This biomechanical study tests eight commercially available reverse shoulder arthroplasty (RSA) devices on a custom biaxial loading fixture to determine which factors — joint compressive force, socket depth (d/R ratio), or glenosphere size — most influence resistance to dislocation, and whether a rigid body mathematical model can predict the answer.
When an RSA patient is at risk for instability or you are selecting implant components, prioritize restoring deltoid tension and soft tissue compressive force first (via humeral lengthening or lateralization), then consider a deeper semiconstrained socket insert — don't simply upsize the glenosphere expecting meaningful stability gains.
This biomechanical study tests eight commercially available reverse shoulder arthroplasty (RSA) devices on a custom biaxial loading fixture to determine which factors — joint compressive force, socket depth (d/R ratio), or glenosphere size — most influence resistance to dislocation, and whether a rigid body mathematical model can predict the answer.
When an RSA patient is at risk for instability or you are selecting implant components, prioritize restoring deltoid tension and soft tissue compressive force first (via humeral lengthening or lateralization), then consider a deeper semiconstrained socket insert — don't simply upsize the glenosphere expecting meaningful stability gains.