Intra-articular osteoid osteoma in the proximal ulna combined with radial head subluxation: a case report.

Osteoid osteoma is a relatively common benign bone tumor that was first described by Jaffe in 1935. Its typical clinical feature is pain, which is worse at night and relieved by nonsteroidal anti-inflammatory drugs (NSAIDs). Typical radiologic findings are a nidus with a small radiolucent area within an extensive reactive cortical thickening. This tumor has a predilection for the diaphysis or metaphysis of long bones, with 50-60% occurring in the femur or tibia. However, localization in the elbow is a very rare presentation, and shows an atypical picture that causes both diagnostic delay and therapeutic problems. We herein report a case of a 19-year-old man who had pain and limited motion of the left elbow as a result of osteoid osteoma at the sigmoid notch of the proximal ulna. Anterior subluxation of the radial head was also observed by simple radiographs. En bloc resection and synovectomy resulted in pain relief, motion recovery, and reduction of the subluxated radial head. The patient consented when asked if data concerning his case could be submitted for publication.