Factors affecting risk of recurrence with periprosthetic infection in shoulder arthroplasty.

BACKGROUND:The goal of treating periprosthetic infection, besides its eradication, is to avoid recurrence. The purpose of this study was to evaluate the impact of increasing Infection Severity (IS) score (based on the 2018 International Consensus Meeting on Orthopedic Infections statement), single-stage revision, and pathogenicity of the infective organism on the risk of infection recurrence. METHODS:A database of 790 revisions performed by a single surgeon from 2004-2020 was reviewed for patients with minimum 2-year follow-up and ≥1 positive culture finding and/or pathology result from the revision surgical procedure. In total, 157 cases performed in 144 patients met the inclusion criteria. These cases were then categorized by infection probability (IS score) according to the 2018 consensus statement. Of 157 cases, 46 (29%) were classified as definitely or probably infected; 25 (16%), possibly infected; and 86 (55%), unlikely to be infected. Additionally, patients were grouped by single-stage surgery and pathogenicity of the infective organism. RESULTS:A recurrence in this study was classified as the growth of the same organism in any patient requiring revision surgery. The 86 cases in the group with unlikely infection showed a recurrence rate of 2.3%. The 25 cases in the group with possible infection showed a recurrence rate of 12%. The 46 cases in the group with definite or probable infection showed a recurrence rate of 17.4%. Patients in the definite/probable infection group had a higher rate of recurrence than those in the groups with possible infection and unlikely infection (P = .009). The IS score was higher in the recurrence group than the non-recurrence group (7.5 ± 4.3 vs. 3.9 ± 3.4, P < .001). Overall, patients who underwent 1-stage revision had a 5.0% recurrence rate, but among the 34 patients with an infection classification of definite or probable who underwent 1-stage revision, the recurrence rate was 5.9%. Cases of highly virulent methicillin-resistant Staphylococcus aureus also showed a recurrence rate of 30.8% compared with 4.0% and 5.9% for Cutibacterium acnes and coagulase-negative staphylococci, respectively (P = .005). CONCLUSION:Recurrent infection after treatment of a periprosthetic infection is associated with increasing severity scores, as defined in the 2018 consensus statement, and more aggressive microorganisms. However, a single-stage surgical procedure, even in patients with higher IS scores, did not impart a significantly increased risk of recurrence.