Abstract
Background
A challenge to obtaining proper glenoid placement in total shoulder arthroplasty is eccentric posterior bone loss and associated glenoid retroversion. This bone loss can lead to poor stability and perforation of the glenoid during arthroplasty. The purpose of this study was to evaluate the three dimensional morphology of the glenoid with associated bone loss for a spectrum of osteoarthritis patients using 3-D computed tomography imaging and simulation software.
Methods
This study included 29 patients with advanced glenohumeral osteoarthritis treated with shoulder arthroplasty. Three-dimensional (3D) reconstruction of preoperative CT images was performed using image analysis software. Glenoid bone loss was measured at ten, vertically equidistant axial planes along the glenoid surface at four distinct anterior-posterior points on each plane for a total of 40 measurements per glenoid. The glenoid images were also fitted with a modeled pegged glenoid implant to predict glenoid perforation.
Results
The average bone loss was greatest posteriorly in the AP plane at the central axis of the glenoid in the SI plane. Walch A2 and B1 shoulders had bone loss more centrally located, while Walch B2 shoulders displayed more posterior and inferior bone loss. There was a significant difference in the overall average bone loss for patients with no predicted peg perforation compared to patients predicted to have peg perforation (p=0.37). Peg perforation was most common in Walch B2 shoulders, in the posterior direction, and involved the central and posterior-inferior peg.
Discussion
These data demonstrate a clear, anatomical pattern of glenoid bone loss for different classes of glenohumeral arthritis. These findings can be used to develop various models of glenoid bone loss to guide surgeons, predict failures, and help develop better glenoid implant.
