Preoperative planning in reverse shoulder arthroplasty: plain radiographs

Reverse shoulder arthroplasty (RSA) has become a highly successful treatment option for various shoulder conditions, leading to a significant increase in its utilization since its approval in 2003. However, postoperative complications, including scapular notching, prosthetic instability, and component loosening, remain a concern. These complications can often be attributed to technical errors during component implantation, emphasizing the importance of proper preoperative planning and accurate positioning of prosthetic components. Improper baseplate and glenosphere positioning in RSA have been linked to impingement, reduced range of motion, and increased scapular notching. Additionally, the relationship between component positioning and intrinsic stability of RSA has been established, with glenoid component retroversion exceeding 10° posing a risk to implant stability. Adequate initial glenoid baseplate fixation, achieved through optimal seating and the use of appropriate screws, is crucial for long-term success and prevention of early failure. Factors such as lateralization and distalization also influence outcomes and complications in RSA, yet standardized guidelines for preoperative planning in these parameters are still lacking. Despite the impact of component position on outcomes, glenoid component implantation remains challenging, with position errors being common even among experienced surgeons. Challenges arise due to factors such as deformity, bone defects, limited exposure, and the absence of reliable bony landmarks intraoperatively. With the evolving understanding of RSA biomechanics and the significance of implant configuration and positioning, advancements in preoperative planning and surgical aids have emerged. This review article explores the current evidence on preoperative planning techniques in RSA, including plain radiographs, three-dimensional imaging, computer planning software, intraoperative navigation, and augmented reality (AR), highlighting their potential benefits and advancements in improving implant position accuracy.