Background: Few studies have assessed the relationship between the quantity of preoperative corticosteroid injections (CSIs) or hyaluronic acid injections (HAIs) and postoperative infection risk after total knee or hip arthroplasty (TKA, THA). We aimed to (1) determine whether the number of injections administered before TKA/THA procedures is associated with postoperative infections and (2) establish whether infection risk varies by injection type.
Methods: This retrospective cohort study included 230,487 THAs and 371,511 TKAs from the 2017 to 2018 Medicare Limited Data Set. The quantity of CSI or HAI, defined as receiving either CSI or HAI ≤2 years before TKA/THA, was identified and categorized as 0, 1, 2, or >2. The primary outcome was 90-day postoperative infection. Multivariable regression models measured the association between the number of injections and 90-day postoperative infection. Odds ratios and 95% confidence intervals were reported.
Results: The percentage of THA patients receiving 1, 2, and >2 preoperative CSIs was 6.1%, 1.6%, and 0.8%, respectively. Receiving >2 CSIs within 2 years before THA was associated with higher odds of 90-day postoperative infection (odds ratios = 1.74, 95% CI = 1.11 to 2.74, P = 0.02). The percentage of TKA patients receiving 1, 2, and >2 CSIs was 3.0%, 1.2%, and 1.1%, respectively. For HAIs in TKA patients, percentage receiving injections was 98.3%, 0.6%, 0.2%, and 0.9%, respectively. Quantity of CSIs or HAIs administered was not associated with postoperative infection among TKA patients.
Conclusion: Patients receiving >2 injections before THA had higher odds of 90-day postoperative infection. This finding was not observed in TKA patients. These results suggest that the use of >2 injections within 2 years of THA should be avoided.
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