Comparison between Titan and Cobalt Hydroxyapatite-Coated Shoulder Prosthesis, during External and Internal Rotation

A comparison study was conducted between titan and cobalt alloy, shoulder prosthesis, with hydroxyapatite coating. We simulated the internal and external rotation of the shoulder in order to compare the deformation, equivalent strain and equivalent mechanical stress appeared for different types of prosthesis covering layers. The results show that the maximum mechanical solicitations appear in similar humeral positions and the minimal solicitations were obtained for cobalt alloy prosthesis with composite coatings. This study is innovative due to the fact that it considers all muscle groups involved in shoulder movement and we obtain a realistic estimate of the mechanical solicitations appeared into the humerus, and gives an estimate of the optimal material to be used for prosthesis cementing. Possible fracture risk can be determined and prevented in case a prosthesis is implanted.