Your rotator cuff has stem cells and gets sick when the number of those stem cells wane. That seems to be what a few different studies are telling us including a new one out last month from stem cell pioneer Phillpe Hernigou. The obvious implication being that to make the rotator cuff healthy, you need to add stem cells.
The rotator cuff is a series of muscles around the shoulder that help to lift the arm and stabilize the ball in the socket. The tendons or muscle areas of the rotator cuff can tear with trauma or wear and tear and all of this gets more likely as we age. There are definitely progenitor and stem cells in the rotator cuff and research has shown that there are fewer of these cells in torn muscles than healthy ones. More recently, Hernigou reported on a large case series of patients undergoing rotator cuff surgery who had stem cells injected and showed that the patients with stem cells added had about half the re-tear rate as those who didn’t get the cells! This is a big deal, as the tendon re-tearing after a surgical repair is a huge problem. To date, while bone marrow stem cells seem to have the effect of helping rotator cuff tears heal, fat stem cells do not.
The most recent study looked at 125 patients who had rotator cuff tears and took samples of these tendons and compared them for stem cell content versus 75 control patients who had healthy shoulders. All of the rotator cuff tear patients had fewer stem cells at the area where the tendon attaches to the arm bone compared to healthy shoulders. Severity of the decrease was correlated with more delay between onset of symptoms and surgery, having more torn tendons, more fat atrophy of the rotator cuff muscle and being older.
The upshot? Are rotator cuff tears stem cell deficient, therefore caused by a problem in the number of stem cells in the shoulder tendons? While we don’t have enough data to make that call yet, this study and some of the early clinical research certainly fits with our experience that precise stem cell injections into the rotator cuff tear can facilitate healing without surgery!