Patient Specific Instruments Versus Standard Surgical Instruments (TIOSO - GPS)

This is a non blinded prospective randomized clinical trial to define the efficacy of a new technology developed at the Cleveland Clinic to improve the positioning of the glenoid component in total shoulder arthroplasty. The Cleveland Clinic research team has worked on the development and validation of this new technology for the last six years. The investigators have validated the pre-operative planning software and published the results in the peer review literature (1, 7, 8, 9). The investigators have used this software in the planning of total shoulder surgery over the last three years. The investigators have validated the accuracy and reproducibility of the patient-specific instrumentation in both cadaver shoulders and Sawbones models of the shoulder using multiple surgeons. These studies also validated our ability to precisely measure component position using 3D CT scan imaging after placement of the implants in a pre-clinical cadaver study, thereby validating our ability to accurately measure and compare component position between the groups described in this proposed clinical trial. The investigators have also proven the ability of the software and techniques to produce an accurate representation of the glenoid morphology in patients with osteoarthritis or rotator cuff deficient arthritis in 13 patients. This was an IRB approved patient safety study performed at the Cleveland Clinic. The investigators have performed extensive studies of the materials and processes for the fabrication, sterilization and packaging of the patient specific instruments. The investigators have selected materials and processes that have met all of the FDA requirements for use of these materials and processes as clinical devices in vivo. These devices (non implanted instruments) are generally classified by FDA as a Class I device not having significant clinical risk. The investigators have studied the materials and process to produce accurate instruments that meet the clinical specification for fit onto the surrogate glenoid surfaces and maintain this shape and fit after sterilization. These same patient specific instruments have been tested in pre-clinical trials (Sawbones and Cadavers), demonstrating their ability to perform the functions specified with a high level of accuracy and much better than the use of standard generic instruments.