The effect of common wrist orthoses on the stiffness of wrist rotations.

Wrist orthoses (also known as splints, braces, or supports) are commonly used to support or restrict the motion of a weak or injured wrist. These orthoses generally function by stiffening the wrist joint. Therefore, choosing the proper orthosis (or improving orthoses) requires that we understand their stiffness properties. In this study, we present a method for measuring the stiffness of wrist orthoses, and we apply this method to 12 of the most common wrist orthoses. We found similarities and differences between these orthoses, indicating that different orthoses have different effects on the wrist joint and, presumably, on wrist behavior. In particular, all six orthoses with a stay on the volar side or the volar and dorsal sides added a significant amount of stiffness to the wrist joint. In contrast, only one of three orthoses with a stay on the dorsal side and none of the three orthoses without stays exhibited a significant amount of stiffness, calling into question their ability to support the wrist joint. This work lays a foundation for future studies investigating the effect of wrist orthosis stiffness on wrist behavior and how wrist orthosis stiffness can be designed to produce behavior that facilitates healing.