Total Knee Arthroplasty Following Mycobacterium Kansasii Septic Arthritis in a Patient with Systemic Lupus Erythematosus and Essential Thrombocythemia

Mycobacterium kansasii, like other nontuberculous mycobacteria (NTM), is rare opportunistic infection that can lead to septic arthritis in immunosuppressed patients. We report the case of a 56†year†old Hispanic female with systemic lupus erythematosus (SLE) and scleroderma, on long†term immunosuppression, who developed an M. kansasii septic arthritis of the left knee, in the setting of chronic lupus arthritis. Total knee arthroplasty (TKA) was delayed as the infection progressed into osteomyelitis of the distal left femur, with an associated chronic, draining wound in the popliteal fossa. There are no reports in the literature documenting the treatment of this manifestation of M. kansasii in a patient with SLE, prior to TKA. Diagnosis requires a high index of suspicion, and was accomplished with synovial fluid culture and tissue biopsy. Treatment was accomplished with staged debridement and anti†mycobacterial drug therapy, along with tapering of her immunosuppressive regimen. Wound closure was achieved with a combination of a split thickness skin graft and negative pressure wound therapy (NPWT). Wound healing was augmented with hyperbaric oxygen therapy HBOT. A TKA was then performed, which yielded excellent results.