ABSTRACT
PURPOSE: To test the ability of ultrasound to diagnose clinically suspected occult scaphoid fractures. METHODS: Eighteen wrists in 18 patients with an average age of 35 years (range, 10-77 years) were seen in the emergency room, each with a single traumatic wrist injury, snuffbox tenderness, swelling, and a negative wrist x-ray result. They were evaluated in this prospective, blind, controlled study by physical examination, x-ray, and high-resolution ultrasound. One hand surgeon performed the examination, and ultrasounds were read by a musculoskeletal radiologist. Patients were immobilized in a thumb spica splint and then seen in the office 1 to 14 days after the emergency room visit, at which time a repeat physical examination, wrist x-ray, and the single investigative ultrasound were done using the opposite wrist as a control. All patients were immobilized and evaluated until symptoms resolved or x-ray showed scaphoid fracture site resorption or callus, in which case they were kept immobilized until healed. RESULTS: Ultrasound identified correctly 7 of 9 cases that were eventually positive for scaphoid fracture on plain x-ray. Ultrasound was read correctly as negative in 8 of 9 x-ray-negative cases; this was statistically significant. The 1 false-positive case had radioscaphoid arthrosis and radial wrist swelling. Sensitivity was 78% and specificity was 89%. The positive predictive value was 88% and negative predictive value was 80%. CONCLUSIONS: We recommend that high-frequency ultrasound be used to investigate occult suspected scaphoid fractures because of its ability to allow early diagnosis and to eliminate the need for a more invasive or expensive diagnostic test in most cases.
