The 70° Supinated Oblique View: A Cadaveric Analysis to Determine Ideal Radial Styloid Screw Position in Locked Volar Plating of Distal Radius Fractures

Abstract

Background: Defining an intraoperative radiographic view to best determine the radial styloid screw position in locked volar plating of distal radius fractures may improve fixation and aid in decreasing cortical penetration and implant complication. We used a cadaveric model to demonstrate a reproducible, oblique radiographic view to identify the radial styloid screw position. Methods: Nine fresh-frozen elbow-to-fingertip cadavers were used for this study. A 2.4-mm variable angle volar distal radius locking plate was applied to the distal radius. A Kirschner wire (K-wire) was inserted into the radial styloid through the plate. Placement of the K-wire through the tip of the styloid at the cortical edge was confirmed through a separate radial incision. A second K-wire was placed through the radius shaft into the ulna to aid in angular measurements. Live fluoroscopic imaging was used as the forearm was brought from full 90° of supination toward neutral. Once the K-wire was abutting the cortical edge, rotation ceased, and a goniometer was used to measure the angle of forearm rotation. This was repeated for a total of 3 repetitions on each specimen. Results: The average angle of supination best depicting the position of the radial styloid screw was 68.5° (range = 64.3°-70.5°). Conclusions: Radial styloid screw fixation in locked volar plating of distal radius fractures increases the ultimate strength to failure, but screw penetration and tendon irritation can occur. The 70° supinated oblique intraoperative view provides the most accurate evaluation of the position of the radial styloid screw.