Hip Morphology Research Articles

The impact of neurological impairment and tone on hip joint development.

The purpose of this study was to define how different force environments by neuromuscular diagnosis (hypertonic versus hypotonic) impact the growth and morphology of the proximal femoral and acetabular regions relative to typically developing children. Children with cerebral palsy and spinal muscular atrophy were compared with typically developing children aged 6 months to 11 years. Routine pelvic radiographs were evaluated using measures of hip geometry for the proximal femur and acetabulum. The data were analyzed using general linear models to estimate the developmental patterns according to age and diagnosis. One hundred eighty-four children met the inclusion criteria: 58 spastic cerebral palsy Gross Motor Function Classification System I-V (263 hips), 32 spinal muscular atrophy (79 hips)), and 94 typically developing (187 hips) were included with a mean age of 4.9 ± 3.1 years. Using spinal muscular atrophy as a reference, significant differences in proximal femoral development included long thin versus short neck (p < 0.01) and round versus flat epiphysis (p = 0.001). A thin neck-wide epiphysis was found in spinal muscular atrophy versus thick neck-small epiphysis for typically developing (p < 0.05). The ratio of acetabular width to proximal femoral epiphysis width differed significantly for typically developing (p = 0.001) compared with cerebral palsy and spinal muscular atrophy. There was a negative correlation between migration percentage and acetabular width to epiphysis width in children with cerebral palsy, but no correlation in children with spinal muscular atrophy. Hip geometry was impacted by the force environment experienced during growth. These findings emphasize the crucial roles of gross motor function, muscle tone, and strength differences in determining hip morphology. III, retrospective case control.

Association Between Hip Translation and Hip Rotation and Anatomy: A Pilot Quasi-static MRI Study.

There is little known about translation of the hip and the relationship with hip rotation and morphology in asymptomatic patients. (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. Cross-sectional study; Level of evidence, 3. 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. 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). 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).

DXA images vs. pelvic radiographs: Reliability of hip morphology measurements

ObjectiveDual-energy x-ray absorptiometry (DXA) images are increasingly used to study hip morphology. Whether hip morphology measurements are consistent between DXA images and radiographs is unknown. Therefore, we investigated the agreement and reliability of the measurements performed on DXA images and radiographs. DesignWe included participants from the Rotterdam study, a population-based cohort study, who received a hip DXA image and pelvic radiograph on the same day. The acetabular depth-width ratio (ADR), modified acetabular index (mAI), alpha angle (AA), Wiberg and lateral center edge angle (WCEA, LCEA), extrusion index (EI) and triangular index ratio (TIR) were automatically determined on both imaging modalities. The intraobserver and intermethod agreement were studied using Bland-Altman methods, and the reliability was assessed using intraclass correlation coefficients (ICC). Secondly, the diagnostic agreement regarding dysplasia, cam, and pincer morphology was assessed using percent agreement and Cohen’s kappa. Results750 hips from 411 individuals, median age 67.3 years (range 52.2 – 90.6), 45.5% male, were included. The following intermethod ICCs (95% CI) were obtained: ADR 0.85 (0.74-0.91), mAI 0.75 (0.52-0.85), AA 0.72 (0.68-0.75), WCEA 0.81 (0.74-0.85), LCEA 0.93 (0.91-0.94), EI 0.88 (0.84-0.91), and TIR 0.81 (0.79-0.84). We found comparable intraobserver ICCs for each morphological measurement. ConclusionDXA images and pelvic radiographs could both reliably be used to study hip morphology. Due to the lower radiation burden, DXA images could be an excellent alternative to pelvic radiographs for research purposes.

The relationship between hip joint morphology and hip range of motion in circus performers with hip-related pain

The relationship between hip joint morphology and hip range of motion in circus performers with hip-related pain

Acetabular morphology variations in a Hispanic population.

