Biomechanics of custom glenoid components in reverse total shoulder arthroplasty-a narrative review of concepts for surgeons.

Severe glenoid bone loss remains a major challenge in reverse total shoulder arthroplasty, as conventional implants often fail to achieve stable fixation. Three-dimensional (3D) printed, custom-made glenoid implants provide a patient-specific solution by optimizing bone-implant congruence, fixation strategy, and biomechanics. This narrative review synthesizes biomechanical principles and surgical considerations underpinning custom glenoid design, including central peg fixation, porous surfaces, bone-implant contact area, and the importance of computed tomography-based pre-operative planning. Current evidence suggests that implant stability is improved by secure central fixation, porous press-fit interfaces, and avoidance of excessive lateralization, which increases torque and failure risk. Custom implants allow tailored peg and screw placement to enhance fixation in compromised bone. Further studies are required to validate these principles and define long-term outcomes.