Characteristic radiographic features of the central ray in Apert syndrome.

We reviewed retrospectively seven patients with Apert acrosyndactyly and measured the size of the capitate ossification centre relative to that of the hamate and determined the relative position of the middle finger metacarpal relative to the ring finger metacarpal. We then compared those parameters in 197 normal children. In all patients, the middle finger metacarpal bone had migrated proximally relative to the ring finger metacarpal and the size of the capitate ossification centre was smaller than that of the hamate. After surgical release of the middle finger, relative proximal migration of the middle finger metacarpal was partially relieved and catch-up growth of the capitate was observed within several months. As fusion of the distal phalanges creates a diamond-shaped configuration, bone growth is markedly impaired in the middle finger ray. Therefore, early separation of the middle finger may be as important as early separation of the border digits.