This study aimed to determine the femoral inclination angle parameters of the proximal femur and acetabulum in both healthy and hip dysplasia-affected Aksaray Malaklı dogs. This data contributes to understanding the breed’s hip morphology and supports treatment planning for hip dysplasia. The study included 15 Aksaray Malaklı dogs (9 females, 6 males), radiographed in a ventrodorsal (V/D) view at 4, 8, and 12 months of age. Hip dysplasia susceptibility was evaluated using the Fédération Cynologique Internationale (FCI) scoring system, and femoral inclination angles were measured. According to FCI scoring, hip dysplasia was detected in 6.6% of dogs at 4 months, 26.6% at 8 months, and 66.6% at 12 months. A progressive increase in femoral inclination angles was also observed: 26.6% at 4 months, 33.3% at 8 months, and 40% at 12 months. After analyzing the femoral inclination indices for left and right hip joints, statistical results showed no significant difference (p>0.05) between sides. It was emphasized that the femoral inclination angle alone is not a sufficient parameter to assess hip dysplasia, as it may lead to misleading conclusions. Although positive statistical changes were observed, an increase in the femoral inclination angle cannot always be correlated with the presence or severity of hip dysplasia. Additionally, orthopedic conditions such as femoral torsion, coxa vara, coxa valga, and arthritis may also be present alongside hip dysplasia.

BackgroundThis study assesses intra- and interobserver reliability in measuring femoral torsion on repeated computed tomography (CT) scanograms and explores variability across training levels and patient characteristics.MethodsPatients from 2001 to 2017 with femur fractures who underwent multiple CT scanograms were included. Measurements were performed by an orthopaedic traumatologist, two orthopaedic residents (PGY-5 and PGY-3), and a musculoskeletal radiologist. Intraobserver reliability was assessed using intraclass correlation coefficients (ICCs), and interobserver reliability using repeated measures ANOVA. Correlations between measurement variability and body mass index (BMI), age, height, gender, and laterality were evaluated using Pearson’s coefficient.ResultsTwenty-nine patients with unilateral uninjured femurs were analyzed. Interobserver analysis revealed significant differences in femoral torsion (p = 0.006) and length (p = 0.019). Intraobserver reliability showed strong agreement in femoral torsion (ICC 0.620–0.950) and length (ICC 0.992–0.999), but moderate to poor agreement in femoral neck axis (ICC 0.394–0.627) and posterior condylar axis (ICC 0.561–0.665). Femoral length measurements were the most consistent across all reviewers. Higher BMI correlated with increased variability in femoral torsion measurements (r = 0.378; p = 0.048). No significant correlation was found for age (p = 0.110), height (p = 0.363), gender (p = 0.610), or laterality (p = 0.830).ConclusionThese findings highlight the reliability of CT scanograms to assess femoral length and torsion when done by the same physician. Although moderate to poor agreement in femoral neck axis and posterior femoral condyle axis, overall femoral torsion was found to be highly reliable. Reliable measurement of native femoral torsion in patients with a higher BMI may be difficult. To ensure reliable measures of femoral torsion, the same clinician should evaluate all pertinent studies for an individual patient.Level of evidenceLevel III Retrospective cohort study.

BackgroundIschiofemoral impingement (IFI) is a cause of posterior hip pain that is caused by the narrowing of the space between the lateral aspect of the ischium and the medial aspect of the lesser trochanter. It’s correlation with femoral morphology variation has been documented, however it is unclear whether the treatment of ischiofemoral impingement alone is sufficient for treating the cases with abnormal anatomical variations such as excessive femur torsion. The purpose of this study is to evaluate the outcome ischiofemoral impingement patients with femoral torsion treated only with arthroscopic ischiofemoral release.MethodsWe retrospectively reviewed all ischiofemoral impingement cases treated in our hospital from 2018 to 2024. Preoperative hip MRI and femur CT-Scan was evaluated to measure the femoral anteversion, femoral neck inclination, ischiofemoral space, quadratus femoris space, and intertuberous distances. Patients were divided into two groups: normal (5-30 degrees of anteversion) and abnormal femoral torsion. All hips were evaluated preoperatively and at 3, 6, 12 months postoperative with modified Harris Hip Score (mHHS).ResultsAmong 23 cases of were treated in our hospital at that period, 8 IFI cases with excessive femoral torsion was identified. Although statistically insignificant, patients with abnormal femoral torsion have narrower ischiofemoral space and quadratus femoral space compared with the normal group. Both groups demonstrated similar outcome at post-operative, 3, 6 and 12-months follow up (p>0.05).ConclusionIschiofemoral impingement patient with excessive femoral torsion treated with isolated endoscopic lesser trochanteric resection demonstrated a similar outcome with those with normal femoral torsion.

