Shoulder Impingement Treatment

What is it?

Shoulder impingement

Shoulder impingement is the collective name for pain that worsens when lifting the arm out to the side. It is therefore a symptom of several conditions of the shoulder, and the treatment modality will depend on the cause. You should talk to your surgeon about your impingement symptoms and possible treatment options.

The pain comes from the tendon and the fluid filled sac known as the bursa. Both the tendon and the bursa get trapped between one of the shoulder bones (humeral head) and the roof of the shoulder (acromion). The impingement occurs because there is not enough space for the tendon to slide under the acromion on lifting the arm, and it becomes pinched, inflamed and sometimes torn.

Internal impingement

This predominantly occurs in athletes, where throwing is the main part of the sport. The underside of the rotator cuff tendons are impinged against the glenoid labrum, which causes pain at the front of the shoulder joint.

With repeated injury, the tendon of the rotator cuff will become worn and a partial articular sided tear can develop. If the head is levered downwards by the internal impingement, secondary damage to the labrum can occur.

Frozen shoulder

Frozen shoulder also known as capsulitis, is thickening of the lining of the joint capsule. The lining of the ball and socket joint is usually thin and stretchy like a rubber balloon. This allows the shoulder joint to have a large range of motion. However due to an inflammatory process, this lining thickens and becomes stiff like tough rubber, resulting in a decreased range of movement. The inflammation of the joint capsule occurs in the early stages of the condition and is very painful. The pain eventually subsides, and the thickened capsule consolidates with scar tissue, resulting in loss of movement.

Why does it occur?

Shoulder impingement

Tendonitis – when the tendon becomes swollen and inflamed. It is then too large for the gap between the acromion and the humeral head, resulting in rubbing as the tendon passes under the acromion when the arm is lifted. This causes further inflammation, and an endless loop of injury and swelling develops. Tendonitis is common in those who perform repetitive over arm activities, including swimmers.
Calcific tendonitis – deposits of calcium collect in the cuff tendon. This irritates the tendon and takes up space, resulting in mechanical impingement and pain as the tendon passes under the acromion when lifting the arm.
Cuff tear – if the rotator cuff has a partial or full tear, the free ends will rub under the acromion. If the tear is large, the cuff will not be able to pull the ball into the socket as the arm is lifted, causing the humeral head to collide with the acromion.
Minor instability – if the ball is not centralised in the socket as the arm is lifted, the humeral head will drift upwards, and the larger muscles will pull it towards the acromion. Minor instability can be caused by poor muscle balance, winged or protracted shoulder blades, or even poor posture. This is the main cause of impingement in young patients.
Bony spur – the acromion can be many shapes and sometimes the joint has a bony spur. With age this spur can increase in size and start to rub on the tendon below.
Acromioclavicular arthritis – the acromioclavicular joint or ACJ is a joint between the acromion and the clavicle (collarbone). When it becomes arthritic, bone builds up on the side of the joint. This build up of bone rubs on the underlying cuff tendon and causes impingement.

Frozen shoulder

The exact cause of frozen shoulder in unknown. There is often a history of injury to the shoulder, and if one shoulder is affected there is a chance that the other will become involved too.

There is an association with frozen shoulder and diabetes, and in these patients it is known to be more aggressive.

What are the symptoms?

Pain associated with overhead use of the shoulder is among the most common symptoms, which can also be felt when lying on the side affected. Restricted movement gradually leads to difficulty performing everyday tasks, such as opening overhead cupboards or carrying heavy shopping. As the shoulder is used less due to the pain, you may start to feel the muscles weaken.

How is it diagnosed?

A detailed history and examination will be essential to determine the nature of the injury and determine the appropriate treatment. X-rays, MRI scans and shoulder arthroscopies (keyhole investigations) can all be used to confirm your surgeon’s diagnosis.

How is it treated?

Non-surgical

Pain relief in the form of anti-inflammatory medications can manage the conditions in the early stages. Physiotherapy is the mainstay of treatment to encourage and maintain movement. Strengthening the shoulder muscles and working on shoulder control can increase stability. This can be difficult during the inflammatory phase; however a steroid injection into the shoulder joint can help to reduce the inflammation. Following an injection, the joint should be rested for 24 hours and the sticky plaster should remain on to prevent anything from entering the injection site.

Once this painful phase has been superseded by stiffness; steroid injections have been shown to have little benefit and surgery is usually required.

Surgical

Following a routine shoulder arthroscopy, a shaver is introduced into the sub acromial space and the bursa, and the underside of the acromion is removed with a burr. This removes the painful, inflamed tissue and creates more space for the tendon in the shoulder joint. The surgery is done with an anaesthetic block to numb the arm. You can be awake during the operation or have some sedation to make you sleepy. As the operation uses water to see inside the joint, the wounds will leak some fluid which will be absorbed by cotton wool dressings. These dressings are removed a few hours after surgery.