 2020 by the Association of Bone and Joint Surgeons.)

Background: Although femoral retroversion has been linked to the onset of slipped capital femoral epiphysis (SCFE), and may result from a rotation of the femoral epiphysis around the epiphyseal tubercle leading to femoral retroversion, femoral version has rarely been described in patients with SCFE. Furthermore, the prevalence of actual femoral retroversion and the effect of different measurement methods on femoral version angles has yet to be studied in SCFE., Questions/purposes: (1) Do femoral version and the prevalence of femoral retroversion differ between hips with SCFE and the asymptomatic contralateral side? (2) How do the mean femoral version angles and the prevalence of femoral retroversion change depending on the measurement method used? (3) What is the interobserver reliability and intraobserver reproducibility of these measurement methods?, Methods: For this retrospective, controlled, single-center study, we reviewed our institutional database for patients who were treated for unilateral SCFE and who had undergone a pelvic CT scan. During the period in question, the general indication for obtaining a CT scan was to define the surgical strategy based on the assessment of deformity severity in patients with newly diagnosed SCFE or with previous in situ fixation. After applying prespecified inclusion and exclusion criteria, we included 79 patients. The mean age was 15 ± 4 years, 48% (38 of 79) of the patients were male, and 56% (44 of 79) were obese (defined as a BMI > 95th percentile (mean BMI 34 ± 9 kg/m2). One radiology resident (6 years of experience) measured femoral version of the entire study group using five different methods. Femoral neck version was measured as the orientation of the femoral neck. Further measurement methods included the femoral head's center and differed regarding the level of landmarks for the proximal femoral reference axis. From proximal to distal, this included the most-proximal methods (Lee et al. and Reikerås et al.) and most-distal methods (Tomczak et al. and Murphy et al.). Most proximally (Lee et al. method), we used the most cephalic junction of the greater trochanter as the landmark and, most distally, we used the center base of the femoral neck superior to the lesser trochanter (Murphy et al.). The orientation of the distal femoral condyles served as the distal reference axis for all five measurement methods. All five methods were compared side-by-side (involved versus uninvolved hip), and comparisons among all five methods were performed using paired t-tests. The prevalence of femoral retroversion (< 0°) was compared using a chi-square test. A subset of patients was measured twice by the first observer and by a second orthopaedic resident (2 years of experience) to assess intraobserver reproducibility and interobserver reliability; for this assessment, we used intraclass correlation coefficients., Results: The mean femoral neck version was lower in hips with SCFE than in the contralateral side (-2° ± 13° versus 7° ± 11°; p < 0.001). This yielded a mean side-by side difference of -8° ± 11° (95% CI -11° to -6°; p < 0.001) and a higher prevalence of femoral retroversion in hips with SCFE (58% [95% CI 47% to 69%]; p < 0.001) than on the contralateral side (29% [95% CI 19% to 39%]). These differences between hips with SCFE and the contralateral side were higher and ranged from -17° ± 11° (95% CI -20° to -15°; p < 0.001) based on the method of Tomczak et al. to -22° ± 13° (95% CI -25° to -19°; p < 0.001) according to the method of Murphy et al. The mean overall femoral version angles increased for hips with SCFE using more-distal landmarks compared with more-proximal landmarks. The prevalence of femoral retroversion was higher in hips with SCFE for the proximal methods of Lee et al. and Reikerås et al. (91% [95% CI 85% to 97%] and 84% [95% CI 76% to 92%], respectively) than for the distal measurement methods of Tomczak et al. and Murphy et al. (47% [95% CI 36% to 58%] and 60% [95% CI 49% to 71%], respectively [all p < 0.001]). We detected mean differences ranging from -19° to 4° (all p < 0.005) for 8 of 10 pairwise comparisons in hips with SCFE. Among these, the greatest differences were between the most-proximal methods and the more-distal methods, with a mean difference of -19° ± 7° (95% CI -21° to -18°; p < 0.001), comparing the methods of Lee et al. and Tomczak et al. In hips with SCFE, we found excellent agreement (intraclass correlation coefficient [ICC] > 0.80) for intraobserver reproducibility (reader 1, ICC 0.93 to 0.96) and interobserver reliability (ICC 0.95 to 0.98) for all five measurement methods. Analogously, we found excellent agreement (ICC > 0.80) for intraobserver reproducibility (reader 1, range 0.91 to 0.96) and interobserver reliability (range 0.89 to 0.98) for all five measurement methods in healthy contralateral hips., Conclusion: We showed that femoral neck version is asymmetrically decreased in unilateral SCFE, and that differences increase when including the femoral head's center. Thus, to assess the full extent of an SCFE deformity, femoral version measurements should consider the position of the displaced epiphysis. The prevalence of femoral retroversion was high in patients with SCFE and increased when using proximal anatomic landmarks. Since the range of femoral version angles was wide, femoral version cannot be predicted in a given hip and must be assessed individually. Based on these findings, we believe it is worthwhile to add evaluation of femoral version to the diagnostic workup of children with SCFE. Doing so may better inform surgeons as they contemplate when to use isolated offset correction or to perform an additional femoral osteotomy for SCFE correction based on the severity of the slip and the rotational deformity. To facilitate communication among physicians and for the design of future studies, we recommend consistently reporting the applied measurement technique., Level of Evidence: Level III, prognostic study., Competing Interests: All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research® editors and board members are on file with the publication and can be viewed on request., (Copyright © 2020 by the Association of Bone and Joint Surgeons.)

