Augmented glenoid component designs for type B2 erosions: A computational comparison by volume of bone removal and quality of remaining bone
Journal of Shoulder and Elbow Surgery
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© 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. Background: The purpose of this computational modeling study was to compare the volume of glenoid bone removal required to implant 3 augmented component designs for management of B2 erosions. In addition, we assessed bone quality of the supporting bone directly beneath the implants by measuring bone density and porosity. Methods: Three augmented component designs-full-wedge, posterior-wedge, and posterior-step-were studied by virtual implantation in a cohort of 16 patients with B2 glenoids. B2 retroversion was corrected to 0° and 10°. The outcome variables were the volume of glenoid bone removal required for implantation and the density and porosity of the bone immediately beneath the implant. Results: Implant design had a significant effect on the volume of bone removal (P<.001). When correcting to 0°, the posterior-wedge implant removed less bone than the posterior-step (P<.001) and the full-wedge (P=.004). At 10° retroversion, the posterior-wedge removed less bone (P=.029) than the posterior-step but was no different than the full-wedge (P=.143). The residual glenoid bone density with the posterior-wedge was significantly greater than with the posterior-step (P=.048), with no other significant differences (P>.05). Residual glenoid bone porosity was not significantly different between implants (P>.262). Conclusions: Augmented components can provide a bone-preserving option for B2 glenoid management. Substantial variations in the volume of bone removal and the quality of the remaining glenoid bone were found between 3 different designs of augmented implants. Simulations with the posterior-wedge implant resulted in substantially less glenoid bone removal, with the remaining supporting bone being of better quality.