Periprosthetic fracture in the setting of periprosthetic joint infection of the hip: evaluation and management of a single-centre cohort with forty six patients

Periprosthetic joint infection (PJI) and periprosthetic fracture (PPF) belong to the most devastating and complex complications following total hip arthroplasty, especially when both occur simultaneously. The aims of this study were (1) to evaluate the clinical outcome of PJI treatment in the setting of concomitant PPF and (2) to determine risk factors for reinfection. This study retrospectively analysed PPF occurring during the treatment of PJI in total hip arthroplasty (THA). In total 46 THA were included with concomitant PJI and PPF, of which 28 fractures occurred during the explantation and 13 fractures occurred during the interval between explantation and reimplantation. The median follow-up period was 66 months (range: 24–90) and minimum follow up of at least two years. Patients without infection recurrence after their surgical management were considered to have a successful clinical outcome. Reinfections rates were estimated through Kaplan-Meier curve and potential risk factors for reinfection were analysed with univariate non-parametric tests. Multivariate Cox hazard regression was used in order to account for confounders. Overall, the success rate in our cohort was 71%. The overall mortality rate at follow-up was 22%. The estimated cumulative reinfection-free survival was 68% (95% CI = 80.9–50.5%) with a reinfection risk of 20% (95% CI = 10.3%-35.3%) in the first 12 months. Two patients (4.8%) had a re-fracture and another two (4.8%) had a recurrent hip dislocation that needed surgical intervention. High virulence pathogens (p = 0.038), difficult-to-treat pathogens (p = 0.016) and number of debridement during the interval (p = 0.043) were significant risk factors for reinfections. Difficult-to-treat pathogens were shown to be independent risk factors (p = 0.040). The reinfection rate of concomitant PJI and PPF is high and target treatment should be achieved. Significant risk factors for reinfection were presence of difficult-to-treat or highly virulent pathogens and increased number of debridement between explantation and reimplantation.