Rotational abnormalities of the hip have been implicated in the etiology of diseases, such as hip dysplasia, osteoarthritis, and femoroacetabular impingement. Despite the extensive literature on hip morphology, there is a gap in knowledge regarding variations in the Hispanic population. To describe the bony anatomy variations of the acetabulum in a Hispanic population. This is a cross-sectional study. We studied 182 computed tomography (CT) images in patients aged older than 21 years, who had undergone pelvic CT for any condition, except hip fracture. Measurements of acetabular version, anterior and posterior acetabular sector angles (AASA/PASA) and horizontal acetabular sector angles (HASA) were made. Acetabular variations were then compared to weight and sex data. The mean acetabular anteversion was greater in women (P < 0.001). Women exhibited a greater PASA (P < 0.05); however, men had a greater AASA (P < 0.05). Underweight individuals had a smaller PASA (P < 0.01) and HASA (P < 0.05) than individuals with a normal weight. The Hispanic hip is morphologically similar to other populations previously reported in the literature; however, Hispanic men have less coverage of the femoral head by the posterior acetabular wall when compared to women of the same ethnicity. These abnormalities have a direct impact on management and surgical approach in patients treated for femoroacetabular impingement and hip dysplasia.

FEMORAL HEAD REDUCTION OSTEOTOMY APPROACH FOR SEVERE PROXIMAL FEMUR DEFORMITIES: SURGICAL TECHNIQUE AND MINIMUM TWO-YEAR RESULTS

Executing an extended retinacular flap containing the blood supply for the femoral head, reduction osteotomy (FHO) can be performed, increasing the potential of correction of complex hip morphologies. The aim of this study was to analyse the safety of the procedure and report the clinical and radiographic results in skeletally mature patients with a minimum follow up of two years.Twelve symptomatic patients (12 hips) with a mean age of 17 years underwent FHO using surgical hip dislocation and an extended soft tissue flap. Radiographs and magnetic resonance imaging producing radial cuts (MRI) were obtained before surgery and radiographs after surgery to evaluate articular congruency, cartilage damage and morphologic parameters. Clinical functional evaluation was done using the Non-Arthritic Hip Score (NAHS), the Hip Outcome Score (HOS), and the modified Harris Hip Score (mHHS).After surgery, at the latest follow-up no symptomatic avascular necrosis was observed and all osteotomies healed without complications. Femoral head size index improved from 120 ± 10% to 100 ± 10% (p&lt;0,05). Femoral head sphericity index improved from 71 ± 10% before surgery to 91 ± 7% after surgery (p&lt;0,05). Femoral head extrusion index improved from 37 ± 17% to 5 ± 6% (p&lt; 0,05). Twenty five percent of patients had an intact Shenton line before surgery. After surgery this percentage was 75% (p&lt;0,05). The NAHS score improved from a mean of 41 ± 18 to 69 ± 9 points after surgery (p&lt; 0,05). The HOS score improve from 56 ± 24 to 83 ± 17 points after surgery (p&lt; 0,05) and the mHHS score improved from 46 ± 15 before surgery to 76 ± 13 points after surgery (p&lt; 0,05).In this series, femoral head osteotomy could be considered as safe procedure with considerable potential to correct hip deformities and improve patients reported outcome measures (PROMS).Level of evidence - Level IV, therapeutic studyKeywords - Femoral head osteotomy, Perthes disease, acetabular dysplasia, coxa plana

Are hip joint imaging findings associated with symptoms and early hip osteoarthritis features in elite male Australian Football League draftees?

ABSTRACT 1) describe intra-articular features (prevalence and severity) and bony hip morphology (prevalence and size) in elite male Australia Football League (AFL) draftees; 2) examine the relationship between bony hip morphology (cam and pincer morphology) and intra-articular features (cartilage defects and labral tears); and 3) examine the relationship between intra-articular features, bony hip morphology, and the Copenhagen Hip and Groin Outcome Score (HAGOS). Cross-sectional study. 58 male AFL draftees underwent 3-tesla hip MRI. Alpha angle determined cam morphology and acetabular depth defined pincer morphology. For each hip, intra-articular features were scored semi-quantitatively. All players completed the HAGOS to determine hip/groin symptoms and sports function. Logistic regression determined whether bony hip morphology was associated with labral tears and cartilage defects. Mann-Whitney U tests evaluated the difference in HAGOS subscale scores between football players with and without intra-articular features and bony hip morphology. Cam and pincer morphology were evident in 20% and 19% of hips, respectively. Nearly half of hips (41%) had a labral tear, with only 14% having a cartilage defect. Greater alpha angle was associated with the presence of labral tears (OR 1.14, 95%CI 1.07 to 1.21, p < 0.001) but not cartilage defects. Hip imaging findings were not associated with lower (worse) HAGOS scores. Hip joint imaging findings were common in elite male AFL draftees but not associated with worse pain, symptoms, or sport function. Cam morphology may contribute to the development of labral tears in male AFL draftees.

