Objectives To investigate predictive factors for good outcome of ultrasound intra-articular glucocorticoids in knee osteoarthritis (OA).

Methods We conducted a prospective monocenter cohort study including 116 patients with knee OA, after failure to standard treatments, with pain >4 (numerical rating scale NRS 0–10). Patients received an ultrasound-guided injection of 40 mg triamcinolone acetonide in their most painful knee. We exhaustively collected demographic and clinical data at inclusion, as well as lab, radiographs and ultrasound parameters of the included knees. WOMAC score was calculated at inclusion and after 4 weeks. Responders were defined as patients with at least 40% improvement of their WOMAC score. Univariate analysis was performed in order to select possible predictive factors, and stepwise multiple logistic regression analyses were conducted to identify predictors of response.

Results Among the 116 patients, 101 were females. Median age was 64 years (40–85) and mean duration of the disease was 14.1±14,8 years. Mean BMI was 29.9±3.8 Kg/m². Mean NRS of pain was 8.4±1.2 and mean WOMAC was 73.3±11,8 at inclusion. 70.0% of the knees were grade 3 or 4 of Kellgren-Lawrence. 98% of knees expressed ultrasound synovial effusion and/or hypertrophy at inclusion. After 4 weeks, 61.2% of patients were responders. Regression analysis showed that patients with a BMI <30 Kg/m² (OR=0.38, 95% CI 0.16–0.89) and an ESR <20 mm (OR=0.27, 95% CI 0.08–0.90) were more likely to respond to ultrasound-guided glucocorticoids injection. Having both predictive factors of good response increases the response rate to 73.5%, whereas having no predictive factor decreases the response rate to 25.0%.

Conclusions Our study is the largest study evaluating predictive factors of response for intra-articular glucocorticoids injections in knee OA. Also, it is the first study of predictive factors for ultrasound-guided injections. Patients with high BMIs and high ESR seem less likely to respond to intra-articular injections.

Disclosure of Interest None declared