Coccidioidal Osteomyelitis of the Patella

Abstract

Known as "Valley Fever," coccidiomycosis is a soil-borne, fungal infection predominately found in endemic regions of the southwestern United States and Latin America. While most infected individuals are asymptomatic, <1% of patients have hematogenous seeding of bone, skin, and soft tissue. When the musculoskeletal system is involved, the knee is most commonly affected, although infection has been described in the spine, hand, wrist, ankle, foot, and pelvis. Treatment typically includes a combination of surgical debridement and antifungal treatment.An 11-year-old boy presented with a 7-month history of left anterior knee pain. Physical examination revealed mild knee effusion and quadriceps atrophy with focal tenderness to palpation to the distal pole of the patella. Laboratory studies were unremarkable and plain radiographs revealed a radiolucency in the inferomedial aspect of the patella. Magnetic resonance imaging revealed a corresponding focus of increased T2 signal with sclerotic margins and peripheral edema within the patella. Open biopsy with curettage confirmed coccidiomycosis, and the patient was successfully managed with long-term antifungal antibiotics.To our knowledge, this article presents the first known case of coccidioidal osteomyelitis of the patella.