The scapholunate allograft: a biomechanical feasibility study.

The feasibility of a new method for reconstruction of the isolated scapholunate ligament tear with a scapholunate allograft was studied biomechanically using a fresh cadaver upper extremity model. Seven specimens were first tested intact for wrist range of motion, contact characteristics of the radiocarpal articulation, and relative motion of the scaphoid with respect to the lunate. Then a segment consisting of the radial third of the lunate, the adjoining scapholunate interosseus ligament, and the proximal pole of the scaphoid was resected. This segment was matched to a donor allograft of similar size and geometry, which was then placed into the recipient carpus and secured with one central transverse Kirschner wire and two shorter interfragmentary Kirschner wires placed into the lunate and scaphoid. The allografted specimen was subjected to the same tests as the intact wrist. Results showed that there were no significant differences in wrist range of motion, radiocarpal articular surface contact area and pressure, and relative flexion-extension rotation between the scaphoid and lunate during passive radioulnar deviation between the intact and allografted wrists.