Assessment of instability factors in adult distal radius fractures.

BACKGROUND: The purpose of this study was to evaluate the radiographic outcome of unstable distal radius fractures treated by closed reduction and sugar tong splinting and to quantitatively evaluate Lafontaines' criteria of instability. METHODS: Fifty patients with 3 or more instability factors as described by Lafontaine were treated by finger trap traction, closed reduction, and sugar-tong splinting. They were evaluated radiographically for initial angulation, radial inclination, radial length, and palmar tilt at the time of injury, after reduction, and 1 week, 2 weeks, and 4 weeks after reduction. The fracture either maintained an adequate reduction or failed to maintain an adequate reduction and showed secondary displacement based on specific criteria. RESULTS: At 4 weeks after reduction 46% of these unstable distal radius fractures maintained an adequate reduction. Of the 54% of fractures that failed to maintain an adequate reduction, age was the only statistically significant predictor of secondary displacement. After obtaining an acceptable initial closed reduction, patients 58 years of age were found to be at 50% risk for secondary displacement. The risk for displacement with an unacceptable radiographic result was found to increase with increasing age and decrease with decreasing age. CONCLUSION: In the closed management of these potentially unstable distal radius fractures, age was the only statistically significant risk factor in predicting secondary displacement and instability. These data help guide treatment by closed reduction and immobilization with serial x-rays or by surgical stabilization.

Ultrasound for the early diagnosis of clinically suspected scaphoid fracture.

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.

Ultrasound visualization of central slip injuries of the finger extensor mechanism.

PURPOSE: To evaluate the ability of ultrasound to detect a central tear of the finger extensor tendon mechanism. METHODS: Twelve fresh-frozen and thawed cadaver fingers were used. All fingers had a midradial incision with exposure of the extensor mechanism over the proximal interphalangeal joint. Six fingers had a sharp transection of the central slip. The other 6 fingers were used as sham dissection controls. All fingers had the exposure closed by suture and then were examined by a musculoskeletal ultrasonographer. RESULTS: All 12 fingers were identified correctly as either sham controls with intact central slips or as injury models that had a transected central slip. Thus there was a sensitivity of 100% a specificity of 100%, and a positive predictive value of 1.000, which were statistically significant. CONCLUSIONS: Diagnostic ultrasound is a very accurate noninvasive study that can identify central slip injuries in the extensor mechanism of the finger. We recommend that clinically suspected cases of boutonniere injury be scanned by high-frequency ultrasound to confirm the diagnosis and allow either early initiation of splinting or eliminate the need for prolonged splinting required for this injury.