Comparing the Risk of Osteonecrosis of the Femoral Head Following Intra-Articular Corticosteroid and Hyaluronic Acid Injections

Background: Although intra-articular corticosteroid injections (CSIs) are a cornerstone in the nonoperative management of hip pathology, recent reports have raised concerns that they may cause osteonecrosis of the femoral head (ONFH). However, these studies might have been limited by nonrepresentative patient samples. Therefore, the purpose of this study was to assess the incidence of ONFH after CSI and compare it with the incidence in a similar patient population that received a non-CSI injection. Methods: This was a retrospective propensity-matched cohort study of patients in the MarketScan database who underwent an intra-articular hip injection from 2007 to 2017. Patients receiving hip CSIs were matched 4:1 with patients receiving hip hyaluronic acid injections (HAIs) based on age, sex, geographic region, comorbidities, type of hip pathology, injection year, and baseline and follow-up time using propensity scores. The patients' first injections were identified, and the time to development of ONFH was analyzed using Kaplan-Meier curves and Cox proportional-hazards models. Patients with a history of osteonecrosis or those who received both types of injections were excluded. Results: A total of 3,710 patients undergoing intra-articular hip injection were included (2,968 CSIs and 742 HAIs; mean [standard deviation] age, 53.1 [9.2] years; 55.4% men). All baseline factors were successfully matched between the groups (all p > 0.57). The estimated cumulative incidence (95% confidence interval [CI]) of ONFH for CSI and HAI patients was 2.4% (1.8% to 3.1%) versus 2.1% (1.1% to 3.5%) at 1 year and 2.9% (2.2% to 3.7%) versus 3.0% (1.7% to 4.8%) at 2 years (hazard ratio, 1.05; 95% CI, 0.59 to 1.84; p = 0.88). The results held across a range of sensitivity analyses. Conclusions: The incidence of ONFH after intra-articular hip injection was similar between patients who received CSIs and those who received HAIs. Although this study could not determine whether intra-articular injections themselves (regardless of the drug that was used) lead to ONFH, the results suggest that ONFH after CSI often may be due, in part, to the natural course of the underlying disease. Future randomized controlled trials are needed to definitively answer this question; in the interim, clinicians may be reassured that they may continue judicious use of CSIs as clinically indicated.