Fixation strength and stress distribution were analyzed using two methods. First, mechanical simulation of physiologic in聽vivo cyclic loading was performed on 1 inset glenoid implant design and 2 standard onlay glenoid implant designs currently on the market. Second, 3-dimensional finite element analysis was performed to compare an inset glenoid implant and a standard onlay glenoid implant with a keel and a standard onlay pegged implant.
After cyclic loading to 100,000 cycles, no glenoid implants demonstrated signs of loosening. Mechanical testing after cyclic loading demonstrated less distraction of the glenoid rim using an inset technique compared with an onlay technique. Finite element analysis results indicated that the inset technique achieved up to an 87%reduction in displacement.
Mechanical tests and finite element analysis support the concept of inset glenoid fixation in minimizing the risk of glenoid loosening.