Does the normal contralateral wrist provide the best reference for X-ray film measurements of the pathologic wrist?

This study compares in normal subjects the variability of wrist x-ray film measurements between the right and left sides with the variability of the distribution of those measurements within the population. Additional purposes were to evaluate possible differences of these measurements according to sex, age, side, and hand dominance. The variability when comparing both sides was found to be statistically less for the carpal height, radiolunate, scapholunate, and capitolunate angles than within the whole group of subjects, and for those measurements, there was a high correlation (r > .88) between the right and left sides. In addition, the carpal height and the carporadial ratios were lower and the capitolunate angle was higher in women than in men. There was also a significant decrease of the scapholunate angle in older individuals. The clinical implication of these findings is that in unilateral wrist diseases, the normal wrist should be used to provide the reference values of the carpal height and of the carpal angles on profile x-ray films. However, for the radial inclination and palmar tilt of the distal radius and for the ulnar variance, the normal side does not provide a better reference than normal values obtained from databases.