Lessons learnt from an atypical mycobacterium infection post-anterior cruciate ligament reconstruction

Infections following anterior cruciate ligament reconstruction are rare, with no previous reports citing Mycobacterium abscessus as the culprit pathogen. A 22-year-old man presented twice over three years with a painful discharging sinus over his right tibia tunnel site necessitating repeated arthroscopy and washout, months of antibiotic therapy, and ultimately culminating in the removal of the implants. In both instances, M. abscessus was present in the wound cultures, along with a coinfection of Staphyloccocus aureus during the second presentation. Though rare, M. abscessus is an important pathogen to consider in postoperative wounds presenting with chronic discharging sinuses, even in healthy non-immunocompromised patients. This case illustrates how the organism can cause an indolent infection, and how the removal of implants can be necessary to prevent the persistence of infection. Coinfection with a second organism is not uncommon and necessitates a timely change in treatment regime as well.