DXA images vs. Pelvic Radiographs: Reliability of Hip Morphology Measurements.

OBJECTIVE: Dual-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. DESIGN: We 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. RESULTS: 750 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. CONCLUSION: DXA 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.

Validation of a computerized model for a new biomechanical concept- the fossa-foveolar mismatch- the answer to lesions of the ligamentous fossa-foveolar complex in the hip?

BACKGROUND: Hip-preserving surgery in young patients frequently reveals lesions of the ligamentum teres (LT). Histological and clinical evidence supports that those lesions could be source of intraarticular hip pain. It has been hypothesized that LT degeneration could be linked to the abnormal positioning of the fovea outside the lunate surface during various daily motions. We introduce the "fossa-foveolar mismatch" (FFM) by determining the trajectory of the fovea in the fossa during hip motions, enabling a comparison across diverse hip-pathomorphologies. AIMS: to determine (1) intraobserver reliability and (2) interobserver reproducibility of our computer-assisted 3-dimensional (3D) model of the FFM. MATERIALS AND METHODS: All patients with joint preserving surgery for femoroacetabular impingement syndrome (FAIS) or developmental dysplasia of the hip (DDH) at our institution (11. 2015-08.2019)were initially eligible. We employed a simple random sampling technique to select 15 patients for analysis. Three-dimensional surface models based on preoperative computed tomography (CT) scans were built, the fossa virtually excised, the fovea capitis marked. Models were subjected to physiological range of motion with validated 3D collision detection software. Using a standardized medial view on the resected fossa and the transparent lunate surface, the FFM-index was calculated for 17 motions. It was obtained by dividing the surface occupied by the fovea outside of the fossa by the total foveolar tracking surface. Three observers independently performed all analyses twice. (1) Intraobserver reliability and (2) interobserver reproducibility were calculated using intraclass correlation coefficients (ICCs). RESULTS: (1) We obtained excellent intraobserver ICCs for the FFM-index averaging 0.92 with 95% CI 0.77-0.9 among the three raters for all motions. (2) Interobserver reproducibility between raters was good to excellent, ranging from 0.76 to 0.98. CONCLUSIONS: The FFM-index showed excellent intraobserver reliability and interobserver reproducibility for all motions. This innovative approach deepens our understanding of biomechanical implications, providing valuable insights for identifying patient populations at risk.

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

BACKGROUND: The 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. METHODS: We 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. RESULTS: The 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. CONCLUSION: Our 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.

Comparison of Step-Based Metrics Under Laboratory and Free-Living Conditions in Femoroacetabular Impingement Syndrome.

CONTEXT: Femoroacetabular impingement syndrome (FAIS) causes pain and functional limitations. Little is known regarding walking characteristics, volume, and intensity evaluated in laboratory and free-living conditions and whether these measures differ between those with FAIS and uninjured individuals. OBJECTIVE: To examine the differences in laboratory gait measures and free-living step-based metrics between individuals with FAIS and uninjured control participants. DESIGN: Comparative, cross-sectional study. PATIENTS OR OTHER PARTICIPANTS: We enrolled 25 participants with FAIS and 14 uninjured controls. MAIN OUTCOME MEASURE(S): We evaluated laboratory spatiotemporal gait measures (cadence, velocity, step length, stride length) during self-selected and fast walking speeds using an instrumented walkway. Participants then wore an accelerometer around the waist during waking hours for 7 consecutive days. Free-living step-based metrics included average daily steps, peak 1- and 30-minute cadence, and average daily time spent in walking cadence bands. We compared laboratory gait measures and step-based metrics between groups. RESULTS: The groups did not differ in laboratory spatiotemporal gait measures during both speeds (all P > .05). The FAIS group took fewer daily steps (5346 ± 2141 versus 7338 ± 2787 steps/d; P = .030) and had lower peak 1-minute (92.9 ± 23.9 versus 119.6 ± 16.3 steps/min; P < .001) and 30-minute cadences (60.9 ± 27.1 versus 86.8 ± 22.4 steps/min; P = .003) compared with uninjured controls, respectively. The FAIS group also spent less time in slow (6.0 ± 3.6 versus 10.3 ± 3.4 min/d; P = .001), medium (4.5 ± 4.2 versus 8.9 ± 4.4 min/d; P = .005), and brisk/moderate (4.5 ± 6.2 versus 12.2 ± 10.3; P = .020) cadence bands compared with uninjured controls. CONCLUSIONS: Clinical/laboratory gait measures alone may not be representative of real-world walking-related physical activity behavior in individuals with FAIS.

