Reliability of the Dorsal Tangential View in Assessment of Distal Radioulnar Joint Reduction in the Neutral, Pronated, and Supinated Positions in a Cadaver Model

Abstract

Intraoperative assessment of distal radioulnar joint (DRUJ) alignment is often based on lateral radiographs whose interpretation is dependent upon positioning the forearm in neutral rotation. The dorsal tangential view (DTV) is a near-axial view of the dorsal wrist used in assessing dorsal screw penetration during radius fixation. The purpose of this study was to determine whether the DTV can also reliably assess DRUJ alignment in multiple forearm positions. Four transhumeral cadaveric specimens were used to simulate an unstable DRUJ. The stabilizing soft tissue structures of the DRUJ were sectioned. Fluoroscopic DTV images were obtained with the DRUJ of each specimen held in 5 positions: dorsally dislocated, dorsally subluxated, reduced, volarly subluxated, and volarly dislocated. In each position, images were taken with the forearm in neutral rotation, full pronation, and full supination. Three observers independently assessed DRUJ position on DTV images. Intra- and interobserver reliability were assessed in each forearm position. Observers correctly identified DRUJ position as reduced, volarly malreduced, or dorsally malreduced on 94% of the DTV images (97%, 95%, and 92% in the neutral, supinated, and pronated forearm positions, respectively). Weighted kappa values for intraobserver reliability were 0.965, 0.964, and 0.965 for the 3 observers. The mean kappas for intraobserver reliability were 1.000, 0.967, and 0.930 with the forearm in neutral, supinated, and pronated positions, respectively. Weighted kappa values for interobserver reliability between paired observers were 0.948, 0.912, and 0.929. The mean kappa for interobserver reliability was 0.926, 0.931, and 0.930 for the forearm in neutral, supinated, and pronated positions, respectively. The DTV reliably demonstrated the position of the DRUJ independent of forearm rotation in a cadaveric model. Surgeons may consider the DTV as another tool for fluoroscopic verification of the DRUJ reduction in the operating room or clinic.