External Validation of the Joint-Specific Bone Involvement, Antimicrobial Options, Coverage of the Soft Tissues, and Host Status (JS-BACH) Classification for Predicting Outcome in Periprosthetic Joint Infections: A Cohort of 653 Patients

Nicolai K Kristensen; Laurens Manning; Jeppe Lange; Joshua S Davis

doi:10.1016/j.arth.2024.03.070

External Validation of the Joint-Specific Bone Involvement, Antimicrobial Options, Coverage of the Soft Tissues, and Host Status (JS-BACH) Classification for Predicting Outcome in Periprosthetic Joint Infections: A Cohort of 653 Patients

J Arthroplasty. 2024 Apr 9:S0883-5403(24)00314-0. doi: 10.1016/j.arth.2024.03.070. Online ahead of print.

Authors

Nicolai K Kristensen¹, Laurens Manning², Jeppe Lange³, Joshua S Davis⁴

Affiliations

¹ Department of Orthopedics, Regional Hospital of Horsens, Horsens, Denmark; Department of Clinical Medicine, Aarhus University, Aarhus, Denmark; Center for Planned Surgery, Regional Hospital of Silkeborg, Silkeborg, Denmark.
² Medical School, University of Western Australia, Perth, Western Australia, Australia; Department of Infectious Diseases, Fiona Stanley Hospital, Perth, Western Australia, Australia.
³ Department of Orthopedics, Regional Hospital of Horsens, Horsens, Denmark; Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.
⁴ School of Medicine and Public Health, University of Newcastle, Newcastle, New South Wales, Australia; Infection Research Program, Hunter Medical Research Institute, Newcastle, New South Wales, Australia.

PMID: 38599531
DOI: 10.1016/j.arth.2024.03.070

Abstract

Background: Periprosthetic joint infection (PJI) is a devastating complication in hip and knee joint arthroplasty. The "Joint-Specific Bone Involvement, Antimicrobial Options, Coverage of the Soft Tissues, and Host Status (JS-BACH)" classification system was developed in 2021 to stratify the complexity of PJI, and more importantly, to act as a tool to guide referrals to specialist centers. The "JS-BACH" classification has not been validated in an external cohort. This study aimed to do so using a large prospective cohort from Australia and New Zealand.

Methods: We applied the JS-BACH classification to the Prosthetic Joint Infection in Australia and New Zealand Observational (PIANO) cohort. This prospective study of newly diagnosed PJI collected 2-year outcome data from 653 participants enrolled in 27 hospitals. The definition of PJI treatment failure at 24 months was any of the following: death, clinical or microbiological signs of infection, destination prosthesis removed, or ongoing antibiotic use. Individual cases were classified as per JS-BACH into "1: uncomplicated" (n = 268), "2: complex" (n = 330), and "3: limited options" (n = 55). This cohort was similar to the original JS-BACH population in terms of baseline characteristics. However, there was a difference in complexity, with more debridement, antibiotics, and implant retention procedures, fewer revision procedures, and a higher proportion of uncomplicated patients in the PIANO cohort.

Results: The risk of treatment failure correlated strongly with the JS-BACH category, with odds ratios (95% confidence interval) for category 2 versus 1 of 1.75 (1.24 to 2.47) and for category 3 versus 1 of 7.12 (3.42 to 16.02).

Conclusions: Despite the PIANO study population being less complicated than the original derivation cohort, the JS-BACH classification showed a clear association with treatment failure in this large external cohort.

Keywords: arthroplasty; classification; hip replacement; knee replacement; periprosthetic joint infection; revision.