Background: Contemporary studies have described the rotational mechanism in patients with slipped capital femoral epiphysis (SCFE). However, there have been limited patient imaging data and information to quantify the rotation. Determining whether the epiphysis is rotated or translated and measuring the epiphyseal displacement in all planes may facilitate planning for surgical reorientation of the epiphysis., Questions/purposes: (1) How does epiphyseal rotation and translation differ among mild, moderate, and severe SCFE? (2) Is there a correlation between epiphyseal rotation and posterior or inferior translation in hips with SCFE? (3) Does epiphyseal rotation correlate with the size of the epiphyseal tubercle or the metaphyseal fossa or with epiphyseal cupping?, Methods: We identified 51 patients (55% boys [28 of 51]; mean age 13 ± 2 years) with stable SCFE who underwent preoperative CT of the pelvis before definitive treatment. Stable SCFE was selected because unstable SCFE would not allow for accurate assessment of rotation given the complete displacement of the femoral head in relation to the neck. The epiphysis and metaphysis were segmented and reconstructed in three-dimensions (3-D) for analysis in this retrospective study. One observer (a second-year orthopaedic resident) performed the image segmentation and measurements of epiphyseal rotation and translation relative to the metaphysis, epiphyseal tubercle, metaphyseal fossa, and the epiphysis extension onto the metaphysis defined as epiphyseal cupping. To assess the reliability of the measurements, a randomly selected subset of 15 hips was remeasured by the primary examiner and by the two experienced examiners independently. We used ANOVA to calculate the intraclass and interclass correlation coefficients (ICCs) for intraobserver and interobserver reliability of rotational and translational measurements. The ICC values for rotation were 0.91 (intraobserver) and 0.87 (interobserver) and the ICC values for translation were 0.92 (intraobserver) and 0.87 (intraobserver). After adjusting for age and sex, we compared the degree of rotation and translation among mild, moderate, and severe SCFE. Pearson correlation analysis was used to assess the associations between rotation and translation and between rotation and tubercle, fossa, and cupping measurements., Results: Hips with severe SCFE had greater epiphyseal rotation than hips with mild SCFE (adjusted mean difference 21° [95% CI 11° to 31°]; p < 0.001) and hips with moderate SCFE (adjusted mean difference 13° [95% CI 3° to 23°]; p = 0.007). Epiphyseal rotation was positively correlated with posterior translation (r = 0.33 [95% CI 0.06 to 0.55]; p = 0.02) but not with inferior translation (r = 0.16 [95% CI -0.12 to 0.41]; p = 0.27). There was a positive correlation between rotation and metaphyseal fossa depth (r = 0.35 [95% CI 0.08 to 0.57]; p = 0.01), width (r = 0.41 [95% CI 0.15 to 0.61]; p = 0.003), and length (r = 0.56 [95% CI 0.38 to 0.75]; p < 0.001)., Conclusion: This study supports a rotational mechanism for the pathogenesis of SCFE. Increased rotation is associated with more severe slips, posterior epiphyseal translation, and enlargement of the metaphyseal fossa. The rotational nature of the deformity, with the center of rotation at the epiphyseal tubercle, should be considered when planning in situ fixation and realignment surgery. Avoiding placing a screw through the epiphyseal tubercle-the pivot point of rotation- may increase the stability of the epiphysis. The realignment of the epiphysis through rotation rather than simple translation is recommended during the open subcapital realignment procedure. Enlargement of the metaphyseal fossa disrupts the interlocking mechanism with the tubercle and increases epiphyseal instability. Even in the setting of a stable SCFE, an increased fossa enlargement may indicate using two screws instead of one screw, given the severity of epiphyseal rotation and the risk of instability. Further biomechanical studies should investigate the number and position of in situ fixation screws in relation to the epiphyseal tubercle and metaphyseal fossa., Level of Evidence: Level III, prognostic study., Competing Interests: All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research® editors and board members are on file with the publication and can be viewed on request. Each author certifies that neither he nor she, nor any member of his or her immediate family, has funding or commercial associations (consultancies, stock ownership, equity interest, patent/licensing arrangements, etc.) that might pose a conflict of interest in connection with the submitted article., (Copyright © 2020 by the Association of Bone and Joint Surgeons.)