PurposeThe Beighton score is a clinical tool for assessing generalized ligamentous laxity and identifying patients at risk for hip instability. This study aims to 1) test whether continuous Beighton scores are associated with radiographic measures of hip instability, and 2) evaluate whether these associations differ by age, sex, and race.MethodsA retrospective analysis was conducted on a cohort of symptomatic patients with femoroacetabular impingement (FAI), hip instability, or abnormal femoroacetabular orientation. Beighton score (assessed on a continuous scale from 0–9) was collected along with demographic information for 720 hips from 554 patients. Radiographic measurements were obtained from 3D reconstructed CT scans and included lateral center edge angle (LCEA), acetabular coverage, acetabular version, femoral torsion, femoral neck shaft angle (FNSA), combined version, and Tonnis angle Linear mixed models examined associations between Beighton score and each radiographic measure. Additional analyses compared hips with and without radiographic instability—defined as combined version ≥35°, FNSA ≥135°, LCEA ≤25°, coverage ≤55%, or Tonnis angle ≥10° and evaluated the influence of sex, age, and race on these relationships.ResultsBeighton scores across all symptomatic hips were not significantly associated with LCEA, acetabular coverage, FNSA, or Tonnis angle. However, in hips with and without radiographic instability, Beighton scores were positively associated with combined version (p ≤ 0.01). In Instability hips, Beighton scores were also associated with acetabular version (p = 0.044) but not femoral torsion (p = 0.079). A significant sex effect was found: in males, Beighton scores were positively associated with combined version and femoral torsion (p < 0.001), while no significant associations were observed in females (p ≥ 0.2). Therefore, associations with combined version were likely driven by male hips. Age and race had no significant influence on these relationships.ConclusionsThese findings suggest that Beighton score is not associated with radiographic indicators of hip instability in female patients but may be related to increased anteversion and torsion in male hips. This association may encourage surgeons to closely evaluate combined version abnormalities in male patients with higher Beighton scores.

PurposeFemoroacetabular impingement syndrome (FAIS) and hip instability, which have sex-specific incidence rates, increase the risk of hip osteoarthritis (OA). However, the relationship between joint space width (JSW) and femoroacetabular morphology in pre-arthritic symptomatic females remains unclear. This study aims to determine if there are differences in JSW between hips with FAIS and instability along with investigating the influence of hip morphology on JSW.MethodsA retrospective review of 493 symptomatic female hips in 410 patients (Age: 32.3±10.4 years, Height: 1.67±0.07 m, Weight: 70.0±14.4 kg, BMI: 25.1±5.0) used standing AP x-rays to measure JSW at the medial, superior, and lateral locations of the acetabular sourcil. Hips were grouped by radiographic measurements, collected from 3D reconstructed CT scan analyses, into the following groups: cam, pincer, mixed, mild instability, instability, and FAI with instability. Associations between JSW and morphology measures such as LCEA, acetabular coverage, Tönnis angle, FNSA, alpha angle, acetabular version, femoral torsion, and combined version were analyzed.ResultsJSW at all locations was significantly lower in pincer hips compared to other pathology groups (p < 0.05) with the exception of mixed hip pathology which including pincer deformities (p > 0.4). Hips with instability and FAI with instability had significantly greater JSW than pincer and mixed groups (p < 0.05). There were no significant JSW differences between instability and FAI with instability groups at any location (p > 0.1). Acetabular coverage and LCEA were negatively associated with JSW (p < 0.001), while Tönnis angle, FNSA, and alpha angle measures at the 1, 2, and 3 o’clock positions were positively associated with JSW (p < 0.05). No significant associations were observed for acetabular version (p ≥ 0.4), femoral torsion (p ≥ 0.3), or combined version (p ≥ 0.3).DiscussionDifferences in JSW across FAIS and instability groups highlight the influence of femoroacetabular morphology and orientation in pre-arthritic female hips. Pincer hips exhibit lower JSW than instability hips at all locations. Therefore, in the young female population, decreased but symmetric joint space should alert the provider to evaluate for pincer-type FAIS.

