IS INTRASOUND VIBRATION USEFUL IN THE DIAGNOSIS OF OCCULT SCAPHOID FRACTURES

This study was designed to confirm the results of Finkenberg et al. (J Hand Surg 1993;18A: 4-7), who found a high sensitivity (100%) and spe cificity (95%) of the intrasound vibration method in diagnosing occult scaphoid fractures. These occult scaphoid fractures are not visible o n x-ray films, but clinically the patients are suspected of having a s caphoid fracture. A vibratory apparatus is placed over the anatomical snuff-box and a vibration of 100 mW is emitted; a painful sensation is produced if the scaphoid is fractured. Thirty-seven consecutive patie nts with a clinically suspected scaphoid fracture were evaluated. In 6 patients, a scaphoid fracture was radiographically identified; in the remaining 31 patients, a 3-phase bone scan was obtained. Eleven wrist s showed increased uptake over the scaphoid and were considered to hav e an occult scaphoid fracture. In this group, bone scintigraphy was us ed as the reference standard. The vibration test was painful in 1 of 6 patients with a proven scaphoid fracture and in 3 of the 11 patients with a positive bone scan. In contrast to the results of Finkenberg et al, the intrasound vibration method shows a sensitivity of 24%, a spe cificity of 85%, a positive predictive value of 40%, and a negative pr edictive value of 65%. We conclude that the accuracy of intrasound vib ration is low and that it is not useful in the diagnosis of scaphoid f ractures. Copyright (C) 1998 by the American Society for Surgery of th e Hand.