The effect of wrist guards on bone strain in the distal forearm.

There are increasing epidemiologic and biomechanical data suggesting that wrist guards are effective in preventing wrist injuries in snowboarders and in-line skaters. However, there have been few studies designed to determine how they function. In this study we explored the load-sharing function of wrist guards at subfailure loading levels. To do so, we measured bone strain in the distal radius, distal ulna, and midshaft of the radius in cadaveric forearms with and without two types of commercially available wrist guards. We also measured construct stiffness and energy absorption during testing. Our most significant findings were that dorsal and volar distal radius bone strain were reduced with both wrist guards, and wrist guards increased energy absorption. We also found a reduction in dorsal distal ulnar bone strain, but only with the one guard in which the volar plate was elevated off the heel of the hand. In our loading configuration, wrist guards did not increase bone strain at the radial midshaft. These findings provide insight into how wrist guards protect the wrist: during low-energy falls they function partly by load-sharing, as well as by absorbing impact energy.