Dysplasia epiphysealis hemimelica

A rare bone development disorder characterized by localized, asymmetric osteochondral overgrowth affecting single or multiple epiphyses, most commonly the distal femur, proximal tibia, and talus. The lesions are typically restricted to one side of the epiphysis, with the medial side being affected twice as often as the lateral side. The condition is usually diagnosed in children, and three times more often in boys than in girls. Patients present with pain, limitation in range of motion, and deformity or swelling of the affected joint.