Because of how the prosthesis' shape is and it being flipped from normal anatomy, it limits the degrees of motion. And it's not SUPER excessively limited, like a regular TSA might regain 160 degrees of flexion and a rTSA only get 145 but both are still functional for reaching overhead to grab something out of a shelf. Also, the rTSA also provides more stability in this way because due to the shape of the new glenohumeral joint, it is now at less of a risk of dislocation. Great question (:
How limited would we expect ROM to be after a rTSA? And why/how does a rTSA provide more stability?
Because of how the prosthesis' shape is and it being flipped from normal anatomy, it limits the degrees of motion. And it's not SUPER excessively limited, like a regular TSA might regain 160 degrees of flexion and a rTSA only get 145 but both are still functional for reaching overhead to grab something out of a shelf. Also, the rTSA also provides more stability in this way because due to the shape of the new glenohumeral joint, it is now at less of a risk of dislocation.
Great question (: