DEFINING THE OXFORD HIP SCORE MEANINGFUL VALUES FOLLOWING ASEPTIC REVISION TOTAL HIP ARTHROPLASTY: A PROSPECTIVE COHORT STUDY

This study aimed to define and predict achievement of the minimal important change (MIC) and patient acceptable symptom state (PASS) score for the Oxford hip score (OHS) following revision total hip arthroplasty (rTHA) at 1- and 2-year follow-up. A prospective cohort of 157 aseptic rTHA cases were included, (83 female [52.9%], mean age 71.0 [SD 13.5] years). MIC and PASS were calculated using receiver operator curve analysis. A logistic regression model predicted threshold achievement. The MIC was 8.5 (95% confidence interval [CI] 3.0 to 13.5, area under the curve [AUC] 0.875) and 5 (95% CI −2.0 to 9.5, AUC 0.83) at 1 and 2 years postoperatively respectively. Preoperative OHS was independently associated with 1- and 2-year MIC achievement (odds ratio [OR] 0.905, 95% CI 0.839 to 0.963, p=0.003), with scores below 31.5 most likely to attain MIC at both 1 and 2 years respectively (AUC 0.541). The PASS was 31.5 (95% CI 22.5 to 42.5, AUC 0.891) at 1 year and 32.5 (95% CI 23.5 to 40.5, AUC 0.931) at 2 years postoperatively. No factors were independently associated with 1 year PASS attainment, and patients with ASA grade 3 was less likely to achieve 2-year PASS (OR 14.756, 95% CI 1.708 to 127.489, p=0.014). This is the first report of OHS MIC and PASS following aseptic rTHA. Preoperative function and ASA were independently associated with PASS and MIC achievement postoperatively.