An often-unrecognized entity as cause of recurrent infection after successfully treated two-stage exchange arthroplasty: hematogenous infection.

INTRODUCTION: Reinfection after two-stage exchange arthroplasty is a difficult clinical scenario with limited data on adequate treatment algorithms. Beside the possibility of treatment failure and a new intraoperative infection at the time of reimplantation, hematogenous seeding could play an up to date underestimated crucial role as another cause of an infection after two-stage exchange. The aim of this study was to evaluate its incidence and treatment possibilities in a prospectively followed case series.

METHODS: All consecutive hip and knee periprosthetic joint infection cases (93 hips and 89 knees) treated according to a standardized diagnostic and therapeutic algorithm at our institution with a two-stage exchange arthroplasty from 2013 to 2015 were included and followed prospectively to identify recurrent infections due to hematogenous seeding.

RESULTS: Six percent from our septic revision hip and knee arthroplasties (11 of 182, including 5 hips and 6 knees) were identified with a hematogenous reinfection after a mean follow-up of 31.8 months (range 14-48 months). The mean time to reinfection after reimplantation was 12.2 months (range 3.1-35.1). In all but two cases was the causative microorganism different than isolated at the time of initial two-stage exchange. In 5 of 11 patients, the primary focus of infection was identified.

CONCLUSION: Hematogenous infection after a successful two-stage exchange arthroplasty is a rare but very important cause of a reinfection. With our work, we aim at raising the awareness for this entity and recommend consideration of irrigation and debridement with implant retention in these cases, as well as possibly the identification of a primary infection source.