Assessment of distal radioulnar joint stability in healthy subjects: Changes with dominant hand, sex, and age.

This study aimed to elucidate the differences in distal radioulnar stability in dominant/nondominant hand, sex, and age. Bilateral wrists of 60 healthy subjects were evaluated using force-monitoring ultrasonography. This apparatus was developed to apply cyclic compression and measure applied force to displacement during an ultrasound exam. The transducer was placed on the dorsal side of the distal radioulnar joint, and the center of the ulnar head was displayed on the monitor. The distance between the dorsal surface of the distal radius and the ulnar head was measured at an initial and at a pressed-down position. The radioulnar displacement, applied force to displacement, and displacement-to-force ratio were evaluated. The results were compared between the dominant and nondominant hands, and between males and females, and among different age groups. There were no significant differences in the parameters between the dominant and nondominant hands. The applied force to displacement was significantly greater in the male group compared with the female group. There were significant effects for the different age groups in all parameters (displacement: F = 3.67, p = .008; applied-force: F = 3.08, p = .019; displacement-to-force ratio: F = 4.66, p = .002). Our results indicated that the stability of distal radioulnar joint differed depending on age and sex. Age and sex should be considered when assessing distal radioulnar joint stability.