Femoral Version Angle Research Articles

Femoral Anteversion Angle as a Predictor of Anterior Hip Labral Length in Patients With Femoroacetabular Impingement Syndrome.

The relationship between hip rotational abnormalities and hip labral size has not been fully investigated. To (1) examine the correlation between rotational abnormalities of the hip and labral size, while also identifying other predictive values for hip labral size, and (2) explore whether femoral torsion will lead to increased labral size. Cross-sectional study; Level of evidence, 3. A total of 180 patients (180 hips) with femoroacetabular impingement syndrome (FAIS) (mean age, 36.81 ± 10.17 years; 67 male, 113 female) who underwent hip arthroscopic surgery between January 2021 and May 2022 were included. The femoral version (FV), acetabular version, and combined version angles were measured on computed tomography, and the labral length and height at the 12-o'clock and 3-o'clock positions were measured on magnetic resonance imaging. The hips were categorized into 3 groups based on FV angle: small (SFV; <10°); moderate (MFV; ≥10° and ≤20°), and large (LFV; >20°), and group comparisons were performed. Linear correlation and regression analysis were employed. Predictive factors for labral length were FV angle (β = 0.298; P = .02), sex (β = -0.302; P < .001), and age (β = -0.169; P = .016) at 3 o'clock and lateral center-edge angle (LCEA; β = -0.208; P = .005) and age (β = -0.186; P = .011) at 12 o'clock. FV angle was positively correlated with labral length at 3 o'clock (r = 0.267; P < .001) and negatively correlated with age (r = -0.222; P = .003) and female sex (r = -0.202; P = .006). LCEA (r = -0.227; P = .002) and age (r = -0.205; P = .006) were negatively correlated with labral length at 12 o'clock. Labral length at 3 o'clock was significantly different between the LFV (n = 49 hips), MFV (n = 65 hips), and SFV (n = 66 hips) groups (9.85 ± 2.28, 8.89 ± 2.44, and 8.30 ± 2.05 mm, respectively; P = .027 for LFV vs MFV; P < .001 for LFV vs SFV). Patients with FAIS who exhibited a higher FV angle were at a greater likelihood of having a larger anterior labral length. Increased femoral anteversion and decreased LCEA, male sex, and younger age were significantly associated with longer hip labral length.

Computed tomography-based automated 3D measurement of femoral version: Validation against standard 2D measurements in symptomatic patients.

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.

Anatomical variations of the equine femur and tibia using statistical shape modeling.

The objective of this study was to provide an overarching description of the inter-subject variability of the equine femur and tibia morphology using statistical shape modeling. Fifteen femora and fourteen tibiae were used for building the femur and tibia statistical shape models, respectively. Geometric variations in each mode were explained by biometrics measured on ±3 standard deviation instances generated by the shape models. Approximately 95% of shape variations within the population were described by 6 and 3 modes in the femur and tibia shape models, respectively. In the femur shape model, the first mode of variation was scaling, followed by notable variation in the femoral mechanical-anatomical angle and femoral neck angle in mode 2. Orientation of the femoral trochlear tubercle and femoral version angle were described in mode 3 and mode 4, respectively. In the tibia shape model, the main mode of variation was also scaling. In mode 2 and mode 3, the angles of the coronal tibial plateau and the medial and lateral caudal tibial slope were described, showing the lateral caudal tibial slope angle being significantly larger than the medial. The presented femur and tibia shape models with quantified biometrics, such as femoral version angle and posterior tibial slope, could serve as a baseline for future investigations on correlation between the equine stifle morphology and joint disorders due to altered biomechanics, as well as facilitate the development of novel surgical treatment and implant design. By generating instances matching patient-specific femorotibial joint anatomy with radiographs, the shape model could assist virtual surgical planning and provide clinicians with opportunities to practice on 3D printed models.

Can a Computational Model Predict the Effect of Lesion Location on Cam-type Hip Impingement?

