Abstract
BACKGROUND: Mixed reality (MR) is an emerging technology that aids surgeons during shoulder arthroplasty. This study aims to evaluate surgeons' ability to reproduce preoperatively planned implant positioning using MR technology as compared to the conventional freehand (FH) technique and the more established guidance technique of navigation for shoulder arthroplasty. METHODS: Three surgeons with different levels of shoulder arthroplasty experience inserted guidewires into five three-dimensional-printed scapula models with varying degrees of glenoid deformity using the FH technique, MR overlay technique, and navigation. Postprocedure computed tomography scans of the sixty three-dimensional-printed glenoid models with inserted guidewire were performed. The executed guidewire entry point, version, and inclination were compared to the preoperative plan. RESULTS: The use of MR for guidewire positioning was significantly better than FH technique for inclination (P < .001), but not for version (P = .221) and entry point (P = .062). Malposition rate decreased from 66.7% with FH technique to 40% when MR was used for guidance, but this did not reach statistical significance (P = .143). MR overlay technique was not shown to be statistically significantly more accurate than navigation. CONCLUSION: MR overlay technique significantly improves the accuracy of guidewire placement in terms of inclination as compared to the standard FH technique. It is still inferior to navigation for all variables. When the two guidance techniques are combined, MR overlay with navigation could be an effective tool and harness the best of both technologies in the future.