PSI and navigation system improve consistency of baseplate placement in reverse shoulder arthroplasty regardless of surgical experience.

Abstract

The success of reverse shoulder arthroplasty (rTSA) relies on accurate glenoid baseplate positioning. Patient-specific instrumentation (PSI) and navigation systems are computer-assisted technologies introduced to improve positioning accuracy; however, no direct comparison of these technologies has been conducted in the same clinical setting. This study aimed to compare baseplate positioning accuracy of conventional technique, PSI, and navigation systems and to investigate whether these computer-assisted technologies enable consistent placement regardless of the surgeon's experience. This retrospective study analyzed 110 shoulders of 108 patients who underwent rTSA between November 2017 and April 2024. Patients were divided into Conventional (n = 36), PSI (n = 24), and Navigation (n = 50) groups. Procedures were performed by eight surgeons classified as novice (<10 rTSA cases) or experienced (≥20 rTSA cases). Postoperative CT was used to evaluate baseplate alignment based on version and inclination. Positioning accuracy was compared among groups and between experience levels. Mean version and inclination showed no significant differences among the groups (P = .552 and P = .051, respectively). Precision in version was significantly higher in the PSI and Navigation groups than in the Conventional group (PSI: P = .014, Navigation: P < .001). Precision in inclination was also higher in these two groups (both P < .001). In the Conventional group, novice surgeons showed significantly lower precision in inclination than experienced surgeons (P = .042), whereas the PSI and Navigation groups showed no significant differences between experience levels. The Navigation group achieved significantly longer screw lengths in multiple positions than the Conventional group, and augmented baseplate use was significantly higher in the PSI group. Both PSI and navigation systems provide better precision in baseplate positioning than conventional techniques and help eliminate the experience gap between novice and experienced surgeons. These computer-assisted technologies may help standardize surgical outcomes across different levels of surgical experience in rTSA.