[Mechanics of the perilunate carpal bones and their injury patterns including post-traumatic instability with reference to rare clinical cases].

There is given a survey of recent findings of the biomechanics of the carpal bones of which the complex of the os scaphoideum, lunatum and capitatum has the key role. The mechanism of injury and posttraumatic instability of the wrist are presented. Rare injuries like subluxation of the os scaphoideum with DISI instability, "scapho-capitate fracture" syndrome, and perilunar dislocation associated with scaphoid fracture (de Quervain) with a proximal fragment of the scaphoid which is turned over about 180 and 90 degrees, are reported in form of clinical cases. In case of subluxation of the os scaphoideum the operation described by Dobyns is recommended, using a split of ECRB tendon for dorsal ligament reconstruction.