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.

Background: 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. Purpose: 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. Study Design: Cohort study; Level of evidence, 3. Methods: 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. Results: 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. Conclusion: 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.

BACKGROUND: MRI-based synthetic CT (sCT) generates CT-like images from MRI data. OBJECTIVE: 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. MATERIALS AND METHODS: 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. RESULTS: 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

Comparison between UK Biobank and Shanghai Changfeng suggests distinct hip morphology may contribute to ethnic differences in the prevalence of hip osteoarthritis.

OBJECTS: Joint morphology is a risk factor for hip osteoarthritis (HOA) and could explain ethnic differences in HOA prevalence. Therefore, we aimed to compare the prevalence of radiographic HOA (rHOA) and hip morphology between the predominantly White UK Biobank (UKB) and exclusively Chinese Shanghai Changfeng (SC) cohorts. METHODS: Left hip iDXA scans were used to quantify rHOA, from a combination of osteophytes (grade ≥1) and joint space narrowing (grade ≥1), and hip morphology. Using an 85-point Statistical Shape Model (SSM) we evaluated cam (alpha angle ≥60°) and pincer (lateral centre-edge angle (LCEA) ≥45°) morphology and acetabular dysplasia (LCEA <25°). Diameter of femoral head (DFH), femoral neck width (FNW), and hip axis length (HAL) were also obtained from these points. Results were adjusted for differences in age, height, and weight and stratified by sex. RESULTS: Complete data were available for 5924 SC and 39,020 White UKB participants with mean ages of 63.4 and 63.7 years old. rHOA prevalence was considerably lower in female (2.2% versus 13.1%) and male (12.0% and 25.1%) SC compared to UKB participants. Cam morphology, rarely seen in females, was less common in SC compared with UKB males (6.3% versus 16.5%). Composite SSM modes, scaled to the same overall size, revealed SC participants to have a wider femoral head compared to UKB participants. FNW and HAL were smaller in SC compared to UKB, whereas DFH/FNW ratio was higher in SC. CONCLUSIONS: rHOA prevalence is lower in Chinese compared with White individuals. Several differences in hip shape were observed, including frequency of cam morphology, FNW, and DFH/FNW ratio. These characteristics have previously been identified as risk factors for HOA and may contribute to observed ethnic differences in HOA prevalence.

Is Cam Pincer Deformity a Predisposing Factor for Patellofemoral Pain Syndrome?

Purpose: This study aimed to investigate whether cam and pincer deformities (CPDs) are a risk factor for patellofemoral pain syndrome (PFPS) in women. In addition, it sought to compare the hip joint range of motion and the hip muscle strength of extremities with and without CPDs and PFPS. Materials and Methods: A total of 82 hips of 41 women with PFPS were included in the study. The mean age of participants was 32.07 ± 7.13 years. The presence of CPDs was detected on digital anterior pelvis radiographs. Pain was evaluated using the visual analog scale, and function using the Kujala scoring system. Maximum isometric muscle strength around the hips was measured using a hand-held dynamometer. Hip joint range of movement angles were measured in all three planes using a universal goniometer. Results: CPDs were found to predict PFPS in women (p = 0.011, p = 0.048). The rate of CPDs was significantly higher in extremities with PFPS compared to those without PFPS (p = 0.007). The Kujala scores of extremities with cam deformity were significantly lower than those of extremities without pincer deformity (p = 0.043). The internal/external muscle strength ratio was greater, and the abduction/adduction muscle strength ratio was lower in extremities with cam and PFPS than in those without (p = 0.040, p = 0.049). The external rotation and abduction range of movement angles were significantly smaller in extremities with pincer and PFPS compared to those without (p = 0.043, p = 0.035). Conclusion: CPDs may be a structural predisposing factor in the development of PFPS in women. CPDs assessment when evaluating predisposing factors for PFPS may present an opportunity for the management of PFPS.