The Warwick consensus defined femoroacetabular impingement syndrome as a motion-related clinical disorder of the hip with a triad of symptoms, clinical signs, and imaging findings representing symptomatic premature contact between the proximal femur and acetabulum. Several factors appear to cause labral and cartilage damage, including joint shape and orientation and patient activities. There is a lack of tools to predict impingement patterns in a patient across activities. Current computational modeling tools either measure pure ROM of the joint or include complexity that reduces reliability and increases time to achieve a solution. The purpose of this study was to examine the efficacy of a low computational cost approach to combining cam-type hip shape and multiple hip motions for predicting impingement. Specifically, we sought to determine (1) the potential to distinguish impingement in individual hip shapes by analyzing the difference between a cam lesion at the anterior femoral neck and one located at the superior femoral neck; (2) sensitivity to three aspects of hip alignment, namely femoral neck-shaft angle, femoral version angle, and pelvic tilt; and (3) the difference in impingement measures between the individual activities in our hip motion dataset. A model of the shape and alignment of a cam-type impinging hip was created and used to describe two locations of a cam lesion on the femoral head-neck junction (superior and anterior) based on joint shape information available in prior studies. Sensitivity to hip alignment was assessed by varying three aspects from a baseline (typical alignment described in prior studies), namely, femoral neck-shaft angle, femoral version, and pelvic tilt. Hip movements were selected from an existing database of 18 volunteers performing 13 activities (10 male, eight female; mean age 44 ± 19 years). A subset was selected to maximize variation in the range of joint angles and maintain a consistent number of people performing each activity, which resulted in nine people per activity, including at least three of each sex. Activities included pivoting during walking, squatting, and golf swing. All selected hip motion cases were applied to each hip shape model. For the first part of the study, the number of motion cases in which impingement was predicted was recorded. Quantitative analyses of the depth of penetration of the cam lesion into the acetabular socket and qualitative observations of impingement location were made for each lesion location (anterior and superior). In the second part of the study, in which we aimed to test the sensitivity of the findings to hip joint orientation, full analysis of both cam lesion locations was repeated for three modified joint orientations. Finally, the results from the first part of the analysis were divided by activity to understand how the composition of the activity dataset affected the results. The two locations of cam lesion generated impingement in a different percentage of motion cases (anterior cam: 56% of motion cases; superior cam: 13% of motion cases) and different areas of impingement in the acetabulum, but there were qualitatively similar penetration depths (anterior cam: 6.8° ± 5.4°; superior cam: 7.9° ± 5.8°). The most substantial effects of changing the joint orientation were a lower femoral version angle for the anterior cam, which increased the percentage of motion cases generating impingement to 67%, and lower neck-shaft angle for the superior cam, which increased the percentage of motion cases generating impingement to 37%. Flexion-dominated activities (for example, squatting) only generated impingement with the anterior cam. The superior cam generated impingement during activities with high internal-external rotation of the joint (for example, the golf swing). This work demonstrated the capability of a simple, rapid computational tool to assess impingement of a specific cam-type hip shape (under 5 minutes for more than 100 motion cases). To our knowledge, this study is the first to do so for a large set of motion cases representing a range of activities affecting the hip, and could be used in planning surgical bone removal. The results of this study imply that patients with femoroacetabular impingement syndrome with cam lesions on the superior femoral head-neck junction may experience impinging during motions that are not strongly represented by current physical diagnostic tests. The use of this tool for surgical planning will require streamlined patient-specific hip shape extraction from imaging, model sensitivity testing, evaluation of the hip activity database, and validation of impingement predictions at an individual patient level.

Coxa valga and antetorta increases differences among different femoral version measurements : potential implications for derotational femoral osteotomy planning.

To evaluate how abnormal proximal femoral anatomy affects different femoral version measurements in young patients with hip pain. 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. 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°). 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 Open2022;3(10):759-766.

Translated article] A 3D method to estimate the effect of derotational osteotomies over femoral maltorsion

Introduction and objectivesAccurate measurement of femoral torsion is essential to diagnosing, correct surgical decision-making, and the preoperative planning of derotational osteotomies in a subgroup of anterior knee pain patients and patellofemoral instability. Several measurement techniques have been described with great variability in the magnitude of the values. Moreover, none of them can predict the effect of rotational osteotomy on the femoral version value. The purpose of the present work is to develop a method to reliably measure femoral torsion as well as to evaluate the effects of osteotomy on the femoral version angle. Material and methods30 patients without previous signs neither symptoms of patellofemoral pain or patellofemoral instability and with a lower limbs CT were selected. Their femoral torsion was measured using the classic Jeanmart and the Murphy's method by two independent radiologists. Independently, two orthopedic surgeons measured femoral torsion with the 3D method described in this study. The intraclass coefficient correlation and the Bland-Altman tests were used to analyze qualitatively and quantitatively the intraobserver and interobserver variability of the method regarding the Jeanmart's and Murphy's method. The confidence interval of the Normal values of the new method were defined and a lineal regression analysis between the 3D-Jeanmart's and 3D-Muphy's methods was performed. ResultsThe mean femoral version with the 3D method was 12.74° (SD 5.96°, 95% CI: 11.67°–13.82°). With Jeanmart's method, it was 12.84° (SD 8.60°, 95% CI: 11.28°–14.39°) and 15.87° (SD 10.68°, 95% CI: 13.94°–17.80°) with Murphy's method, being these differences not statistically significant. Both interobserver and intraobserver agreement of the 3D method were high. ConclusionThe method presented in this study allows for the reliable quantification of femoral torsion in a reproducible way. This method can be applied in several open access 3D image programmes what makes its implementation in the healthcare centres possible from now on.

