The humeral head is the “ball” part of the socket and ball joint; in case of a severe injury, the humeral head can be replaced by an artificial head and the glenoid (socket part) by an artificial socket in order to regain mobility in the shoulder joint and to guarantee healing (Walch and Boileau, 2009).
The reverse total shoulder arthroplasty is a commonly used surgery for patients who suffer from severe rotator cuff deficiency additional to shoulder joint pathologies (Berliner et al., 2015), such as unreconstructable fractures of the humeral head.
Another reason for this kind of procedure is in elderly patients after a failed hemiarthroplasty.
Post surgery treatment is similar to a normal shoulder joint replacement with regard to achieving a slightly worse range of movement outcome (reduced flexion, abduction and rotational movement).
Berliner J.L. et al., 2015, Biomechanics of reverse total shoulder arthroplasty,
Walch G. and Boileau P., Shoulder Arthroplasty, Springer Verlag, Berlin, Germany, p: 13