Diagnosis of Prosthetic Joint Infection.

An 81-year-old male with an infected aortic valve presents to the orthopaedic service with a painful total knee of unclear chronicity and several weeks of intravenous antibiotics. While some prosthetic joint infections (PJI) present very clearly, many come as consultations after previous partial work-up, administration of antibiotics, and an unclear history or timeline. Even in these more "real-world" clinical scenarios, the development of evidence-based practices will allow the orthopaedic surgeon the ability to accurately detect PJI and prudently determine when to take a patient to the operating room. The most widely-accepted algorithm is that developed by the Musculoskeletal Infection Society (MSIS), which utilizes major and minor criteria and a scoring system that diagnoses PJI. Beyond this scoring system, recent studies have also shown the utility of laboratory tests, including serum and synovial fluid tests, as well as next generation sequencing techniques. These, with the addition of both simple radioimaging and more advanced nuclear imaging tests, provide surgeons the tools required to make the determination of PJI even in the most complex or difficult clinical scenarios. (Journal of Surgical Orthopaedic Advances 30(4):212-215, 2021).