Total hip and total knee arthroplasty (THA, TKA) are the effective therapy, which can improve quality of life of patients. Prosthetic joint infection (PJI) is an uncommon but major complication following this surgery. Mycobacteria are unusual pathogen of PJI. The study aimed to determine clinical characteristics, associated factors, and outcome of mycobacterial PJI.
A retrospective case control study of patients who age ≥18 years and were diagnosed PJI of hip or knee in Siriraj Hospital, Thailand during January 2000 through December 2012 was conducted. Patients’ characteristics, clinical data, microbiological findings, treatment, and outcome were studied.
Total 191 subjects from non-mycobacterial PJI (175) and mycobacterial PJI (16) were obtained. Rapidly growing mycobacteria (RGM)- M. fortuitum, M. abscessus, M. peregrinum, and M. tuberculosis (MTB) were etiologic agents of mycobacterial PJI. Median duration (365 vs. 90 days, p= 0.04), onset of PJI (p< 0.01), median synovial fluid WBC count (47,950 vs. 2,150 cell/mm3, p= 0.04), appropriate use of initial antibiotics (p< 0.01), maintenance antibiotic regimen (p< 0.01), and median duration of oral antibiotics (129 vs. 365 days, p= 0.01) were significantly different between non-mycobacterial and mycobacterial PJI. Onset of PJI within 90 days post arthroplasty was a significant factor associated with mycobacterial PJI [OR 13.56 (1.89-97.54), p= 0.01]. Removal of prosthesis was the strongest associated factor with favorable outcome at 6 months [OR 6.47 (1.88-22.33), p< 0.01] and 12 months [OR 5.96 (1.88-18.88), p< 0.01].
RGM particularly in early onset PJI and MTB are the putative etiology of PJI post THA and TKA. High index of suspicion and mycobacterial culture are warranted when dealing with PJI with routinely negative culture and/or refractory to antibacterial agents. Removal of infected implant is a significant factor associated with successful outcome.
V. Yuenyongviwat, None
M. Chayakulkeeree, None
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