Improved Science and Outcome Reporting in Randomized Multicentre Trials of New Treatment for Periprosthetic Joint Infection of Hip and Knee

Background: Periprosthetic joint infection (PJI) is a rare, morbid condition that affects 1-2% of individuals who undergo hip or knee arthroplasty.Two-stage exchange arthroplasty has been considered the gold-standard for PJI treatment.However, published PJI treatment studies are largely retrospective single-site reports, and historical treatment outcome reporting for two-stage exchange arthroplasty has been inconsistent and potentially misleading.In 2019, the Musculoskeletal Infection Society (MSIS) published guidelines for PJI research including standards for outcomes reporting which have been variably adopted.Key Objective: To describe the research methods of two trials of a new PJI treatment that incorporate the MSIS research guidelines and contrast them with previously published PJI treatment studies.Methods: APEX and APEX-2 are two prospective, multicenter, randomized controlled trials comparing VT-X7, a new treatment for PJI, to conventional two-stage exchange arthroplasty.The APEX trials use intention-to-treat analysis, incorporating all individuals who initiate treatment into the outcomes reporting.The APEX trials make use of a composite success measure based upon the MSIS Tiered outcomes including a) successful implantation of Stage 2 revision prosthesis, b) absence of PJI post-Stage 2, c) absence of antibiotics for PJI treatment, d) absence of reoperation of the affected joint pre-and post-Stage 2, and e) absence of mortality.Conclusions: The APEX and APEX-2 trials represent a significant improvement in the quality of science applied to the care of individuals with PJI.Previous reports of two-stage treatment arthroplasty outcomes should be reconsidered in the context of the MSIS outcome reporting guidelines.