Ball-and-socket ankle joint with hypoplastic sustentaculum tali.

A case of unilateral ball-and-socket ankle joint associated with short limb and hypoplastic sustentaculum tali is reported. We think that hypoplastic sustentaculum tali was the cardinal feature in the anatomical and kinematic alterations of the foot in this patient. We review the embryonic development of hindfoot to ascertain the possible origin of this unusual finding.