The research recently confirmed that the existing effusion‐synovitis for past one and a half year or more can lead to progression of cartilage damage. Synovitis is a term that represents the synovial membrane inflammation which is the main characteristic of articular cartilage damage and knee osteoarthritis. The study investigated the relationships between baseline and changes in effusion-synovitis on changes in cartilage damage depth and size past one and a half years among 221 patients with OA and meniscal tear.

The data was collected from the Meniscal Tear in Osteoarthritis Research (MeTeOR) trial of surgery vs physical therapy. Semiquantitative grading of cartilage damage and effusion-synovitis was done as extensive (medium/large) or minimal (none/small) using dichotomized effusion-synovitis and magnetic resonance imaging (MRI). Poisson regression models were used to evaluate the associations between baseline and changes in effusion-synovitis on changes in cartilage damage. Analyses were adjusted for baseline cartilage damage, treatment and demographics.

A total of 21.3% and 45.3% of patients presented persistently extensive and minimal effusion-synovitis, respectively after one and a half year. Other 33.5% exhibited extensive synovitis on one time and minimal on the other. The extensive effusion-synovitis at baseline was correlated with the progression of cartilage damage depth (relative risk (RR) of 1.7) during the adjusted analyses. Moreover, the persistently extensive effusion-synovitis showed a significant risk of progression of cartilage damage depth as compared to persistently minimal effusion-synovitis (RR 2.0). Also, due to the persistence of extensive effusion-synovitis over time, the risk of concomitant cartilage damage raises. These results showed a significant association between cartilage damage and extensive effusion-synovitis.