Periarticular osteoid osteoma of the ankle: a report of nine arthroscopically treated patients.

Periarticular osteoid osteoma often presents with unspecific clinical symptoms, mimicking other clinical conditions. This can lead a clinician to a ''diagnostic side path'' and a delayed or missed diagnosis compared with extra-articular osteoid osteoma. We report the cases of 9 patients with a mean age of 22 (range 14 to 32) years who were diagnosed with periarticular osteoid osteoma of the ankle and were surgically treated in our department during a 12-year period. The diagnostic difficulties associated with periarticular osteoid osteoma must be resolved by obtaining a detailed patient history and performing a thorough physical examination. Computed tomography is the ultimate imaging method to confirm the suspicion of osteoid osteoma. Arthroscopic removal of the osteoid osteoma was performed in all 9 patients in the present case series, with synovectomy performed when indicated. Under arthroscopic visualization, a specimen was obtained for histopathologic analysis to confirm the diagnosis, followed by tumor excision. All the patients were pain free at the final follow-up visit after a mean duration of 6 years (range 6 months to 12.7 years) postoperatively. We suggest arthroscopic removal of periarticular osteoid osteomas of the ankle as an effective treatment method, because it allows complete tumor excision, synovectomy when needed, a short postoperative rehabilitation period, and satisfactory functional results.