DIAGNOSIS OF OCCULT SCAPHOID FRACTURES BY INTRASOUND VIBRATION

We investigated a new means of diagnosing occult scaphoid fractures. Eighty-six patients underwent vibratory testing at presentation, while the clinical examination and standard four-view x-ray examination findings were unknown to the persons who performed the vibratory testing of both the injured and uninjured wrists. Thirty-six patients had radiographically confirmed scaphoid fractures and, after their vibratory tests, were eliminated from the study. Fifty patients, 39 men and 11 women, were believed to have scaphoid fractures on the basis of history and clinical examination findings but were included in the occult scaphoid study group because standard four-view x-ray films of the wrists did not reveal a scaphoid fracture. Distinction between the fracture and no-fracture patients was made with a limited two-phase technetium bone scan and delayed x-ray examination. All patients with known scaphoid fractures (36) had positive findings on vibratory examination. Vibratory testing identified all six of the patients with occult scaphoid fractures (sensitivity 100%). Results of two examinations were false-positive, and none were false-negative (specificity 95%). One of the patients with false-positive results had a fracture of the trapezium, and the other had reflex sympathetic dystrophy. The vibratory testing of injured wrists is inexpensive, noninvasive, and easy to perform, and it involves no ionizing radiation.