Background: Femoroacetabular impingement and acetabular dysplasia have gained increased attention as nonarthritic sources of pain and dysfunction in young, active patients. To date, no standardized approach to the diagnostic evaluation of nonarthritic hip pain has been identified, as previous work has focused on the diagnostic evaluation and management of patients with femoroacetabular impingement undergoing hip arthroscopy., Purpose: To explore the standard diagnostic evaluation practice of experts in the field of hip preservation surgery and combine their expertise through the Delphi method to form a standardized approach to the diagnostic evaluation of patients with nonarthritic hip pain., Study Design: Consensus statement., Methods: An expert panel made up of 18 orthopaedic surgeons with extensive experience in the treatment of nonarthritic hip disorders participated in this Delphi study. The Delphi panelists were presented with 4 clinical vignettes representing a spectrum of patients with nonarthritic hip pain. Three iterative survey rounds were presented to the panelists based on these clinical vignettes, and a 3-step classic Delphi method was used to establish consensus techniques in the diagnostic evaluation of nonarthritic hip pain., Results: Total (100%) participation was gained, with all 18 experts completing all 3 Delphi survey rounds. Consensus (≥75% support) was achieved for some, if not all, vignettes for each of the following diagnostic domains: historical features, physical examination, radiographic sequences, radiographic interpretation, cross-sectional imaging, and ancillary diagnostics., Conclusion: In this Delphi study, we identified standardized diagnostic treatment approaches as derived from expert opinion for patients with nonarthritic hip pathomorphologies., Competing Interests: One or more of the authors has declared the following potential conflict of interest or source of funding: M.P.M. has received royalties from Elizur. J.D.W. has received educational support from Smith & Nephew. M.P.M., J.D.W., and E.N.N. have received educational support from Arthrex. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto., (© The Author(s) 2021.)

Background Often used for T1 mapping of hip cartilage, three-dimensional (3D) dual-flip-angle (DFA) techniques are highly sensitive to flip angle variations related to B 1 inhomogeneities. The authors hypothesized that 3D magnetization-prepared 2 rapid gradient-echo (MP2RAGE) MRI would help provide more accurate T1 mapping of hip cartilage at 3.0 T than would 3D DFA techniques. Purpose To compare 3D MP2RAGE MRI with 3D DFA techniques using two-dimensional (2D) inversion recovery T1 mapping as a standard of reference for hip cartilage T1 mapping in phantoms, healthy volunteers, and participants with hip pain. Materials and Methods T1 mapping at 3.0 T was performed in phantoms and in healthy volunteers using 3D MP2RAGE MRI and 3D DFA techniques with B 1 field mapping for flip angle correction. Participants with hip pain prospectively (July 2019-January 2020) underwent indirect MR arthrography (with intravenous administration of 0.2 mmol/kg of gadoterate meglumine), including 3D MP2RAGE MRI. A 2D inversion recovery-based sequence served as a T1 reference in phantoms and in participants with hip pain. In healthy volunteers, cartilage T1 was compared between 3D MP2RAGE MRI and 3D DFA techniques. Paired t tests and Bland-Altman analysis were performed. Results Eleven phantoms, 10 healthy volunteers (median age, 27 years; range, 26-30 years; five men), and 20 participants with hip pain (mean age, 34 years ± 10 [standard deviation]; 17 women) were evaluated. In phantoms, T1 bias from 2D inversion recovery was lower for 3D MP2RAGE MRI than for 3D DFA techniques (mean, 3 msec ± 11 vs 253 msec ± 85; P < .001), and, unlike 3D DFA techniques, the deviation found with MP2RAGE MRI did not correlate with increasing B 1 deviation. In healthy volunteers, regional cartilage T1 difference (109 msec ± 163; P = .008) was observed only for the 3D DFA technique. In participants with hip pain, the mean T1 bias of 3D MP2RAGE MRI from 2D inversion recovery was -23 msec ± 31 ( P < .001). Conclusion Compared with three-dimensional (3D) dual-flip-angle techniques, 3D magnetization-prepared 2 rapid gradient-echo MRI enabled more accurate T1 mapping of hip cartilage, was less affected by B 1 inhomogeneities, and showed high accuracy against a T1 reference in participants with hip pain. © RSNA, 2021.

The epiphyseal tubercle, a posterosuperior projection of the epiphysis into the metaphysis, serves as the axis of rotation in slipped capital femoral epiphysis (SCFE) and a source of physeal stability. We hypothesized that in a biomechanical model of single screw fixation of stable SCFE, a screw passing through the epiphyseal tubercle (the axis of rotation) would confer less rotational stability than a centrally placed screw. Three femurs were selected from a sample population of 8- to 15-year-old healthy hips to represent three stages of maturation: a "young" femur with a prominent epiphyseal tubercle and decreased epiphyseal cupping around the metaphysis, a "median" femur with a subsiding tubercle, and a "mature" femur with a subsided epiphyseal tubercle and increased peripheral epiphyseal cupping. Specimens were three-dimensional printed with one of two screw trajectories: passing centrally in the epiphysis or directly through the epiphyseal tubercle. Resistance to rotational displacement was measured through stiffness and maximum torque over 30° degrees of displacement. In the "young" model, epiphyseal tubercle screw position conferred less rotational stiffness and required less maximum torque during rotational displacement when compared to a centrally placed screw (P < .001). In the "median" and "mature" models where the tubercle has subsided and is replaced by peripheral epiphyseal cupping, screw position through the tubercle was associated with equal or greater rotational stiffness and maximum torque during displacement as a centrally placed screw., (© 2020 Orthopaedic Research Society. Published by Wiley Periodicals LLC.)

