title: Augmented glenoid component designs for type B2 erosions: a computational comparison by volume of bone removal and quality of remaining bone.
abstract: 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.
authors: Roth|McFarlane Hand and Upper Limb Centre, Bioengineering Laboratory, St. Joseph's Health Care, London, ON, Canada; Department of Mechanical and Materials Engineering, University of Western Ontario, London, ON, Canada.
authors: Nikolas K
authors: NK
authors: Knowles
authors: Roth|McFarlane Hand and Upper Limb Centre, Bioengineering Laboratory, St. Joseph's Health Care, London, ON, Canada; Department of Mechanical and Materials Engineering, University of Western Ontario, London, ON, Canada.
authors: Louis M
authors: LM
authors: Ferreira
authors: Roth|McFarlane Hand and Upper Limb Centre, Bioengineering Laboratory, St. Joseph's Health Care, London, ON, Canada. Electronic address: gathwal@uwo.ca.
authors: George S
authors: GS
authors: Athwal
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019643:Arthroplasty, Replacement / Q000379:methods*; D015519:Bone Density; D003198:Computer Simulation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000175:diagnosis / Q000601:surgery*; D019736:Prostheses and Implants; D011474:Prosthesis Design; D012540:Scapula / Q000473:pathology / Q000601:surgery; D012785:Shoulder Joint / Q000473:pathology / Q000601:surgery*
keywords: B2; Biconcave; arthroplasty; augmented implant; osteoarthritis; replacement; shoulder