Mechanical characteristics of a novel posterior-step prosthesis for biconcave glenoid defects

Yatin M. Kirane, Gregory S. Lewis, Neil A. Sharkey, April D. Armstrong

Research output: Contribution to journalArticlepeer-review

36 Scopus citations


Background: Posterior glenoid defects increase the risk of glenoid component loosening after total shoulder arthroplasty (TSA). The goal of this work was to evaluate the mechanical performance of a novel posterior-step glenoid prosthesis, designed to compensate for biconcave (type B2) glenoid defects. Two prototypes (" Poly-step" and "Ti-step") were constructed by attaching polyethylene or titanium step-blocks onto standard (STD) glenoid prostheses. We hypothesized that the mechanical performance of the experimental prostheses in the presence of a B2 defect would be similar to that of an STD prosthesis in the absence of a defect. Methods: Fifteen normal shoulder specimens were consistently loaded under simulated muscle activity while peri-glenoid bone strains were measured. In 5 specimens, arthroplasty was performed with an STD glenoid prosthesis. In the remaining 10 specimens, a 20° B2 glenoid defect was created before arthroplasty was performed with the Poly-step or Ti-step prosthesis. Results: Load-induced peri-glenoid strains after TSA with either the STD or Poly-step prosthesis did not show statistical differences as compared with the native joints (P > .05). A posterior defect decreased superior glenoid strain as compared with the intact specimens (P < .05). The change in strains after Poly-step prosthesis implantation in the presence of a biconcave glenoid defect was not different than the change induced by STD prosthesis implantation in the absence of a defect. In contrast, strains after Ti-step prosthesis implantation were statistically different from those induced by the STD and Poly-step prostheses (P < .05). Conclusions: The Poly-step prosthesis may be a viable option for treating posterior glenoid defects.

Original languageEnglish (US)
Pages (from-to)105-115
Number of pages11
JournalJournal of Shoulder and Elbow Surgery
Issue number1
StatePublished - Jan 2012

All Science Journal Classification (ASJC) codes

  • Surgery
  • Orthopedics and Sports Medicine


Dive into the research topics of 'Mechanical characteristics of a novel posterior-step prosthesis for biconcave glenoid defects'. Together they form a unique fingerprint.

Cite this