Periprosthetic Joint Infection Surrounding Lower-Extremity Endoprostheses After Tumor Resection: Causative Microorganisms, Effectiveness of DAIR, and Risk Factors for Treatment Failure.

Background: Periprosthetic joint infection (PJI) surrounding an endoprosthesis after reconstruction of a lower extremity following tumor resection is a common complication, and the treatment of these infections is challenging and often requires multiple surgical interventions or even implant removal. Because there has been limited evidence to support treatment strategies and understanding of the epidemiology of the causative microorganisms, we analyzed the effectiveness of debridement, antibiotics, and implant retention (DAIR), risk factors for the failure of DAIR, and causative microorganisms in patients with a PJI surrounding a lower-extremity endoprosthesis after tumor resection. Methods: A retrospective cohort study was conducted in a tertiary referral center for orthopaedic oncology. All patients treated between 2000 and 2018 for PJI surrounding a lower-extremity endoprosthesis after tumor resection were included. Treatment outcomes and risk factors for failure were analyzed in patients primarily treated with DAIR. Causative microorganisms were recorded. The minimum follow-up period was 2 years. Results: Of the 337 patients who underwent endoprosthetic reconstruction of a lower extremity after tumor resection, 67 patients (20%) developed a PJI surrounding the endoprosthesis. Of those patients, 55 were primarily treated with DAIR. The functional cure rate of DAIR was 65% (36 of 55). A median of 2 debridements per patient was needed. Chemotherapy (odds ratio [OR], 3.1 [95% confidence interval (CI), 1.0 to 9.3]) and an erythrocyte sedimentation rate of >50 mm/hr at diagnosis (OR, 4.5 [95% CI, 1.3 to 15.4]) were associated with treatment failure. Nineteen patients (28%) had a polymicrobial infection. Conclusions: Although sequential procedures are often needed, DAIR has acceptable clinical outcomes and should be considered, dependent on expected survival and the risk factors for treatment failure noted in this study. Level of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.