Swings, roundabouts, and CSAWs!

Healthcare can be a bit like a playground at times with lots of clinicians swinging from treatment to treatment, patients feeling like they’re on roundabouts going around in circles, and all of us have felt the see-sawing highs and lows of trying to help people with pain and disability.

As a shoulder ‘specialist’ one area I have had many highs and lows with over the years is sub-acromial shoulder pain. I find it a fascinating yet infuriating condition, not only due to the difficulties in its diagnosis but also in its uncertainty in how to manage it.

One uncertainty I have had for a long time is what role does surgery have, in particular, arthroscopic sub-acromial decompression surgery? Who is best suited for this operation which involves shaving the bone of the acromion and the removal of the sub-acromial bursa and sometimes the coracoacromial ligament which is believed to reduce compression forces on the rotator cuff underneath?

I have discussed my concerns and issues with this operation before, having seen it performed too often, too quickly, and seen too many patients worsen afterwards. But I have also seen some great success and some very satisfied patients with this surgery. The questions are why do some do well and others not? Is it the surgery, the rest and rehab after, or maybe its something else?

Read this!

To try and answer these questions a highly anticipated paper was published a few weeks ago in the Lancet called Can Shoulder Arthroscopy Work or CSAW. It’s free to access and I urge you all to read it as I believe it to be one of the most important papers on sub-acromial shoulder pain published in a decade.

This large, rigorously conducted, blinded randomised controlled trial compared three groups of patients with sub-acromial shoulder pain who had failed conservative treatments. One group served as a control and were not given any further treatment at all, being followed up at 6 and 12 months using the Oxford Shoulder Score.

The other two groups had arthroscopic surgery on their shoulders. Half were randomly allocated to have a diagnostic arthroscopy only which only involved placing the surgical instruments into their shoulders under anaesthetic and then removing them. The others had a ‘routine’ or usual arthroscopic decompression which involved shaving of the acromion, +/- removal of the bursa and the coracoacromial ligament as deemed necessary by the surgeon.

All the patients and those involved in the follow-up care were blinded so no-one knew who had the arthroscopy or the decompression, and both groups had the same aftercare and physiotherapy treatment. They were also followed up at 6 and 12 months using the Oxford Shoulder Score just like the control group.

The results below show that there is NO significant difference between the two surgical groups, demonstrating that shaving the acromion and/or removing the bursa and ligament is not needed to reduce sub-acromial shoulder pain and disability.

Essentially this demonstrates that arthroscopic sub-acromial decompression surgery is a placebo, and due to the costs and risks involved for this operation it strongly questions its continued use in the management of those with sub-acromial shoulder pain. There was a significant difference between the two surgical groups and the control group, demonstrating that something did have an effect on the surgical groups the question is what is that?

Physio, the new gold standard?

Well, it could be the effect of the physiotherapy and rehabilitation that was given to both surgical groups after their operations. However, before all the physios get too carried away and start to think their treatments are the new gold standard for sub-acromial shoulder pain, we need to look a little more closely at the results and put our critical thinking caps on.

First, we need to remember that statically significant doesn’t automatically mean clinically meaningful. If you look closer at the results you will see that the difference between the waiting list control group and the surgical/rehab groups is small, really small, and the authors state that they are uncertain if this difference is meaningful with the Oxford Shoulder Score they used having around a 5 point minimal clinical important difference (MCID).

We also need to remember that control groups in research trials often suffer from the phenomenon of resentful demoralisation. This is when subjects who consent to a trial realise that they are not having any treatment and start to feel hard done by. This means they often report their symptoms are worse than they actually are, possibly meaning that this control group could be even better than reported, further reducing that statistical difference!

Looking at these results we have to ask ourselves is natural history the gold standard treatment and both surgery and the physiotherapy are doing very little for a lot of cost and some risks? Does the cost, time, and resources of the surgery, or the usual 6-12 physiotherapy sessions justify the small improvements and changes in outcome seen here?

Over-treated and Over-complicated?

Now you might think I am being overly harsh and negative on physiotherapy yet again, but we have to put our practice under the same critical lens as we do with others. I am and always will be an advocate of physiotherapy and I do think we can be effective in helping those with sub-acromial shoulder pain. However, currently, I think many physios over complicate and over treat this condition doing some weird, wonderful, and wacky stuff such as scapular setting, taping, needling, and not forgetting all that shoulder symptom modification procedure business.