PurposeHip surgeons seek to understand the complexity and interconnectedness of relationships between preoperative patient-reported symptoms, demographics, and radiographic features. Machine learning (ML) approaches might help to elucidate these potentially non-linear relationships. This study used ML regression modeling to identify radiographic and demographic features that most influence preoperative symptom severity in patients with hip-related symptoms.MethodsA retrospective chart review was performed to identify patients with hip-related symptoms of femoroacetabular impingement and hip instability at a single center. Demographics and radiographic measures (e.g., femoral and acetabular measurements) from 3D CT scans were used as ML model inputs. Separate ML predictive model outcomes were preoperative iHOT-12 (n = 618 hips) and PROMIS Pain Interference (PI) scores (n = 566 hips). The random forest ML model framework was selected for its strength in modeling complex, non-linear relationships. To assess generalizability, models were developed using a train-test split (i.e., 70/30), cross-validation, hyperparameter tuning, and repeated random sampling. Model performance was evaluated using R-squared. SHapley Additive exPlanations (SHAP) analysis was used to identify the most influential model inputs (radiographic and demographic variables).ResultsML models consistently overfit the training data and generalized poorly when predicting iHOT-12 and PROMIS PI scores. Although overfitting occurred, SHAP analysis identified consistent demographic and radiographic features across models that were important for symptom severity prediction: acetabular surface area, femoral torsion, alpha angle at 12 o’clock, and weight for iHOT-12 scores and acetabular surface area, femoral neck shaft angle, acetabular version at 3 o’clock, and combined version for PROMIS PI.ConclusionML models had poor predictive ability to generalize but consistently identified radiographic variables (e.g., acetabular surface area) associated with preoperative symptom severity. Poor model generalizability suggests this study’s specific clinical variables may not adequately represent the complexity of patient symptom variability. Ongoing work aims to clarify whether these relationships exist between demographic and radiographic features and patient-reported preoperative symptoms.

IntroductionHip preservation surgery is a complex field tasking physicians with determining causes for intra-articular hip pain often based on an underlying biomechanical diagnosis. One major consideration in creating a biomechanical diagnosis is femoral torsion. This measurement has high variability depending on the technique employed. Sutter et al developed a method of converting the more reliable axial oblique measurement of femoral antetorsion on axial imaging to a transverse angle in line with posterior femoral condyles. We sought with this study to validate this conversion using photographs of cadaveric specimens and computed topography (CT) imaging of those specimens.MethodsForty femora were harvested from cadavers. Various photographs were taken in predetermined positions. ImageJ software was used to measure antetorsion in both the standard axial (transverse) and axial oblique orientations. Femoral neck shaft angles of the photographs were also measured. Visage imaging software was used to measure antetorsion in the axial oblique plane and neck shaft angle on CT. The Sutter conversion was used to convert axial oblique measurements to transverse and compared to photographic measurements.ResultsTransverse antetorsion angles calculated using the Sutter conversion of axial oblique CT measurements were significantly different from transverse measurements using photographs and ImageJ software (p=0.0049). All other antetorsion measurement comparisons, including axial oblique CT v. photograph were not significantly different. Notably, measurements of the NSA on CT (126.2, 5.1) were different from tNSA measurements (129.6, 5.2) using ImageJ software (p<0.000001).ConclusionsAxial oblique measurements re-oriented by surgeon are no different from the gold standard photographs. The Sutter conversion, which is dependent on the inclination angle (a function of femoral neck shaft angle), may introduce measurement error related to variable neck shaft angle measurements.

BackgroundThe purpose of this study is to report outcomes of a unique periacetabular osteotomy (PAO) technique for hip dysplasia developed at our institution.MethodsThis was a retrospective, single-surgeon case series of prospectively collected data on all PAOs performed by the senior surgeon between April 2015 and April 2024. The technique has previously been described in the literature. This technique allows for immediate weight bearing postoperatively. All patients underwent hip arthroscopy for treatment of intra-articular pathology and cam type FAI 3–10 days prior to PAO. Some patients also underwent de-rotational femoral osteotomy (DFO) for treatment of femoral torsion abnormalities. Follow-up occurred at 6 weeks; 3 and 6 months; and 1, 2, and 5 and 7 years postoperatively. Patient-reported outcomes (PROs) included the Non-Arthritic Hip Score (NAHS) and the International Hip Outcome Tool (iHOT-12). A sub-analysis was performed to compare 2-year PROs between three groups of patients based on age at the time of surgery: 13-29 years, 30-39 years, and 40-61 years.ResultsA total of 750 hips underwent primary PAO during the study period. Revision PAO’s or cases with concomitant hamstrings or glut repair where excluded. The mean age at the time of surgery was 31 years (range, 13 to 61 years). Females accounted for 92% of hips included in this study. A concomitant DFO was performed in 7%. The mean NAHS improved from 56.2 preoperatively to 86.3 at minimum 2-year follow-up (p < 0.0001) and 84.8 at 5-year follow-up (p < 0.0001). The mean iHOT-12 improved from 43.0 preoperatively to 79.2 at 2-year follow-up (p < 0.0001) and 77.7 at 5-year follow-up (p < 0.0001). No significant differences were found in postoperative NAHS (p = 0.82) or iHOT-12 scores (p = 0.73) between age groups.ConclusionsPeriacetabular osteotomy enables corrective realignment of symptomatic acetabular dysplasia, accelerated rehab and good midterm outcomes. Careful patient selection can result in good outcomes regardless of patient age at the time of surgery.