The epiphyseal tubercle plays an important role in epiphyseal stabilization. While the majority of studies have focused on tubercle morphology, there is a paucity of information on the morphological features of the metaphyseal fossa, where the tubercle sits on the metaphysis. The goal of this study was to determine the developmental changes in the capital femoral metaphyseal fossa. Computed tomography of the pelvis from 80 children and adolescents 8-15 years old were used to create three-dimensional models of the proximal femur. Depth, width, length, and surface area of the metaphyseal fossa were measured and the impact of age and sex on fossa morphology was assessed using the linear regression and two-way analysis of variance, respectively. The metaphyseal fossa was located in the posterosuperior quadrant of the metaphysis without any variations in the location with increasing age (P > .1). However, with increasing age, there was a reduction in all metaphyseal fossa measurements including the depth, length, width, and surface area (P < .01). No significant differences were noted for the metaphyseal fossa measurements between males and females (P > .1). The metaphyseal fossa reduces in size from 8 to 15 years of age in a similar fashion in males and females. As the metaphyseal fossa adjacent to the tubercle matches the area where a focal radiolucency has been observed in early slipped capital femoral epiphysis (SCFE), further studies should clarify the mechanisms by which the interlocking interaction of the epiphyseal tubercle and its fossa contributes to or is affected by SCFE., (© 2020 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.)

Background: Peripheral cupping of the capital femoral epiphysis over the metaphysis has been reported as a precursor of cam morphology, but may also confer stability of the epiphysis protecting it from slipped capital femoral epiphysis (SCFE). The purpose of this study was to investigate the relationship between a novel morphologic parameter of inherent physeal stability, epiphyseal cupping, and the development of SCFE in a dual-center matched-control cohort study., Methods: We performed a dual-center age-matched and sex-matched cohort study comparing 279 subjects with unilateral SCFE and 279 radiographically normal controls from 2 tertiary children's hospitals. All SCFE patients had at least 18 months of radiographic follow-up for contralateral slip surveillance. Anteroposterior and frog lateral pelvis radiographs were utilized to measure the epiphyseal cupping ratio and the current standard measure of inherent physeal stability, the epiphyseal extension ratio., Results: Control hips were found to have greater epiphyseal cupping than the contralateral uninvolved hip of SCFE subjects both superiorly (0.28±0.08 vs. 0.24±0.06; P<0.001) and anteriorly (0.22±0.07 vs. 0.19±0.06; P<0.001). The 58/279 (21%) subjects who went on to develop contralateral slip had decreased epiphyseal cupping superiorly (0.25±0.07 vs. 0.23±0.05; P=0.03) and anteriorly (0.20±0.06 vs. 0.17±0.04; P<0.001). When we compared controls with hips that did not progress to contralateral slip and hips that further developed a contralateral SCFE, 1-way ANOVA demonstrated a stepwise decrease in epiphyseal cupping and epiphyseal extension ratio in the anterior and superior planes from control hips to contralateral hips without subsequent slip to contralateral hips that developed a SCFE (P<0.01 for each)., Conclusions: This study provides further evidence that epiphyseal cupping around the metaphysis is associated with decreased likelihood of SCFE and may reflect increased inherent physeal stability. Epiphyseal cupping may represent an adaptive mechanism to stabilize the epiphysis during adolescence at the long-term cost of the eventual development of associated cam-femoroacetabular impingement deformity., Levels of Evidence: Level III-prognostic Study.

Background Assessment of femoral torsion at preoperative hip imaging is commonly recommended. However, it is unclear whether MRI is as accurate as CT and how different methods affect femoral torsion measurements. Purpose To compare MRI- and CT-based assessment of femoral torsion by using four commonly used measurement methods in terms of agreement, reproducibility, and reliability and to compare femoral torsion angles between the four different measurement methods. Materials and Methods This retrospective study evaluated patients with hip pain who underwent CT and 3-T MRI of the hip including sequences of the pelvis and distal condyles between May 2017 and June 2018. The four measurement methods differed regarding the landmark levels for the proximal femoral reference axis and included measurements at the level of the greater trochanter, femoral neck, base of the femoral neck, and level of the lesser trochanter. Intraclass correlation coefficients (ICCs) were calculated, and Bland-Altman analysis was performed. Results Forty-five patients (mean age ± standard deviation, 19 years ± 5; 27 female) and 57 hips were evaluated. Inter- and intrarater reliability were excellent for each of the four CT- and MRI-based measurement methods (ICC range, 0.97-0.99). Mean difference between CT- and MRI-based measurement ranged from 0.3° ± 3.4 ( P = .58) to 2.1° ± 4.1 ( P < .001). Differences between CT and MRI were within the corresponding ICC variation for all four measurement methods. Mean torsion angles were greater by 17.6° for CT and 18.7° for MRI (all P < .001) between the most proximal to the most distal measurement methods. Conclusion MRI- and CT-based femoral torsion measurements showed high agreement and comparable reliability and reproducibility but were dependent on the level of selected landmarks used to define the proximal reference axis. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Zoga in this issue.