Imaging evaluation of hip capsule disorders: a comprehensive review.

The hip capsule and capsular ligaments play crucial roles in providing hip stability and mobility. Their role in hip pathologies is being increasingly recognized, underscoring the need for thorough imaging evaluation, which is better performed through MRI-arthrography. Various diseases affect the hip capsule directly or indirectly. Improper mechanical loading, as seen in conditions such as femoroacetabular impingement or chondrolabral pathology, can induce capsule thickening, whereas thinning and laxity of the capsule are characteristics of microinstability. Inflammatory conditions, including adhesive capsulitis of the hip, crystal deposition disease, polymyalgia rheumatica, and infections, also lead to capsular changes. Traumatic events, particularly posterior hip dislocations, cause capsule ligament disruption and may lead to hip macroinstability. Friction syndromes can lead to capsular edema due to impingement of the adjacent capsule. Hip arthroscopy can result in various postoperative findings ranging from fibrotic adhesions to focal or extensive capsule discontinuation. Although the significance of hip capsule thickness and morphology in the pathogenesis of hip diseases remains unclear, radiologists must recognize capsule alterations on imaging evaluation. These insights can aid clinicians in accurately diagnosing and effectively managing patients with hip conditions.

Morphological features of the acetabulum with coxa profunda in women: a retrospective observational study

BackgroundThe morphology of coxa profunda remains inadequately understood. However, knowledge about the characteristics of the acetabulum in coxa profunda can help to predict pelvic morphology in three dimensions based on radiographic findings, as well as help to diagnose and predict hip pathologies. Therefore, this study aimed to investigate the relationship between the morphological characteristics of the pelvis and coxa profunda.MethodsWe conducted a retrospective analysis including women who had undergone unilateral total hip arthroplasty. Only those with normal hip joint morphology on the opposite side, as evidenced by anteroposterior pelvic radiography showing a distance of ≥ 2 mm between the ilioischial line and acetabular floor, were included. Five parameters related to acetabular anteversion, thickness, and the position of the ilioischial line were measured using axial computed tomography at the central hip joint. The coxa profunda group (n = 39) and control group (n = 34) were compared.ResultsThe mean acetabular anteversion angle was 12.5° ± 4° in the control group and 22.3° ± 5.6° in the coxa profunda group. The mean thickness from the acetabular fossa to the medial wall was 7.5 ± 1.7 mm in the control group and 3.9 ± 1.2 mm in the coxa profunda group. Furthermore, the bony region representing the ilioischial line was positioned more posteriorly in the coxa profunda group than it was in the control group.ConclusionOur findings suggest that coxa profunda in women is associated with anterior acetabular dysplasia and a thin acetabulum, in contrast to previous interpretations of excessive coverage. This insight suggests a conversion of coxa profunda from a finding of pincer-type femoroacetabular impingement to a finding of acetabular dysplasia, a revelation that also draws attention to cup positioning for total hip arthroplasty.

Morphology of the dysplastic hip and the relationship with sex and acetabular version.

The dysplastic hip is characterized by incomplete coverage of the femoral head, resulting in increased risk of early osteoarthritis. The morphological variation of the hip joint is diverse and clear differences exist between females and males. The aim of this observational study was therefore to investigate the relationship between the morphology of the hip, sex, and hip dysplasia using a three-dimensional model. Statistical shape models of the combined femur and pelvic bones were created from bilateral hips of 75 patients. Using manual angle measurements and regression analysis, the characteristic shape differences associated with sex and hip dysplasia were determined. The model showed clear differences associated with sex and hip dysplasia. We found that the acetabular anteversion in females was significantly higher (p < 0.0001) than in males while no significant difference in acetabular anteversion was found between normal and dysplastic hips (p = 0.11). The model showed that decreased acetabular anteversion resulted in the appearance of the cross-over sign and the prominent ischial spine sign commonly associated with retroversion. Sex could be predicted with an area under the curve of 0.99 and hip dysplasia could be predicted with an area under the curve of ≥0.73. Our findings suggest that retroversion is a result of decreased anteversion of the acetabulum and is primarily associated with sex. This finding should be taken into account during the reorientation of the acetabulum in the surgical treatment of hip dysplasia.

