Comparison of radiographic stress views for scapholunate dynamic instability in a cadaver model.

Overview

PURPOSE: Many different stress views for the diagnosis of scapholunate (SL) instability have been described in the literature. The purpose of this study is to compare these stress views and determine which view has the greatest utility for demonstrating SL gap radiographically. METHODS: We performed a literature search for articles describing SL radiographic stress views. We created SL instability in 9 cadaveric wrists by ligamentous sectioning and imaged each specimen using all radiographic views found in the literature. These included the "clenched pencil" view, clenched fist views in varying positions, and traction views. Scapholunate gaps were measured using digital calipers. RESULTS: We found 8 different SL radiographic stress views specifically described in the literature. In order to further characterize the best stress views, we studied additional parameters, including varied ulnar deviation and degree of obliquity. The clenched pencil view resulted in the most consistent views with the widest SL gaps. With clenched fist views, SL gap trended to a peak at 30° of ulnar deviation. CONCLUSIONS: The clenched pencil view was the best stress view to demonstrate dynamic SL instability. It also allows for a contralateral comparison on 1 radiograph. We recommend this view when evaluating for SL pathology. CLINICAL RELEVANCE: This assessment of relative diagnostic utility might assist clinicians in the creation and use of protocols for the diagnosis of dynamic SL instability.