Ultrasound Imaging Improves Identification of Prominent Hardware in the Surgical Treatment of Distal Radius Fractures: A Cadaveric and Prospective Clinical Study

Abstract

Background Volarly applied locking plates are one of several current treatment options for displaced fractures of the distal radius. Presently, surgeons use intraoperative depth gauges and fluoroscopy to select and confirm proper screw length. The contour of the dorsal cortex beneath the extensor compartments along with fracture comminution may limit the accuracy of screw length selection. Question/Purpose To evaluate the accuracy of ultrasound (US) and fluoroscopy in the detection of dorsally prominent screws placed during volar plating of experimentally created distal radius fractures and extend this prospectively into the clinical setting. Patients and Methods Distal radius fractures were experimentally induced in fresh cadaveric arms. The fractures were then internally fixated with volar locking plates utilizing fluoroscopic imaging. US imaging of the dorsal surface of the radius was then performed followed by dorsal dissection and direct caliper measurements to quantitate screw tips as recessed, flush, or protruding from the dorsal cortex. A small, prospective clinical study was also conducted to validate the clinical usefulness of using US to provide additional information regarding screw tip prominence. Results Our study demonstrated that US was able to detect dorsally prominent screw tips not visible on fluoroscopy. Cadaveric dissection showed a higher statistical correlation between US imaging and actual prominence than between fluoroscopy and actual prominence. Conclusions US examination after volar plate fixation of comminuted distal radius fractures may detect dorsal screw tip prominence when screw lengths are selected to engage the dorsal cortex. Level of Evidence IV.

Keywords: distal radius; fluoroscopy; fracture; ultrasound; volar plate.

Fig. 1

(A) Lateral radiograph at presentation with no evidence of screw tip prominence. (B) Dorsal ultrasound of wrist demonstrating screw prominence; arrow identifies stair-step appearance of screw threads into fourth dorsal compartment. (C) Intraoperative picture of extensor digitorum communis fraying. (D) Prominent screw projecting into fourth dorsal compartment.

Fig. 2

(A) FOOSH simulator device. (B) Experimentally created distal radius fracture.

Fig. 3

Right DVR plate with labeled holes. Numbers of screws in the cadaveric specimens found prominent on US and dissection but missed by fluoroscopy are in parenthesis. In the clinical portion, prominent screws were found in P2, P3, and D4.

Fig. 4

(A) Lateral fluoroscopic image with red arrow at tip of screw and dashed line showing dorsal cortex. Screw tip appears safely within bone and below the cortex. (B) Ultrasound image of same wrist showing the bright stair-step echogenic reflection of the screw protruding into soft tissue. Ultrasound measurement (yellow arrows) demonstrated 1.62-mm prominence (right arrow points to tip of screw, dotted yellow line is best estimation of dorsal cortex by ultrasound). (C) Actual dissection showing tip of screw (black arrow). Screw protrudes into the extensor carpi radialis longus and brevis tendons 2.1 mm.