Shoulder Impingement

What is shoulder impingement?

Shoulder pain is a very common complaint. Your shoulder is made up of several joints, tendons and muscles that allow a wide range of motion of the joint and whole arm. Because the shoulder is so complex, it is vulnerable to a variety of problems. The rotator cuff is a frequent source of pain in the shoulder and this pain can be the result of shoulder impingement.

The word impingement basically means "rubbing" or "catching" of structures. In this context, we refer to structures within the shoulder. It is the impingement of the rotator cuff against other structures within the shoulder which form the basis of impingement syndromes.

When you raise your arm to shoulder height, the space between the rotator cuff and acromion decreases, this causes rubbing ("impingement") between the tendon and the bursa, leading to irritation and pain. This is a shoulder impingement.

Rotator cuff pain is common in both young athletes and middle-aged people. People who use their arms overhead for tennis, swimming and other overhead sports are particularly vulnerable. Those who do repetitive lifting or overhead activities/work using the arm (such as construction or painting) are also susceptible. Pain may also develop as the result of a minor injury. Sometimes, it occurs with no apparent cause.

A shoulder impingement may become a serious problem for some people and disturb their normal activities. This is when treatment is needed.

Types of impingement

External impingement

What is an external shoulder impingement?

External impingement (also known as Subacromial Impingement, Trapped tendons, Tendinitis or Bursitis) is where the rotator cuff is impinged in a part of the shoulder known as the sub-acromial space.

There is a lubricating sac called a bursa between the rotator cuff and the bone on top of your shoulder (acromion). The bursa allows the rotator cuff tendons to glide freely when you move your arm.

Any abnormality affecting the rotator cuff could lead to the humeral head riding upwards closer to the Acromion. This effect could lead to impingement. The following may be the cause for this type of shoulder impingement:

  • Rotator cuff strain

  • Partial or full thickness tear

  • Calcific tendonitis (calcium in rotator cuff)

  • Chronic overuse leading to wear and tear of the rotator cuff tendons (tendinopathy).


Rotator cuff pain commonly causes pain and swelling in the front of the shoulder. You may have pain and stiffness when you lift your arm. There may also be pain when the arm is lowered from an overhead position. Initially symptoms may be mild. Patients frequently do not seek treatment at an early stage.

These symptoms may include:

  • Minor pain that is present both with activity and at rest

  • Pain radiating from the front of the shoulder to the side of the arm

  • Sudden pain with lifting and reaching forwards or backwards

  • Athletes in overhead sports may have pain when swimming, throwing or serving a tennis ball

As the problem progresses, the symptoms increase:

  • Pain at night that may wake you

  • Weakness and stiffness

  • Difficulty doing activities behind the back such as tucking in a shirt or fixing a bra

If the pain comes on suddenly, the shoulder may be severely tender. All movement may be limited and painful and thus you should see Dr van der Berg.

How are external shoulder impingements diagnosed?

After discussing your medical history and symptoms, your doctor will examine your shoulder. He will check to see whether it is tender in any area or whether there is a deformity. To measure the range of motion of your shoulder and arm strength, your doctor will have you move your arm in several different directions and do several specific tests.

Your doctor will also examine your neck to make sure that the pain is not coming from a "pinched nerve" and to rule out other conditions, such as arthritis.

Imaging tests such as the following may also be done to diagnose an external shoulder impingement:

  • X-rays: X-rays shows the bones of the shoulder but do not show the soft tissues of your shoulder like the rotator cuff. X-rays of a shoulder with rotator cuff pain are usually normal or may show a small bone spur. A special x-ray view, called an "outlet view", sometimes will show a small bone spur on the front edge of the acromion.

  • Ultrasound and Magnetic resonance imaging (MRI): MRIs create better images of soft tissues like the rotator cuff tendons, ligaments and muscles. They can show fluid or inflammation in the bursa and rotator cuff. In some cases, a partial tear of the rotator cuff may be seen.

How are external shoulder impingements treated?

The goal of treatment is to reduce pain and restore function. In planning your treatment, your doctor will consider several factors including your age, activity level, and general health.

Nonsurgical Treatment

In most cases, initial treatment of shoulder dislocations is nonsurgical. Although nonsurgical treatment may take several weeks to months, many patients experience a gradual improvement and return to function.