Total hip arthroplasty in hereditary multiple exostosis patients: literature review and evaluation of 10 cases.

BACKGROUND: Acquired hip deformities in patients affected by hereditary multiple exostosis (HME) may incur in early hip osteoarthritis and functional limitation requiring primary total hip arthroplasty (THA). Characteristic coxo-femoral joint dysmorphisms in HME may pose a challenge for the orthopaedic surgeon. Here we report our experience in a series of patients with HME treated in our hospital with THA. METHODS: With a mean follow-up of 5 years, 10 primary THAs were reviewed; proximal femur deformities, acetabular dysplasia and joint osteoarthritis has been assessed through x-rays and CT-scan evaluation. In all cases hemispheric press-fit cups were used; 4 stem had metaphyseal engagement, 5 had proximal diaphyseal engagement and 1, with anatomical geometry, had metaphyseal fixation. 2 cases required stem cementation, 3 modular neck and 1 lateralised. The clinical data, complications and clinical outcomes, were recorded and analysed. RESULTS: The mean Harris Hip Score (HHS) increased from 34 preoperative to 86 postoperative; preoperative mean neck shaft angle (NSA) was 150°, head/neck ratio 0.6, offset 31 mm; Wiberg angle 28°, Sharp angle 38°, 1 patient had subluxation grade 4 according to Crowe, 8 hips showed osteoarthritis (Tönnis grade ⩾2 ); 5 femurs were classified as Dorr type C, 2 as type B and 3 as type A. Perioperative complications were not observed. CONCLUSIONS: Primary THA in HME significantly improved clinical and functional outcomes. Press-fit cup fixation together with metaphyseal and proximal diaphyseal stem engagement on reliable bone quality femur, represents a valid option in HME patients with normal acetabular morphology, wide broaden neck and valgus NSA.

The association between statistical shape modeling-defined hip morphology and features of early hip osteoarthritis in young adult football players: Data from the femoroacetabular impingement and hip osteoarthritis cohort (FORCe) study.

Objective: To explore the relationship between radiographic hip shape and features of early hip osteoarthritis (OA) on magnetic resonance imaging (MRI) in young male and female football players without radiographic hip OA. Design: We used baseline data from a cohort of symptomatic and asymptomatic football players aged 18-50 years. Hip shape was assessed on anteroposterior radiographs with statistical shape modeling (SSM) for men and women separately. Cartilage defects and labral tears were graded using the Scoring Hip Osteoarthritis with MRI (SHOMRI) system. We used logistic regression with generalized estimating equations to estimate associations between each hip shape variant, called shape modes, and cartilage defects or labral tears. Results: We included 229 participants (446 hips, 77.4% male). For each sex, 15 shape modes were analyzed. In men, three shape modes were associated with cartilage defects: adjusted odds ratios (aOR) 0.75 (95%CI 0.58-0.97) per standard deviation (SD) for mode 1; 1.34 (95%CI 1.05-1.69) per SD for mode 12; and 0.61 (95%CI 0.48-0.78) per SD for mode 15; and one also with labral tears: aOR 1.30 (95%CI 1.01-1.69) per SD for mode 12. These modes generally represented variations in the femoral neck and subtypes of cam morphology, with and without pincer morphology. For women, there was no evidence for associations with the outcomes. Conclusions: Several hip shape variants were associated with cartilage defects on MRI in young male football players. Specifically, one subtype of cam morphology was associated with both cartilage defects and labral tears. Hip shape was not associated with early OA features in women.

Mismatch between Conventional Femoral Arthroplasty Stems and Hip Morphology in the Elderly Chinese Hip Fracture Population.

