Ensuring Accurate Component Placement in Glenoid Bone Loss.

Glenoid component malposition has important implications for implant wear and longevity after shoulder arthroplasty. Although not confirmed by long-term clinical studies, multiple biomechanical studies have identified altered wear forces, increased contact pressures, decreased contact area, eccentric loading, and potential for loosening associated with inaccurate component placement. Accurate placement is especially challenging with glenoid bone loss. Developments in the improvement of component placement include advanced imaging modalities (MRI and two- and three-dimensional CT), improved surgical exposure techniques, augmented glenoid components, and surgical guidance systems, such as patient-specific and generic reusable guides. Long-term clinical studies to establish the link between glenoid component position and ultimate implant success and longevity are still needed.