EP2.16 Can Standing Antero-Posterior Pelvic Radiographs Depict Loading Asymmetry?
Bibliographic record
Abstract
Abstract Introduction: The optimal patient position (supine or standing) for obtaining anteroposterior (AP) pelvic radiographs in patients presenting with hip symptoms is debatable. Although the difference in patient position may influence acetabular and femoral morphological appearances, a standing radiograph might also be able to provide more accurate information regarding functional leg length differences in conditions of loading. Variations in loading patterns might influence the rate of cartilage degeneration and thus the development of symptoms. Aims: Assess differences in functional/apparent leg-length discrepancy (between supine and standing AP pelvic radiographs) amongst asymptomatic, high functioning, volunteers.Measure gait parameters differences between sides during walking.Test for an association between functional LLD and gait parameters. Methods: This is a prospective, cohort study of 30 healthy, asymptomatic, young-adult hip participants (50% females, age: 30.9±9 years-old), consisting of affiliated healthcare workers and medical students. All participants underwent supine and standing AP pelvic radiograph and underwent performance-based assessments (PBA) using inertial measuring devices (sensors) to assess loading patterns. Five sensors were mounted (Sacrum (S1); 2 mid-thigh sensors; 2 ankle sensors) that can measure impact loading, gait velocity, impact intensity and stride length. Participants performed several assessments, including gait which allowed for measurements of gait characteristics. Apparent leg length discrepancy was measured from AP pelvic radiographs determining the obliquity (vertical difference) of the hip joint centers relative to the horizontal. Results: The average apparent LLD was similar between standing (5mm ±2) and supine (5.2mm± 2.5) radiographs (p=0.291) on standing and supine AP pelvic radiographs were and, respectively. The mean loading asymmetry was 9%. Mean gait velocity was 1.71 ± 0.18m/s, and 1.36 ± 0.15ft for stride length. There was no correlation between apparent LLD when standing and any of the gait parameters tested (r2=.253, p=0.261). Conclusion: Although load asymmetry can be quite common, its presence and magnitude can not be predicted by the presence of mild apparent LLD in standing radiographs. Thus, any LL and obliquity assessments made on standing AP pelvic radiographs should be considered for morphological bony parameters but cannot be used to predict loading patterns.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".