Treatment success rates of PJI varied by definition of success
PHILADELPHIA — Depending on the definition for success of periprosthetic joint infection treatment, results presented at the Musculoskeletal Infection Society Annual Open Scientific Meeting showed a variation in treatment success rates.
Alexander J. Rondon, MD, and colleagues retrospectively reviewed intraoperative cultures at the time of spacer, reimplantation and any subsequent reinfections of surgeries following spacer insertion among 570 periprosthetic joint infections (PJIs) that underwent two-stage exchange from 1999 to 2015. Researchers assessed five definitions of treatment success, including Delphi consensus success, modified Delphi consensus success, microbiological success, implant success and surgical success.
At a mean of 4.1 months, Rondon noted 458 patients had a reimplantation.
“Mortality was almost 14%, with almost 7% occurring prior to reimplantation,” Rondon said. “Of these 79 cases of mortality, three were attributed to PJI or infection.”
Although 77.1% of patients qualified as successful treatment for PJI when the Delphi consensus definition was used, Rondon said 20% of the cohort could not be assessed as reimplantation never occurred, with 67% of these patients undergoing reoperations not accounted for in the previous definition. When considering patients who did not undergo reimplantation, he added survivorship was significantly different.
“When looking at differences in organisms in the initial spacer vs. reimplanted, no recurrence of infection with the initial organism was 96.8%; no recurrence of any organism was 88.9%; and of the failures, organisms differed by 71.4% at the time,” Rondon said.
When determining the ideal follow-up, according to Rondon, 570 patients had 1-year follow-up; 355 patients had 2-year follow-up; 166 patients had 5-year follow-up; and 27 patients had 10-year follow-up.
“So, 1-year follow-up may thus be sufficient considering that over 75% of our failures by reoperation occurred during this time period,” Rondon said. “If you extrapolated it to 2 years, it would be 80% and 3-year follow-up would be 18%. So, considering the difficulty and loss to follow-up when failure occurs, 1 year might be the ideal balance.” – by Casey Tingle
Tan TL, et al. Defining treatment success after two-stage exchange arthroplasty for periprosthetic joint infection. Presented at: Musculoskeletal Infection Society Annual Open Scientific Meeting; July 27-28, 2018; Philadelphia.
Disclosure: Rondon reports no relevant financial disclosures.