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 61 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 mode-is that had a transected central slip. Thus there was I 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. (Copyright (C) 2003 by the American Society for Surgery of the Hand.)