Un método 3D para estimar el efecto de osteotomías desrotadoras sobre alteraciones torsionales de fémur

Introduction and objectivesAccurate measurement of femoral torsion is essential to diagnosing, correct surgical decision-making, and the preoperative planning of derotational osteotomies in a subgroup of anterior knee pain patients and patellofemoral instability. Several measurement techniques have been described with great variability in the magnitude of the values. Moreover, none of them can predict the effect of rotational osteotomy on the femoral version value. The purpose of the present work is to develop a method to reliably measure femoral torsion as well as to evaluate the effects of osteotomy on the femoral version angle. Material and methods30 patients without previous signs neither symptoms of patellofemoral pain or patellofemoral instability and with a lower limbs CT were selected. Their femoral torsion was measured using the classic Jeanmart and the Murphy's method by two independent radiologists. Independently, two orthopedic surgeons measured femoral torsion with the 3D method described in this study. The intraclass coefficient correlation and the Bland–Altman tests were used to analyze qualitatively and quantitatively the intraobserver and interobserver variability of the method regarding the Jeanmart's and Murphy's method. The confidence interval of the Normal values of the new method were defined and a lineal regression analysis between the 3D-Jeanmart's and 3D-Muphy's methods was performed. ResultsThe mean femoral version with the 3D method was 12.74° (SD 5.96°, 95% CI: 11.67° to 13.82°). With Jeanmart's method, it was 12.84° (SD 8.60°, 95% CI: 11.28° to 14.39°) and 15.87° (SD 10.68°, 95% CI: 13.94° to 17.80°) with Murphy's method, being these differences not statistically significant. Both interobserver and intraobserver agreement of the 3D method were high. ConclusionThe method presented in this study allows for the reliable quantification of femoral torsion in a reproducible way. This method can be applied in several open access 3D image programs what makes its implementation in the healthcare centers possible from now on.

Generalized Joint Laxity Is Associated With Dynamic Hip Ultrasonography Measures in Female Athlete Patients Who Are Not Hypermobile.

To investigate ultrasound (US) femoroacetabular translation measurements in female athlete patients. 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. 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 ( = 0.9; 95% CI=0.3-1.43; P=.002) and EER by 0.8 mm ( = 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]). Beighton score was independently associated with dynamic US measures in female athlete patients who are not hypermobile when controlling for other factors.

Femoroacetabular translation in female athletes and dancers assessed by dynamic hip ultrasonography

ObjectiveTo compare femoroacetabular (FA) translation between dancers and athletes with hip pain and between dancers with and without hip pain.MethodsIn this cross-sectional study, 171 female athletes and dancers with hip...

Predicting the Risk of Subsequent Hip Surgery Before Primary Hip Arthroscopy for Femoroacetabular Impingement Syndrome: A Machine Learning Analysis of Preoperative Risk Factors in Hip Preservation

