This retrospective bicentric cohort compared three reverse shoulder arthroplasty designs in cuff tear arthropathy patients. It asks whether combining lateralization and distalization improves range of motion and reduces scapular notching versus the Grammont design or a purely lateralized design. The three groups differed in neck-shaft angle, inlay vs onlay humeral geometry, and glenosphere configuration.
When choosing an RSA design for cuff tear arthropathy, remember that outcome scores like the Constant-Murley are comparable across designs, but range of motion and notching are not. The mental model: distalization buys you flexion, a reduced neck-shaft angle and lateralization buy you rotation, and glenoid lateralization plus inferior glenosphere overhang protect against notching.
A combined lateralized-distalized onlay (145° NSA) captured all three benefits, yielding the best flexion, abduction, and least notching in this cohort. Be cautious interpreting the functional gains. The 7-point Constant advantage over the Grammont design fell below the 8-point MCID, so score-based superiority remains debated.
Also weigh the tradeoff: greater lateralization increases glenoid shear and acromial stress, a theoretical driver of scapular spine stress fractures. This study was underpowered and too short to confirm that risk.
This retrospective bicentric cohort compared three reverse shoulder arthroplasty designs in cuff tear arthropathy patients. It asks whether combining lateralization and distalization improves range of motion and reduces scapular notching versus the Grammont design or a purely lateralized design. The three groups differed in neck-shaft angle, inlay vs onlay humeral geometry, and glenosphere configuration.
When choosing an RSA design for cuff tear arthropathy, remember that outcome scores like the Constant-Murley are comparable across designs, but range of motion and notching are not. The mental model: distalization buys you flexion, a reduced neck-shaft angle and lateralization buy you rotation, and glenoid lateralization plus inferior glenosphere overhang protect against notching.
A combined lateralized-distalized onlay (145° NSA) captured all three benefits, yielding the best flexion, abduction, and least notching in this cohort. Be cautious interpreting the functional gains. The 7-point Constant advantage over the Grammont design fell below the 8-point MCID, so score-based superiority remains debated.
Also weigh the tradeoff: greater lateralization increases glenoid shear and acromial stress, a theoretical driver of scapular spine stress fractures. This study was underpowered and too short to confirm that risk.