Background: The Bernese periacetabular osteotomy (PAO) is one of the most-used surgical techniques to treat symptomatic acetabular dysplasia. Although good functional and radiographic short-term and long-term outcomes have been reported, several complications after PAO have been described. One complication that may compromise clinical results is nonunion of an osteotomy. However, the exact prevalence and risk factors associated with nonunion are poorly elucidated., Questions/purposes: (1) What proportion of patients have complete bony healing versus nonunion during the first year after PAO? (2) What is the clinical and functional impact of nonunion at a minimum of 1 year after PAO, as assessed by the modified Harris hip score (mHHS) and the Hip Disability and Osteoarthritis Outcome Score (HOOS)? (3) What patient-specific or surgery-specific factors are associated with nonunion at 6 months and at a minimum of 1 year postoperatively?, Methods: Between January 2012 and December 2015, we retrospectively identified 314 patients who underwent PAO at our institution. During this period, 28 patients with a diagnosis different from symptomatic acetabular dysplasia (reverse PAO for acetabular over-coverage: n = 25; PAO for skeletal chondrodysplasia: n = 3) underwent PAO but were ineligible to participate. Hence, 286 patients underwent PAO to treat symptomatic acetabular dysplasia during the study period and were considered eligible. Inclusion criteria were patients with a complete set of postoperative radiographs (AP, Dunn lateral, and false-profile) at 12 months or more postoperatively. Eighteen percent (51 of 286) of the patients underwent staged, bilateral PAOs, but we only included the first PAO. Finally, 14% (41 of 286) of the patients were excluded because they had an incomplete set of postoperative radiographs at 12 months or more. The study comprised 245 patients. Eighty-five percent (209 of 245) of the patients were female and the mean age at surgery was 24 years ± 9 years. The healing status (complete healing vs. nonunion) was recorded for ischial, superior pubic, supraacetabular, and posterior column osteotomies at each subsequent visit. Nonunion was defined as noncontiguous osseous union with a persistent radiolucent line across any osteotomy site and was recorded at 3 months, approximately 6 months, and approximately 12 months postoperatively. Calculation of Cohen's kappa statistic coefficients showed the classification had perfect interobserver agreement (0.53; 95% confidence interval, 0.12-0.93), but there was moderate intraobserver agreement between those who healed and those with nonunion. The HOOS and mHHS were collected preoperatively and at a minimum of 1 year after PAO. The HOOS contains five separate subscales for pain, symptoms, activity of daily living, sport and recreational function, and hip-related quality of life. The HOOS responses are normalized on a scale of 0 (worst) to 100 (best). The mHHS includes pain and function scales and is overall interpreted on a scale from 0 (worst) to 100 (best). Eighty-six percent (211 of 245) of the patients with a complete set of images at their 12-month visit completed the mHHS and 89% (217 of 245) completed the HOOS. We collected information from the patients' medical records about their symptomatic status and additional treatment for nonunion. A logistic regression analysis was used to investigate factors associated with nonunion at 6 and 12 months postoperatively., Results: Only 45% (96 of 215) of the patients had complete radiographic healing of all osteotomy sites at the 6-month visit and 55% (119 of 215) had not healed completely. However, 92% (225 of 245) demonstrated complete radiographic healing of all osteotomy sites at approximately 1 year postoperatively. The proportion of nonunion at a minimum of 12 months after PAO was 8% (20 of 245 patients). There was no difference in the mHHS after 1 year or more of follow-up between patients with nonunion and patients with complete healing after PAO (nonunion mean mHHS: 73; 95% CI, 62-85 versus healed: 82; 95% CI, 80-85; p = 0.13) and HOOS pain (nonunion mean HOOS pain: 80; 95% CI, 71-90 versus healed: 86; 95% CI, 83-88; p = 0.16). Similarly, no difference was identified for HOOS symptoms (nonunion mean: 72; 95% CI, 63-80 versus healed: 78; 95% CI, 75-81; p = 0.11), HOOS activities of daily living (nonunion mean: 86; 95% CI, 78-94 versus healed: 91; 95% CI, 89-93; p = 0.09), HOOS sports and recreation (nonunion mean: 70; 95% CI, 57-83 versus healed: 78; 95% CI, 75-82; p = 0.18); and HOOS quality of life (nonunion mean: 60; 95% CI, 46-75 versus healed: 69; 95% CI, 65-72; p = 0.28). After controlling for potentially confounding variables such as gender, age, chisel type, and preoperative anterior center-edge angle, we found that higher BMI (per 1 k/m; odds ratio 1.14; 95% CI, 1.06-1.22; p < 0.01), older age (per 1 year; OR 1.05; 95% CI, 1.01-1.08; p < 0.01) and more-severe acetabular dysplasia as assessed by a decreased preoperative lateral center-edge angle (per 1°; OR 1.06; 95% CI, 1.02-1.11; p < 0.01) were independently associated with nonunion of one or more osteotomy sites at 6 months postoperatively. Only age was an independent predictor of nonunion at 12 months postoperatively (per 1 year; OR 1.06; 95% CI, 1.01-1.11; p = 0.02)., Conclusions: Our study helps us to understand radiographic healing during the first year after PAO to treat symptomatic acetabular dysplasia. Fewer than half of the patients had complete healing of their osteotomies at 6 months postoperatively. More than 90% of patients can expect to have completely healed osteotomy sites at 12 months postoperatively. Surgeons should avoid unnecessary interventions if nonunion is observed radiographically at 6 months postoperatively. Although there was no difference in the HOOS and mHHS between patients with nonunion and those with complete healing, further research with a larger cohort is needed to clarify the impact of nonunion on clinical and functional outcomes after PAO. Surgeons should consider using strategies to enhance osteotomy healing in those who undergo PAO, such as optimizing vitamin D levels and using local bone grafts in older patients, those with a high BMI, and patients with severe acetabular dysplasia., Level of Evidence: Level III, therapeutic study.

