Shoulder decompression under more pressure…

Arthroscopic shoulder decompression surgery is a very common operation. It is often used for patients whose pain is thought to be caused by excessive compression of the rotator cuff and its bursa between the acromion and the humeral head. It is believed that by shaving the bony arch of the acromion and removing the coracoacromial ligament it will reduce compressive forces on the rotator cuff and help it recover and function better.
However, the effectiveness of this surgery first proposed by Neer decades ago has been challenged for many years, by many people, and recently some research has challenged it further. This paper here discusses how removing the coracoacromial ligament and shaving the acromial arch means the rotator cuff has to actually work HARDER not less! This is completely the opposite and contradictory to how this surgery is often explained to patients, and it also explains why many patients don’t do well after this surgery.
In this paper, the authors explain how the acromion and the coracoacromial ligament are normal physical barriers to superior humeral head translation. Contrary to common belief and teaching the cuff and the bursa contact the acromion all the time in all of us whenever we lift our arms up and down (ref, ref), and hence why I hate the term ‘impingement’ as it is meaningless.
Anyway, the authors of this paper continue to explain that by removing this barrier the humeral head it is now free to translate superiorly, forcing the rotator cuff to compensate and work up to 25-30% harder to prevent the humeral head escaping through the gap created by the decompression surgery. Or it doesn’t and the humeral head does actually escape superiorly.

Diagram of how the acromial arch & coracoacromial ligament act as a barrier to the humeral head.

There are some limitations with this study, mainly that it is a cadaveric study so we can not extrapolate these findings onto living patients. But it does make us think and ask some awkward questions.
For example, if we have a painful shoulder that already has a weakened and struggling rotator cuff due to tendinopathy, or a structural defect such as a tear, and we then remove the superior structures of the acromion and its ligament, we could be making matters worse by further overloading the rotator cuff. It may be that the acromion and the coracoacromial ligament are actually helping not hindering matters in many patients with subacromial shoulder pain.
The belief that these sub acromial issues such as rotator cuff tendinopathy, tears and bursitis are caused by excessive compression forces from the acromion pushing down is becoming challenged more and more, and for many years. For example, if the acromion is to blame then why do the majority of the rotator cuff issues seen tend to occur on the opposite humeral head side (ref, refref). And why would an acromion that has been the same shape since skeletal maturity and that doesn’t change shape due to external factors suddenly start causing problems all of a sudden (ref).
The big question is does the acromion push down or the humeral head push up, or is it the tendon and bursal ‘swelling’ in-between? As I said at the start arthroscopic shoulder decompression surgery is a very common procedure, in fact, it is the fastest growing operative procedure in the UK, and has increased nearly 750% in the last decade (ref). However, the common belief of how this helps some is looking more and more doubtful and other less invasive, less costly, and less risky methods such as exercise can be just as effective (ref, ref, ref).
However, as much as I have questions about it, shoulder decompression surgery does appear to work for many patients, I see it every day. The question is how and why? I think we will gain more insights into the effects of this surgery once the first randomised placebo control trial of it is released soon (ref), and I for one am waiting with baited breath…
As always thanks for reading



  1. Hi Adam
    Thanks for blog.
    Do you know any thing about a reversed shoulder arthroplasty? I’m sure you do!
    The wife of a client of mine has been told that this is what she needs. Scans have suggested, she has severe arthritis, but she also has rheumatoid arthritis and is taking medication accordingly. She is 76 years young. She is a carer and looks after her husband who has ms and is totally wheel chair bound.
    Do you know of any research that highlights the success or not of this particular operation? She herself feels that nerves may also be part the issue, but isn’t seeing a physio who has nerve experience.
    Could recommend anyone this way, West Berks, Newbury, that may be able to help?
    Many thanks.
    Sue Pitts [email protected] Phone 01635273210 Mobile 07795552910
    wellbeing naturally

    • Hi Sue.
      The reverse shoulder replacement is normally used for arthritic shoulders that are constantly painful and severely disabling and that have no rotator cuff due to tears.
      They do have a good outcome in the literature, and in my experience as log as the surgeon is experienced in using them. However I always recommend that patients only go for this operation when the pain and disability becomes too much to live with. On average it takes 6-9 months to fully recover from this operation.
      I hope that helps

  2. Interesting read! As a physio working in Sweden, I too come across patients who’ve had these surgeries. Could it be that the positive outcomes experienced by some patients after having one of these surgeries is due to a combination of complete rest from aggravating activies, as well as a rehab programme that starts off on a very basic level and then progresses in a slow and controlled manor? If this is indeed the case, maybe the same results can be achieved without the surgery. Any thoughts on this?

