Bread Mold Osteomyelitis in the Femur

Abstract

Rhizopus osteomyelitis is an uncommon and often fatal infection that usually occurs in immunocompromised patients. The infection is commonly referred to as "bread mold." The usual course of treatment is Amphotericin B, debridement, and, if needed, amputation of the affected limb. This article details a rare case of postoperative Rhizopus osteomyelitis in an otherwise healthy patient. The patient originally presented at another institution for anterior cruciate ligament repair after a ski injury. Postoperatively, he developed clinical evidence of infection. He was referred to our institution with stiffness and swelling in the knee as well as weight loss and decreased range of motion. Fluid collection was visible on magnetic resonance imaging. Arthroscentesis was cultured for fungus and bacteria, and the fungal cultures were positive for Rhizopus species. An attempt at limb salvage was made. Debridement, use of a cement spacer loaded with Amphotericin B, systemic antifungal therapy, and 23 hyperbaric oxygen treatments were used to eradicate the disease. Four surgeries were needed to eradicate the disease, and 10 months after initial presentation, the patient had a distal femoral endoprosthesis placed in his leg. Laboratory tests returned to normal and frozen sections were negative for fungus. At 3-year follow-up, the patient reported a musculoskeletal functional score of 50% and had no evidence of recurrent infection.