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.

The results of revision carpal tunnel release following previous open versus endoscopic surgery.

This study compared the outcomes of revision open carpal tunnel release following previous open versus endoscopic release to determine whether revision surgery has different results based on the type of initial surgical treatment. Thirty revision carpal tunnel releases were performed in 13 wrists that had previous endoscopic release and in 17 wrists with prior open release. At a follow-up visit an average of 30 months after surgery, self-assessment questionnaires demonstrated improved or complete symptom relief in 77% of the postendoscopic release group versus 47% in the previous open release group. Combining both groups, 18% of workers' compensation patients improved after revision surgery compared with 84% of those with conventional insurance (p < .05). Patients having persistent or recurrent symptoms following a previous endoscopic carpal tunnel release have a greater chance of symptom improvement or resolution compared with patients who had previous open carpal tunnel surgery. Our results support the observation that a higher incidence of incomplete release of the carpal tunnel is found with endoscopic surgery than with open release.