Subacromial impingement is the most common cause of shoulder pain after 40 years. It refers to abnormal friction between part of the scapula and the upper part of the arm bone. Several treatment options can be considered depending on the case.

Definition of subacromial impingement

Subacromial impingement, or subacromial impingement syndrome, refers to a disorder occurring in the acromion. The latter is a part of the scapula which is located at the level of the shoulder. The acromion is more precisely located above the rotator cuff, which constitutes a set of tendons surrounding the head of the humerus (bones of the arm).

We speak of a subacromial impingement when an abnormal friction appears between the acromion and the rotator cuff. This abnormal situation results in a painful inflammatory reaction in the shoulder.

Causes of subacromial impingement

This abnormal friction can have different explanations:

• osteoarthritis of the shoulder which is characterized by wear and tear of the cartilage;
• the osteophyte, commonly called parrot’s beak, which is an abnormal bone growth that can accompany osteoarthritis of the shoulder;
• wear and tear on the muscles that lower the humerus;
• local tendonitis, an inflammation of the tendons that is often caused by overworking this area of ​​the body.

Risk factors

It has been shown that the subacromial conflict could in particular be favored by:

• aging ;
• repeated and / or demanding actions with the arms in the air;
• a trauma;
• certain bone diseases.

Diagnosis of subacromial impingement

It is initially based on a clinical examination. Different tests can be performed to observe the onset of pain during certain movements.

Secondly, the healthcare professional can ask for medical imaging examinations to be performed. An x-ray can be done to assess the condition of the acromion, confirm the diagnosis of subacromial impingement, and investigate possible causes.

The subacromial conflict most often appears in the forties or fifties. It is also the most common cause of shoulder pain after 40 years.

Shoulder pain

The subacromial impingement results in a painful inflammatory reaction in the shoulder. At first, the pain manifests itself during certain common movements of the arm and shoulder (putting on or taking off clothing, pouring liquid at arm’s length, etc.). Over time, the pain progresses and may appear spontaneously at rest. Shoulder pain can especially occur at night, and cause unwanted awakenings.

Risk of complications

In the absence of appropriate management, the subacromial impingement can settle chronically and be the cause of complications. The abnormal friction between the scapula and the arm bone can cause the rotator cuff to rupture. It is a progressive rupture of the muscles subjected to friction.

Conservative treatments

The management of the subacromial impingement is generally based on conservative treatments. Healthcare professionals may recommend:

• preventive measures during recovery, which consist in particular of avoiding movements in the shoulder to limit pain and the risk of complications;
• anti-inflammatory treatment if the pain persists, especially at rest;
• physiotherapy sessions to strengthen the muscles of the shoulder.

Surgical intervention

Conservative treatments are generally carried out over a period of at least 2 to 3 months. If they prove to be insufficient, surgical intervention may be considered. It aims to remove the conflict by widening the subacromial space and thinning the acromion. After surgery, the shoulder is immobilized for 15 days using a splint. A rehabilitation of 1 to 2 months is also necessary.

The prevention of subacromial impingement essentially consists in limiting over-straining of the shoulder:

• limit repeated actions with the arms in the air;
• limit actions with outstretched arm;
• avoid getting up with your hands;
• adapt the ergonomics of their workspace;
• etc.

If shoulder pain manifests itself and settles recurrently, it is strongly recommended to contact a health professional. Early treatment helps to limit complications and increase the success of recovery.