INTRODUCTION: The morphology of the proximal femur differs in various populations. Based on our clinical experience, conventional femoral stems used in hip arthroplasty do not fit the Chinese population well. Hence, this study aims to evaluate the suitability of conventional femoral stems in the elderly Chinese hip fracture population requiring hip arthroplasty and to establish if gender and age related differences exist within this population. MATERIAL AND METHODS: We retrospectively analysed radiographic data of 300 patients from a tertiary hospital's geriatric hip fracture database who underwent either hip hemi-arthroplasties or total hip arthroplasties. Proximal femur morphological measurements were recorded, analysed and compared to that of commonly used femoral stems. Subgroup analysis was performed to compare age and gender related differences. RESULTS: A total of 18.3% of the study population had a medial femoral offset (MFO) of less than 30mm, which is the smallest available offset for the implants studied. 22.6% of female and 3% of male subjects had MFOs that were less than 30mm. In our subgroup analysis, males had significantly larger femoral head diameters, MFO and vertical femoral offsets compared to females. Older subjects (75-90 years old) had significantly smaller femoral head diameters, vertical femoral offsets and neck shaft angles compared to younger subjects (60-75 years old). CONCLUSION: Commonly used femoral stem implants have measurements that do not suit our Chinese population with small medial femoral offsets. In addition, elderly males have significantly larger femoral head diameters, medial and vertical femoral offsets whereas older subjects have significantly smaller femoral head diameters, vertical femoral offsets and neck shaft angles.

The Three-Dimensional Morphology of Femoral Medullary Cavity in the Developmental Dysplasia of the Hip.

OBJECTIVE: This study aimed to assess the morphology of the femoral medullary canal in subjects with developmental dysplasia of the hip (DDH) with the intent of improving the design of femoral stems in total hip arthroplasty. METHODS: Computed tomography images of 56 DDH hips, which were classified into Crowe I to Crowe IV, and 30 normal hips were collected and used to reconstruct three-dimensional morphology of the femoral medullary cavity. Images of twenty-one cross sections were taken from 20 mm above the apex of the lesser trochanter to the isthmus. The morphology of femoral cavity was evaluated on each cross section for the longest canal diameter, the femoral medullary torsion angle (FMTA), and the femoral medullary roundness index (FMRI). RESULTS: The Crowe IV group displayed the narrowest medullary canal in the region superior to the end of the lesser trochanter, but then gradually aligned with the medullary diameter of the other groups down to the isthmus. The FMTA along the femoral cavity increased with the severity of DDH, but the rate of variation of FMTA along the femoral canal was consistent in the DDH groups. The DDH hips generally showed a larger FMRI than the normal hips, indicating more elliptical shapes. CONCLUSION: A femoral stem with a cone shape in the proximal femur and a cylindrical shape for the remainder down to the isthmus may benefit the subjects with severe DDH. This design could protect bone, recover excessive femoral anteversion and facilitate the implantation in the narrow medullary canal.

A comparative radiographic morphometric analysis to assess the normal radiological morphology of the adult hip in indian population.

OBJECTIVE: Our objective is to analyze the normal radiological morphologic parameters of the adult hip joint of the Indian population and compare it with standard measurements and with other populations to assess the variations. METHODS: A prospective analysis of the normal pelvis X-rays of 800 persons (1600 hips) was done. We have calculated the acetabular inclination, acetabular index, lateral center edge angle (LCEA) and neck-shaft angle (NSA), sphericity of the femoral head, congruity of the joint, version of the acetabulum, depth of acetabulum, and lateralization of the femoral head in normal X-rays of the pelvis in adult persons. We used RadiAnt DICOM viewer version 4.6.5.18450 (64bit) for measurement. Statistical analysis and mean values were calculated using SPSS software. RESULTS: There were 978 X-rays of the male hip and 622 female. The acetabular inclination varied from 1 to 9. The mean acetabular index was 26.5. The LCEA was between 20 and 50. The mean neck-shaft angle was 133. There were 35, hips with an aspherical head. 94.2% X-rays the hip joint was congruent. There was 2.9% of the retroversion of acetabulum, 3.3% lateralization. CONCLUSION: Most of the parameters were comparable to standard values the acetabular index was lower. LCEA and NSA were higher. The acetabular angle was lower. There were femoral head asphericity, joint incongruity, and lateralization of the femoral head in a small proportion of our general population.

Differences in knee joint degeneration between primary hip osteoarthritis and hip osteoarthritis secondary to hip developmental dysplasia: A propensity score-based analysis.