Hip Joint Stability during and after Femoral Lengthening in Congenital Femoral Deficiency.

Hip stability remains a major preoccupation during femoral lengthening in Congenital Femoral Deficiency (CFD). We aimed to review hip stability in Paley type 1a CFD patients undergoing femoral lengthening. A total of 33 patients with unilateral CFD, who were treated between 2014 and 2023, were retrospectively reviewed. In 20/33 cases (60.6%) the SUPERhip preparatory surgery was performed at a mean age of 4.3 years (range 2.7-8.1). The femoral lengthening using an external fixator was performed at a mean age of 7.8 years (range 4.3-14.3). All patients presented with a stable hip joint after preparatory surgery and during femoral lengthening. Six cases of hip instability at a mean of 637 days after the external fixator removal were observed (range 127 to 1447 days). No significant differences between stable and unstable hips were noted for (1) Center-Edge Angle: 23.7 vs. 26.1 deg; (2) Acetabular Inclination: 12.8 vs. 11.7 deg; and (3) Ex-Fix Index: 35.6 days/cm vs. 42.4 days/cm; p > 0.05. Late hip instability was related to Coxa Vara and decreased femoral antetorsion before lengthening. Late hip joint instability in Paley type 1a CFD patients may occur long after femoral lengthening despite hip morphology appearing to be normal on radiograms before and at the end of femoral lengthening. Coxa Vara, femoral torsional deformity, and posterior acetabular deficiency might be risk factors for hip instability.

Automated radiographic hip morphology measurements: An open-access method

ObjectiveThe aim of this study is to present a newly developed automated method to determine radiographic measurements of hip morphology on dual-energy x-ray absorptiometry (DXA) images. The secondary aim was to compare the performance of the automated and manual measurements. Design30 DXA scans from 13-year-olds of the prospective population-based cohort study Generation R were randomly selected. The hip shape was outlined automatically using radiographic landmarks from which the acetabular depth-width ratio (ADR), acetabular index (AI), alpha angle (AA), Wiberg and lateral center edge angle (WCEA) (LCEA), extrusion index (EI), neck-shaft angle (NSA), and the triangular index (TI) were determined. Manual assessments were performed twice by two orthopedic surgeons. The agreement within and between observers and methods was visualized using Bland-Altman plots, and the reliability was studied using the intraclass correlation coefficient (ICC) with 95 % confidence intervals (CI). ResultsThe automated method was able to perform all radiographic hip morphology measurements. The intermethod reliability between the automated and manual measurements ranged from 0.57 to 0.96 and was comparable to or better than the manual interobserver reliability, except for the AI. ConclusionThis open-access, automated method allows fast and reproducible calculation of radiographic measurements of hip morphology on right hip DXA images. It is a promising tool for performing automated radiographic measurements of hip morphology in large population studies and clinical practice.

Pincer Morphology Is Not Associated With Hip Osteoarthritis Unless Hip Pain Is Present: Follow-Up Data From a Prospective Cohort Study.

The objective of this study was to assess the relationship between pincer morphology and radiographic hip osteoarthritis (RHOA) over 2, 5, 8, and 10 years' follow-up and to study the interaction between pincer morphology and pain. Individuals from the prospective Cohort Hip and Cohort Knee study were drawn. Anteroposterior pelvic and false profile radiographs were obtained. Hips free of definite RHOA (Kellgren and Lawrence [KL] grade 0 or 1) at baseline were included. Pincer morphology was defined as a lateral or anterior center edge angle or both ≥40° at baseline. Incident RHOA was defined as KL ≥ 2 or total hip replacement at follow-up. Multivariable logistic regression with generalized estimating equations estimated the associations at follow-up. Associations were expressed as unadjusted odds ratios (ORs) and adjusted ORs with 95% confidence intervals (CIs). An interaction term was added to investigate whether pincer morphology had a different effect on symptomatic hips. Incident RHOA developed in 69 hips (5%) at2 years' follow-up, in 178 hips (14%) at 5 years' follow-up, in 279 hips (24%) at 8 years' follow-up, and in 495 hips (42%) at 10 years' follow-up. No significant associations were found between pincer morphology and incident RHOA (adjusted OR 0.35 [95% CI 0.06-2.15]; adjusted OR 1.50 [95% CI 0.94-2.38]). Significant interactions between pain and anterior pincer morphology in predicting incident RHOA were found at 5, 8, and 10 years' follow-up (OR 1.97 [95% CI 1.03-3.78]; OR 3.41 [95% CI 1.35-8.61]). No associations were found between radiographic pincer morphology and incident RHOA at any follow-up moment. Anteriorly located pincer morphology with hip pain, however, was significantly associated with incident RHOA. This highlights the importance of studying symptoms and hip morphology simultaneously.

