Three-dimensional computed tomography evaluation of the ulnocarpal joint under stress loading

We investigated which stress position of the wrist would result in the most significant reduction in the ulnocarpal distance using three-dimensional computed tomography (3DCT) images. 3DCT scans of 10 normal individuals and 19 patients with ulnar impaction syndrome were taken in neutral, radial/ulnar deviation and weightbearing pronation/supination wrist positions, and the shortest ulnolunate and ulnotriquetral distances were evaluated separately in each position. Both the ulnolunate and the ulnotriquetral distances were shortest in the weightbearing supination position in all participants. The ulnolunate distance was significantly decreased ( p = 0.00) in the weightbearing supination position compared with the neutral position in the ulnar impaction syndrome (UIS) group. However, the change in ulnotriquetral distance did not differ between the normal group and the UIS group. This study demonstrated that supination may be more vulnerable than pronation to UIS.Level of evidence:IV