Prosthesis position in shoulder arthroplasty. A cadaver study of the humeral component.

In six cadaver shoulder joints, the external rotation was measured applying a constant external torque to the humerus before and after insertion of a non-constrained shoulder joint prosthesis at different degrees of retroversion. At 35-45 degrees of retroversion there was no difference between the external rotation of the inserted prosthesis and the external rotation of the joint before arthroplasty.