Abstract
We investigated the accuracy of radiography and computed tomography in the diagnosis of distal radio-ulnar joint (DRUJ) congruity in 10 healthy hands and 84 rheumatoid hands. Operated-on joints were excluded from this series. The CT study of DRUJ was done in positions of 90°, 70°, 45°, 20° and 0° in pronation and supination of the forearm. The radiographic study was done of the lateral view of the wrist with the forearm in neutral rotation, and of the P -A view with the forearm in full pronation. The evaluation was done with Mino's and Snook's criteria. All computed tomograms showed good congruity in the 10 healthy hands, so we evaluated radiograms using these results. In healthy hands, the accuracy of the lateral radiograms was 60% and of the P-A view ones' 80%. In the computed tomograms, good congruity was noted in 29 joints, subluxation in 57 joints and dislocation in no joints in 84 rheumatoid hands clinically diagnosed as having DRUJ incongruity, The accuracy of the lateral view radiograms was 60.5% and of the P-A view ones' 35.7%. Evaluation of the P-A view radiogram was impossible in 18.9% due to bony destruction of the ulnar styloid process in RA. In the lateral view radiograms of 23 joints which showed subluxation in natural rotation by computed tomography, subluxation was noted in 11 joints, good congruity in 8 joints and dislocation in 4 joints.
This study suggests that as the radiographic evaluation of DRUJ incongruity is difficult in rheumatoid hands because of severe bony and articular destruction, computed tomography is necessary for the diagnosis of DRUJ subluxation.
