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

Abstract

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.

Keywords: 1.5-stage spacer; Mycobacterium avium; Periprosthetic joint infection; Septic knee arthritis.

Figure 1

Plain radiographs (a) anteroposterior and (b) lateral of the patient’s knee at his initial clinic assessment for knee pain in February 2021. RL, radiographers initials.

Figure 2

Magnetic resonance imaging (a) coronal and (b) sagittal of the patient’s knee at his initial clinic assessment for knee pain in February 2021 demonstrating severe bone involvement of the infection.

Figure 3

Intraoperative imaging demonstrating the (a) infected synovium, (b) metaphyseal bone erosion, and (c) normal bone margins after infected bone was resected.

Figure 4

Immediate postoperative radiographs (a) anteroposterior and (b) lateral demonstrating stable TKA in expected alignment without evidence of loosening, fracture, or dislocation. RE, radiographers initials.

Figure 5

Three-year postoperative radiographs (a) anteroposterior and (b) lateral demonstrating stable TKA without evidence of loosening, fracture, dislocation, or further osseous destruction. KBM, radiographers initials.