    • A progressive and comprehensive rehab program (and a patient willing to follow it) are important in achieving a good outcome from many ortho procedures

  3. Hi Adam,
    Interesting read as always. Im currently in orthopaedics as part of my rotations and see this operation on a daily basis. I’ve had my suspicions regarding its effects for a while so will keep an eye out for that trial!
    What i’m interested to know is how would you tackle a patient who is of the belief they require this surgery… both from a psychological and exercise treatment perspective? Load it like you’ve mentioned in previous blogs/podcasts?

    • Hi John
      Patient beliefs are to be respected. We know that the BIGGEST predictor of a successful outcome is if the patient believes the treatment will help them.
      However that doesn’t mean we just do what the patients wants, so a lot of my time is spent exploring patients beliefs, and then I look for ways to change them so that they eventually believe that they DONT need the surgery… And that Physio is the best option for them.
      I then load the f**k out of them ?

  4. Dear Adam, I think the patient gets better because of the Physical therapy after the operation……
    Paul van der Tas – Holland – SportsPhysical Therapist and MSU-Ultrasonographer

  5. Hi Adam thankyou for the read. I work in secondary care more and more i am seeing pts who have complained of sub acromial pain pre op and still post op it is not until they’ve undertaken progressive exercises that they then improve. Why they are not offered this prior to surgery is something I hope to address.
    I also see a number of rotator cuff repairs. What confuses me are repairs that no matter what i seem to do just don’t improve!
    And non operable tears, I address as much as I can but the odd patient remains to have significant weakness pain and disablement. Is this likely to be as good as they get or am I missing a trick?!
    Your thoughts would be greatly appreciated.

    • Hi Kate
      When the placebo surgery trial research is published we will see if decompression adds anything to the rehab afterwards. And all patients should be offered Physio before surgery but sadly this doesn’t always happen.
      As for cuff repairs and tears, you’re right some can be tricky and fail to improve. Some key points for me are be patient and persistent, both you and the patient.
      Find activities that are challenging but not impossible and work towards making them easy
      Don’t ‘fear’ some pain when rehabbing, but of course be sensible.
      Hope that helps a little

  6. Seeing a lot of these ASDs at the moment being performed and they are becoming particularly difficult to rehab. A lot of them presenting with great weakness in the cuff and no matter what form of exercise given to them (even gentle isometrics for the cuff), it seems to flare up and cause pain. Not all but most.
    Thinking of simplifying it right down and practicing the grip stuff for cuff activation as mentioned in one of your blogs Adam or is that a touch soft?
    Is this increase in pain in the first 3/4 weeks of rehab expected or am I missing something?
    Much appreciated!

  7. Hi Adam
    Thanks for the interesting read. I am a physiotherapist working in Melbourne, Australia and have seen a number of sub – acromial decompressions in the previous few years.
    I find that more often than not the patients are left in more pain for an extended period of time post surgery….obviously the rehab program has to be extensive to return to full function. If their main health practitioner has only been the surgeon or doctor, the extensive rehab protocol may not have been discussed in detail.
    I would also agree with some of the above comments in that a period of rest and gradual physio program can be the reason behind improvements in pain rather than the surgery itself, and I have seen some studies discussing this topic.
    Mark Anile
    Physiotherapy Essendon HTML link.

  8. Hi Adam,
    Great blog as always.
    Lewis (2011) challenged the myth of subacromial impingement as well suggesting rotator cuff tendinopathy is a better term. Looking forward to the placebo article.

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