SUCCESS RATE AFTER 2-STAGE SPACER-FREE TOTAL HIP ARTHROPLASTY EXCHANGE AND RISK FACTORS FOR REINFECTION: A PROSPECTIVE COHORT STUDY OF 187 PATIENTS

BackgroundTwo-stage prosthesis exchange is the treatment of choice for chronic periprosthetic joint infection (PJI) of a total hip arthroplasty (THA), especially when the bone and surrounding soft tissues are compromised or difficult-to-treat pathogens are implicated. The aims of our study were: (1) to determine the outcome of two-stage prosthesis exchange for the treatment of PJI after THA; and (2) to determine risk factors for reinfection leading to subsequent revision surgeries after reimplantation.MethodsWe prospectively enrolled 187 consecutive patients who underwent a two-stage THA exchange with resection arthroplasty for PJI from 2013 to 2019. The mean (± SD [standard deviation]) duration of follow-up was 54.2 ± 24.9 months (range, 36 to 96), and the mean interval until reimplantation was 9.8 ± 8.9 weeks (range, 2 to 38). All patients remained in a spacer-free girdlestone situation between the two stages of treatment. Patients who remained infection-free after their two-stage treatment were considered to have achieved treatment success.ResultsThe overall success rate was 85.6%. The cumulative probability of reinfection was 11.5% after one year and 14% after two years after reimplantation. High virulence or DTT (difficult-to-treat) pathogens were significant and independent risk factors for reinfection (HR [hazard ratio] = 3.71, 95% CI [confidence interval]: 1.47 to 9.36, P = 0.006 and HR = 3.85, 95% CI: 1.73 to 8.57, respectively, P = 0.001), as was previous two-stage hip prosthesis exchange (HR = 3.58, 95% CI: 1.33 to 9.62, P = 0.01). Overall reoperation and revision rates were 26.2 and 16.6%, respectively. Re-infected patients had an 80% higher probability of reoperation than non-infected ones (P < 0.001, log-rank = 102.6), and they were 55% more likely to undergo revision surgery during their follow-up (P < 0.001, log-rank = 55.4).ConclusionReinfection rates after two-stage spacer-free THA revision for PJI still remain high, but are comparable to those including cement spacers. Patients who have had prior failed two-stage implant exchanges or are infected by high-grade or difficult-to-treat pathogens are at high risk for treatment failure.