A view of a right shoulder from behind. The area of impingement is colored red.
Shoulder impingement is a very common cause of shoulder pain. It usually causes pain on the lateral side of the shoulder and is worse with raising the arm up overhead since this can bring the rotator cuff into contact with the acromion, the bony "roof" of the shoulder. The problem can often be treated with physical therapy or injections, but many people end up getting surgery to fix the problem. Whether treated in isolation or alongside other problems of the shoulder, the surgery for impingement is called a subacromial decompression. This is a surgery done through an arthroscope and involves smoothing the undersurface of the acromion. A recent study showed that this is the most commonly performed surgery of the shoulder. So it is interesting to see that there are many who question whether the surgery really helps people.
The British Medical Journal just published this study on subacromial decompression. This was a multi center double-blind triple group randomized trial comparing a group of patients who receieved subacromial decompression against a group who had a simple diagnostic arthroscopy where no intervention was performed. They also included a group who only got treated with an exercise program. At 24 months, no clinically important difference could be found between the group who had subacromial decompression and the diagnostic arthroscopy or exercise groups.
Comment:
I very rarely do a subacromial decompression on my patients with shoulder impingement. I find that most people who have impingement get better with physical therapy as they improve their mechanics. Occasionally, people need an injection. If people don't get better after those treatments I start to suspect other problems such as bicep tendinitis or a rotator cuff tear. I do a subacromial decompression if there are signs of bone spurs pushing down on the rotator cuff.