Teachable moment in classrooms:

  1. tissues chapter – tendons are made of dense regular connective tissue
  2. appendicular skeleton chapter – structures of the scapula and humerus
  3. muscle tissue chapter – the role of tendons in muscle function
  4. muscular system chapter – insertions, origins and actions for rotator cuff muscles

The news item:  Recently this article appeared online:

RFK Jr. undergoes shoulder surgery. Doctors say rotator cuff injuries are painful and slow to heal

Health Secretary RFK Jr recently underwent surgery for an injured rotator cuff. The 72 year-old is expected to return to work soon, according to a spokesperson for HHS.

The article states that the rotator cuff is made of four muscles and their tendons: infraspinatus, supraspinatus, teres minor and subscapularis. Injury to those structures may make movements such as brushing hair, reaching for objects on a shelf painful.  The article also states that surgical repair is usually done arthroscopically, and recovery, with arm in a sling, may take four to six weeks. The article also mention an unconventional treatment, peptide BPC-157.

So, Why Do I Care??  Each year about 2 million people in the US alone develop rotator cuff injury. Because the injury limits daily physical activities, the biggest effect is on the quality of life. People with rotator cuff injury may not be able to drive a car, to continue their job, or to take care of household tasks. The fact that Robert F. Kennedy, Jr., the US Secretary of Health and Human Services, needed rotator cuff repair is just one more reason why to look at this disorder.

Plain English, Please!!! First, let’s talk about the structure of the rotator cuff. The rotator cuff is an essential anatomical structure that makes sure our arm (humerus bone) is moving in the shoulder articulation with the scapula bone. The humerus is moved in several directions by muscles that start (originate) on the scapula and insert around the head of the humerus. Four muscles: supraspinatus, infraspinatus, teres minor, and subscapularis can act in a way to rotate the humerus in the shoulder joint. While the body of the muscles are hugging the surface of the scapula, the tendons of the muscles are situated around the head of the humerus. The four tendons create a cup-looking arrangement, and this complex of tendons is called the rotator cuff.

Second, let’s talk about why the healing time is so long. The tendons that form the rotator cuff are made up by a tissue called dense regular connective tissue. This tissue type has very poor blood supply. The incoming oxygen and nutrients are enough for the tendon fibroblasts to carry out microscopic repairs of the tendon, but when a visible tear of the tendon happens, the fibroblasts don’t get enough oxygen and nutrients to suddenly increase the speed of the repair. Imagine a town that has one road to bring bricks, concrete, wooden beams, windows to build houses. That single road allows the passage of building materials to build 10 houses. No matter how fast the builder crew could work, the supply limits their speed of housebuilding, even when the town would need to have 50 houses to be built.

Third, let’s talk about BPC-157.  Blood vessels can be stimulated to grow branches, and the increased number of branches allows the movement of more blood. BPC-157 is the name of a peptide that can stimulate blood vessel growth and branching (in other words, angiogenesis).  Treatment with the peptide increases blood vessel branching around the torn rotator cuff, and thus, increases blood flow to the tendon tear. Using our metaphor, BPC-157 stimulates the town to build an additional five roads, so building material can be brought in for 50 more houses to be built. In the injured tendon the increased blood flow ensures that the fibroblasts now have more oxygen and nutrients to speed up the repair of the injured area.