Biomechanical analysis of the stability of the distal radioulnar joint

Objective To assess the stabilization structures of the distal radioulnar joint (DRUJ) from biomechanical point of view, and evaluate their role in stability of the joint and in forearm movement. Methods 8 fresh cadaver upper extremities were fixed in a custom-made jig which holds the limb rigidly and yet allows forearm rotation. The major stabilization structures of DRUJ were resected step by step, and biomechenical assessment was done. Results After resection of anterior half segment in the horizontal part of the triangular fibrocartilage complex (TFCC), DRUJ was unstable in supination position. After resection of posterior half segment in the horizontal part of TFCC, DRUJ was unstable in pronation. After resection of entire horizontal part of TFCC and the distal interosseous membrane, DRUJ was unstable in every position. Conclusions Stability of DRUJ relies mainly on the horizontal portion of TFCC and the distal interosseous membrane. The dorsal radioulnar ligament (DRUL) was more important than the palmer radioulnar ligament (PRUL) in maintaining DRUJ stability in full pronation, while the PRUL was more important than the DRUL in full supination.