Stress computed tomography analysis of the distal radioulnar joint: a diagnostic tool for determining translational motion.

Sixteen distal radioulnar joints in eight normal volunteers (five females, three males) were evaluated by use of a special stress computed tomography technique. The mean palmar and dorsal translational motion was 2.2 millimeters +/- 1.6 and 1.0 millimeters +/- 0.9, respectively, for the combined group. The mean stress range was 3.3 millimeters +/- 1.4 for the entire group. There was no statistical difference for the amount of motion noted on palmar stress, dorsal stress, and the stress-range between males and females. There was also no statistical difference between contralateral sides and hand dominance. The average contralateral difference was 0.1 millimeters, 0.1 millimeters, and 0.3 millimeters for palmar, no stress, dorsal studies, respectively. We conclude the limits of maximal translational motion of the distal radioulnar joints can be determined by computed tomography stress analysis. Unilateral analysis allows the determination of frank instability. However, bilateral analysis allows the determination of frank instability, subluxation, and dynamic instability. This technique is useful in evaluating distal radioulnar joint stability.