  1. Rest: Your doctor may suggest rest and activity modification.

  2. Medication: Non-steroidal anti-inflammatory medicines (like ibuprofen and naproxen) and paracetamol-based tablets will reduce pain and swelling.

  3. Physiotherapy: A physiotherapist will focus on restoring normal motion to your shoulder. Stretching exercises to improve range of motion are very helpful. Once your pain is improving, your therapist can start you on a strengthening program for the rotator cuff muscles.

  4. Steroid injection: If rest, medications, and physiotherapy do not relieve your pain, an injection of a local anesthetic and cortisone in the shoulder may be helpful. Cortisone is a very effective anti-inflammatory medicine. Injecting it into the bursa below the acromion can relieve pain.

  5. Side and top view of shoulder
Surgical Treatment

Subacromial bursitis and impingement

Subacromial decompression:

When nonsurgical treatment does not relieve pain, your doctor may recommend surgery to repair such a shoulder dislocation. The goal of surgery is to create more space for the rotator cuff. Your doctor will remove the inflamed portion of the bursa and perform an anterior acromioplasty (part of the acromion is removed). This is also known as a subacromial decompression. This procedure is done arthroscopically (keyhole surgery).

During arthroscopic shoulder surgery thin surgical instruments are inserted into 3 or 4 small puncture wounds around your shoulder. Your doctor examines your shoulder through a fiber-optic scope connected to a television camera. The surgeon guides the small instruments using a video monitor and removes bone and soft tissue. In most cases, the front edge of the acromion is removed (acromioplasty) along with some of the bursal tissue (bursectomy).

Your surgeon may also treat other conditions present in the shoulder at the time of surgery. These can include:

  • Arthritis between the clavicle (collarbone) and the acromion (Acromioclavicular arthritis)

  • Inflammation of the biceps tendon (biceps tendonitis)

  • Partial or complete rotator cuff tears


After surgery, your arm will be placed in a sling for a short period of time (if no rotator cuff repair was necessary). This allows for early healing and movement. As soon as your comfort allows, you may remove the sling to begin exercise and use of the arm. Your doctor will provide a rehabilitation program (guided by a specific physiotherapist) based on your needs and the findings at surgery. This will include exercises to regain range of motion of the shoulder and strengthen the arm. It typically takes three to six months to achieve complete relief of pain, but it may take up to a year.

Internal impingement

What is an internal shoulder impingement?

Internal shoulder impingement involves other structures within the main shoulder joint itself (Glenohumeral joint). This condition is mainly seen in athletes, where overhead activity is a major part of their sport, particularly throwing athletes. In-fact, the condition is sometimes called "The Throwers Shoulder" and is also seen in the "Swimmer’s Shoulder". It is for this reason that it is mainly seen in a younger athletic population.

This picture shows how all the components of the shoulder come together during throwing.

Components of the shoulder Components of the shoulder Components of the shoulder


The main symptom of an internal shoulder impingement is usually pain in the shoulder. This is made worse by over-head activity or throwing. There may also be shoulder instability as a result of the damage done to the labrum. The damage done to the rotator cuff may cause a weakness in the movements of the shoulder.

How are internal shoulder impingements diagnosed?

Internal impingement is usually diagnosed on clinical examination. Special tests such as a MR-arthrogram (MRI with contrast injected in the shoulder) may be useful. Similar things may also be picked up on an ultrasound scan.

How are internal shoulder impingements treated?

Nonsurgical Treatment
  • Rest: This allows inflammation in the tendons, joint capsule and bursa to subside.

  • NSAIDS (non-steroidal anti-inflammatory) and steroid injection: This will help to decrease the inflammation.

  • Physiotherapy: Aimed at the rotator cuff muscles and other muscles of the shoulder and upper back.

  • Sports / Job specific training: Rehabilitation aimed at a specific area of performance; in this case it is likely to be throwing.
Components of the shoulder
Surgical Treatment

When nonsurgical treatment does not relieve pain, your orthopaedic surgeon may recommend surgery. This is aimed at repairing rotator cuff damage or labral damage. If the rotator cuff is badly damaged, repair must be considered.