Background: The number of patients requiring reoperation has increased as the volume of hip arthroscopy for femoroacetabular impingement syndrome (FAIS) has increased. The factors most important in determining patients who are likely to require reoperation remain elusive. Purpose: To leverage machine learning to better characterize the complex relationship across various preoperative factors (patient characteristics, radiographic parameters, patient-reported outcome measures [PROMs]) for patients undergoing primary hip arthroscopy for FAIS to determine which features predict the need for future ipsilateral hip reoperation, namely, revision hip arthroscopy, total hip arthroplasty (THA), hip resurfacing arthroplasty (HRA), or periacetabular osteotomy (PAO). Study Design: Cohort study; Level of evidence, 3. Methods: A cohort of 3147 patients undergoing 3748 primary hip arthroscopy procedures were included from an institutional hip preservation registry. Preoperative computed tomography of the hip was obtained for each patient, from which the following parameters were calculated: the alpha angle; the coronal center-edge angle; the neck-shaft angle; the acetabular version angle at 1, 2, and 3 o’clock; and the femoral version angle. Preoperative PROMs included the modified Harris Hip Score (mHHS), the Hip Outcome Score (HOS)–Activities of Daily Living subscale (HOS-ADL) and the Sport Specific subscale, and the international Hip Outcome Tool (iHOT-33). Random forest models were created for revision hip arthroscopy, the THA, the HRA, and the PAO. Area under the curve (AUC) for the receiver operating characteristic curve and accuracy were calculated to evaluate each model. Results: A total of 171 patients (4.6%) underwent subsequent hip surgery after primary hip arthroscopy for FAIS. The AUC and accuracy, respectively, were 0.77 (fair) and 76% for revision hip arthroscopy (mean, 26.4-month follow-up); 0.80 (good) and 81% for THA (mean, 32.5-month follow-up); 0.62 (poor) and 69% for HRA (mean, 45.4-month follow-up); and 0.76 (fair) and 74% for PAO (mean, 30.4-month follow-up). The most important factors in predicting reoperation after primary hip arthroscopy were higher body mass index (BMI) and lower preoperative HOS-ADL for revision hip arthroscopy, greater age and lower preoperative iHOT-33 for THA, increased BMI for HRA, and larger neck-shaft angle and lower preoperative mHHS for PAO. Conclusion: Despite the low failure rate of hip arthroscopy for FAIS, our study demonstrated that machine learning has the capability to identify key preoperative risk factors that may predict subsequent ipsilateral hip surgery before the index hip arthroscopy. Knowledge of these demographic, radiographic, and patient-reported outcome data may aid in preoperative counseling and expectation management to better optimize hip preservation.

Dependency of lower limb joint reaction forces on femoral version.

Musculoskeletal (MSK) models based on literature data are meant to represent a generic anatomy and are a popular tool employed by biomechanists to estimate the internal loads occurring in the lower limb joints, such as joint reaction forces (JRFs). However, since these models are normally just linearly scaled to an individual's anthropometry, it is unclear how their estimations would be affected by the personalization of key features of the MSK anatomy, one of which is the femoral version angle. How are the lower limb JRF magnitudes computed through a generic MSK model affected by changes in the femoral version? We developed a bone-deformation tool in MATLAB (shared at https://simtk.org/projects/bone_deformity) and used it to create a set of seven OpenSim models spanning from 2˚ femoral retroversion to 40˚ anteversion. We used these models to simulate the gait of an elderly individual with an instrumented prosthesis implanted at their knee joint (5th Grand Challenge dataset) and quantified both the changes in JRFs magnitude due to varying the skeletal anatomy and their accuracy against the correspondent in vivo measurements at the knee joint. Hip and knee JRF magnitudes were affected by the femoral version with variations from the unmodified generic model up to 17.9 ± 4.5% at the hip and 43.4 ± 27.1% at the knee joint. The ankle joint was unaffected by the femoral geometry. The MSK models providing the most accurate knee JRFs (root mean squared error: 0.370 ± 0.068 body weight, coefficient of determination: 0.757 ± 0.104, peak error range: 0.09-0.42 body weight) were those with femoral anteversion angle closer to that measured on the segmented bone of the individual. Femoral version substantially affects hip and knee JRFs estimated with generic MSK models, suggesting that personalizing key MSK anatomical features might be necessary for accurate estimation of JRFs with these models.

Radiographic Indices Are Not Predictive of Clinical Outcomes Among 1735 Patients Indicated for Hip Arthroscopic Surgery: A Machine Learning Analysis

