Subacromial decompression

Expert reviewer, Mr Roger Tillman, Consultant Orthopaedic Surgeon
Next review due February 2022

Subacromial decompression is an operation on your shoulder which treats a condition called shoulder impingement, where you feel pain when you raise your arm. It’s usually done through keyhole surgery (arthroscopy). You might also hear subacromial decompression referred to as ‘acromioplasty’.

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What is shoulder impingement?

Shoulder impingement is a common type of shoulder pain.

You have a group of muscles called the ‘rotator cuff’ which surround and support your shoulder. The tendons for these muscles lie in a narrow space between the top of your arm bone and the bone at the top of your shoulder blade. Shoulder impingement is the name given to the pain you feel if the tendons within this space become damaged. Doctors aren’t certain why this happens but it may be due to a number of causes, perhaps acting together. These may include:

  • your tendons becoming swollen or torn from overuse (for instance, doing sports) or ‘wear and tear’ as you get older
  • the shape of the bone at the top of your shoulder blade (the acromion), causing it to rub against your tendons
  • getting bony growths (spurs) on the acromion as you get older

If you have shoulder impingement, you’ll feel pain when you raise your arm. You may have some muscle wasting of the affected arm, and your arm movements may be restricted.

Preparing for subacromial decompression

Your operation will be carried out by an orthopaedic surgeon (a doctor who specialises in bone surgery). They’ll explain how to prepare for your procedure. For example, if you smoke, you’ll be asked to stop. This is because smoking increases your risk of getting a chest or wound infection, which can slow your recovery.

Before you go into hospital, you’ll need to make some preparations for after your surgery. The operation is usually done as a day case, which means you can go home later the same day. You’ll need to arrange for someone to collect you from hospital after your surgery and take you home. And make plans for someone to be with you for at least the first day after you come home.

You’ll probably be having a general anaesthetic, so you’ll be asked to follow fasting instructions. This means not eating or drinking, typically for about six hours beforehand. Follow your anaesthetist or surgeon’s advice carefully.

Your surgeon will discuss with you what will happen before, during and after your procedure, and any pain you might have. This is your opportunity to ask questions so that you understand what will be happening. You don’t have to go ahead with the procedure if you decide you don’t want it. Once you understand the procedure and if you agree to have it, you’ll be asked to sign a consent form.

What are the alternatives to subacromial decompression?

Shoulder pain has various causes and the symptoms can often be eased with other options such as:

Your surgeon will usually only recommend you have subacromial decompression if other treatments haven’t worked for you.

At the moment, there is some uncertainty about how well subacromial decompression surgery works for shoulder pain. You can ask your surgeon to explain why they feel it is the best option for you.

What happens during subacromial decompression?

During a subacromial decompression procedure, your surgeon will aim to make more space under your acromion by removing some of the bone and tissue from its underside.

Subacromial decompression is most often done as a keyhole procedure using a narrow, flexible, tube-like telescopic camera called an arthroscope. It’s usually done under general anaesthesia, which means that you’ll be asleep during the procedure. You may also be given a local anaesthetic into the nerves around your shoulder. This helps to reduce any pain you may feel after your operation.

Using the arthroscope through small cuts in your skin, your surgeon will look inside your shoulder. They’ll insert specially designed surgical instruments to carry out the subacromial decompression procedure. Your surgeon may also decide to repair any damaged tendons at the same time. This may mean they have to change from keyhole surgery to an open operation and will make a larger cut in your shoulder. See our FAQ on arthroscopy or open surgery below for more information.

At the end of the operation, your surgeon will remove the surgical instruments and close the cuts, usually with stitches.

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What to expect after a subacromial decompression

You’ll need to rest until the effects of the anaesthetic have passed. Let your nurse know if you’re in pain. You’ll be offered pain relief to help with any discomfort as the anaesthetic wears off.

You’ll usually be able to go home when you feel ready. Someone else should drive you home. Try to have a friend or relative stay with you for the first 24 hours.

Having general anaesthesia can temporarily affect your co-ordination and reasoning skills. So don’t drive, drink alcohol, operate machinery or sign legal documents for 24 hours afterwards. If you’re in any doubt about driving, contact your motor insurer so that you’re aware of their recommendations, and always follow your surgeon’s advice.

Before you leave hospital, your nurse will give you advice about caring for your wounds and tell you what to do about any stitches you have. You may need to keep your arm in a sling for a few days after your operation.

