Do Glucocorticoid Injections Increase the Risk of Knee Osteoarthritis Progression Over 5 Years?

OBJECTIVE: Recent findings have demonstrated that intraarticular (IA) glucocorticoid injections can be deleterious for knees with osteoarthritis (OA). This study was undertaken to assess, in a real-life setting, the risk of knee OA progression in patients who received IA glucocorticoid injections over a 5-year follow-up period. METHODS: We used marginal structural modeling with inverse probability of treatment weighting to determine the causal association between IA glucocorticoid injections and the 5-year risk of disease progression in patients with symptomatic knee OA from the Knee and Hip Osteoarthritis Long-term Assessment cohort. OA progression was defined as an incident total knee replacement (TKR) and/or radiographic worsening (Kellgren/Lawrence [K/L] grade or joint space narrowing [JSN]). We also examined these outcomes in knees that received IA hyaluronan (IAHA) injections. RESULTS: Among the 564 patients with knee OA included in the study sample, 51 (9.0%) and 99 (17.5%) received IA glucocorticoid or IAHA injections, respectively, and 414 (63.1%) did not receive any injection during follow-up. Compared to untreated knees, those treated with IA glucocorticoid injections had a similar risk of incident TKR (hazard ratio [HR] 0.92 [95% confidence interval (95% CI) 0.20, 4.14]; P = 0.91) or K/L grade worsening (HR 1.33 [95% CI 0.64, 2.79]; P = 0.44). IAHA injections had no effect on the risk of TKR (HR 0.81 [95% CI 0.14, 4.63]; P = 0.81) or K/L grade worsening (HR 1.36 [95% CI 0.85, 2.17]; P = 0.20). Similar results were obtained for JSN, and when TKR and radiographic outcomes were combined. CONCLUSION: In this study, IA glucocorticoid injections for symptomatic knee OA did not significantly increase the 5-year risk of incident TKR or radiographic worsening. These findings should be interpreted cautiously and replicated in other cohorts.