| A rare osteonecrosis with characteristics of bone necrosis due to disrupted blood supply in the absence of a known cause. Affected bones include the femoral head, talus, vertebral body, humerus and scaphoid among others. Patients may initially be asymptomatic but subsequently present with gradually developing refractory pain, swelling and reduced range of motion. If left untreated the condition may progress to bone collapse with secondary degeneration, fragmentation and pathological fracture as well as osteoarthritis. |
