Recent intraarticular steroid injection may increase infection rates in primary THA

We retrospectively determined the rate of therapeutic intraarticular steroid injection within 1 year before total hip arthroplasty (THA) for osteoarthritis and whether the injection of the steroid increased the risk of infection. In a retrospective matched cohort study, 224 primary THAs (217 patients) implanted within 1 year of intraarticular steroid injection (Group 1) were compared with 224 primary THAs (220 patients) in patients who had not received an injection (Group 2). The mean time between injection and THA was 112 days (SD, 81 days). In Group 1, there were three deep and 11 superficial infections compared with one deep and eight superficial infections in Group 2. The hazard ratios of deep and superficial infections were 3 (95% CI, 0.3, 29.8) and 1.5 (95% CI, 0.6, 3.6), respectively. Intraarticular steroid injection within 1 year of THA did not affect postoperative rates of infection. However, the mean time from steroid injection to THA was 44 days (SD, 23 days) in the few patients who had deep infection develop. While not statistically significant, this raises a concern of increased risk of deep infection when receiving a steroid injection within 6 weeks of THA. Caution should be used before giving an intraarticular steroid injection within 2 months before THA.