Preoperative Corticosteroid Injections are not Associated with Deep Infection after Unicompartmental Knee Arthroplasty.

Postoperative deep infections occurred in 64 patients with CSI 0-3 months prior to surgery (0.7%), compared with 0 patients with CSI 3-12 months before surgery (0.0%) and 182 controls (0.8%, P=0.58). CSI within 1 month prior to UKA was not statistically associated with postoperative infection (P=0.66). Two or more CSI within 3 months prior to UKA was associated with a 2-fold elevated odds of infection, compared to receiving a single injection (odds ratio 2.08, P=0.03). Univariable predictors of infection included younger age, increasing CCI, smoking, asthma, chronic obstructive pulmonary disease, chronic kidney disease, diabetes, liver disease, and obesity. Multivariable analysis controlling for these characteristics elicited no relationship between recent CSI administration and postoperative infection. CSI within 3 months of surgery (1.5%) or 3-12 months (1.8%) were associated with increased conversion to TKA compared to those who did not receive an injection (1.1%, P=0.01) although TKA for indication of periprosthetic joint infection were not statistically different (P=0.72) Conclusions: Preoperative CSI within 3 months of UKA is not associated with postoperative infection, although significant medical comorbidity does show an association. Preoperative CSI is associated with increased conversion from UKA to TKA for non-infectious indications.