Abstract
The distal radioulnar joint (DRUJ) is a substantially unstable joint, and the dorsal and palmar radioulnar ligaments (RUL) are considered to play an important role for the stability. We investigated six cases of acute or subacute DRUJ instability. All were males which age ranged from 15 to 44 years (average: 23 years). Instability was examined using manual test, lateral X-ray of the wrist, and computed tomography (CT) including radio-ulnar line method and congruity method. Accompanied bone injuries were one Galeazzi fracture-dislocation, one perilunate transscaphoid fracture-dislocation, five ulnar styloid fractures, and one ulnar styloid non-union.
Soft tissue injuries were variable: there were two lacerations between dorsal RUL and dorsal DRUJ capsule, two TFCC dorsal tears, two avulsions of RUL from the fovea, one laceration of dorsal DRUJ capsule, one tear of dorsal RUL, and one palmar dislocation of extensor carpi ulnaris tendon. There were two patterns of ulnar head instability. One was straightforward instability to the dorsal and the other was external rotational instability. Diagnosis using only the radio-ulnar line method is sometimes unreliable, thus total judgement including manual test, roentogenography, and congruity method in CT is necessary.
