Quantitative 3-dimensional Computerized Tomography Modeling of Isolated Greater Tuberosity Fractures with and without Shoulder Dislocation

Abstract

Background: The aim of this study was to assess differences in fracture morphology and displacement between<br />isolated greater tuberosity (GT) fractures (i.e. fractures of the greater tuberosity without other fractures of the proximal<br />humerus) with and without shoulder dislocation utilizing quantitative 3-dimensional CT imaging.<br />Methods: Thirty-four CT-scans of isolated greater tuberosity fractures were measured with 3-dimensional modeling.<br />Twenty patients (59%) had concomitant dislocation of the shoulder that was reduced prior to CT-scanning. We<br />measured: degree and direction of GT displacement, size of the main fracture fragment, the number of fracture<br />fragments, and overlap of the GT fracture fragment over the intact proximal humerus.<br />Results: We found: (1) more overlap –over the intact humerus– in patients without concomitant shoulder dislocation<br />as compared to those with shoulder dislocation (P=0.03), (2) there was a trend towards greater magnitude of<br />displacement between those without (mean 19mm) and those with (mean 11mm) a concomitant shoulder dislocation<br />(P=0.07), and (3) fractures were comparable in direction of displacement (P=0.50) and size of the fracture fragment<br />(P=0.53).<br />Conclusion: We found substantial variation in degree and direction of displacement of GT fracture fragments. Variation<br />in degree of overlap and displacement is partially explained by concomitant shoulder dislocation.<br />Level of evidence: IV