Shoulder Prosthesis Telerehab Care Trial

The goal of this clinical trial is to compare the rehabilitation by use of a smartphone-app with the usual care of physical therapy in patients, 60 years and older, who underwent a primary shoulder arthroplasty. The main questions it aims to answer are: * is the outcome of rehabilitation with the app as good as the usual care? * is the outcome for both types of shoulder arthroplasty similar? * what is the usability of the app?. Participants will * have treatment according to the group they are allocated to * fill in questionnaires at specific moments during the rehabilitation stage (0 - 3 months ) and at 1 year post-surgery