Implant-associated Mycobacterium tuberculosis infection (IMTI) in long-term, well-fixed implants

Background: Orthopedic device infections caused by Mycobacterium tuberculosis, including Periprosthetic joint infection (PJI), are rare and peculiar due to its poor adherence to implant surface and weak ability of biofilm formation. We present successful treatment of 2 cases of implant associated Mycobacterium tuberculosis infection (IMTI) by meticulous surgical debridement and long-term anti-tubercular chemotherapy with retention of implant.

Case descriptions: Case 1 : A case of Culture-Negative PJI, 4 years after left total hip replacement (THR) caused by M. tuberculosis. The patient presented with acute onset (<7 days) low grade fever and development of discharging sinus from the site of left surgical scar mark. Case 2: A patient with Kuntscher nailing done for open fracture right femur 22 years ago presented to clinic with complaints of discharging sinus (<7 days) from the surgical scar mark on right side. Both patients had negative cultures on presentation and underwent meticulous debridement with implant retention. Intra-operative samples were positive for M. tuberculosis on CB-NAAT and histopathology. They underwent successful treatment with 18 months of Anti Tubercular Treatment (ATT) without any relapse at 2 year-follow-up.

Conclusion: Atypical, late onset discharging sinus with negative cultures should raise suspicion of IMTI. Intra-operative deep tissue samples should be analyzed for CB-NAAT for M. tuberculosis and histopathological analysis in all these cases. Meticulous debridement with 18 months chemotherapy poses viable option for successful treatment of IMTI, allowing retention of prosthesis.