Abstract
We present three cases of osteoid osteoma with arthritis of the adjacent joint. Two lesions were in the ankle and one in the elbow. All cases presented specific nocturnal joint pain and all showed joint swelling and limb atrophy. Delay in diagnosis was a feature in all cases and ranged from 5 to 12 months. Lack of familiarity with the radiologic and histologic features of intra-articular osteoid osteoma caused diagnostic errors. CT scanning has proven to be a valuable method of revealing a small nidus, especially for those lesions located in bones with complex anatomy.