Your shoulder joint is likely to feel sore and stiff for a while. Applying a cold compress such as an ice pack or a bag of frozen peas wrapped in a towel may help to reduce swelling and bruising. But don’t apply ice directly to your bare shoulder because it can damage your skin.

If you need pain relief, you can take over-the-counter painkillers such as paracetamol or ibuprofen. Always read the patient information leaflet that comes with the medicine and if you have any questions, ask your pharmacist.

Recovering from subacromial decompression

It usually takes up to four months to make a full recovery after a subacromial decompression procedure. You’ll probably need help to wash and dress yourself at first. This should get easier after a few weeks.

You may see a physiotherapist (a health professional who specialises in maintaining and improving movement and mobility) after your operation. It’s really important that you do any exercises that your physiotherapist or surgeon recommends. These may help to stop your shoulder becoming stiff.

How long it will be before you can return to work after your operation will depend on how complicated your operation was and the type of job you have. Ask your surgeon or physiotherapist for advice about returning to work and other activities.

Side-effects of subacromial decompression

Side-effects are the unwanted but mostly temporary effects you may get after the procedure.

You may have some pain and stiffness around your shoulder after surgery. This may make moving around uncomfortable at first.

If you develop any of the following symptoms, contact your hospital immediately because it may indicate you have an infection or other complication.

  • Your wound becomes hot, red or swollen.
  • Your wound bleeds or becomes more painful.
  • You have a high temperature.

Complications of subacromial decompression

Complications are when problems occur during or after a procedure.

There are several possible complications of any operation. These include an unexpected reaction to the anaesthetic, a blood clot in the veins of your leg (deep vein thrombosis – DVT), and excessive bleeding or infection.

A possible complication of subacromial decompression is accidental damage to the tissues around your shoulder joint, including nerves or blood vessels.

Some people develop stiffness in their shoulder (‘frozen shoulder’) after a subacromial decompression procedure. This usually gets better after three to six months.

You can ask your surgeon about possible complications, and how they might relate to your individual circumstances.

Frequently asked questions

  • Your surgeon or physiotherapist will give you a range of exercises to do after your surgery. It’s important to do these exercises as they will help you to keep your shoulder moving properly and avoid stiffness. These may include exercises to:

    • stretch the muscles around your shoulder
    • improve the range of motion of your shoulder
    • improve the strength of your muscles around your shoulder

    You will be advised when you can start these exercises, and how many you need to do. You’ll have exercises to do at home and you may also be offered a course of hospital-based physiotherapy sessions.

    You’ll probably be able to get back to your usual activities after about three to four months.

  • It’s common for subacromial decompression to be done using keyhole surgery (arthroscopy). This means your surgeon will make small cuts in your shoulder to pass specially adapted surgical equipment through to repair your shoulder. Having small cuts means you may recover more quickly than with open surgery – getting back to your usual activities sooner.

    Open surgery means your surgeon makes a larger cut in your shoulder. This allows them to see your shoulder blade, rotator cuff muscles and tendons directly. Your surgeon may have to convert from using keyhole surgery to open surgery if your rotator cuff tendons need to be repaired as well.

    Doctors aren’t sure yet, but it doesn’t seem that you’re any more likely to get complications after open surgery than keyhole surgery.

    Ask your surgeon to explain which is the best option for you in your circumstances.

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Related information

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    • Rotator cuff disease. Medscape., updated August 2018
    • Shoulder pain. PatientPlus., last edited June 2015
    • Kulkarni R, Gibson J, Brownson P, et al. Subacromial shoulder pain. BESS/BOA Patient Care Pathways. Shoulder & Elbow 2015; 7(2):135–43. doi:10.1177/1758573215576456
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    • Paavola M, Malmivaara Ai, Taimela S, et al. Subacromial decompression versus diagnostic arthroscopy for shoulder impingement: randomised, placebo surgery controlled clinical trial. BMJ 2018; 362:k2860. doi:10.1136/bmj.k2860
    • Common postoperative complications. PatientPlus., last edited July 2016
    • Personal communication, Mr Roger Tillman, Consultant Orthopaedic Surgeon, February 2019
  • Reviewed by Dr Kristina Routh, Freelance Health Editor, Bupa Health Content Team, February 2019
    Expert reviewer, Mr Roger Tillman, Consultant Orthopaedic Surgeon
    Next review due February 2022