Abstract
BACKGROUND: Although arthritis in other affected major joints and back pain are known to lead to worse outcomes following total hip replacement, to our knowledge, these risk factors have not previously been operationalized as a musculoskeletal morbidity profile. The aim of this study was to measure the influence of other major joints and the spine (as grades of musculoskeletal morbidity) on the 1-year outcome of primary total hip replacement. METHODS: The EUROHIP study consists of 1,327 patients undergoing primary total hip replacement for arthritis across 20 European orthopaedic centers. The primary outcome was the responder rate at 12 months calculated with the relative effect per patient for total hip replacement using the total Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score. The primary predictor of interest was different combinations of arthritis of major joints and the spine grouped into 4 musculoskeletal morbidity grades: 1 (single major joint), 2 (multiple major joints), 3 (single major joint and spine), and 4 (multiple major joints and spine). The confounders adjusted for were age, sex, body mass index, living situation, years of hip pain, American Society of Anesthesiologists (ASA) class, anxiety or depression, and preoperative WOMAC subscales. RESULTS: For this analysis, 845 patients were included with complete 12-month follow-up WOMAC scores. The mean patient age was 65.7 years, and 55.2% of patients were female. CONCLUSIONS: The involvement of other major joints and the spine assessed as 1 of 4 musculoskeletal morbidity grades had a strong influence on the 1-year outcome after total hip replacement. The effect size was large compared with other risk factors. Even so, the majority of patients in musculoskeletal morbidity grade 4 had favorable outcomes from the surgical procedure (>74% response to surgical procedures). LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.