[Intraarticular osteoid osteoma as a cause of chronic ankle pain].

Osteoid osteoma is a benign osteoblastic tumoral lesion. It is seldom intraarticularly localized and presents nonspecific signs and symptoms, such as swelling, slight warmth, and nocturnal pain. Because of unusual clinical findings and the frequent absence of typical bone sclerosis, diagnosis often takes longer than for extraarticular osteoid osteoma. Complete arthroscopic en bloc excision of the lesion is the treatment of choice, offering complete relief of symptoms following surgery. Extirpation of the nidus may prevent damage to the articular surface.