FP6.12 Are spinopelvic characteristics different among patients with hip dysplasia treated with peri-acetabular osteotomy compared to asymptomatic volunteers? – A matched case-control study
Bibliographic record
Abstract
Abstract Introduction: Increased lumbar lordosis (LL) and reduced pelvic tilt (PT) decreases acetabular anteversion, which may improve joint stability in patients with symptomatic hip dysplasia. However, this may also be associated with development of low back pain (LBP) due to increased pressure on the facet joints. Peri-acetabular osteotomy (PAO) improves femoral head coverage in patients with hip dysplasia, but it is unknown how this affects spinopelvic characteristics. Aims: This study aimed to (1) compare static (standing) and dynamic (standing to flexed-seated) spinopelvic characteristics between patients with hip dysplasia and asymptomatic volunteers, (2) assess how spinopelvic characteristics change following PAO, and (3) whether changes in acetabular fragment orientation correlate with differences in spinopelvic characteristics. Methods: This is a prospective case-control study at a tertiary referral hospital amongst 15 patients with symptomatic hip dysplasia (age: 32±7 years-old, 96% females, LCEA: 17±4°) and a matched group of 15 asymptomatic volunteers (Oxford Hip Score ≥45) without osteoarthritis (Tonnis ≤1). All underwent standing and deep-seated spinopelvic radiographs pre-operatively and at 1-year post-operatively. Difference between standing and flexed-seated measurements allowed for calculation of lumbar- (∆LL), pelvic- (∆PT) and hip- (∆PFA) mobility. Results: Compared to controls, patients with dysplasia had greater standing sacral slope (SS) (43°±6° vs. 37°±7°; p=0.05), but similar standing LL (63°±9° vs. 60°±10°; p=0.3), standing PFA (192°±5° vs. 192°±8°; p=0.9), and no differences in ∆LL (56°±13° vs. 53°±14°; p=0.4), ∆PT (10°±20° vs. 14°±16°; p=0.8) or ∆PFA (101°±18° vs. 101°±17°; p=0.9). Following PAO, standing LL decreased (63°±9° vs. 58°±9°; p=0.004) and standing PT increased (13°±6° vs. 15°±4°; p=0.05). Standing PFA did not change (191±5° vs. 190°±9°; p=0.8). There was no difference ∆LL (56°±13° vs. 53°±19°; p=0.4), ∆PT (10°±20° vs. 17°±14°; p=0.1) or ∆PFA (101°±17° vs. 100°±20°; p=0.4). Change in standing PT with PAO correlated moderately with change in LCEA (rho 0.29), AWI (rho 0.3) and PWI (rho 0.5). Conclusions: When standing, patients with dysplasia have increased LL and decreased PT, allowing them to compensate for their reduced femoral head coverage. The change in acetabular orientation following PAO affects these functional spinopelvic characteristics, which has implications on pre-operative planning prior to PAO.
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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 | 0.000 | 0.000 |
| 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 | 0.000 |
| 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".