Intra-Articular Corticosteroid Injections Into a Preexisting Total Knee Arthroplasty are Associated With Increased Risk of Periprosthetic Joint Infection and Revision

BACKGROUND: This study aims to determine the risks of periprosthetic joint infection (PJI) and revision associated with injecting a preexisting total knee arthroplasty (TKA) with intra-articular corticosteroids (IACSs). METHODS: The PearlDiver database was used to identify patients who underwent elective, primary TKA between 2015 and 2019. Patients who received IACS injections into the ipsilateral knee within 1 year after their primary TKA were matched 2:1 on age, gender, and Charlson comorbidity index and compared to a no-injection control group. The incidence of PJI at 1 year postoperatively and revision at 2 years postoperatively were compared between groups. RESULTS: A total of 27,059 patients were in the injection cohort and 54,116 patients in the control cohort. The overall PJI rate was 1.3% in the injection cohort and 0.8% in the control cohort (P < .001). The rate of PJI increased with the number of post-TKA IACS injections received: 1 injection (1.3%), 2 injections (1.4%), and >3 injections (1.8%) (P < .001 for all, compared to controls). The revision rate was 3.1% in the injection cohort and 1.3% in the control cohort (P < .001). Revision rates increased with the number of post-TKA IACS injections received: 1 injection (2.5%), 2 injections (4.2%), and >3 injections (7.3%) (P < .001 for all, compared to controls). CONCLUSIONS: IACS injections into a preexisting TKA are associated with an incremental increased risk of prosthetic joint infection and revision. Considering the potential deleterious impact of PJI and complexity of revision procedures, IACS injections into a preexisting TKA should be strongly discouraged.