Fracture of the radius with instability of the wrist.

Review of 190 consecutive fractures of the distal radius revealed 14 instances of ligamentous carpal instability (7.4%). Instability was more likely to occur in older patients but was not related to the degree of fracture displacement. There was an association between instability and radial styloid fracture, and in five of nine Colles fractures a separate radial styloid fragment was present, suggesting a component of avulsive force. The relatively common coexistence of fracture and instability is not generally appreciated, and the findings of instability often are overlooked.