[Radiographic diagnosis of dislocated inverted shoulder prosthesis: two cases of unrecognized dislocation]

Dislocation of inverted shoulder prostheses are rarely described in the literature. Diagnosis is relatively difficult as illustrated by two cases reported here which went unrecognized. The problem is the absence of any clear clinical sign of dislocation and the rather difficult interpretation of the radiographic images. We propose a method for analyzing the radiographic images which can be used to confirm the absence of dislocation on the AP view.