Case report on Brucella periprosthetic joint infection after knee replacementTwo rare knee infections treated with specific antibiotics and surgery

ObjectiveTo explore the clinical characteristics, diagnostic methods, and therapeutic strategies of Brucella-induced periprosthetic joint infection (PJI) after total knee arthroplasty (TKA), so as to provide references for clinical diagnosis and treatment.MethodsThe clinical data of 2 patients with Brucella-induced PJI after TKA were analyzed retrospectively. One patient had an insidious onset 8 years after TKA, presenting with progressive joint pain and low-grade fever; the other had an acute onset 1 month after TKA, with wound redness, swelling, and exudation as the main symptoms, and initial negative bacterial culture. The key points of diagnosis and treatment were summarized by integrating epidemiological history, laboratory examinations, imaging findings, and the efficacy of surgical intervention.ResultsFor patients with a chronic onset and no prosthetic loosening, long-term anti-infective therapy with ceftriaxone sodium combined with doxycycline is administered. For those with an acute onset, debridement and implant retention (DAIR) surgery is performed, followed by anti-infective therapy with ceftriaxone sodium combined with rifampicin. After treatment, the inflammatory markers of the two patients returned to normal, the titer of the Brucella agglutination test decreased to the normal range, and the knee joint range of motion was restored.ConclusionBrucella-induced PJI has atypical clinical manifestations and is easily confused with aseptic loosening and synovitis. The acute case received DAIR while the chronic case was treated with antibiotics alone。Diagnosis should emphasize the history of exposure to pastoral areas or consumption of undercooked livestock products. Preliminary experience suggests that extended culture, Brucella PCR, and adjunctive SPECT/CT may help improve diagnostic yield. Surgical intervention combined with long-term sensitive antibiotic therapy and prolonged follow-up for at least 12 months is the preferred treatment strategy. This report can serve as a reference for the diagnosis and treatment of such rare infections in livestock-farming regions.