Intra-articular Knee Injections and Progression of Knee Osteoarthritis: Data from the Osteoarthritis Initiative.

Background At least 10% of all patients with knee osteoarthritis (OA) undergo treatment with injectable corticosteroids or hyaluronic acid (HA). Although both have been shown to help with symptomatic pain relief, their long-term effects on knee OA progression remain inconclusive. Purpose To investigate the association between intra-articular knee injections, specifically corticosteroids and HA, and OA progression using a detailed whole-joint semiquantitative MRI evaluation and clinical outcomes for a period of 2 years. Materials and Methods This secondary analysis uses data from the Osteoarthritis Initiative (OAI), a multicenter, longitudinal, prospective study (February 2004 to January 2015). Participants who received a reported injection of corticosteroid or HA and propensity-score-matched controls (on age, sex, body mass index [calculated as weight in kilograms divided by height in meters squared], and clinical variables) were analyzed. Using the Whole-Organ MRI Score (WORMS) system for cartilage, bone marrow lesions, and meniscus, 3-T MRI performed at the time of injection, 2 years prior, and 2 years after were semiquantitatively graded. Postinjection progression was quantified using WORMS difference between time of injection and the 2-year follow-up. Associations with injection type were analyzed using repeated measures of analysis of covariance. Results There were 210 participants analyzed (mean age, 64 years ± 7.9 years [SD]; 126 female participants). Corticosteroids were associated with greater WORMS progression compared with controls (mean difference, 0.39; 95% CI: 0.05, 0.75;