[Isolated synovial chondromatosis of the proximal tibiofibular joint]

Synovial chondromatosis is a chronic, progressive disease of the synovial tissue where free chondral loose bodies are formed after metaplasia. It is mostly seen as a monoarticular disease in the knee, hip, shoulder, ankle, and elbow joints. To our knowledge, isolated synovial chondromatosis of the proximal tibiofibular joint has not been reported. A 36-year-old male patient presented with a complaint of pain on the lateral side of the right knee, whose severity gradually increased within the past two years. Radiological findings were suggestive of synovial chondromatosis of the proximal tibiofibular joint. The patient was treated with resection of the fibular head, including the satellite lesions. Histopathological examination confirmed the diagnosis. At one-year follow-up, the patient was symptomless, had full range of motion of the knee without pain, and had no problems in maintaining daily activities. Pathologies of the proximal tibiofibular joint must be kept in mind in patients with lateral knee pain.