Shoulder Impingement

The Basics

  • Shoulder Impingement is the most common cause of shoulder pain and is the result of compression of the rotator cuff tendon and the subacromial bursa which lies between the humeral head and the acromion. This leads to chronic inflammation of the bursa (bursitis) and the rotator cuff tendon (tendinitis) and often bone spurs on the undersurface of the acromion. As the impingement progresses it can lead to partial thickness rotator cuff tears and ultimately full thickness rotator cuff tears.

  • The shoulder is a ball (humeral head) and socket (glenoid) joint. The glenoid is surrounded by a rim of cartilage called the labrum. The long head of the bicep runs up the front of the shoulder and attaches into the glenoid. The rotator cuff tendons surround the ball and socket joint and move the shoulder in different directions. The rotator cuff tendons are covered with a bursa. Above the bursa is the acromion bone and the clavicle and connect to form the acromioclavicular joint.

  • The patient usually has a sudden onset of pain. This is exacerbated with any movement of the shoulder and overhead activities. Patients will often complain of pain at night which disrupts sleep.

  • Almost everyone has some shoulder impingement upon reaching middle age. Most patients have some rotator cuff tendinitis or partial tears.. Many people are asymptomatic or have symptoms that quickly resolve. If a patient has weak rotator cuff muscles the compression will be worse and is more likely to cause symptoms. Many activities can exacerbate the inflammation and pain including falls onto the arm, repetitive overuse work or sports activities and overhead lifting.

  • Patients with shoulder Impingement frequently have other related conditions. These conditions can be asymptomatic or they can exacerbate the shoulder pain. Such conditions include proximal bicep tendonitis or partial tears, acromioclavicular arthritis, and degenerative labral tears. (the labrum is a thick cartilage ring around the shoulder socket)

  • The diagnosis is usually made during the physical exam. A series of shoulder movements that increase compression on the rotator cuff will result in discomfort. The patients with moderate inflammation will have full motion. With more severe inflammation the patient may feel like they have limited motion but the physician will be able to move their shoulder fully. They will have full strength although they may feel weak due to pain.

  • 1) An Xray is often the first test ordered. If there is any trauma such as a fall or direct blow a fracture needs to be ruled out. With no history of trauma an Xray is helpful to rule out arthritis of the glenohumeral joint or arthritis that has resulted from a chronic massive rotator cuff tear called rotator cuff tear arthropathy. The Xray can show calcific tendinitis which is tendinitis that has resulted in calcium deposits in the tendon. Finally the XRay is used to evaluate the type of acromion bone and the development of bone spurs. The three common types are flat, curved ,and hooked which result in varying degrees of space for the rotator cuff tendon to occupy

    2) An MRI will show the soft tissues including the rotator cuff , the bicep tendon, and the labrum. As stated before most middle aged patients will have some degree of rotator cuff tendinitis or partial tears, bicep tendonitis or partial tears, degenerative labral tears , and acromioclavicular arthritis. It is more likely an injury irritated these pre existing conditions than actually caused them. It is presumed a patient has some of these findings so an MRI is often reserved for patients who fail to heal with conservative care.

    3) CT arthrography is a CT scan with dye injected into the shoulder. It is useful in patients who are not allowed to get an MRI due to certain medical implants or small metallic objects embedded in the eye ( metal workers ) to evaluate for rotator cuff tears.

    4) Ultrasound is another test that can be used when a patient can not get an MRI to evaluate for rotator cuff tears.

Treatment

  • Mild cases will often resolve with gentle stretching and anti inflammatory medications or supplements

  • Physical therapy is the first line of treatment for shoulder impingement. The therapy includes modalities to help improve the pain and rotator cuff strengthening exercises to improve the impingement. Once the therapy is completed it will be recommended the patient do 5-10 minutes of shoulder exercises 2-3 times a week to prevent the symptoms from returning. Any middle age person who would like to prevent shoulder impingement or future rotator cuff issues should be on a rotator cuff strengthening program. A common misconception is that patients who lift weights in the gym or at work feel they do not need therapy because they are already strong. However most of our lifting activities work the large muscle groups like the deltoids, biceps, triceps, and pecs while ignoring the rotator cuff. You may hear me say “ Tom Brady’s arm would fall off if he did not do these types of exercises.” Studies show that the number one factor if a patient will ultimately need surgery or not is their belief that therapy will work.

  • an injection into the subacromial space will often resolve the pain. It only causes mild discomfort and will usually take 3-4 days to improve the inflammation in the bursa and tendon and therefore improve the pain. You can receive up to 3 injections per year to control the pain. It is recommended that you start therapy with the therapist or a home program after an injection. If you do not improve your rotator cuff strength it is likely the pain will return.

  • Stem Cells and Protein Rich Plasma are used to treat inflammation or partial tears of the rotator cuff. In theory these injections have many healing factors that can help the tendon. However, these treatments are costly and insurance does not cover them. The cost is significant and this can be frustrating if it does not work. It is often used in professional athletes because therapy and rest could result in missing a substantial part of the season.

  • Surgery is usually fully arthroscopic. An arthroscopic camera and instruments are placed through a few poke holes around the shoulder. A shaver is used to debride cartilage tears , degenerative labral tears , or partial thickness joint sided rotator cuff tears. If the proximal bicep is inflamed or torn it will often be released so it is no longer compressed. In Older patients the tendon is released and in some younger patients it will be reattached in the upper part of the arm. The arthroscope is then placed above the rotator cuff. The inflamed bursa is removed to visualize the rotator cuff. The under surface of the acromion and bone spurs are often shaved to increase the subacromial space and diminish impingement. Partial tears of the rotator cuff are debrided and full tears ( the tendon is detached from the bone ) are repaired. An anchor with sutures will be placed in the bone and the tendon will be tied down to the bony surface.

    Additional Considerations:

    Anesthesia - The surgery is an outpatient procedure done under sedation with a regional nerve block. This is an injection which numbs the nerves going into the arm. Most patients will require a pre op workup from their PCP, they will need to abstain from eating or drinking after midnight the night before surgery, and they will need a ride home after surgery.

    Recovery - The shoulder will be covered in gauze and tape. The dressing will be removed 4-7 days after surgery. You will be placed in an arm sling. The arm will usually be numb for 6-8 hours after surgery but it could last longer. Post operative therapy will be critical to recovery. It will usually start 1-2 weeks after surgery. Therapy will work on range of motion and rotator cuff strengthening. If the tendon is repaired the therapy will be more restricted to avoid tearing the repair. Most patients will return to full activities 3-6 months after surgery. Heavy lifting and certain sports activities could take longer

    Results - The vast majority of patients who follow the post op instructions and comply with therapy will make a full recovery. Continued home therapy to maintain the strength of the rotator cuff will decrease the chance of having a symptomatic tear in the future.

    Revision Surgery - if the patient’s rotator cuff fails to heal or has a re-tear in the future they may benefit from a revision rotator cuff repair. Some tears are not repairable or not completely repairable and may need a tendon augmentation or tendon transfer. Some patients' tears are associated with severe arthritis and they may need a shoulder replacement.

Prevention

The best prevention is to maintain the strength of the rotator cuff muscles. This can be done with a home exercise program working on the shoulder for 5-10 minutes 2-3 times a week. We know that many patients have significant rotator cuff disease including massive tears without any symptoms. This is because their other shoulder muscles compensate for the rotator cuff and they have less chronic inflammation. Chronic inflammation causes the pain of rotator cuff disease and shoulder impingement and can be decreased by working on your nutrition, fitness, sleep and stress reduction.