Association of 5-Year Hip Arthroscopy Outcomes with Hip Morphology and Cartilage Status at Time of Surgery: A National Registry Study With HAGOS Outcomes in 281 Patients With Femoroacetabular Impingement Syndrome.

The effects of specific bony hip morphologies, cam and dysplasia, and cartilage damage on mid- and long-term (≥5 years) patient-reported outcomes (PROs) are understudied. To investigate if changes in PROs from preoperatively to 5 years after hip arthroscopy are associated with preoperative bony hip morphology and cartilage status in patients with femoroacetabular impingement syndrome. Cohort study; Level of evidence, 3. Patients were identified in the Danish Hip Arthroscopy Registry. Hip and groin function was assessed from preoperatively to 5 years postoperatively with the Copenhagen Hip and Groin Outcome Score (HAGOS) Activities of Daily Living (ADL) and Sports and Recreation (Sport) subscales. Morphology was defined using the anterior alpha angle (AA) and lateral center-edge angle (LCEA) as follows: mild to moderate cam (55°≤ AA < 78°), severe cam (AA ≥ 78°), pincer (LCEA > 39°), and borderline dysplasia (20°≤ LCEA < 25°). Joint space width (JSW) was defined as slightly reduced (3.1 mm ≤ JSW ≤ 4 mm) or severely reduced (2.1 mm ≤ JSW ≤ 3 mm). Acetabular cartilage status was defined by modified Beck grades 0 to 4 and femoral head cartilage status by International Cartilage Regeneration & Joint Preservation Society grades 0 to 4. Acetabular and femoral cartilage injury areas were categorized as <1, 1 to 2, or >2 cm2. Multiple regression analyses assessed adjusted associations between hip morphology and cartilage injuries with improvement in HAGOS-ADL and HAGOS-Sport. The study included 281 patients (age, 35 ± 10 years; 52.3% female). No cam and mild-to-moderate cam were associated with greater improvement in HAGOS-ADL (16 points [P = .002] and 7 points [P = .038], respectively) compared with severe cam. Normal JSW was associated with greater improvement in HAGOS-ADL (21 points; P = .026) compared with severely reduced JSW. Femoral head cartilage injury area <1 cm2 was associated with greater improvements in HAGOS-ADL (17 points; P = .03) and HAGOS-Sport (21 points; P = .035) compared with femoral cartilage injury area >2 cm2. Patients having no-to-moderate cam morphology, normal JSW, or femoral head cartilage injury area <1 cm2 had greater improvement in PROs 5 years after hip arthroscopy compared with patients having severe cam morphology, severely reduced JSW, or femoral cartilage injury area >2 cm2.

Morphometric and clinical comparison of MRI-based synthetic CT to conventional CT of the hip in children.

