Comparison of Glenoid Position Using SmartBones

The investigators propose a randomized clinical trial to evaluate the accuracy of glenoid implant placement comparing four groups of patients. Group 1 consists of 3D imaging and computer-generated surgical planning using standard DePuy instrumentation for placement of the glenoid implant. This group is considered the standard of care. Group 2 consists of 3D imaging and computer-generated surgical planning, with use of a SmartBone to trial the standard DePuy instrumentation. (Group 2 is Group 1 with addition of the use of a SmartBone.) Group 3 consists of 3D imaging and computer-generated surgical planning, with use of the IRI technology including a SmartBone, but with metal legs instead of plastic legs in the IRB#13-652 study. Group 4 consists of 3D imaging and computer-generated surgical planning, with use of the RTI technology including a SmartBone. We will measure implant placement based on 3D CT imaging. We will measure pre-operative bone quality using quantitative CT scan to measure trabecular bone volume and correlate these findings with bone samples removed from the humeral head and measured by microCT and mechanical testing of the bone samples. These bone samples will be obtained as part of the routine preparation of the humeral head for implant placement. This bone tissue is normally removed and discarded as part of the standard of care for preparation of the bone for placement of the humeral stem. By comparing a computer generated pre-operative plan to the post-operative glenoid component placement, we will be looking at three outcomes. First, we will determine the overall difference in glenoid component placement between the four treatment groups. Second, we will compare the placement between the technologies within and among surgeons. Third, we will evaluate the difference in implant position between technologies based on severity of pathology. The quality of the humeral head sample will be correlated to the possible loosening of the implants.