BackgroundBorderline developmental dysplasia of the hip (BDDH), defined by a lateral center-edge angle (LCEA) of 18° to 25°, presents significant challenges in determining optimal treatment strategies. While periacetabular osteotomy (PAO) and conservative treatment are both viable options, the radiographic parameters that should guide this decision remain unclear. We asked: (1) Which radiographic parameters differentiate between BDDH patients requiring PAO versus those succeeding with conservative treatment? (2) What are the optimal radiographic thresholds ? (3) How reliable are these measurements?MethodsWe conducted a retrospective analysis of consecutive BDDH patients (LCEA 18°-25°) treated at our institution between 2018-2023. Two independent observers evaluated radiographic parameters including lateral center-edge angle (LCEA), anterior center-edge angle (ACEA), Tönnis angle, crossover sign (COS), posterior wall sign (PWS), ischial spine sign (ISS), femoral head coverage, femoro-epiphyseal acetabular roof (FEAR) index and Femoral torsion angle (FTA). Interobserver reliability was assessed using intraclass correlation coefficients (ICC). ROC analysis determined threshold values for surgical intervention. Radiographic parameters were compared between PAO and conservative treatment groups.ResultsThe PAO group showed significantly greater dysplasia across multiple parameters other than LCEA. Key findings included lower ACEA (21.0° ± 8.0° vs 24.7° ± 6.2°, p = 0.036), higher Tönnis angle (13.4° ± 5.3° vs 8.5° ± 4.6°, p < 0.001), and greater FTA (36.5° ± 10.9° vs 30.1° ± 9.2°, p = 0.013). Crossover sign positivity (33.3% vs 6.9%, p = 0.009) and posterior wall sign positivity (72.2% vs 34.5%, p = 0.007) were more prevalent in the PAO group. Tönnis angle emerged as the sole independent predictor of PAO necessity (OR: 1.194, 95% CI: 1.038-1.373, p = 0.013), with an optimal threshold of 11.7° (sensitivity 66.7%, specificity 79.3%, AUC = 0.750). All measurements demonstrated excellent interobserver reliability (ICC > 0.81), with Tönnis angle showing highest reliability (ICC = 0.89, 95% CI 0.85-0.93).ConclusionsMultiple radiographic parameters can reliably distinguish BDDH patients requiring PAO from those suitable for conservative management. A Tönnis angle threshold of 11.7°, combined with ACEA, FTA, crossover sign, and posterior wall sign provides comprehensive guidance for surgical decision-making. These findings offer criteria for treatment selection in BDDH patients.

Hip joint preservation is influenced by three primary factors: femoroacetabular impingement (FAI), hip dysplasia or instability, and femoral torsion abnormalities. When femoral torsion abnormalities are ignored, patients may not achieve optimal clinical outcomes. A de-rotational femoral osteotomy (DFO) is a critical procedure for correcting these torsional abnormalities.The purpose of this abstract is to provide a standardized and reproducible technique for DFO to address both excessive femoral antetorsion or retrotorsion in patients experiencing intra-articular hip pain.

PurposeThe purpose of this study was to systematically review the literature on delays in diagnosis or treatment of hip preservation patients.MethodsA systematic review was performed by searching PubMed, the Cochrane Library, and Embase to identify any study reporting on delays in diagnosis or treatment of hip preservation patients i.e. patients with femoroacetabular impingement (FAI), hip dysplasia, or femoral torsion abnormalities. The search terms used were: delay AND (diagnosis OR treatment) AND ("femoroacetabular impingement" OR "hip dysplasia" OR "hip arthroscopy" OR "periacetabular osteotomy"). Outcomes reported included demographics, preoperative duration of symptoms, and patient-reported outcomes (PROs).ResultsTwelve articles (1 Level II, 1 Level III, 10 Level IV) met inclusion criteria, with a total of 2,883 hips. Mean patient age ranged from 16.4 to 45.0 years, and the overall percentage of males ranged from 0 to 56.9%. The mean time from symptom onset to accurate diagnosis for hip preservation patients ranged from 17.2 to 61.5 months across studies. Prior healthcare providers consulted were largely other orthopaedic surgeons and primary care physicians; each patient consulted with an average of 1.9 to 4.2 providers and received a multitude of alternate diagnoses, imaging, and treatment attempts before presentation to a hip preservation specialist. Of the studies comparing outcomes between patients with short- and long duration of symptoms, there were significantly worse postoperative PROs in groups with longer symptom duration.ConclusionPatients presenting with hip preservation pathologies commonly experience diagnostic delays and consult with multiple healthcare providers across specialties before receiving an accurate diagnosis and appropriate treatment. In turn, this leads to poorer post-treatment outcomes compared to patients who receive appropriate treatment in a timely manner.

