Hello @wwill, while we wait for others to chime in, here is a discussion you may find worth your time to look through, https://connect.mayoclinic.org/discussion/stem-cell-therapy-for-rotator-cuff-tears/ - It is a discussion on the topic of stem cells for rotator tears and arthritis. You also mentioned a reverse shoulder replacement, here is another discussion on that specific type of shoulder replacement, https://connect.mayoclinic.org/discussion/reverse-shoulder-replacement/.