JSES - 2026-04-09 - Journal Article
Three-Dimensional Characterization of Glenoid Defects in Failed Shoulder Arthroplasties.
Christy KB, Zitnay JL, Zhang C, Kirkham MS, King PL, Hardy BJ, Presson AP, Joyce CD, Chalmers PN, Henninger HB, Tashjian RZ
Topics
Key Takeaway
3D CT analysis of 100 failed shoulder arthroplasties identified two distinct glenoid defect clusters differing significantly in 6 morphologic parameters, with Cluster A showing greater height, thickness, retroversion, and smaller radii of curvature than Cluster B.
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Summary
This study 3D-reconstructed CT scans of 100 patients undergoing revision to rTSA and 35 cadaveric control scapulae to characterize glenoid vault defect morphology. Cluster analysis using 9 principal measures of size, angulation, and curvature identified two distinct morphologic clusters with statistically significant differences in 6 parameters including height, retroversion, maximum projection thickness, and radius of curvature. The revision group demonstrated substantially greater morphologic variability than controls, suggesting current single-design revision implant strategies may be inadequate.
Key Limitation
Cluster analysis was performed without correlation to index arthroplasty type, failure mechanism, or prior surgical history, making it impossible to determine whether the two clusters represent distinct failure pathways or simply a spectrum of the same process.
Original Abstract
BACKGROUND
Glenoid vault defects are often observed in revision shoulder arthroplasty, and improper management of glenoid bone loss during revision to reverse total shoulder arthroplasty (rTSA) increases the risk of complications. However, there is limited understanding of the types of glenoid vault defects that occur in patients. Therefore, the purpose of this study was to three-dimensionally characterize the underlying glenoid morphology of patients with failed shoulder arthroplasties subsequently undergoing revision arthroplasty to rTSA.
METHODS
Computed tomography scans of 100 patients pre-operative to revision arthroplasty to rTSA (Revision Group) and 35 healthy cadaveric control scapulae (Control Group) were three-dimensionally reconstructed. A negative projection glenoid vault was created and residual screw or peg holes were removed and smoothed. Glenoid defects were quantified using various size, area, volume, and geometric measures of the negative projection and the glenoid. A cluster analysis was performed on the Revision Group to group patients based on glenoid shape and find patterns in the underlying glenoid morphology using principal measures: normalized distance (height; width; maximum projection thickness; smoothed maximum residual vault thickness), angular (anterior tilt; inclination; version), and radius of curvature (ROC) (superior-inferior ROC; anterior-posterior ROC; vault-sphere ROC).
RESULTS
When compared to the Control Group, the measures of the Revision Group showed more variation with higher standard deviations. The cluster analysis formed two clusters, between which 6 of the principal measures had statistically significant differences. Of the principal measures, Cluster A had larger height and maximum projection thickness, more retroversion, and smaller ROCs when compared to Cluster B. Of the other measurements, projection volume, lateral surface area, circumferential surface area, and height-width ratio were larger in Cluster A than in Cluster B.
CONCLUSIONS
Glenoid morphology after failed arthroplasty is highly variable and may require novel defect management strategies. Additionally, the formation of clusters based on glenoid morphology indicates that patterns exist in the types of glenoid defects, highlighting a need to further investigate a three-dimensional classification system and potentially new standardized revision implant component designs for revision to rTSA cases.