Hip dysplasia is an increasingly recognized source of pain and dysfunction among young, active individuals. Whilst hip dysplasia is most commonly attributed to acetabular dysplasia, it can also be related to femoral version abnormalities. Standard treatment for symptomatic acetabular dysplasia is a periacetabular osteotomy (PAO), involving surgical realignment of the pelvis to increase acetabular coverage of the femoral head. Femoral version abnormalities are addressed surgically by a derotational femoral osteotomy (DFO), surgically cutting the femur and rotating it to correct femoral torsion. Fixation in the new position can be done through either plate or intramedullary nail. Correction of both acetabular dysplasia and femoral version is necessary in about 5-15% of cases when they coexist.2,3Recently there has been a greater focus on the development of evidence-based protocols outlining post-operative rehabilitation after PAO surgeries. However, evidence describing rehabilitation protocols after PAO+DFO procedures are limited. Therefore, the purpose of this commentary is to highlight differences between a PAO only and a combined PAO+DFO post-operative rehabilitation protocol.Post-operative rehabilitation guidelines after PAO only and PAO+DFO procedures include emphasis on patient education, a period of decreased weight-bearing and protected range of motion to allow for tissue healing followed by progressive strengthening. Early PROM including hip circumduction may be beneficial to reduce risk of postoperative stiffness and development of intraarticular adhesions as mobility is significantly limited in early postoperative period.5 This early PROM is especially important if hip arthroscopy is performed in the same setting as the osteotomy procedures.6,7More variability and prolonged recovery patterns are seen following combined PAO+DFO procedures compared to an isolated PAO. This may be due to pre-operative impairments often associated with the pathology as well the more invasive procedure. Fixation hardware can cause irritation to the local soft tissues which can also slow down healing time. Further, rotational changes to the femur can result in changes in limb length and changes in soft tissue orientation which can cause challenges with neuromotor control and lead to other impairments including knee pain. Patients should be educated about extended crutch use and long length of rehabilitation following combined PAO+DFO procedures.

Abstract Purpose To compare the patellar tendon–lateral trochlear ridge (PT‐LTR) distance and patellar tendon–trochlear groove angle (PT‐TGA) between patients with lateral patellar instability (LPI) and those with malalignment‐induced patellofemoral pain (PFP), and to evaluate their differential diagnostic validity. Methods Sixty patients with LPI (mean age: 24.2 ± 7.1 years) and 60 patients with malalignment‐induced PFP (mean age: 25.3 ± 6.2 years) were included. PT‐LTR, PT‐TGA, as defined by Dai et al. (PT‐TGA1) and Hinckel et al. (PT‐TGA2), and additional patellofemoral alignment parameters—including the tibial tubercle–trochlear groove (TT–TG) distance, tibial tubercle–posterior cruciate ligament (TT‐PCL) distance, lateral trochlear inclination (LTI) angle, patellar height, valgus deviation, femoral and tibial torsion, knee rotation and leg axis—were measured. The unpaired t tests with Welch's correction, receiver operating characteristic (ROC) curve analysis via the Youden index, and parametric power analysis were utilized. Results PT‐LTR, PT‐TGA1 and PT‐TGA2 values were significantly greater in LPI patients compared to those with PFP (PT‐LTR: 8.8 ± 6.7 mm vs. 3.9 ± 5.3 mm; PT‐TGA1: 29.1 ± 11.3° vs. 17.3 ± 8.9°; PT‐TGA2: 35 ± 9.6° vs. 24.9 ± 8.5°; all p &lt; 0.0001). ROC analysis revealed AUCs of 0.73 (PT‐LTR), 0.79 (PT‐TGA1) and 0.78 (PT‐TGA2). PT‐TGA1 demonstrated the highest sensitivity (85%), whereas PT‐TGA2 showed the highest specificity (83%). Significant differences were also found for LTI ( p &lt; 0.0001), patellar height ( p &lt; 0.0001), TT–PCL ( p &lt; 0.0001) and valgus deviation ( p = 0.004), but not for TT–TG, femur/tibia torsion, or knee rotation. Power analysis confirmed robust statistical validity ( Z ≈ 5.60; power = 99.987%). Conclusions While PT‐LTR and PT‐TGA measurements were significantly greater in patients with LPIs than in those with malalignment‐induced PFP, only PT‐TGA measurements demonstrated sufficient diagnostic accuracy to identify LPI. The results reinforce the conceptual advantage of angular over linear measurements of the extensor apparatus. Level of Evidence Level III, diagnostic cohort study.

