The in-vivo effect of orthotics on the kinematics of the thumb joints

The influence of orthotics on the kinematics of the trapeziometacarpal (TMC) and scaphotrapeziotrapezoidal (STT) joints during thumb and wrist movement were measured in healthy volunteers using a CT-based approach. Comparison of different types of orthoses show that prefabricated orthoses immobilize less than custom-made orthoses. This difference might be due to the different locations of the orthoses trim lines, material properties and goodness of fit. The study also shows that wrist radioulnar deviation causes larger movements at the STT joint compared to wrist flexion-extension.