Imaging plays an important role in determining structural disease severity and potential eligibility of patients recruited to disease modifying osteoarthritis drug (DMOAD) trials. BICL authors were the first to recognize the role of different structural phenotypes of osteoarthritis, which is paramount in targeted treatment of knee OA. In this current publication Dr Roemer and colleagues describe patterns of progression of the cartilage-meniscus phenotype and the relevance of different thresholds for tailored definitions of such phenotypes. The analyses are based on the FNIH cohort, a subsample of the larger OAI study comparable to a clinical trial population.

BICL authors showed in this paper that phenotypic stratification of the cartilage-meniscus phenotype in different subtypes is feasible and may help in defining trial cohorts at screening. Increased odds for progression were seen for KL2 knees and all definitions, while a seemingly protective effect was observed for KL3 knees. The latter can be explained by the fact that KL3 knees stratified by the suggested definitions have comparably mild cartilage damage at screening. One-third of knees with KL2 do not have medial cartilage damage, which is an important finding and needs to be considered when selecting patients for clinical trials based on X-ray assessment only.