AimsThe distal femoral epiphysis and epiphyseal plate are essential for skeletal morphogenesis during development. However, it is unclear how these growth mechanisms are affected by distal femoral torsion (DFT) and patellar instability. This study aimed to investigate how DFT development affects epiphyseal plate growth mechanisms.MethodsThis study evaluated CT-based 3D reconstructed images of the distal femoral epiphyseal plates in 98 knees exhibiting trochlear dysplasia (50 patients). Morphological parameters including femoral anteversion, DFT, and the anatomical epicondylar axis-posterior condylar line (AEA-PCL) angle were measured to determine their relationship with epiphyseal plate development. Finite element modelling was then performed to evaluate how patellar displacement and distal femoral rotation influence epiphyseal stress in juvenile knees. A rat model that had undergone femoral rotational osteotomy was established (n = 12), and trochlear morphology (groove angle and depth) and trabecular microarchitecture (bone volume fraction, thickness, number, and separation) were compared with control specimens by micro-CT analysis at skeletal maturity.ResultsUnderdeveloped medial femoral epiphyseal plates were associated with excessive DFT and a large AEA-PCL angle. The medial-to-lateral epiphyseal plate ratio was inversely correlated with DFT and the AEA-PCL angle, suggesting mechanical influences on growth plate morphology. Finite element analysis revealed that medial patellar displacement and femoral external rotation decreased overall epiphyseal stress and shifted its distribution medially. Compared with control specimens, the experimental rats had significantly increased trochlear angles accompanied by reduced trochlear depth and subchondral bone loss in the medial femoral condyles and anterior medial epiphyses.ConclusionDFT alters stress distribution across the epiphysis and epiphyseal plate, which modifies the trabecular microarchitecture in both medial femoral condyles and anterior medial epiphyses, and results in different medial-to-lateral ratio of the distal femoral epiphyseal plate which indicates the severity of trochlear dysplasia, although genetic investigations are needed to establish its causality.Cite this article: Bone Joint Res 2025;14(12):1109–1122.

Background:Femoral version (FV) is an anatomic parameter that has recently received increased attention in its role in multiple hip pathologies, including femoroacetabular impingement (FAI) and cam lesion development.Purpose:To evaluate site-specific femoral version and assess the relationship with the size and location of cam deformity in cadaveric specimens.Study Design:Descriptive laboratory study.Methods:A total of 1058 cadaveric femurs were selected from a historical osteologic collection. Each femur was assessed to determine the α angle, total FV, neck-based FV, and shaft-based FV. Cam morphology was defined as an α angle >60°. Pearson correlation and multiple regression analysis were performed to determine the relationship between site-specific FV location and α angle.Results:Of the cadaveric femurs, the mean ± SD α angle was 54°± 11°. There were 354 (33%) cam deformities. The mean ± SD was 11°± 12° for total FV among all specimens, 24°± 10° for the femoral shaft version, and −13°± 19° for the femoral neck version. On multivariate analysis, sex, race, femoral neck version, and femoral shaft version were independent predictors for α angle (P < .05). Each degree increase predicted an increase in α angle of 0.09° (P = .006) for the femoral neck version and 0.14° (P = .02) for the femoral shaft version.Conclusion:Our study reveals an anatomic relationship between site-specific FV and cam deformity; an increase in shaft FV and neck FV predicted an increased α angle. While the observed absolute value of this relationship is small, site-specific FV remains a previously unrecognized area of interest that could help explain differences previously reported in the literature regarding the multifactorial symptomology in FAI.Clinical Relevance:FV is classically reported as one value combining the femoral neck version and torsion of the femoral shaft. In addition to the identified relationship between site-specific FV and cam deformity, this study encourages clinicians to consider both contributing anatomic components of femoral version, especially when identifying the level of deformity before corrective femoral osteotomy in patients with FAI.

