Frank W. Roemer

Objective To investigate which magnetic resonance imaging (MRI)–based articular pathologies are predictive of subsequent medial femorotibial compartment quantitative cartilage thickness loss and therefore suitable for enrichment of clinical trials with participants showing a high likelihood for structural progression. Methods Semiquantitative MRI Osteoarthritis Knee Score (MOAKS) assessments at baseline and quantitative cartilage thickness measurements at baseline and year‐2 follow‐up were performed in 599 participants (age 62 years; body mass index 31 kg/m 2 ; 59% female) from the Osteoarthritis Initiative–based Foundation for the National Institutes of Health Osteoarthritis Biomarkers Consortium. Knees were classified as medial femorotibial compartment (MFTC) progressors or nonprogressors based on MFTC cartilage thickness change (smallest detectable change threshold −111 μm). Logistic regression was used to investigate the association between baseline presence and severity of MFTC MOAKS pathologies with subsequent MFTC progression. The standardized response mean (SRM) was computed to estimate the sensitivity to change that can be achieved when selecting knees based on MOAKS pathologies. Results Presence of MFTC MOAKS cartilage damage (odds ratio [OR] 2.77 [95% confidence interval (95% CI) 1.76, 4.36]), MFTC bone marrow lesions (OR 2.69 [95% CI 1.89, 3.83]), medial meniscus extrusion or damage (OR 2.21 [95% CI 1.37, 3.55]), as well as MOAKS severity subscales for cartilage and meniscus damage were associated with subsequent progression. The SRM was greater in knees with than in knees without the presence of these pathologies and was associated with the severity of those pathologies. Conclusion MRI‐based grading of articular pathologies makes it possible to specifically select progressor knees suitable for inclusion in clinical trials but also to identify knees in which treatment is not indicated (e.g., knees without cartilage damage despite presence of radiographic osteoarthritis).