Native Knee Septic Arthritis With Mycobacterium Avium Complex Treated With Primary Total Knee Arthroplasty With Antibiotic-Eluting Cement.

Native knee septic arthritis due to Mycobacterium avium complex (MAC) is extremely rare. Disseminated MAC infections are often associated with an immunosuppressed state; however, they can occur in immunocompetent patients. We describe a case of MAC infection in the native knee in an immunocompetent patient resulting in osseous destruction and secondary arthritic changes. Both the infection and destructive arthropathy were successfully treated with a single procedure consisting of radical debridement, primary total knee arthroplasty with high-dose pathogen-specific antibiotic therapy, and subsequent systemic antibiotic therapy. At 3.5 years since surgery, the patient is off antibiotic therapy and continues to have a well-functioning total knee arthroplasty.