From early radiographic knee osteoarthritis to joint arthroplasty: Determinants of structural progression and symptoms

Objective Aims were to assess (1) structural progression in knees with no/mild radiographic osteoarthritis (ROA) (i.e. Kellgren-Lawrence (K-L) grades 0 to 2) that will undergo knee replacement (KR) during a 5-year period; (2) differences in structural damage on MRI between knees with no/mild ROA vs. those with severe ROA (i.e. K-L 3 and 4) at baseline; and (3) differences in pain levels between those groups. Methods All participants who underwent KR from baseline (BL) to 60 months were drawn from the Osteoarthritis Initiative. MRIs were assessed for bone marrow lesions (BMLs), Hoffa- and effusion-synovitis (i.e. hyperintensity signal changes in the fat pad and abnormal amount of capsular distension due to intraaticular joint fluid and/or synovial thickening) at BL and the time point before KR (T0). The measures of WOMAC and KOOS pain were used for pain characterization. WOMAC Activity of Daily Life (ADL) and KOOS Quality of Life (QoL) were applied to characterize functional status of the included participants. Logistic regression was used to assess the association of no/mild ROA with these MRI features and pain. Results Based on inclusion criteria 181 knees were selected. Participants were predominantly female (57.8%) with a mean age of 64.4 years. 51 (28.2%) knees had no/mild ROA at BL. Of these, 51.0% progressed to severe ROA. No/mild ROA knees showed higher odds of BMLs in the patellofemoral joint (PFJ) at BL (OR 7.92 95%CI [3.45,18.16]) and T0 (OR 9.44 95%CI [4.00, 22.28]) compared to severe ROA knees. In addition, no/mild ROA knees were associated with change from “no pain” to “pain” from BL to T0 (aOR 5.48, 95%CI [1.25, 24.00]). Conclusion Over half of the knees with no/mild ROA before KR progressed to severe ROA over 4 years of follow-up. BMLs in the PFJ were more often seen among knees that had no/mild ROA. Worsening pain status may contribute to KR in knees with no/mild ROA. This article is protected by copyright. All rights reserved.