A rare case of a ball and socket ankle joint.

1 of 2 DESCRIPTION A 50-year-old otherwise well gentleman presented with mild pain and stiffness in his right ankle. Remarkably, radiographs revealed gross congenital deformities. The ankle mortice was semicircular and the subtalar joints fused ( fi gure 1 ). There were only three metatarsals. The bases of the proximal phalanges of the fi rst and second toes were fused and articulated with the head of the fi rst metatarsal ( fi gure 2 ). The ball and socket ankle joint was fi rst described in English literature by Lamb in 1958. 1 The aetiology of this abnormality is most often congenital but can be acquired due to poliomyelitis or postsubtalar arthrodesis. 2 It is most often found in association with other congenital deformities which can result in leg length discrepancy, instability, pain and stiffness. However, the reports suggest although the aforementioned symptoms can occur, what is surprising is the lack of symptoms that can occur with this malformation. The patient had mild stiffness and pain which did not impact upon his lifestyle. On examination, he had a 2 cm leg length discrepancy, which the authors treated with an orthotic supplement. The possible future operative interventions include fusion of the ankle joint should his symptoms progress to be more debilitating. Image In...