Two-stage revision for periprosthetic joint infection in unicompartmental knee arthroplasty: clinical and radiological results

Introduction Unicompartmental knee arthroplasty (UKA) has an infection rate of 0.1-0.8%. Despite the wide amount of literature about septic total knee arthroplasty management, few data are available for UKA infection treatment. The aim is to present the clinical and radiological outcomes along with complication rates of a series of septic UKA treated with two-stage exchange. Methods We retrospectively reviewed 16 patient treated with staged UKA revision for infection between June 2015 and September 2019 in a single bone infection unit. The main demographic and surgical data were recorded. Clinical scores (VAS, KSS, OKS, postoperative ROM), radiological parameters (osseointegration, loosening and radiolucencies) and complications were reported. The mean follow-up was 33.5 +/- 6.9 months. Results Mean age at surgery was 68.5 +/- 9.1. All but two were medial UKA. The mean number of previous surgeries was 2.9 +/- 1.9. The mean ROM, VAS, KSS and OKS of the entire population improved significantly (p < 0.01). Radiological analysis did not show any migration or implant loosening. Ten constrained condylar and six posterior stabilized prosthesis were finally implanted. One intraoperative pathogen isolation was recorded and managed with suppressive therapy and good final outcome. The implant survivorship free from infection was 100% at the final follow-up. The overall survival rate for any reason of revision was 100% Conclusion According to our results, staged revision represents a reliable ad effective option in delayed and late UKA infections. This technique provides optimal clinical and radiological results with acceptable complication rates. To the best of our knowledge, this represent the widest case series on infected UKA managed with two-stage exchange.