Short-term Total Hip Replacement Outcomes in Ankylosing Spondylitis
Bibliographic record
Abstract
BACKGROUND: While rates of total hip replacement (THR) in spondyloarthritis are increasing, contemporary outcomes are not well described. OBJECTIVES: This study analyzes 2-year outcomes in a contemporary cohort of ankylosing spondylitis (AS) patients undergoing THR. METHODS: A case-control study was performed using data from an institutional arthroplasty registry. Validated AS cases were matched 4:1 by age and procedure to patients with osteoarthritis (OA). Data were obtained prior to surgery and at 2 years. Multiple imputation techniques were performed to avoid systematic bias due to missing data. RESULTS: Thirty eligible AS cases were identified between May 2007 and February 2010. Ankylosing spondylitis cases had worse American Society of Anesthesia class (P < 0.001) and more comorbidities (P = 0.02) compared with OA. Ankylosing spondylitis had worse preoperative lower-extremity Western Ontario and McMaster Universities Arthritis Index pain (46.8 vs 55.4; P = 0.03), function (43.0 vs 55.1; P = 0.04), and general health status measured as SF-12 (Short-Form Health Survey) physical component scale (PCS) score (29.6 vs 36.0; P < 0.001), however, there was no difference at two years in pain (89.4 vs 92.5; P = 0.23) or function (83.9 vs 90.1; P = 0.04). Physical component scale score remained significantly worse (41.2 vs 50.1; P < 0.001). Better preoperative SF-12 PCS score significantly decreased the risk of a poor pain outcome (odds ratio, 0.06; 95% confidence interval, 0.01-0.40). Overall satisfaction was high. CONCLUSIONS: Although patients with AS in a contemporary cohort have more comorbidities and worse physical function prior to THR, they achieve similar gains as OA. In a multivariate regression controlling for multiple potential confounders including back pain, only preoperative health status measured as SF-12 PCS score was a significant risk factor for a poor 2-year pain. Among contemporary patients, AS is not an independent risk factor for poor THR outcomes.Take-Home Message Patients with AS have significant improvement in pain and function after THR.Poor preoperative function and low-back pain are not risk factors for poor THR outcomes for patients with AS.Despite improvements, low SF-12 PCS scores indicate persistent limitations due to health.
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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 | 0.001 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".