This study examined 77 reverse Delta III shoulder arthroplasties to determine what causes inferior scapular notching and whether it matters clinically. It tested how glenosphere craniocaudal position and the prosthesis-scapular neck angle relate to notch formation and outcome.
When you position a reverse shoulder glenosphere, go low. Craniocaudal height carries roughly eightfold the influence of the prosthesis-scapular neck angle on notching, so an inferior placement with slight overhang beyond the glenoid rim is your main protective move.
This paper answered a debated question: earlier work was inconclusive about whether notching mattered. Here it clearly tracked with worse Constant scores, motion, and strength, so it is not just a radiographic curiosity. The authors also warn against excessive medial reaming, which shifts the glenosphere toward the lateral pillar and raises the prosthesis-scapular neck angle.
As a Level II prognostic study from a single expert surgeon with rigorously standardized fluoroscopic imaging, the internal validity is strong, but reproducing the exact index values requires the same imaging discipline. Note the authors' recommendation to place the guide-pin inferiorly contradicts the manufacturer's neutral-center recommendation.
This study examined 77 reverse Delta III shoulder arthroplasties to determine what causes inferior scapular notching and whether it matters clinically. It tested how glenosphere craniocaudal position and the prosthesis-scapular neck angle relate to notch formation and outcome.
When you position a reverse shoulder glenosphere, go low. Craniocaudal height carries roughly eightfold the influence of the prosthesis-scapular neck angle on notching, so an inferior placement with slight overhang beyond the glenoid rim is your main protective move.
This paper answered a debated question: earlier work was inconclusive about whether notching mattered. Here it clearly tracked with worse Constant scores, motion, and strength, so it is not just a radiographic curiosity. The authors also warn against excessive medial reaming, which shifts the glenosphere toward the lateral pillar and raises the prosthesis-scapular neck angle.
As a Level II prognostic study from a single expert surgeon with rigorously standardized fluoroscopic imaging, the internal validity is strong, but reproducing the exact index values requires the same imaging discipline. Note the authors' recommendation to place the guide-pin inferiorly contradicts the manufacturer's neutral-center recommendation.