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Arthroscopic Subacromial Decompression



This is a keyhole operation that aims to relieve the pain you feel from impingement and tendinopathy.   There is some controversy regarding the efficacy and mechanism of action of this operation when performed a sole procedure in patients with an intact rotator cuff.  It is important to recognise that some patients may improve without surgery over time and with good physiotherapy.  

As a sole procedure therefore, this operation is recommended only when non-surgical measures, such as an injection and a good course of exercise-based physiotherapy have failed to cure your problem.  However, the procedure is often carried out alongside another keyhole shoulder surgical procedure  in order to improve visualisation and access to the areas that require treatment.  A common example of this would be as part of an arthroscopic rotator cuff repair or arthroscopic excision of the acromioclavicular joint. 

The operation is performed under general anaesthesia and a regional nerve block.  After your joint has been inspected, the arthroscope is passed into your subacromial space (the space above your rotator cuff tendons and below the acromion process of your shoulder blade.  The inflamed soft tissue of the bursa is then cleared.  Removal of the bursal tissue is thought to clear pain-sensitized nerve endings from your subacromial space. It also clears the view so your surgeon can inspect and treat your acromion bone, your acromio-clavicular joint (above) and your rotator cuff tendons (below).  Often patients have a spur, or a hook of bone, at the front of their acromion and  a thickened and frayed ligament at the front. In some patients, these cause rubbing against your rotator cuff tendons, so any spur or thickened ligament tissue is shaved back to a smooth surface using a high-speed burr. As well as increasing the space in your shoulder (decompression), the raw bone surface is then able to release growth factors into your shoulder that improve tendon healing.  

Below is a photograph of the exposed underside of the acromion bone.  The radiofrequency instrument has been used to clear the inflamed bursal tissue sbefore this photograph was taken.  The dotted red line shows the spur, which is then resected using a shaver in the next image. This leaves more space for the rotator cuff tendons and a smooth freshened bone surface on the acromion (final image).

View of a typical acromion spur from within subacromial bursa. The inflamed bursal

tissue has been removed using the radiofrequency instrument.  Note the tight space

between the acromion above and the rotator cuff tendons below

A high-speed burr is then used to resect the acromial spur

The bone resection is complete and the subacromial space is decompressed 

What is my recovery after surgery? Patient information leaflet - recovery from decompression

You will normally go home a few hours after your operation.  Please take your prescribed painkillers regularly for the first few days and start them before your nerve block wears off.   You will be given a sling, but you can discard this after a few days.  Please begin begin your rehabilitation as soon as you can.  You can take down any bulky padded dressings on day 2 after surgery, but keep your wounds covered with the waterproof dressings for 12 days.  Showering is fine after four days with dressings on.

Rehab Plan

As no structure is repaired or reconstructed in a decompression, there is no need for a period of protection after a decompression.  We therefore ask you to try to get your shoulder moving soon after your operation. Your physiotherapist will help you regain range of motion and control of your shoulder.  Once you have achieved this, then you can focus on regaining strength.

Patients vary in their recovery after surgery, but in general you can expect to return to:

Office work after three weeks for some, but other may still be too sore

Light physical work after 8 weeks, but some may find this too sore for a while longer

Heavy labour or overhead sport may take 18  weeks

Driving will take 3-8 weeks for most patients

What are my chances of success?

Overall this operation works well, but it can take a while to recover:

By six weeks, 60% of patients will have noticed a significant improvement and most will be comfortable during daily activities. however, certain movements will still be restricted and uncomfortable.  Do not worry if you remain sore at this point: it can take a while longer to recover from this operation.  

By six months, 90% feel their shoulder is better, although some patients take even longer to benefit. 

What can go wrong?

Arthroscopic shoulder surgery is generally very safe, but specific risks of subacromial decompression include:

Stiffness (5%) which occasionally requires further surgery

Lack of benefit (approx. 10%)  - remember, it can take 9 months for full benefit to be realised after this operation.