MRI-based synthetic CT (sCT) generates CT-like images from MRI data. To evaluate equivalence, inter- and intraobserver reliability, and image quality of sCT compared to conventional (cCT) for assessing hip morphology and maturity in pediatric patients. We prospectively enrolled patients <21 years old with cCT and 3T MRI of the hips/pelvis. A dual-echo gradient-echo sequence was used to generate sCT via a commercially available post-processing software (BoneMRI v1.5 research version, MRIguidance BV, Utrecht, NL). Two pediatric musculoskeletal radiologists measured seven morphologic hip parameters. 3D surface distances between cCT and sCT were computed. Physeal status was established at seven locations with cCT as reference standard. Images were qualitatively scored on a 5-point Likert scale regarding diagnostic quality, signal-to-noise ratio, clarity of bony margin, corticomedullary differentiation, and presence and severity of artifacts. Quantitative evaluation of Hounsfield units (HU) was performed in bone, muscle, and fat tissue.Inter- and intraobserver reliability were measured by intraclass correlation coefficients. The cCT-to-sCT intermodal agreement was assessed via Bland-Altman analysis. The equivalence between modalities was tested using paired two one-sided tests. The quality parameter scores of each imaging modality were compared via Wilcoxon signed-rank test. For tissue-specific HU measurements, mean absolute error and mean percentage error values were calculated using the cCT as the reference standard. Thirty-eight hips in 19 patients were included (16.6 ± 3 years, range 9.9-20.9; male = 5). cCT- and sCT-based morphologic measurements demonstrated good to excellent inter- and intraobserver correlation (0.77<ICC<0.98). Measurements were statistically equivalent (P< 0.05), with average intermodal differences <2°. Mean surface distance between cCT and sCT was 0.23 ± 0.18mm. Accuracy to determine physeal maturity status by sCT was 98.4% (242/246, 95% CI 96.0-99.6). No significant differences were found on overall diagnostic quality, bony margin clarity, corticomedullary differentiation, and artifacts between sCT and cCT; signal-to-noise ratio was higher on sCT (P< 0.001). HU were within reference values on both sCT and cCT. sCT is equivalent to cCT for the assessment of hip morphology, physeal status, and radiodensity assessment in pediatric patients.

Cam-type hip morphology in asymptomatic patients.

The alpha angle has been widely used in the assessment of cam-type of impingement, but recent studies have shown that this angle may also be high in asymptomatic patients. The aim of this study is to report the prevalence of cam-type morphology in asymptomatic volunteers and explore its correlation with hip clinical and radiological parameters. This single-centre prospective study included 48 asymptomatic male volunteers (96 hips). All candidates fulfilled the inclusion and exclusion criteria. Physical examination and 1.5 -T MRI imaging were done for bilateral hips on the same day. Alpha angle measurements were obtained from 4 different positions and cam-type morphology was considered positive using 2 different cut points >55° and >60°. Descriptive statistics were analysed and correlations were performed where appropriate and p-value < 0.05 was considered to be significant. The prevalence of cam-type morphology using alpha angle >55° was 68.8%, 87.5%, 50% and 34.4% in the 12, 1, 2 and 3 o'clock positions respectively. While it was 38.5%, 69.8%, 26% and 12.5% in the 12, 1, 2 and 3 o'clock positions of the studied hips respectively using alpha angle >60°. The maximum alpha angle was more frequently prevalent at the 1 o'clock position in 71 (74%). Labral tear was detected in 26 (27.1%) hips and impingement test was positive in 12 (12.5%) hips. There was no correlation between the presence of cam-type morphology and range of motion of the hip, presence of positive impingement test nor labral tears. Cam-type morphology prevalence is high among asymptomatic males, and mostly pronounced at the 1 o'clock position. A correlation between high alpha angle and positive impingement test or labral tear was not found in our cohort. Future studies are required to determine the natural history of asymptomatic cam-type morphology and risk of hip derangement.

What Is the Relevance of Post-Reduction MRI Today and Where Do We Go from Here?: Commentary on an article by Florian Schmaranzer, MD, et al.: "Hip Morphology on Post-Reduction MRI Predicts Residual Dysplasia 10 Years After Open or Closed Reduction".

What Is the Relevance of Post-Reduction MRI Today and Where Do We Go from Here?: Commentary on an article by Florian Schmaranzer, MD, et al.: "Hip Morphology on Post-Reduction MRI Predicts Residual Dysplasia 10 Years After Open or Closed Reduction".

Is Subcapital Realignment for Slipped Capital Femoral Epiphysis a Reproducible Technique? Midterm Results.