Purpose: To compare the 3D morphology of the metaphyseal fossa among mild, moderate and severe stable slipped capital femoral epiphysis (SCFE) and normal hips., Methods: We identified pelvic CT of 51 patients (55% male; mean 12.7 years (sd 1.9; 8-15)) with stable SCFE. In all, 16 of 51 hips (31%) had mild, 14 (27%) moderate and 21 (41%) severe SCFE. A total of 80 patients (50% male; mean age 11.5 years (sd 2.3; 8 to 15)) with normal hips who underwent pelvic CT due to abdominal pain made up the control cohort. CT scans were segmented, and the femur was reformatted using 3D software. We measured the metaphyseal fossa depth, width, length and surface area after the epiphysis was subtracted from the metaphysis in the 3D model., Results: The metaphyseal fossa width was significantly larger in severe (adjusted difference: 6.9%; 95% confidence interval (CI) 2.1 to 11.8; p = 0.001), moderate (6.5%; 95% CI 0.8 to 12.2; p = 0.02) and mild SCFE (6.2%; 95% CI 0.8 to 11.6; p = 0.01), in comparison with normal hips. Severe SCFE showed larger fossa length compared with mild SCFE (6.8%; 95% CI 0.6 to 13.0; p = 0.02) and normal hips (6.0%; 95% CI 1.4 to 10.6; p = 0.004). The fossa surface area was larger in severe (3.5%; 95% CI 1.3 to 5.7; p < 0.001) and moderate SCFE (2.7%; 95% CI 0.1 to 5.2; p = 0.03) when compared with normal hips. There were no differences in fossa depth between SCFE and normal hips., Conclusion: The metaphyseal fossa is wider and more extensive but not deeper in hips with moderate and severe SCFE in comparison with normal hips. Although hips with severe SCFE had larger length and surface area than mild SCFE hips, further research is needed to clarify whether enlargement of the metaphyseal fossa is a consequence of slip progression., Level of Evidence: III., (Copyright © 2020, The author(s).)

