MECHANICAL EVALUATION OF THE SCAPHOID SHIFT TEST

Manipulative examination of the carpal bones is an important facet of the examination of the wrist. Abnormal translation of portions of the carpus in response to applied force is a commonly used clinical indica tor of ligament injury. Unilateral scaphoid hypermobility during the s o-called scaphoid shift test is felt to represent traumatic instabilit y, especially in the context of wrist injury. The test, however, is su bjective, and requires considerable experience to correlate the degree of scaphoid mobility with pathologic significance. We used an instrum ent that quantifies the load-displacement behavior of the scaphoid and its supporting ligaments during application of a dorsally directed lo ad at the scaphoid tubercle. We evaluated 18 uninjured (normal) wrists with clinical ligament examination and with mechanical testing. Subje cts who exhibited a positive scaphoid shift had significantly increase d displacement and significantly decreased stiffness when compared wit h subjects who did not have a shift.