Osteoid osteoma of the calcaneus misdiagnosed as subtalar sprain.

Osteoid osteoma of foot and ankle account for ten percent of benign bone tumors and commonly involve the talus and metatarsals. Its occurrence in calcaneus is extremely rare and can mimic ankle instability, subtalar arthritis, osteochondritis or plantar fasciitis leading to delay in diagnosis. We present the case of a 17 year old boy with periarticular osteoid osteoma in the calcaneum, who presented following an ankle sprain. He was successfully treated with CT guided percutaneous radiofrequency ablation and we feel that it is a safe, precise and effective treatment option for even periarticular osteoid osteoma in the foot and ankle region.