What is a subacromial impingement ?
From the age of 40, pain in the shoulder is often caused by what is called subacromial impingement, a syndrome linked to the aging of the rotator cuff tendons.
The muscles and tendons surrounding the head of the humerus make up the rotator cuffs, part of the shoulder joint, which enable lifting and rotation of the arm, and help stabilise the shoulder.
With age, the tendons lose their elasticity, in particular the supraspinatus tendon, which is most often affected. As they thicken, they rub against the acromion, the bony process located on the scapula, resulting in the formation of a bone spur called osteophyte. This in turn damages the superficial part of the tendon, accelerating its wear. As the subacromial impingement progresses, the pain worsens.
Diagnosis of subacromial impingement
A subacromial impingement is suspected in a patient over 40 with sudden shoulder pain that is not linked to any specific exertion or trauma. The patient feels the pain during everyday movements such as getting dressed. The pain worsens as the subacromial impingement progresses, and can even wake the patient.
An x-ray is insufficient to assess the condition of the tendons, but it is useful to determine the formation of a bone spur. An ultrasound or MRI scan can however reveal a subacromial impingement; an injection can be performed if there is any doubt. A few drops of corticosteroids are injected between the tendons and the acromion. Significant relief within 15 days following this injection confirms the diagnosis.
Treatment of subacromial impingement
In the early stages of subacromial impingement, a conservative treatment is preferred: anti-inflammatories to relieve the patient, rehabilitation. A few injections can also be considered and will be renewed according to the result.
When the pain relief is insufficient and the discomfort becomes too much, surgery will be considered. Very minor, it is performed arthoscopically and consists in removing the spur caused by the subacromial impingement: it is an acromioplasty.