ObjectivesOblique placement of tension band plates is a common surgical variance in guided growth, raising concerns about its clinical safety, particularly the potential for inducing iatrogenic deformities. This study aimed to evaluate the comprehensive impact of this plate autocorrection on limb torsion, as well as on coronal and sagittal plane alignment.MethodsThis retrospective study analyzed 56 children who underwent guided growth for genu varum or valgum. At treatment initiation and termination, we measured the plate-diaphysis angle (α), femoral/tibial torsion, and coronal/sagittal plane alignment. Coronal plane correction was assessed using mechanical and anatomic lateral distal femoral angles (mLDFA, aLDFA) and medial proximal tibial angles (mMPTA, aMPTA). Sagittal plane stability was evaluated using the posterior distal femoral angle (PDFA) and posterior proximal tibial angle (PPTA).ResultsA significant autocorrection of the plates toward the diaphyseal axis was observed (p < 0.001). The intended coronal plane correction was successfully achieved, as evidenced by statistically significant improvements in all four coronal alignment parameters (mLDFA, aLDFA, mMPTA, aMPTA; all p < 0.05). Critically, this rotation was not associated with any significant change in femoral or tibial torsion (p > 0.05 for both). Furthermore, sagittal plane alignment remained stable throughout the treatment period, with no significant alterations in PDFA or PPTA (all p > 0.05).ConclusionInadvertent obliquity of tension band plates and their subsequent autocorrection is a clinically benign phenomenon. It effectively achieves the desired coronal correction without inducing adverse torsional or sagittal plane deformities. This study provides robust, evidence-based reassurance for surgeons that guided growth remains a safe and effective procedure despite this common surgical variance.Supplementary InformationThe online version contains supplementary material available at 10.1186/s13018-025-06496-3.

To evaluate the effectiveness of interfragmentary compression in feline femoral transverse fractures treated with a dynamic compression angle-stable interlocking nail implanted via minimally invasive nail osteosynthesis. Thirty femurs from 15 feline cadavers were allocated into three groups according to fracture location (n = 10 per group): proximal (GPD), mid- (GMD) and distal diaphysis (GDD). Radiographic and computed tomography scans were performed preoperatively for surgical planning and measurement of the anatomical lateral distal femoral angle, anatomical lateral proximal femoral angle and femoral torsion angle. Standardised transverse osteotomies were created per group allocation and stabilised using dynamic compression angle-stable interlocking nail implanted via minimally invasive nail osteosynthesis technique. Postoperative imaging assessed residual fracture gap and femoral angles. Data were analysed using one-way ANOVA with Tukey's post hoc test, and effect sizes were estimated using generalised eta squared (ges). All groups achieved effective interfragmentary compression, with residual fracture gaps <1 mm (range: 0 to 0.3 mm). The anatomical lateral distal femoral angle remained consistent before and after osteosynthesis. The anatomical lateral proximal femoral angle remained unchanged in proximal diaphysis and distal diaphysis but showed a moderate increase in mid-diaphysis (ges = .445). The femoral torsion angle increased in all groups postoperatively, with large, moderate and small effect sizes in proximal diaphysis (ges = .655), mid-diaphysis (ges = .385) and distal diaphysis (ges = .213), respectively. Dynamic compression angle-stable interlocking nail provided consistent interfragmentary compression. However, deviations in the transverse plane were observed following the minimally invasive nail osteosynthesis approach. These findings support dynamic compression angle-stable interlocking nail as a promising option for stabilising femoral transverse fractures in cats.

Cephalomedullary nail (CMN) is an ideal internal implant for the treatment of Basicervical femoral neck fracture (BFNF). This study uses finite element analysis techniques to compare the biomechanical characteristics of three types of CMN systems, namely proximal femoral nail antirotation (PFNA) InterTAN and proximal femur bionic nail (PFBN), in fixing BFNF using three cannulated screws (CSs) as controls, and analyzed their clinical significance. Based on femoral CT and internal implant data, a finite element analysis model for BFNF internal fixation was established: CSs, PFNA, InterTAN, and PFBN. The three types of loads, namely one-legged stance, torsion the femoral head, and walking, were simulated based on reference literature to obtain extreme values and cloud maps of data, including stress on fracture fragments and internal fixation devices, pressure between fracture surfaces, separation displacement, and sliding displacement. The biomechanical characteristics of different internal fixation devices were compared and analyzed. The finite element analysis data showed that in the one-legged stance group, the stress between the InterTAN fracture block and the internal fixation device, the extreme value of the pressure and sliding displacement between the fracture surfaces were lower than those of the other three models; In the femoral head torsion group, InterTAN had lower extreme values for both femoral head torsion displacement and fracture surface sliding displacement. The extreme values of separation displacement are second only to PFBN. In the walking exercise group, the extreme values of all indicators in InterTAN were lower than those in other models. Compared with PFNA and PFBN, InterTAN has better anti rotation ability and anti-inversion deformity ability, can provide better stability and safety, and provide guarantees for early functional exercise. This study provides clinical reference significance for the use of InterTAN in the treatment of BFNF.

