What is the Rotator Cuff?

By Adam Hutchison PT, DPT and Dr. Gregory Smith

Understanding the Rotator Cuff 

The rotator cuff is actually not a single muscle but instead a group of four muscles. One key function of this muscle group is to keep your shoulder in place. The shoulder is a ball and socket joint. As you can imagine the ball and socket joint has a lot of movement. This can cause it to be more prone to injury due to excessive movement.

Muscles of the Rotator Cuff

The muscles of the rotator cuff keep the head of your humerus ( the ball) in the glenoid fossa (the shoulder socket). Additionally, The four muscles are the primary movers of the shoulder.

• Supraspinatus: Helps with shoulder flexion and abduction (lifting the shoulder forwards and laterally).
• Infraspinatus: Main driver of shoulder external rotation (rotation away from body) and extension
• Teres Minor: This is the smallest rotator cuff muscle and also contributes to shoulder external rotation.
• Subscapularis: Aids in shoulder internal rotation (rotation towards the body) and assists with lowering the arm from an overhead position.

When one or more of these muscles that make up the rotator cuff become injured people experience pain and weakness and/or a loss of mobility in the shoulder.

Most Common Injuries 

1. Tendonitis                                                                                                             

   Sometimes the first stage of any injury and the most minor type of the ones discussed in this article is rotator cuff tendonitis. Rotator cuff tendonitis and a shoulder impingement are interchangeable. These are all different names for the same problem. In the simplest terms it means that there is pain and swelling of the cuff tendons and the surrounding tissue.

   Tendonitis is usually an “overuse injury”.” Although there is micro-tearing of the muscle. Rotator cuff tendonitis often happens when a person subjects their shoulder to a load or strain that it is not normally used under. Causes of tendonitis in the cuff include but are not limited to: golfing, playing tennis and lifting heavy objects while cleaning/completing household chores.

   When appropriate your medical doctor may recommend oral medication or a cortisone injection to help minimize pain. Additionally, physical therapy can be helpful in treating and preventing symptoms from returning.

2. Partial Thickness Tears                                                                                   

   A partial thickness rotator cuff tear is an incomplete tear of the rotator cuff. The injury is just what it sounds like – a portion of the rotator cuff muscle is partially torn.

   Partial thickness tears are most common in people over the age of 50 and may be chronic or related to minor trauma, such as a recent fall.

   Rotator cuff injuries are most often a result of progressive wear and tear of the tendon tissue over time (progression of tendonitis as was mentioned above). Other causes of rotator cuff tears include: repetitive overhead activity, long bouts of heavy lifting or the rotator cuff can also suffer an injury in a single incident such as a fall.

   Partial thickness tears can be treated both operatively and nonoperatively. It all depends on the size and severity of the tear. Your doctor may recommend a cortisone injection and physical therapy to help with pain management. Strengthening the rotator cuff and its accessory muscles may prevent further injury. Small partial tears can heal on their own and therefore be managed conservatively.

   When conservative treatment isn’t warranted or isn’t effective, surgery could be the next step. Typically the surgical procedure to treat a partial rotator cuff tear is an arthroscopy (also known as a shoulder scope).

3. Full Thickness Tears                                                                                         

   Full thickness tears are when the rotator cuff has become completely removed from the bone. Sometimes these injuries are not painful when the shoulder is at rest because muscle tissue is no longer viable. However pain can arise because the shoulder range of motion and strength is significantly limited and additional strain is placed on other shoulder muscles.

   Full thickness tears usually have a specific mechanism of injury. The most common causes are when lifting something heavy overhead. Another is when a person tries to prevent a fall with one of their upper extremities.

   Conservative treatment can be helpful for full thickness tears but because the muscle is damaged beyond the body’s ability to heal the injury site, therapy would be compensatory not restorative. The only way to restore full function would be via a repair surgery.

Non-Surgical Treatment

Treating a rotator cuff tear without surgery can involve a combination of interventions from a medical doctor and physical therapy.

Your doctor may try oral anti-inflammatories or the aforementioned cortisone injection to decrease inflammation in the shoulder (the source of pain).

Physical Therapy for Rotator Cuff Injuries

• Stretching: Gentle stretching can be helpful to tendonitis and has been proven to promote healing within the tissue that has an injury. Additionally there are stretches you can do at home with and without equipment. A skilled clinician can help educate and train you on these shoulder stretches. For partial and full thickness tears, stretching is important to prevent the shoulder joint from becoming stiff and causing long-term mobility deficits.
• Soft Tissue Mobilization(STM)/Shoulder Mobilizations: STM and shoulder mobilization can be helpful to reduce pain as pain receptors within the shoulder become desensitized.
• Therapeutic Exercise: Strengthening the specific muscles injured in rotator cuff tendonitis can also be helpful for reducing pain and preventing progression of injury. Eccentric exercises have been proven to be effective for tendonitis. For partial and full thickness tears. The strengthening the other rotator cuff muscles that have not sustained an injury can minimize stress/strain on the tissue with damage. Strengthening of the accessory muscles (biceps, triceps, deltoid and shoulder blade stabilizers) can also be a highly effective treatment method to improve function and prevent pain.

Surgical Treatment

If a rotator cuff tear is present and conservative treatment did not work, then surgery may be the next option. The type of surgery depends largely on the type of injury (partial tear vs. full thickness).

• Surgery for Partial Thickness Tears – Arthroscopy

During an arthroscopy, a small shaver can be brought through a small incision(s) in the shoulder and the damaged tissue is removed. If bone spurs are present, they are filed down and a bony tunnel is opened to give the tendons more room to move. Physical Therapy is recommended post-op but recovery is rapid – typically 4-6 weeks.

• Surgery for Full Thickness Tears – Repair of the Tear

Rotator cuff tears involve a portion of the shoulder arthroscopy procedure mentioned above and stitching the damaged muscle back together anchoring it to bone. Physical therapy is also a requirement after surgery but recovery takes much longer. Lifting is not allowed for one month to allow for healing. You can begin stretching prior to strengthening starting around the 3 month mark. Overall the full recovery time for this type of repair is between 9-12 months.

By: Adam Hutchison PT, DPT and Dr. Gregory Smith

Related Articles: 5 Shoulder Symptoms You Should Not Ignore, 5 Things that May Cause Shoulder Pain, and Shoulder Tendonitis

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