Learning curve of augmented reality surgical application for reverse shoulder arthroplasty

BACKGROUND: Accurate positioning of the glenoid component in reverse total shoulder arthroplasty is important since it reduces prosthesis-related complications. Conventional instrumentation is still the gold standard. However, patient-specific instrumentation using 3-D printed guides, as well as computer-assisted navigation, is gaining more and more importance. Augmented reality has been established to enable the surgeon to have more precision in the positioning and inclination of the glenoid component. A new technique called "NextAR" (©Medacta) supports the surgeon during operation by guidance on bone preparation, instrument navigation, and implant placement, using virtual reality goggles or displays. The aim of this study was to determine a learning curve for reversed total shoulder arthroplasty by a high-volume single shoulder surgeon using the NextAR system.

METHODS: We performed retrospective data analysis of the first 20 cases of one high-volume single shoulder surgeon performing reversed total shoulder arthroplasty using the NextAR system. Parameters such as anesthesia time, surgical time, length of hospital stay, classification of the American Society of Anesthesiologists, body mass index, intraoperative blood loss, and complications were analyzed.

RESULTS: We found significant decreases in measures like surgery time (p = 0,001), amount of blood loss during surgery (p = 0,005), and anesthesia time (p = 0,08). A remarkable turning point of blood loss occurs within the fifteenth surgery. A significant reduction of the operation time is shown at the fourteenth operation. Looking at blood loss and operation time together using a standardized cumulative curve, a significant reduction of the cumulative score is found within the fifteenth surgery.

CONCLUSION: Significance was found in surgery time as well as in the amount of blood loss. However, these results may not be generalizable since they depend on further conditions. Future studies could provide information about other outcome parameters and learning curves of several surgeons performing reversed total shoulder arthroplasty with augmented reality applications.