Femoroacetabular impingement (FAI) is one of the leading causes of early hip osteoarthritis and mostly characterized by an enlarged femoral head-neck junction (cam-type). Although patients commonly present with bilateral FAI morphologies, they typically only experience unilateral symptoms. This suggests that additional anatomic factors other than the cam deformity may contribute to earlier symptoms. The purpose of this study was to directly compare the anatomic variations between the symptomatic and asymptomatic hips in bilateral FAI patients using planar imaging measurements and 3D statistical shape modelling. Twenty-seven patients awaiting surgery (n = 27, m:f = 15:12, age = 25 ± 6 years) were included if they indicated bilateral cam FAI morphologies but unilateral symptoms (IRB #114897). Patients were excluded if they indicated other hip pathologies (e.g. dysplasia, slipped capital femoral epiphysis, Legg-Calve-Perthes) or history of lower-limb trauma or surgery. Each patient's pelvic and knee regions were imaged using a computed tomography scanner (SIEMENS Somatom, Germany) to confirm cam morphology (e.g. 3:00 alpha angle &gt; 50.5° or 1:30 alpha angle &gt; 60°). Anatomic measurements of the femoral neck (femoral neck-shaft angle, medial proximal femoral angle, femoral torsion), acetabular coverage (lateral centre-edge angle, acetabular version at 1:00, 2:00, 3:00) and spinopelvic parameters (sacral slope, pelvic tilt, pelvic incidence) were assessed from each patient's CT data. Paired sample t-tests compared the measurements between symptomatic and asymptomatic sides using statistical software (CI = 95%; GraphPad Prism, USA). Each patient's symptomatic and asymptomatic 3D hip models were segmented (Synopsys Simpleware, USA) and statistical shape modelling compared anatomic differences between mean symptomatic and asymptomatic shape models (ShapeWorks 6.4, USA). From imaging measurements, although both symptomatic and asymptomatic sides showed similar femoral cam deformities, femoral torsions, lateral centre-edge angles, and spinopelvic parameters, the symptomatic sides had smaller femoral neck-shaft angles (p = 0.001), medial proximal femoral angles (p = 0.001), and acetabular versions at 1:00 (p = 0.004) than the contralateral asymptomatic sides. From the statistical shape models, the symptomatic group showed a more varus neck and a retroverted acetabulum with slightly increased anterosuperior and decreased posterior acetabular coverage. Additionally, the symptomatic sides’ sacroiliac joint and sacral alar were smaller and anteriorly tilted compared to their contralateral asymptomatic sides. The most important finding was that the symptomatic sides indicated a more varus neck, retroverted acetabulum, and anterior sacral tilt in addition to the cam deformities. A varus neck can bring the cam deformity closer to the chondrolabral junction and restrict hip mobility, resulting in earlier mechanical impingement and symptoms. Moreover, an anterior sacral tilt and retroverted acetabulum increases anterosuperior cam engagement and also decreases posterior hip joint stability. These anatomic variances may provide insights into symptomatic hip impingement and instability, therefore, including them would help optimize treatment planning. As the cam deformity alone may not be the only indicator for symptoms, characterizing these anatomic relationships through statistical shape modelling can help guide patient-specific diagnosis and treatment strategies for FAI to improve patient outcomes and delay the progression of early hip osteoarthritis.

Introduction:Rotational malalignment is a frequently overlooked yet clinically significant complication following closed intramedullary nailing (IMN) of femoral shaft fractures. Malrotation may result in functional impairment, altered gait biomechanics, and patient dissatisfaction. Computed tomography (CT) remains the most accurate modality for quantifying femoral torsion. This study aimed to determine the incidence, degree, and functional consequences of malrotation following IMN in diaphyseal and diaphyseo-metaphyseal femur fractures using CT-based assessment.Materials and Methods:This prospective observational study was conducted at a tertiary trauma center in Delhi over 18 months. Thirty skeletally mature patients with closed diaphyseal or diaphyseo-metaphyseal femur fractures treated with closed antegrade IMN were included. Post-operative femoral torsion was assessed through axial CT scans using the method described by Jeanmart. Lower extremity functional scale (LEFS) scores were recorded preoperatively and at 6 weeks, 12 weeks, and 6 months postoperatively. Correlation analyses were performed between malrotation magnitude, fracture comminution, timing of surgery, and functional outcomes. Significant malrotation (defined as >10° difference compared to the contralateral limb) was observed in 20% of patients. Internal rotation deformities (mean: 12.6°) and external rotation deformities (mean: 8°) occurred in equal proportion. Malrotation >10° was significantly associated with lower LEFS scores at 6-month follow-up (P < 0.05). Fracture comminution and delay in surgical fixation (>10 days) were independently correlated with greater degrees of malrotation and worse functional recovery (P < 0.001 and P = 0.0086, respectively). All patients eventually achieved radiological union by 6 months.Conclusion:CT-based assessment revealed a notable incidence of malrotation following IMN of femoral shaft fractures, with deformities >10° adversely affecting functional outcomes. Intraoperative vigilance in fracture reduction and early fixation may reduce the risk of malalignment. Routine CT evaluation in selected patients may be warranted to detect clinically relevant torsional deformities.