CARPAL BONE DISLOCATIONS - AN ANALYSIS OF 20 CASES WITH RELATIVE EMPHASIS ON THE ROLE OF CRUSHING MECHANISMS

Twenty cases of carpal bone dislocation were encountered during a 7-ye ar period, with an average of 27 months of follow-up. There were ten t ypes of dislocation in this series; the most common type was transscap hoid perilunate dislocation which was seen in nine cases. In addition, there were two scaphoid subluxations; one volar lunate dislocation; o ne dorsal perilunate dislocation; one scaphoid perilunate dislocation; one hamate and pisiform dislocation; one transhamate pisiform disloca tion; one trapezoid dislocation with dislocation of carpometacarpal jo ints two to five; one dislocation of the trapezium, trapezoid, and car pometacarpal joints two to four; and two trapezium periscapholunate di slocations. Methods of treatment included open reduction, closed reduc tion, proximal row carpectomy, total wrist arthrodesis, and excision o f the lunate. In this series, the patterns of dislocation were differe nt for crushing injuries and dorsiflexion injuries. The clinical resul ts associated with the soft-tissue injuries of the ipsilateral hand we re mostly caused by crushing forces. Although carpal instabilities wer e noted, there was no significant correlation between the clinical and roentgenographic results in some of our cases. Best results invariabl y relied on a stable anatomic reduction and an adequate period of immo bilization. Poor results were demonstrated in the cases with incomplet e initial reduction, secondary degenerative arthrosis, or nonunion.