Two-Stage Exchange Arthroplasty and Positive Cultures

New research performed at Rothman Institute in Philadelphia has found that even one positive culture could mean bad news for outcomes in a reimplantation that is part of a two-stage exchange arthroplasty. Investigators looked at 259 patients with periprosthetic joint infection (PJI) who underwent both stages of two-stage exchange arthroplasty at Rothman from 1999 to 2013.

Researchers found that of the 33 cases with PJI, 15 had a later failure of the two-stage exchange arthroplasty compared with 49 of the cases that were culture-negative at reimplantation. They also found that the risk of treatment failure was higher and reinfection occurred earlier for the cases with a positive culture during reimplantation.

Antonia Chen, M.D., M.B.A. is with Rothman Institute. She told OTW, “As an arthroplasty surgeon who treats periprosthetic joint infection patients, I routinely treat patients with two-stage exchange arthroplasty and always obtain cultures at both stages. Even after obtaining a negative culture result from aspirating patients between stages following an antibiotic holiday, patients can still have a positive culture at the time of reimplantation. These culture positive patients at reimplantation raise a dilemma for orthopaedic surgeons—should these patients be treated as a persistent periprosthetic joint infection, or are these cultures contaminants and should they be ignored? Thus, the purpose of this study was to selectively study this patient population to potentially provide guidelines for treating them.

“I had a patient who had a single positive culture at the time of reimplantation, and the patient had a negative culture at a previous aspirate after a two-week antibiotic holiday. Prior to this study, I may not have placed the patient on antibiotics for treatment after surgery, but based on the results of this study, I treated this patient with antibiotics in conjunction with consultation with my infectious disease colleagues. To date, my patient has not had a recurrence of periprosthetic joint infection.

“For me, the take home message is that all positive cultures should be taken seriously at the time of reimplantation. Even one positive culture can be predictive of a poor outcome. Thus, all patients who have positive cultures at the time of reimplantation are treated as periprosthetic joint infections, and we hope to reduce treatment failure after two-stage exchange arthroplasty.

“This study has the potential to impact the collaboration between orthopaedic surgeons and infectious disease physicians. If a patient has a positive culture at reimplantation, it may be beneficial to involve infectious disease physicians earlier for treatment options to prevent recurrent periprosthetic joint infection.”