Fatty Atrophy of the Rotator Cuff can’t be Reversed by Successful Shoulder Surgery
What happens to a rotator cuff tear after a few years? The muscle can begin to suffer from fat atrophy. Fatty atrophy means that the torn rotator cuff muscle shrinks with time and get replaced by fat. This phenomenon is seen in many areas of the body and is either caused by disuse or nerve irritation or both. It means that there’s less muscle, which means the stabilizer of the shoulder (rotator cuff), can’t protect the shoulder joint. Since this weaker muscle is caused by not using the painful shoulder, it would make sense that repairing the rotator cuff tear with shoulder surgery might help the patient get the lost muscle back. According to this study, that assumption would be wrong.They found that this fatty shoulder rotator cuff atrophy couldn’t be reversed by successful arthroscopic repair of the rotator cuff tear. In addition, those patients with more of this atrophy had a higher rate of tear recurrence. This makes sense, as the weakened rotator cuff isn’t able to protect itself or the shoulder joint with activity. Some researchers theorize that this fatty atrophy is caused by lack of blood flow to the area which actually causes shoulder muscle cells to turn into fat (myoblasts into adipocytes). In addition, it’s known that CD34+ stem cells (like those found in Regenexx-SD) can cause new blood vessels to form in muscle. Is it possible that injecting these stem cells into a rotator cuff with poor blood supply might increase the blood supply and prevent fatty atrophy of the rotator cuff? While we haven’t documented that this occurs with the Regenexx-SD procedure, it may be one reason we see patients reporting good improvement in their symptoms and return to normal activities.