Chip fractures of the triquetrum. Mechanism, classification and results.

Of 231 patients with fractures of the triquetrum, 65 were followed up after a mean period of 46.8 months. The fractures were classified and radiological and clinical follow-up was carried out. Pathomechanical aspects of the origin of the fracture were also considered. It appears that the chisel action of the dorso-proximal edge of the hamate striking against the fully extended and ulnar-deviated wrist is the major cause of the dorsal chip fracture of the triquetrum. Conservative therapy involving immobilization of the injured wrist for 3 weeks proved to be successful. If the bone fragment healed, it took 6 to 8 weeks. There was no indication for surgical intervention. We found no signs of post-traumatic instability of the joint. There was good vascularization of the bone, which excluded the possibility of avascular necrosis. All fractures involving the main body of the triquetrum united.