Distal radio-ulnar ligament motion during supination and pronation.

The dorsal and palmar distal radio-ulnar ligaments (DRUL) play an important role in the stability of the distal radio-ulnar joint (DRUJ). Various authorities, however, hold opposite opinions regarding DRUL motion during DRUJ pronation and supination, thus implying opposite techniques for reconstruction of the unstable DRUJ. With the hypothesis that relative displacement would increase in the dorsal DRUL during pronation and would increase in the palmar DRUL during supination, measurements were made of the relative DRUL displacement with a Hall-effect displacement transducer during DRUJ pronation and supination in six fresh cadaver wrists. The hypothesis was confirmed that the dorsal radio-ulnar ligament undergoes relative displacement during pronation, while the palmar radio-ulnar ligament undergoes relative displacement during supination.