Preoperative Corticosteroid Injections Within 4 weeks of Arthroscopic Shoulder Procedures is Associated with Increased Postoperative Infection Rates

To refine the understanding of the effect of timing of corticosteroid injections (CSIs) and shoulder arthroscopy on postoperative infection.An insurance database was used to determine all patients who underwent shoulder arthroscopy for a 5-year period with an associated preoperative ipsilateral corticosteroid injection. Patients were stratified into cohorts based on timing of preoperative CSI: (1) 0-<2 weeks, (2) 2-<4 weeks, (3) 4-<6 weeks, and (4) 6-<8 weeks. Patients were pooled to include all patients who had a CSI less than 4 weeks and those longer than 4 weeks. A cohort of patients who never had a corticosteroid injection before undergoing arthroscopy were used as a control. All patients had a follow-up of 2 years. Multivariable regression analyses were performed using R Studio with significance defined as P < .05.Multivariate logistic regression showed a greater odds ratio (OR) for postoperative infection in patients who received CSI 0-<2 weeks before shoulder arthroscopy at 90 days (3.10, 95% confidence interval [CI] 1.62-5.57, P < .001), 1 year (2.51, 95% CI 1.46-4.12, P < .001), and 2 years (2.08, 95% CI 1.27-3.28, P = .002) compared with the control group. Patients who received CSI 2-<4 weeks before shoulder arthroscopy had greater OR for infection at 90 days (2.26, 95% CI 1.28-3.83, P = .03), 1 year (1.82, 95% CI 1.13-2,82, P = .01), and 2 years (1.62, 95% CI 1.10-2.47, P = .012). Patients who received CSI after 4 weeks had similar ORs of infection at 90 days (OR 1.15, 95% CI 0.78-1.69, P = .48) 1 year (OR 1.18, 95% CI 0.85-1.63 P = .33), and 2 years (OR 1.09, 95% CI 0.83-1.42, P = .54), compared with the control cohort.The present study shows the postoperative infection risk is greatest when CSIs are given within 2 weeks of shoulder arthroscopy, whereas CSIs given within 2-<4 weeks also portend increased risk, albeit to a lesser degree. The risk of postoperative infection is not significantly increased when CSIs are given more than 1 month before surgery.Level III, retrospective comparative; prognosis study.