Associations between clinical evidence of inflammation and synovitis in symptomatic knee osteoarthritis: A substudy of the VIDEO trial.
Wallace G., Cro S., Doré C., King L., Kluzek S., Price A., Roemer F., Guermazi A., Keen R., Arden N.
Objective Painful knee osteoarthritis (KOA) has been associated with joint inflammation. There is however little literature correlating signs of localised inflammation with Contrast-enhanced (CE) Magnetic resonance imaging (MRI) of synovium. This study examined the relationship between clinical and functional markers of localised knee inflammation and CE MRI based synovial scores. Methods Patients with symptomatic KOA were enrolled into the randomised, double-blind, Vitamin D Evaluation in Osteoarthritis (VIDEO) trial. In this cross-sectional substudy, associations between validated MRI based semi-quantitative synovial scores of the knee and the following markers of inflammation were investigated; self-reported pain and stiffness, effusion, warmth, joint line tenderness, erythrocyte sedimentation rate, radiographic severity and functional ability tests. Results 107 patients satisfied the inclusion criteria of complete data and were included in the analysis. Significant associations were found between the number of regions affected by synovitis and WOMAC pain, effusion and joint line tenderness. Each additional region affected by synovitis was associated with an increase in WOMAC pain (1.82; 95% CI 0.05-3.58; p=0.04) and the association with extent of medial synovitis was particularly strong (3.21; 95% CI 0.43-5.99; p=0.02). Extent of synovitis was positively associated with effusion (OR=1.69; 95% CI 1.37-2.08, p<0.01), and negatively associated with joint line tenderness (RR= 0.87; 95% CI 0.84-0.90; p<0.01). Conclusion There is a strong positive association between synovitis, and self-reported patient pain and clinically detectable effusion. Non-operative treatments directed at management of inflammation and future trials targeting the synovial tissue for treating KOA should consider these two factors as potential inclusion criteria. This article is protected by copyright. All rights reserved.