309. The Infected Spacer: The Impact of Spacer Exchanges and Debridements on Two-Stage Exchange Arthroplasty Outcomes

BACKGROUND: Prosthetic joint infection (PJI) is a grave complication of total joint arthroplasty (TJA). Data on patients who require further surgery for infection between explantation and reimplantation (i.e., while the spacer is in place) are limited. We investigated the effect of spacer exchange or irrigation and debridement (I&D) on clinical outcomes in patients undergoing two-stage exchange for PJI. METHODS: A retrospective cohort of hip and knee PJI treated with two-stage exchange was identified by query of hospital coding records from 2009 to 2014, with subsequent chart review. All cases met Musculoskeletal Infection Society International Consensus criteria for PJI. The primary endpoint was defined as prosthesis retention for 2 years from reimplantation. Spacer intervention was defined as undergoing a spacer exchange or I&D for infection purposes prior to reimplantation. Descriptive statistics were completed using the Fisher’s exact test for categorical variables and the Mann–Whitney U test for continuous variables. RESULTS: Three hundred patients undergoing two-stage exchange for TJA PJI were identified (141 hips and 159 knees). The average age was 66 years and 42% were female. Forty-two patients (14%) underwent spacer intervention, 22 knees (14%), and 20 hips (14%). 34 of these underwent spacer exchange. Of the 42 patients with spacer intervention, 28 (67%) met the primary endpoint. In univariate analysis, there was an association between spacer intervention and outcome (P = 0.02). Comorbidities including age, sex, and BMI were not associated with outcome. The association appeared more pronounced among the TKA subgroup. Patients who underwent spacer intervention were 2.1[CI: 1.11–4.42] times more likely to fail than TKA patients who did not require such an intervention (P = 0.02). CONCLUSION: We present 2-year outcomes on a large cohort of TJA PJI treated with two-stage exchange arthroplasty. Patients requiring spacer exchange or I&D after TJA explantation have worse outcomes than their counterparts who do not. Because patients who fail two-stage exchange arthroplasties often proceed to arthrodesis or amputation, our findings may help guide clinical decision-making prior to reimplantation. DISCLOSURES: All authors: No reported disclosures.