Lateralisation in reverse shoulder arthroplasty - A narrative review

Reverse shoulder arthroplasty (RSA) has witnessed a significant advancement with the introduction of lateralisation techniques, aiming to enhance shoulder function and implant durability. Traditional medialised designs, following Grammont's principles, have encountered challenges such as scapular notching, reduced rotational strength, and instability. In contrast, lateralisation methods, which reposition the joint center of rotation laterally on the glenoid, humerus, or both, seek to improve deltoid leverage, optimize the rotator cuff muscles' length-tension relationship, and enhance joint stability. Strategies for achieving lateralisation include bone grafts, lateralised glenosphere designs, and metallic augmented base plates. Clinical and biomechanical studies have shown that lateralised RSA designs decrease scapular notching, enhance range of motion, and promote stability. However, these advantages come with drawbacks like heightened shear forces, potential acromial stress fractures, and the risk of joint overstuffing. The future of RSA involves striking a balance between these aspects through tailored implant configurations and the utilization of cutting-edge technologies such as artificial intelligence, 3D modeling, and augmented reality to optimize surgical results. Further research is imperative to validate the long-term efficacy of lateralised RSA and refine these novel approaches to shoulder arthroplasty.