Total joint replacement of hip or knee as an outcome measure for structure modifying trials in osteoarthritis

At this time, GREES cannot recommend time to joint surgery as a primary endpoint of failure for structure modifying trials of hip or knee OA-as the parameter has sensitivity but lacks specificity. In contrast, in existing trials, a lack of progression of joint space narrowing has predictive value of >90% for not having surgery. GREES suggests utilizing joint space narrowing (e.g., >0.3-0.7 mm) combined with a lack of clinically relevant improvement in symptoms (e.g., ≥20-25%) for 'failure' of a secondary outcome in structure modifying trials of the hip and knee.