The associations between a diagnosis of early-stage knee osteoarthritis and the presence of MRI abnormalities in knees without radiographic osteoarthritis: Data from 1513 knees of the osteoarthritis initiative

To determine the association between Criteria for the Early Diagnosis of Knee osteoarthritis (CREDO) defined early-stage knee osteoarthritis (KOA) and the prevalence of MRI structural abnormalities, using prevalence risk ratios (PRs). This study used cross-sectional Osteoarthritis Initiative (OAI) data from 1500 knees without radiographic KOA (KL-grade <2) and with available MRI assessments, after excluding 13 knees with missing data. Using clinical factors (e.g. demographics, symptoms, effusion and crepitus), knees were identified with early-stage KOA (&#x2265;70% probability for CREDO), potential early-stage KOA (30-69% probability) or no KOA (<30% probability). Log binomial regression assessed the PRs of cartilage defects, bone marrow lesions (BMLs), meniscal abnormalities, and abnormalities in at least one, multiple, or all investigated structures, across CREDO-defined KOA statuses. Of the 1500 included knees, early-stage KOA was present in 7.7%, potential early-stage KOA in 43.7%, and no KOA in 48.5%. Early-stage KOA generally showed higher PRs versus no KOA and versus potential early-stage KOA for cartilage defects (PR 1.37, 95% CI 1.23-1.53: no KOA; PR 1.08, 95% CI 0.98-1.19: potential), BMLs (2.38, 1.78-3.19; 1.48, 1.13-1.93), meniscal lesion (1.26, 0.96-1.65; 1.35, 1.03-1.78), meniscal extrusion (4.53, 2.28-9.01; 2.03, 1.11-3.71), at least one abnormality (1.30, 1.19-1.41; 1.09, 1.01-1.18), multiple abnormalities (1.81, 1.48-2.22; 1.38, 1.14-1.67), and all investigated structures (3.22, 1.92-5.41; 2.09, 1.28-3.42). In non-radiographic OA knees, CREDO-defined early-stage KOA was associated with higher PRs of OA features on MRI compared with no KOA. Early-stage KOA also showed higher PRs of these features compared with potential early-stage KOA.