OBJECTIVES: This study aimed to investigate differences in lower limb alignment and the prevalence of knee osteoarthritis (OA) among patients with primary hip osteoarthritis (PHOA) versus those with hip osteoarthritis secondary to developmental dysplasia of the hip (DDH-OA). METHODS: We compared 83 patients who underwent primary total hip arthroplasty for unilateral PHOA or DDH-OA after performing propensity score matching. The prevalence of knee OA and lower limb alignment were evaluated on preoperative plain radiographs. RESULTS: The prevalence of knee OA on the ipsilateral side was significantly higher in the PHOA group than in the DDH-OA group (p =.019), whereas there was no difference between the groups on the contralateral side (p = .631). Lower-limb alignment was more valgus on the ipsilateral side in the DDH-OA group than the PHOA group, whereas it was not significantly different on the contralateral side between groups. CONCLUSION: The prevalence of knee OA and lower-limb malalignment on the ipsilateral side of hip OA were different for PHOA and DDH-OA patients. Shifting the mechanical axis of lower limbs might be associated with the prevalence of knee OA and lower limb malalignment in the presence of unilateral hip OA.

Hip Dysplasia Is Not More Common in W-Sitters.

Parents are frequently cautioned by therapists, teachers, physicians, and online resources about potential negative effects of w-sitting in children (including hip dysplasia), despite lack of evidence. To examine relationships between w-sitting and hip dysplasia, a prospective cohort study was conducted of 104 patients (196 hips), aged 9.9 (standard deviation = 5.7) years, who underwent hip/pelvis radiography at a pediatric tertiary care center. Measures of hip dysplasia were taken from radiographs. Parents/patients completed a questionnaire regarding the patients' sitting habits. Associations between hip dysplasia and w-sitting were analyzed statistically. About 48/104 parents/patients (46%) reported current or past w-sitting: 11/104 (11%) current, preferred position; 23/104 (22%) current, nonpreferred position, 14/104 (13%) w-sat in past, and 56/104 (54%) never w-sat. There was no difference in measures of hip dysplasia (P > .12) or hip dysplasia frequency between w-sitters (9%) and non-w-sitters (10%; P = .81), or among w-sitting persistence groups (P = .26). W-sitting in children is not associated with hip dysplasia.

Does hip morphology correlate with proximal femoral fracture type?

PURPOSE: To determine if boney morphology influences the anatomic location of hip fractures in elderly patients. METHODS: All patients with hip fractures between 2008 and 2012 who had hip radiographs taken prior to the fracture were reviewed. Fractures were classified as intracapsular or extracapsular and hip morphology was measured on the pre-fracture x-rays. Hip morphology was determined by alpha angle, lateral central edge angle, acetabular index, neck-shaft angle, hip axis length, femoral neck diameter, Tönnis classification for hip osteoarthritis (OA) and the presence of a crossover sign. RESULTS: 148 subjects (78.4% female, age 83.5 years) with proximal femur fractures were included. 44 patients (29.7%) had intracapsular fractures and 104 (70.3%) had extracapsular fractures. 48% of patients had previous hip fractures on the contralateral side and 74.6% had the same type of fracture bilaterally. The rates of bilateral intracapsular and extracapsular fractures were similar (33.7% vs. 40.9% respectively, p = 0.39). Extracapsular fractures had a statically significant higher neck-shaft angle, a shorter hip axis length, a narrower femoral neck diameter and a higher grade of Tönnis classification of OA (p = 0.04, 0.046, 0.03, 0.02 respectively). Acetabular coverage and the proximal femoral head-neck junction, which were evaluated by lateral centre-edge angle (LCEA), acetabular index and the presence of a crossover sign, did not correlate with fracture type. The alpha angle > 40° had a statistically significant higher likelihood for extracapsular fractures (p = 0.013). CONCLUSIONS: Acetabular coverage and proximal femoral head-neck junction morphology, were found to partially correlate with the location of hip fractures and do not fully elucidate fracture type susceptibility.

Upper Femur Anatomy Depends on Age and Gender: A Three-Dimensional Computed Tomography Comparative Bone Morphometric Analysis of 628 Healthy Patients' Hips.

