Strains in the articular disk of the triangular fibrocartilage complex: a biomechanical study.

The articular disk of the triangular fibrocartilage complex was studied using a video imaging system in a cadaveric laboratory experiment. Changes in disk configuration consistently occurred during pronation and supination and resulted in a nonuniform strain distribution that was dependent upon forearm position. Strains occurred primarily in the radioulnar axis of the disk, with dorsoanterior strains being negligible. Strains were concentrated in the radial portion of the disk and were highest with the forearm pronated. Application of a distraction load to the distal radioulnar joint to simulate the effect of axial wrist loading caused strains to increase the most in the radial portion. These findings suggest that joint distraction loading and forearm pronation are important components of the injury mechanism for the most common type of traumatic tear that occurs near the radial attachment of the disk.