Abstract

Background: A systemic lupus erythematosus (SLE) patient presented with right knee swelling after right total knee arthroplasty, which eventually turned out to be Mycobacterium tuberculosis infection. She was successfully treated with debridement and retention of implant, together with commencement of anti-tuberculosis medications.

Case report: A 58 years-old SLE patient presented with acute, painful right knee swelling 4 months after undergoing right total knee arthroplasty. Upon examination, her right knee was diffusely swollen and warm. The initial blood parameters were normal. She was empirically started on intravenous ceftriaxone. As there was no sign of regression, she underwent arthrotomy washout and exchange of polyethylene insert, during which intraoperatively it was noted that there was presence of reactive synovitis. Post-operatively, she developed a pus-draining sinus and thus underwent another debridement with implant retention. The subsequent culture and histopathological examination of the synovial tissue confirmed the diagnosis of Mycobacterium tuberculosis infection. The patient was started on anti-tuberculosis therapy and showed marked improvement in terms of clinical parameters and functional outcomes.

Conclusion: This is a rare case of Mycobacterium infection post total knee arthroplasty. It was diagnosed by confirmation of both culture and histopathological examination of synovial tissue. The relationship between SLE and TB infection and the possibility of reactivation of pre-existing TB was explored. Surgical debridement with adjuvant anti-tuberculosis therapy remains as the mainstay treatment of such prosthetic joint infection.

Keywords: Mycobacterium tuberculosis; Prosthetic joint; Total knee arthroplasty; Systemic lupus erythematosus