Mycobacterium abscessus: A Rare Cause of Periprosthetic Knee Joint Infection
TAKE-HOME POINTS:
- Periprosthetic joint infections due to Mycobacterium abscess have been rarely reported, and no specific guidlines exist to inform treatment.
- Medical management alone was not successful in our clinical case and cannot be recommended.
- Combination medical and surgical management may provide the best opportunity for clincal cure of periprosthetic infections.
- In complicated periprosthetic joint infections involving rare and intrinsically resistant organisms, a collaborative multidisciplinary approach likley represents the preferred path to clinical cure.
- Successful erradiation of periprosthetic infection with M. abscessus may not preclude acceptable outcomes after revision TKA.
One month postoperatively, her constitutional symptoms, including fevers and night sweats, abated and inflammatory markers (ESR and CRP) had normalized. There were no clinical signs of infection. Amikacin was discontinued due to a 10-dB change on audiologic screening (4-6 kHz range), and tigecycline was substituted. Ultimately, she underwent 15 weeks of antimycobacterial therapy, 10 of which were after the explantation.
Eight weeks after cessation of her antibiotics, she underwent open biopsy. Multiple operative tissue samples showed negative results in pathology and culture tests.
Replantation was performed 14 weeks after stopping antimicrobials and 24 weeks after her explantation. The bone appeared healthy without evidence of osteomyelitis. A constrained reconstruction was secured with tobramycin-impregnated cement. One small island of necrotizing granuloma was observed within the bony cortex on histologic review; the granulomata appeared active with scattered neutrophils along with histiocytes and lymphocytes. AFB stains were negative. Intraoperative cultures, including mycobacterial cultures, were negative.
Based on the histologic evidence that infection may have persisted, and given the high stakes, antimicrobial treatment was reinitiated. Amikacin was again stopped after 3 weeks due to the development of tinnitus; tigecycline was substituted to complete the fourth and final week, at which point all antibiotics were discontinued. The patient was followed up uneventfully for 4 years (Figures 4A-4D and 5A-5C) with normal ESR and CRP. She continues to be ambulatory without assistive devices and walks an average of 30 miles per week without pain or constitutional symptoms.
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