Abstract
It is strongly recommended that tissue and synovial fluid culture samples be obtained during reimplantation performed as part of a two-stage exchange arthroplasty. The incidence of positive cultures during reimplantation and the influence of positive cultures on subsequent outcome are unknown. This aim of this study was to determine the incidence of positive cultures during reimplantation and to investigate the association between positive cultures at reimplantation and the subsequent outcome
A retrospective review was conducted on 267 patients that met the Musculoskeletal Infection Society (MSIS) criteria for PJI that completed both stages of two-stage exchange arthroplasty (Table 1). Intraoperative culture results from tissue and/or synovial fluid were obtained. Cultures were positive in 33 cases (12.4%) undergoing reimplantation surgery (Figure 1). Treatment failure was assessed based on the Delphi consensus definition. Logistic regression analysis was performed to assess the predictors of positive culture and risk factors for failure of two-stage exchange arthroplasty.
Treatment failure was 45.5% for those with a positive intraoperative culture and 20.9% in those with negative cultures at the time of reimplantation. When controlling for organism virulence, comorbidities, and other confounding factors, treatment failure was higher (odds ratio [OR]: 3.3; 95% confidence interval [CI]: 1.3–4.5) and occurred at an earlier time point (hazard ratio: 2.5; 95% CI: 1.3–4.5) in patients with a positive reimplantation culture. The treatment failure rate was not different between cases with two or more positive cultures (36.4%) and one positive culture (42.8%).
Positive intraoperative cultures during reimplantation, regardless of the number of positive samples were independently associated with two times the risk of subsequent infection and earlier treatment failure. Surgeons should be aware that a positive culture at the time of reimplantation independently increases the risk of subsequent failure and needs to be taken seriously. Given the significance of these findings, future studies are needed to evaluate the optimal management of positive cultures during reimplantation surgery.