Background: The relationship between the preoperative radiographic indices for femoroacetabular impingement syndrome (FAIS) and postoperative patient-reported outcome measure (PROM) scores continues to be under investigation, with inconsistent findings reported. Purpose: To apply a machine learning model to determine which preoperative radiographic indices, if any, among patients indicated for the arthroscopic correction of FAIS predict whether a patient will achieve the minimal clinically important difference (MCID) for 1- and 2-year PROM scores. Study Design: Cohort study; Level of evidence, 3. Methods: A total of 1735 consecutive patients undergoing primary hip arthroscopic surgery for FAIS were included from an institutional hip preservation registry. Patients underwent preoperative computed tomography of the hip, from which the following radiographic indices were calculated by a musculoskeletal radiologist: alpha angle, beta angle, sagittal center-edge angle, coronal center-edge angle, neck shaft angle, acetabular version angle, and femoral version angle. PROM scores were collected preoperatively, at 1 year postoperatively, and at 2 years postoperatively for the modified Harris Hip Score (mHHS), the Hip Outcome Score (HOS)–Activities of Daily Living (HOS-ADL) and –Sport Specific (HOS-SS), and the International Hip Outcome Tool (iHOT-33). Random forest models were created for each PROM at 1 and 2 years’ follow-up, with each PROM’s MCID used to establish clinical meaningfulness. Data inputted into the models included ethnicity, laterality, sex, age, body mass index, and radiographic indices. Comprehensive and separate models were built specifically to assess the association of the alpha angle, femoral version angle, coronal center-edge angle, McKibbin index, and hip impingement index with respect to each PROM. Results: As evidenced by poor area under the curves and P values >.05 for each model created, no combination of radiographic indices or isolated index (alpha angle, coronal center-edge angle, femoral version angle, McKibbin index, hip impingement index) was a significant predictor of a clinically meaningful improvement in scores on the mHHS, HOS-ADL, HOS-SS, or iHOT-33. The mean difference between 1- and 2-year PROM scores compared with preoperative values exceeded the respective MCIDs for the cohort. Conclusion: In patients appropriately indicated for FAIS corrective surgery, clinical improvements can be achieved, regardless of preoperative radiographic indices, such as the femoral version angle, coronal center-edge angle, and alpha angle. No specific radiographic parameter or combination of indices was found to be predictive of reaching the MCID for any of the 4 studied hip-specific PROMs at either 1 or 2 years’ follow-up.

Is Dynamic Ultrasound Of Femoroacetabular Translation Increased In Female Dancers With Acetabular Dysplasia?

BACKGROUND: Hip pain is common in dancers. A contributing factor to hip pathology in dancers may be the high prevalence of acetabular dysplasia. Dynamic ultrasound (US) of femoroacetabular translation has been shown as a reliable measure of femoroacetabular motion and may serve to assist in the evaluation of hip microinstability. Evidence regarding associations between acetabular dysplasia and femoroacetabular translation is unknown. PURPOSE: To investigate associations between acetabular dysplasia and dynamic US femoroacetabular translation in female dancers with hip pain. METHODS: Prospective cross-sectional study design. Dynamic US of femoroacetabular translation was performed in three positions: neutral (N), neutral with contralateral hip flexion (NF), and the apprehension position with contralateral hip flexion (EER flexed). Dysplasia was defined using radiographic measures: LCEA<25 or ACEA<20. Multivariable linear regression analysis was used to assess variation in femoroacetabular translation between dancers and non-dancers with and without dysplasia controlling for covariates. Independent variables included age, Beighton score, hypermobility (Beighton score≥5), BMI, and femoral version angles. P-values<0.05 were considered significant. RESULTS: The study included 64 female dancers and 92 non-dancer athletes. Dancers were younger (p=0.001), had a higher Beighton score (p=0.006), and were more likely to be hypermobile (p=0.005) compared to non-dancer athletes. Dynamic US femoroacetabular translation was not different in dancers with and without dysplasia (N, p=0.55; NF, p=0.78; EER flexed, p=0.93). Dancers showed greater dynamic US femoroacetabular translation when compared to non-dancer athletes in both the NF position (5.0±2.57 mm, 4.2±2.50 mm; p=0.04) and EER flexed position (6.0±2.53 mm, 5.2±2.41 mm, respectively; p=0.04). CONCLUSION: Acetabular dysplasia was not associated with increased dynamic US femoroacetabular translation in this cohort. Dancers showed increased US femoroacetabular translation compared to non-dancer athletes. This finding is likely related to increased ligamentous laxity and stretched ligaments inherent to dance training. Future research is warranted to collect data in asymptomatic dancers with and without acetabular dysplasia.

Anatomical analysis of the pelvis to identify any predisposing anatomical factors for ischiofemoral space pathology: a retrospective study.

