[Pseudarthrosis of the scaphoid bone and carpal instability. Correlations--development--consequences].

In combination with its ligamentous connections, the scaphoid bone represents an essential stabilizing factor within the wrist. This stabilizing function disappears after trauma causing a displaced fracture of the scaphoid bone or extensive rupture of ligamentous structures fixing the scaphoid in its position. Hence carpal instability results, detectible radiographically by alteration of defined wrist angles. Since this is so, one might suppose that, together with other wellknown reasons, carpal instability would be of great importance in the development of a scaphoid nonunion. However, after evaluation of 76 cases, a scaphoid nonunion with carpal instability was found in only 27.6%. Moreover, surgical treatment of the scaphoid nonunion alone does not correct the abnormal wrist angles. Despite this observation, we do not consider simultaneous ligamentous repair to be necessary, because few problems remained after bony healing in such cases.