Risk of Infection After Intra-articular Steroid Injection at the Time of Ankle Arthroscopy in a Medicare Population.

PURPOSE

To employ a national database to evaluate the association between intraoperative corticosteroid injection at the time of ankle arthroscopy and postoperative infection rates in Medicare patients.

METHODS

A national insurance database was queried for Medicare patients who underwent ankle arthroscopy, including arthroscopic removal of loose body, synovectomy, and limited or extensive debridement. Two groups were created: ankle arthroscopy with concomitant local steroid injection (n = 459) and a control group of patients who underwent ankle arthroscopy without intraoperative local steroid injection (n = 9,327). The demographics and Charlson Comorbidity Index of each group were compared. Infection rates within 6 months postoperatively were assessed using International Classification of Diseases, 9th revision, and Current Procedural Terminology codes and compared between groups using χ(2)-tests.

RESULTS

A total of 9,786 unique patients who underwent ankle arthroscopy were included in the study. There were no statistically significant differences between the steroid injection study group and controls for the assessed infection-related variables, including gender, age group, obesity, smoking, and average Charlson Comorbidity Index. The infection rate for patients who had a local steroid injection at the time of surgery was 3.9% (18/459 patients), compared with 1.8% (168/9,327 patients) in the control group (odds ratio, 2.2; 95% confidence interval, 1.4 to 3.7; P = .002.) The majority of this difference was noted between the 65 and 79 years age groups.

CONCLUSIONS

The use of intraoperative intraarticular corticosteroid injection at the time of ankle arthroscopy in Medicare patients is associated with significantly increased rates of postoperative infection compared with controls without intraoperative steroid injections.