Presumptive infection of a total hip prosthesis by Mycobacterium tuberculosis: a case report

Infection of a total hip prosthesis by Mycobacterium tuberculosis (MT) is an uncommon complication. We report a patient with septic loosening of a total hip prosthesis with a presumptive diagnosis of MT infection. His previous history was negative to any form of tuberculosis, and there was no evidence of a primary focus on the radiological study of the chest. He was diagnosed initially as presenting aseptic loosening and revision surgery was performed. Six months after surgery, septic loosening was diagnosed. The prosthesis was then removed. The histological study showed caseum granulomas and acid-fast bacilli, and routine cultures of the synovial fluid were negative. Since only a positive Löwenstein culture would have confirmed the diagnosis with certainty, a presumptive diagnosis of MR infection was made based on the findings in the histological study. Tuberculostatic treatment was administered for 9 months. At six years follow-up no signs of infection are present, neither by clinical or radiological criteria.