Anatomical analysis of the hips and pelvis was performed using MRI to evaluate morphological characteristics and associations between them. We identified correlations between the ischiofemoral space (IFS), quadratus femoris space (QFS), femoral version angle (FVA) and cervicodiaphyseal angle (CDA). This study involved a retrospective search of a database of consecutive reports of adult hip MRI examinations carried out between January and September 2016. Patients with a medical history likely to affect pelvic and hip morphometry were excluded. A total of 137 adult patients were enrolled in the study (45.3% males and 54.7% females), with a mean age of 50.16 ± 13.87 years. The mean IFS was 20.88 ± 5.96 mm, mean QFS was 15.2 ± 6.18 mm, mean FVA was 12.43 ± 6.98, and mean CDA was 121.27 ± 4.6°. The IFS measurements were significantly correlated with femoral measurements (p = 0.025). These visible differences showed a slight negative relationship (-0.191), and females had a smaller distance between these anatomical structures than males (p < 0.001). Females had a significantly smaller QFS than males (12.42 ± 5.94 vs 18.73 ± 4.48 mm, p = 0.000). There was a small but significant positive relationship between CDA and FVA (p = 0.022), with a correlation coefficient of 0.195. A higher FVA was correlated with a smaller IFS. Furthermore, an increase in the CDA appeared in tandem with an increase in the FVA. A single conventional MRI sequence can alert us to how anatomical factors could predispose individuals to a decrease in IFS.

Is Femoral Version Associated with Changes in Hip Muscle Strength in Females with Symptomatic Femoroacetabular Impingement?

Objective The aim of the present study was to evaluate the association between femoral anteversion and hip muscle strength in subjects with femoroacetabular impingement syndrome. Method The femoral version angles described in the arthro-magnetic resonance images and isokinetic tests were retrospectively evaluated from July 2016 to December 2017. The inclusion criteria were: a) femoral version evaluated by the same radiologist; b) α angle ≥ 55°; and c) no limiting pain during the isokinetic test. Flexion/extension, abduction/adduction, and internal/external rotation peak torques were evaluated at 30° per second in 5 repetitions. The correlation between femoral version and muscle strength was evaluated by simple linear regression at a 5% significance level. Results A total of 37 females filled the inclusion criteria, and 51 symptomatic hips were evaluated. There was no correlation of the femoral anteversion in the flexion, extension, abduction, adduction, external rotation and internal rotation peak torques. Conclusion Femoral anteversion did not show a correlation with hip muscle strength in females with symptomatic femoroacetabular impingement.

A semi-automated method for measuring femoral shape to derive version and its comparison with existing methods.

The measurement of femoral version is important in surgical planning of derotational osteotomies particularly for patients with proximal femoral deformity. It is, however, difficult to measure version accurately and differences of 10° to 15° have been found between repeated measurements. The aim of this work was first to develop a method of measuring femoral version angle where the definition of the neck axis is based on the three-dimensional point cloud making up the neck, second to automate many of the processes involved thus reducing the influence of human error and third to ensure the method could run on freely available software suitable for most computer platforms. A CT scan was performed on 44 cadaveric femurs to generate point clouds of the femoral surfaces. The point clouds were then analysed semi-automatically to determine femoral version angle between a neck axis defined by the bone surface points belonging only to the neck and a femoral condylar axis. The results from the neck fitting method were compared against three other methods typically used in the clinic (Murphy, Reikeras and Lee methods). Version angle measured by the new method gave 19.1° ± 7.3° (mean ± standard deviation) for the set of cadaveric femurs, 3.5° lower than the Murphy method and 6.8° and 11.0° higher than the Reikeras and Lee 2D methods respectively. The results demonstrate a method of measuring femoral version angle incorporating a high level of automation running on free software.

Hip Configuration and Function in Bladder Exstrophy Treated Without Pelvic Osteotomy

Nine children with congenital bladder exstrophy treated without pelvic osteotomy were analyzed clinically and radiologically at a mean age of 13 years (range 9-16 years). The acetabular and femoral version angles were measured by computed tomography (CT) imaging. Two of the children had a slight waddling gait, but none of them had any pain and they could participate in sports without problems. They had a normal range of hip movements and a normal foot progression angle. The acetabulum was retroverted by an average of 5 degrees, but was balanced by an increased anteversion of the femur which on the average was 10 degrees-20 degrees higher than normal. The femoral head in all hips was spherical, and no hip showed dysplasia. In bladder exstrophy, retroversion of the acetabulum was balanced by an increased anteversion of the femur, resulting in a normal range of hip movements and a normal gait in later childhood.