An unusual pathogen for prosthetic joint infection

In 2012, an 84-year-old Chinese man presented with progressive, chronic left atraumatic knee pain and swelling. His medical history was notable for pulmonary tuberculosis treated in China in 1951 and rheumatoid arthritis diagnosed in 2006. His joint pain progressed despite use of disease modifying drugs and steroid injections. Antitumor necrosis factor inhibitors were not used because of concerns of tuberculosis reactivation. Clinical examination showed he had antalgic gait, knee effusion, stiffness, and joint-line tenderness. Laboratory results included erythrocyte sedimentation rate of 88 mm/h and C-reactive protein of 205 mg/L. Radiographs showed severe tri-compartmental degenerative arthritis (figure A).