10-year-old boy with history of ankle pain and Trevor's disease. TENDONS: The peroneus longus and brevis tendons are normal. The anterior and posterior tibial compartment tendons are normal. The Achilles tendon is normal.LIGAMENTS: The anterior talofibular ligament is intact. The spring ligament is intact.ARTICULAR SURFACES AND BONE: A 24 x 19 x 9 mm lesion is seen immediately posterior to the medial process of the talus with signal characteristics of bone and cartilage (series 5, image 16; series 4, image 18). No direct communication with the talus is identified. Additionally, multiple smaller osseous lesions are seen posterior to the talar dome measuring up to 8 mm (series 12, images 32, 59, and 60). These lesions were not visualized on the prior, outside study from 3/12/2013.Irregularity of the medial facet of the talus and sustentaculum tali is noted.ADDITIONAL
1.Large osteochondroma posterior to the medial process of the talus without osseous communication seen.2.Additional, smaller osseous lesions posterior to the talus.3.Irregularity of the middle subtalar joint, may be degenerative.