The modified Dunn procedure, which is based on the development of an extended retinacular flap containing the blood supply for the femoral head, allows anatomic reestablishment in patients with moderate to severe slipped capital femoral epiphysis (SCFE). Some controversy exists regarding the short-term to midterm risk of avascular necrosis (AVN) and other complications resulting from the surgical technique. (1) What percentage of patients treated with an extended retinacular flap during the modified Dunn procedure for SCFE with a moderate (slip angle from 30° to 60°) or severe slip (slip angle equal or greater than 60°) develop symptomatic AVN, and what percentage underwent further surgery or had other complications? (2) What femoral head-neck alignment and position parameters relative to the greater trochanter are achieved after surgery? (3) Can we identify radiographic signs of osteoarthritis at a minimum of 4 years after surgery? Between January 2006 and December 2018, we treated 61 patients for SCFE. During this time, we generally used the modified Dunn procedure when the slip angle was ≥ 30°. Based on this indication, the modified Dunn procedure was performed in 37 patients (41 hips) during that time period, and those patients were potentially eligible for this retrospective study. Because bilateral hips in the same patient are not statistically independent, for our analyses, we analyzed only the hip with the longer follow-up time. Of those who remained, 11% (4) were lost before the minimum study follow-up of 48 months or had incomplete datasets, leaving 89% (33) for analysis here at a median follow-up of 80 months (range 49 to 208 months). Periacetabular osteotomy or subtrochanteric rotational femoral osteotomy was added under the same anaesthesia time in 33% (11 patients). We added periacetabular osteotomy in 24% (8) when intraoperative anterior instability was present in external rotation. A femoral rotational osteotomy was added in 9% (3) when posterior instability was present in flexion and internal rotation. The mean ± standard deviation age at the time of surgery was 13 ± 1 years, and 33% (11 of 33) of patients were female. The mean slip angle was 51° ± 16º, and 15% (5) of hips had unstable slips, defined as an inability to walk with or without crutches. We documented chronic presentations in 82% (27) of patients, acute and chronic in 12% (4), and acute in 6% (2). The rate of symptomatic AVN was determined by reviewing all radiographs obtained at the latest follow-up interval. Further surgery and other complications were assessed through an electronic medical record review. Radiographic morphologic parameters were measured before surgery and at a minimum follow-up of 4 years by two senior orthopaedic surgeons. Radiographs obtained at the latest follow-up visit were also screened for signs of osteoarthritis by the same surgeons. At the latest follow-up, 3% (1 patient) of patients developed symptomatic AVN and underwent further surgery and 3% (1) underwent revision surgery for screw breakage after a high-energy fall. Postoperatively, the alpha angle was restored to 39º ± 6º, the anterior head-neck offset was restored to 8 ± 3 mm, the neck-shaft angle was 136º ± 6º, and the presence of a positive Klein line decreased from 64% (21 hips) to 0% (0 hips). No patients showed radiographic signs of osteoarthritis at the minimum follow-up of 4 years. In this series, the modified Dunn procedure in moderate and severe slips was a reproducible procedure, and few patients developed symptomatic AVN or experienced other complications. Hip morphology was restored, but a longer follow-up duration and a detailed analysis of the results from other centers is warranted to assess the possible long-term risk of progression to AVN or osteoarthritis. Level IV, therapeutic study.

Functional adaptation after femoral intertrochanteric valgus osteotomy in Legg–Calvé–Perthes disease

Legg–Calvé–Perthes disease (LCPD) requires individualized treatment in order to regain a functional hip joint. In severe cases, in which a congruent joint cannot be achieved, other options are necessary in order to improve functionality and prevent early osteoarthritis. Therefore, we analysed the clinical and radiologic outcome of 28 patients after valgus osteotomy of the proximal femur (VOF). We examined the range of hip motion, functionality and health-related quality of life (HRQoL) via modified Harris Hip Score (mHHS) and Kidscreen-10. Radiographic analysis contained quantitative and qualitative measurements of hip morphology. In particular, we correlated the results with the change of the pelvic-femoral angle (PFA). PFA was defined as the angle between the anatomical diaphyseal line of the femur and a vertical line through the pelvis. The mean follow-up was 5.5 years. Patients showed high mHHS and good HRQoL postoperatively. An increase in ROM with an improvement of 30.5° abduction and 10.3° internal rotation was evident. PFA correlated with adduction contracture and improved significantly after surgery. In consideration of careful patient selection, VOF showed a positive effect on ROM, pain, HRQoL, radiographic congruence and outcome. We identified the age at surgery and an increasing adduction contracture—objectified by a decreased PFA—as a prognostic factor.

Hip Morphology on Post-Reduction MRI Predicts Residual Dysplasia 10 Years After Open or Closed Reduction.

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). 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. 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%). 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. Diagnostic Level IV . See Instructions for Authors for a complete description of levels of evidence.