BACKGROUND: The knowledge of proximal femur geometry is essential in the understanding and treatment of hip pathologies. Our aim is to evaluate the range of "normal anatomical values of the proximal femur" and their relationship to age, gender, and ethnicity in a cohort of healthy population, using a 3-dimensional computed tomography automated software. METHODS: The pelvis and bilateral femora of 628 healthy individuals (394 males/234 females, mean age 61.5 ± 16.5 years, mean body mass index [BMI] 26.9 ± 5.2 kg/m2) including 2 ethnicities (226 Asians and 406 Caucasians) were assessed with a 3-dimensional computed tomography scan-based system using algorithm-calculated landmarks. The demographic parameters recorded were age, gender, BMI, and ethnicity. The femoral neck-shaft angle (NSA), femoral neck version, femoral offset (FO), and femoral canal flare index (fCFI) were calculated for each individual. Analyses were performed using SPSS version 22. P-values <.05 were considered to indicate statistical significance. RESULTS: Overall, the mean NSA was 124.7° (standard deviation [SD] 6.2), mean femoral neck version was 14.5° (SD 8.1), mean FO was 42.9 mm (SD 6.8), and mean fCFI was 3.4 (SD 0.5). Gender was associated with all parameters, with the females presenting more valgus and anteverted hips. Multivariate analysis revealed a lower NSA and fCFI and a higher FO for older individuals. Ethnicity and BMI were not associated with any parameters. CONCLUSION: Our results showed that there is a direct relationship of age and gender to the variations in the investigated proximal femur anatomical parameters in a large cohort of healthy individuals. Those important gender-based and age-based differences might advocate for more varus and lateralized component to reproduce preoperative anatomy of male and patients older than 50 years.

Hip morphology predicts posterior hip impingement in a cadaveric model.

INTRODUCTION: Posterior hip impingement is a recently-identified cause of hip pain. The purpose of this study is to characterise posterior femoroacetabular and ischiofemoral impingement and identify its predisposing morphologic traits. METHODS: Two hundred and six cadaveric hips were randomly selected and taken through controlled motion in two pure axes associated with posterior hip impingement: external rotation (through the mechanical axis) and adduction (coronal plane). The range of motion and location of impingement was noted for each specimen. Morphologic traits including femoral/acetabular version, and true neck-shaft angle (TNSA) were also measured. RESULTS: External rotation impingement occurred between the femoral neck and acetabulum in 83.0% of hips, and between the lesser trochanter and ischial tuberosity in 17.0%. Adduction impingement occurred between the lesser trochanter and ischial tuberosity in 78.6% of hips, and between the femoral neck and acetabulum in 21.4%. Multiple regression revealed that increased femoral/acetabular version predicted earlier external rotation and adduction impingement. Unstandardised betas ranging from -0.39 to -0.64 reflect that each degree of increased femoral/acetabular version individually accounts for a loss of external rotation or adduction of approximately half a degree before impingement ( p < 0.001 for each). Increased TNSA was associated with earlier adduction impingement only (unstandardised beta -0.35, p = 0.005). DISCUSSION: Relative femoral/acetabular anteversion was associated with earlier posterior hip impingement. Coxa valga was associated with earlier adduction impingement, but protective against external rotation impingement. These findings highlight the importance of monitoring correction during femoral/acetabular osteotomies, as overcorrection of retroversion may predispose to earlier posterior impingement.

The importance of hip shape in predicting hip osteoarthritis.

PURPOSE OF REVIEW: This narrative review summarizes the evidence relating hip shape and risk of osteoarthritis at the hip, with a focus on the most recent body of work. RECENT FINDINGS: Hip OA is a prevalent and potentially disabling condition with few effective non-surgical treatment options. Risk factors for hip OA appear to differ somewhat from those at other sites. Variations in hip morphology, whether assessed through standard geometric measures or statistical modeling methods, seem to increase hip OA risk and may provide a novel approach to interventions to reduce or prevent OA. Such variations have also led to focused surgical interventions to "correct" abnormal shape, although comparisons with non-surgical management are lacking. SUMMARY: There remains a lack of understanding regarding the optimal management, whether surgical, non-surgical, or a combination, for FAI syndrome. Even less is known regarding other potential morphologic variations that may contribute to OA risk. Additionally, many individuals who have shape variations that would seem to increase their risk will never develop hip OA. Questions remain regarding key risk factors for hip OA development, which individuals should be targeted for therapies, whether directed at symptoms, function, or prevention, and which therapies should be studied and offered. Trials are underway to help address some of these questions.