Carpal bone dislocations: an analysis of twenty cases with relative emphasis on the role of crushing mechanisms.

Twenty cases of carpal bone dislocation were encountered during a 7-year period, with an average of 27 months of follow-up. There were ten types of dislocation in this series; the most common type was transscaphoid perilunate dislocation which was seen in nine cases. In addition, there were two scaphoid subluxations; one volar lunate dislocation; one dorsal perilunate dislocation; one scaphoid perilunate dislocation; one hamate and pisiform dislocation; one transhamate pisiform dislocation; one trapezoid dislocation with dislocation of carpometacarpal joints two to five; one dislocation of the trapezium, trapezoid, and carpometacarpal joints two to four; and two trapezium periscapholunate dislocations. Methods of treatment included open reduction, closed reduction, proximal row carpectomy, total wrist arthrodesis, and excision of the lunate. In this series, the patterns of dislocation were different for crushing injuries and dorsiflexion injuries. The clinical results associated with the soft-tissue injuries of the ipsilateral hand were mostly caused by crushing forces. Although carpal instabilities were noted, there was no significant correlation between the clinical and roentgenographic results in some of our cases. Best results invariably relied on a stable anatomic reduction and an adequate period of immobilization. Poor results were demonstrated in the cases with incomplete initial reduction, secondary degenerative arthrosis, or nonunion.