Background: Periacetabular osteotomy (PAO) is a hip preserving procedure performed often in younger, highly active patients. However, counseling patients is difficult, as there are limited data regarding activity level after PAO. The purpose of this study is to analyze the physical activity levels after PAO in a large, prospective multicenter cohort., Methods: Prospectively collected data from a multicenter study group included 359 hips treated by PAO for hip dysplasia at a mean age of 25.1 years. Patient demographics, radiographic measures, operative data, and clinical outcomes were evaluated preoperatively, at 1 year, and at minimum 2 years postoperatively. Activity level was assessed with the University of California Los Angeles (UCLA) activity score, and patients were stratified into low activity, moderate activity, and high activity groups based on preoperative function., Results: Compared to preoperative scores across the complete cohort, postoperative UCLA scores were improved on average 0.6 points at final follow-up (P = .001). The low activity and moderate activity groups had significant improvement in UCLA scores (P < .001 and P = .0007, respectively), while the high activity groups saw a significant decrease in UCLA activity scores (P < .0001). Modified Harris Hip Score, Hip Disability and Osteoarthritis Score Pain, and Hip Disability and Osteoarthritis Score Sports and Recreation scores were significantly improved across all preoperative activity levels. Multivariable linear regression (r 2  = 0.45) confirmed prior ipsilateral surgery as a predictor for change in UCLA score (P = .002)., Conclusion: Overall, these data suggest that consistent improvements in activity level and function can be expected following PAO surgery, with greater gains experienced by patients with lower preoperative levels of activity., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Purpose: To investigate whether body mass index (BMI) percentile impacts the morphology of the capital femoral epiphysis in children and adolescents without hip disorders., Methods: We assessed 68 subjects with healthy hips who underwent a pelvic CT for evaluation of appendicitis. There were 32 male patients (47%) and the mean age was 11.6 years (sd 2.3). The BMI (k/m 2 ) was calculated for sex- and age-related percentiles according to the Centers for Disease Control and Prevention growth charts. CT images were segmented, and the epiphysis and metaphysis were reformatted using 3D software. We measured the epiphyseal tubercle (height, width and length), the metaphyseal fossa (depth, width and length) and the peripheral cupping of the epiphysis. All measurements were normalized to the diameter of the epiphysis. Pearson's correlation analysis was used to assess the correlations between the variables measured and BMI percentile adjusted for age., Results: Following adjustment to age, increased BMI correlated to decreased tubercle height (r =-0.34; 95% confidence interval (CI) -0.53 to -0.11; p = 0.005), decreased tubercle length (r = -0.32; 95%CI -0.52 to -0.09; p = 0.008) and decreased tubercle width (r = -0.3; 95% CI -0.5 to -0.07; p = 0.01). There was no correlation between BMI and metaphyseal fossa and epiphyseal cupping measurements., Conclusion: The association between increased BMI percentile and decreased epiphyseal tubercle size, without changes of the metaphyseal fossa and peripheral cupping suggests another morphological change of the femur that may be associated with decreased growth plate resistance to shear stress. Further study is necessary to investigate whether the epiphyseal tubercle size plays a role in the pathogenesis of slipped capital femoral epiphysis in obese children and adolescents., Level of Evidence: Level IV., (Copyright © 2020, The author(s).)

Background: The diagnosis of slipped capital femoral epiphysis (SCFE) often is delayed. Although lack of clinical suspicion is the main cause of delayed diagnosis, typical radiographic changes may not be present during the initial phases of SCFE. The peritubercle lucency sign for follow-up of the contralateral hip in patients with unilateral SCFE may be beneficial in assisting the early diagnosis. However, the accuracy and reliability of this sign in patients with SCFE is unknown., Questions/purposes: (1) What is the accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the peritubercle lucency sign on radiographs for the early diagnosis of SCFE compared with MRI as the gold standard? (2) What are the interobserver and intraobserver reliabilities of the peritubercle lucency sign on radiographs?, Methods: Between 2000 and 2017, 71 patients underwent MRI for an evaluation of pre-slip or a minimally displaced SCFE. Sixty percent of hips (43 of 71) had confirmed SCFE or pre-slip based on the presence of hip pain and MRI changes, and these patients underwent in situ pinning. Three independent experienced observers reviewed MR images of the 71 hips and agreed on the presence of a juxtaphyseal bright-fluid signal suggesting bone marrow edema in these 43 hips with SCFE, and absence MRI changes in the remaining 28 hips. The same three experienced observers and two inexperienced observers, including a general radiologist and an orthopaedic surgery resident, blindly assessed the radiographs for the presence or absence of the peritubercle lucency sign, without information about the diagnosis. Diagnostic accuracy measures including sensitivity, specificity, PPV, and NPV were evaluated. Intraobserver and interobserver agreements were calculated using kappa statistics., Results: The overall accuracy of the peritubercle lucency sign on radiographs was 94% (95% CI 91 to 96), sensitivity was 97% (95% CI 95 to 99), specificity was 89% (95% CI 90 to 96), PPV was 93% (95% CI 90 to 96), and NPV was 95% (95% CI 92 to 99). All accuracy parameters were greater than 85% for the five observers, regardless of experience level. Intraobserver agreement was perfect (kappa 1.0), and interobserver agreement was excellent for the peritubercle lucency sign on radiographs across the five observers (kappa 0.81 [95% CI 0.73 to 0.88]). The reliability was excellent for experienced observers (kappa 0.88 [95% CI 0.74 to 1.00]) and substantial for inexperienced observers (kappa 0.70 [95% CI 0.46 to 0.93]), although no difference was found with the numbers available (p = 0.18)., Conclusions: The peritubercle lucency sign on radiographs is accurate and reliable for the early diagnosis of SCFE compared with MRI as the gold standard. Improving the early diagnosis of SCFE may be possible with increased awareness, high clinical suspicion, and a scrutinized evaluation of radiographs including an assessment of the peritubercle lucency sign., Level of Evidence: Level III, diagnostic study.

