Testing and comparison of a novel point-of-care electrochemical assay to detect and help diagnose periprosthetic joint infection on the hip and knee to the standard of care test

The primary objective of this study is to assess the equivalence of a semi-quantitative electrochemical leukocyte esterase test system and off-label use of the Roche Chemstrip leukocyte esterase (LE) test for the diagnosis of periprosthetic joint infection (PJI) in synovial fluid from hip and knee joints. In this study, the qualitative outcome of each of the two methodologies for detecting leukocyte esterase enzyme will be compared. The hypothesis of this study is that the two tests will demonstrate equivalence. The leukocyte esterase enzyme level will also be compared to synovial white blood cell count, which will be considered as a secondary reference.

Inclusion Criteria:

1. Age greater than 18 years
2. Willing and able to sign the informed consent document
3. Subjects presenting with presumed aseptic failure of a prosthetic joint and expected to undergo revision arthroplasty, or subjects presenting with presumed PJI and expected to undergo either DAIR or radical implant resection, and subjects being investigated for PJI having joint aspiration outside of the operating room who may or may not require surgical intervention.

Exclusion Criteria:

1. Subjects with known active crystalline deposition disease (e.g. gout)
2. Subjects with adverse local tissue reaction (ALTR) as a result of corrosion of components or metal-on-metal bearing surface in the hip
3. Subjects with active inflammatory arthropathy (e.g. rheumatoid arthritis)
4. Subjects undergoing a second-stage re-implantation procedure for PJI
5. Subjects in which standard of care assessments, at a minimum serology (ESR and CRP) and synovial fluid analysis (synovial WBC count, neutrophil percentage, and culture), cannot be performed.
6. Subjects in whom there is an insufficient amount of synovial fluid to perform the required investigational tests.

Subjects undergoing planned aseptic revision surgery to replace part or all of their hip or knee implant or subjects undergoing planned revision for infection