The Bipolar Hip: How Acetabular and Femoral Pathomorphology Affects Hip Motion in Femoral Acetabular Impingement Syndrome
Bibliographic record
Abstract
PURPOSE: To investigate the individual and combined contributions of acetabular and femoral morphology to hip range of motion (ROM) in patients with femoroacetabular impingement syndrome (FAIS) by use of computed tomography measurements and hip ROM evaluated on physical examination. METHODS: A retrospective chart and radiographic analysis of patients presenting with hip pain suggestive of FAIS was performed. The femoral neck-shaft angle, femoral version, magnitude and clock-face location of the alpha angle, midcoronal center-edge angle (CEA), midsagittal CEA, acetabular version, and McKibbin index were measured on computed tomography scans. Univariate and multivariate linear regression analyses determined which measurements correlated with hip ROM, including hip flexion as well as hip internal and external rotation with the hip in 90° of flexion. RESULTS: Two hundred hips that met the inclusion and exclusion criteria during the eligibility period were included in the analysis. The mean age was 31.9 ±10.0 years, there were 145 female patients (72%), and the mean body mass index was 25.2 ± 5.0. Multivariate linear regression analysis showed that the midsagittal CEA was the only measurement correlating with flexion (q = .031) whereas the femoral neck-shaft angle and McKibbin index were the only significant variables that correlated with external rotation (q = .031 and q < .001, respectively). Finally, the McKibbin index and maximum alpha angle were the only variables that correlated with internal rotation (q < .001 and q = .034, respectively). CONCLUSIONS: Multivariate analysis showed that combined acetabular and femoral version significantly correlated with internal and external rotation whereas femoral version in isolation did not. Increased cam morphology remained a significant contributor to reduced internal rotation but did not affect hip flexion. These data suggest that hip ROM is affected by both femoral pathomorphology and acetabular pathomorphology and that careful evaluation of both should be conducted prior to corrective osteoplasty or osteotomy. LEVEL OF EVIDENCE: Level IV, retrospective case series.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".