Overcoverage of the femoral head by the acetabulum, increased acetabular depth and retroversion have been associated with the etiology of slipped capital femoral epiphysis (SCFE). However, limited evidence exists about the impact of the acetabular morphology on the development of a contralateral slip following an initial presentation of unilateral SCFE. We aimed to investigate whether acetabular overcoverage as assessed by an increased lateral center-edge angle (LCEA) and low Tönnis angle, increased acetabular depth assessed by the acetabular depth-width ratio (ADR) and the presence of coxa profunda; and acetabular retroversion assessed by the presence of the crossover sign were associated with a contralateral slip in patients presenting with unilateral SCFE. We evaluated 250 patients with initial diagnosis of unilateral SCFE (average age, 12.5 ± 1.7 years), who had not undergone prophylactic fixation on the contralateral hip for a median follow-up of 49 months (interquartile range: 25-76 months). Endpoints were the development of a contralateral slip (70 patients, 28%) or skeletal maturity assessed by complete closure of the proximal femoral growth plate (180 patients, 72%). We measured the LCEA, Tönnis angle, ADR, and the coxa profunda sign on an anteroposterior pelvic radiograph. The crossover sign was assessed in 208 hips who had a secondary ossification center in the posterior acetabular rim. For each additional degree of LCEA, the odds of contralateral slip decreased 8% [odds ratio = 0.92; 95% confidence interval (CI), 0.87-0.98; P = 0.009]. Tönnis angle (P = 0.11), ADR (P = 0.20) and coxa profunda (p = 0.37) had no association with a contralateral slip. The presence of crossover sign increased two and half times the odds for a contralateral slip (odds ratio = 2.5; 95% CI = 1.12-5.64; P = 0.03). Acetabular retroversion, but not acetabular overcoverage or increased acetabular depth, was associated with contralateral SCFE development in patients with unilateral SCFE. Level of evidence: prognostic level II.

Purpose: Our primary research question was to investigate the severity of deformity and articular damage as well as outcomes in patients undergoing hip arthroscopy compared with open surgery for the treatment of symptomatic slipped capital femoral epiphysis (SCFE) deformity., Methods: Retrospective review of surgical treatment of symptomatic SCFE deformity with a minimum one-year follow-up. Patients were divided into three groups: the arthroscopic group, surgical hip dislocation(SHD) group and SHD with femoral osteotomy (SHD+ITO) group. Deformity severity was quantified. Hip outcome was assessed by the modified Merle d'Aubigné Postel (MDP) scores., Results: There were more severe slips treated by SHD and SHD+ITO. There was more severe deformity in the SHD+ITO group than the arthroscopy group (p < 0.001). There were more full thickness acetabular cartilage defects in the SHD and the SHD+ITO groups (> 40%) compared with the arthroscopy group (11%; p = 0.03). The SHD+ITO and SHD group had lower MDP scores compared with the arthroscopy group both before and after surgery but no difference was detected in the amount of improvement from surgery across groups (p > 0.05). Moderate and severe SCFEs had worse preoperative scores but improvement was not different compared with mild SCFEs (p > 0.05)., Conclusion: Patients undergoing open treatment had more severe SCFE deformity with more extensive articular damage at reconstructive surgery compared with patients undergoing arthroscopy. All groups with SCFE deformity had improved pain and hip function postoperatively., Level of Evidence: III., (Copyright © 2020, The author(s).)

To evaluate the acetabular morphology in healed Legg-Calvé-Perthes disease after skeletal maturity using computed tomography (CT) scan and to compare with matched controls. We identified 33 (37 hips) patients with healed Legg-Calvé-Perthes disease and closed triradiate cartilage who underwent pelvic CT scan. Each patient was matched based on sex, age and side to a subject with no history of hip disease who had undergone pelvic CT evaluation because of abdominal pain. Both cohorts had 23 (70%) males and mean age of 16.4-16.5 ± 3.6 years. Two independent readers assessed lateral center-edge angle (LCEA), acetabular inclination angle (IA), acetabular depth-width ratio (ADR), acetabular version 10 mm below the dome (cranial) and at the acetabular center and anterior (AASA) and posterior acetabular sector angles (PASA). All measurements had good to excellent interobserver agreement (intraclass coefficients ≥ 0.87). The hips in the Legg-Calvé-Perthes disease cohort had a smaller mean ± standard deviation (SD) superior, anterior and posterior acetabular coverage as assessed by LCEA (13.2° ± 10.7° versus 28.2° ± 3.4°; P  < 0.0001), IA (11.6° ± 6.7° versus 3.5° ± 2.8°; P  < 0.0001), AASA (52.4° ± 9.5° versus 59.3° ± 5.0°; P  = 0.001) and PASA (79.3° ± 5.9° versus 92.3° ± 5.5°; P  < 0.0001) compared with controls. The acetabulum was shallower (ADR 287 ± 45 versus 323 ± 28; P  = 0.0002) and the acetabular version was decreased cranially (0.4°±9.2° versus 8.2°±6.8°; P  = 0.0002) and at the acetabular center (13.7°±5.1° versus 17.2° ±3.8°; P  = 0.004) in Legg-Calvé-Perthes disease hips. After skeletal maturity, hips with healed Legg-Calvé-Perthes disease have shallower and more cranially retroverted acetabula, with globally reduced coverage of the femoral head compared with age-, sex- and side-matched control hips., (© The Author(s) 2020. Published by Oxford University Press.)