What is the rotator cuff?
The rotator cuff is a group of four muscles and their tendons that cover the head of the upper arm bone (humerus), and work to keep it in its socket. The cuff stabilizes the shoulder and allows us to lift and rotate the arm. Rotator cuff tears cause pain that can be severe and make it difficult to perform basic, daily activities like showering and shopping; and playing with grandchildren.
What is RCA?
Rotator cuff arthropathy affects the glenohumeral joint (GH), the ball and socket joint made of the head of the upper arm bone (humerus) which fits in the socket of the shoulder blade, called the glenoid. Rotator cuff arthropathy is a chronic condition that develops over time.
RCA is defined by three critical features:
- A massive tear causes the cuff to become dysfunctional and alters the mechanics of shoulder function. A massive rotator cuff tear typically involves damage to two or more rotator cuff tendons which creates instability in the joint and allows the ball of the joint to drift out of position.The tear may have begun small but was left untreated which allowed the tear to enlarge. The tear renders the rotator cuff dysfunctional. This is a perfect example of what can happen when a patient continues to use the painful arm after a rotator cuff tear and over time causes additional severe damage to the shoulder joint.
- The dysfunctional rotator cuff allows the head of the humerus to shift out of alignment which results in abnormal wear and tear on the joint.
- Abnormal wear and tear results in severe arthritis that destroys the cartilage in the GH joint.
Who is at risk for RCA?
RCA affects about 4% of patients with rotator cuff tears. Women in their 60s and 70s are the most frequent victims of RCA. Usually the dominant arm is affected but in 10-25% of cases the condition affects both arms. Patients with RCA have a poor quality of life due to pain and significant functional limitations.
Symptoms
- progressive, chronic, severe pain and swelling
- nighttime pain
- loss of range of motion
- loss of shoulder strength
- joint stiffness
- painful pseudo-paralysis – the remaining shoulder muscles cannot lift the arm above the chest. This symptom is the main reason to undergo surgery.
How is it diagnosed?
X-rays will reveal that joint anatomy is abnormal, and that there is advanced arthritis in the joint. Sometimes there will also be osteoporosis of the humerus. Physical exam may reveal muscle atrophy and in some cases the rupture of the biceps muscle tendon. Advanced imaging may be ordered to visualize the soft tissues to reveal the size of the tear, the health of the tendons, muscles and other soft tissues.
What are the treatment options?
When this condition develops, it is may not be possible to restore normal mechanical function without joint replacement surgery. However, shoulder joint replacement surgery relies on the rotator cuff to provide normal mechanical function.
When the rotator cuff is dysfunctional, and the joint is out of alignment, the treatment is reverse shoulder replacement surgery which does not require a functioning rotator cuff to improve shoulder mechanics. Reverse shoulder arthroplasty is an excellent option to treat patients with RCA.
Dr. Joe Cooper is an orthopedic surgeon and sports medicine expert whose focus is on the shoulder problems. Contact him to schedule a consultation.