In my opinion, most with sub-acromial shoulder pain can and should be managed by being confidently and compassionately reassured that the pain they feel is not serious or sinister, that it will get better over time, but this will be longer than they expect or anticipate. They should be advised to carry on as best as they can and not let the pain worry them that they are harming themselves, nor should it deter them from doing activities and of course they should be encouraged to do some exercise, and try to reduce any other stressors in their lives.

It would have been interesting to see what would have happened if there was another 4th group to the CSAW trial, one that was given the information and advice that I have just mentioned as well as some general upper limb exercise. Would we have seen something like I hypothesis below? Who knows, this is just my bias and maybe for the CSAW V 2.0.

So it looks like the end is nigh for the arthroscopic shoulder decompression operation after this CSAW trial… or does it? Well, let me give you an example of one patient I had with sub-acromial shoulder pain recently and show you how sometimes it isn’t as black or white as this.

A Case Study

Last year I had a 36-year-old, very keen recreational triathlete who regularly competes in ironmans come and see me about his chronic right shoulder pain he was feeling during his swimming. He reported no previous injuries but this shoulder pain had been slowly building on and off for about a year when swimming. It was now becoming more pronounced and was limiting his ability to swim much at all, and he had also started to notice it on other activities during the day and at night when sleeping on it. He had no past medical history, he was fit and healthy, had low levels of stress, was in a job he enjoyed and had a happy family and social life.

He had already seen a specialist shoulder orthopaedic consultant privately and had an assessment and MRI. From this, he was told that he had no tears or splits of his rotator cuff and his ACJ and acromion was normal with no large spurs seen but he was recommended to have an arthroscopic decompression to give more space for his shoulder when swimming and reduce the pressure on his rotator cuff.

However, he had done some reading and knew that physio and exercise-based rehab is also an option and he was not keen for surgery. During the history taking, I could tell he was well-read on this topic, and he had hopeful yet realistic expectations of physiotherapy which we know is a strong predictor of successful outcome.

My physical assessment of him was unremarkable, he had no gross loss of movement or asymmetry, he also had no sub-acromial or ACJ pain provocation signs. The only thing I could highlight was a 25% loss of external rotation and flexion strength on handheld dynamometry testing with no major pain felt. I was unable to elicit any signs of subscapularis issues or anterior internal impingement pain on testing which is now thought to be a factor in swimmers shoulder pain. This clearly was a high performing low irritable shoulder with no major structural or biomechanical deficits that I could see.

Based on this assessment we first got him to start recording his training keeping an accurate log of his swimming volume ensuring he kept his weekly volumes between 0.75-1.5 of the previous weeks. He also started working with a swimming coach to look at his technique and had some minor adjustments but was told there was nothing major amiss here.

I also got him to look at and address any other potential stressors at home and work, and we improved his recovery strategies mainly his erratic sleeping patterns and times. And finally, of course, I strengthened the shit out of him. I got him to do two 30-45 minute sessions of S&C a week which included two upper limb exercises performed over 3-5 sets, using high load (>60%RM) moderate reps (6-12) mainly focusing on his external rotators and posterior chain, which we changed every 4-6 weeks.

Better, but…

At the end of 6 months he was more organised, better focused, feeling stronger than ever but…  he still had the same bloody shoulder pain when swimming. After some deliberation, he decided to go ahead and have the arthroscopic shoulder decompression much to my disappointment.

He was well aware, thanks to my constant harping on about it, that this operation was not guaranteed to be successful. He was well aware that there are small but significant risks. He was aware he would be set back and would need to do all stuff we were currently doing all over again. Regardless he went ahead with the decompression.

I next saw him 3 weeks after the operation which went without any issues. The surgeons’ report was unremarkable just a standard acromioplasty with no other significant pathology noted. He had already gone back swimming a few days ago to tentatively test it out and he reported an instant improvement in his shoulder already. He knew that this could all be placebo but he didn’t care, something felt better after the operation that wasn’t before despite our best evidence-based efforts.

This case just highlights to me how despite knowing what we know, there is still a lot we don’t know. It also makes me wonder if the arthroscopic sub-acromial decompression surgery still does have a role in SOME patients who are FULLY informed of the risks and the uncertainty of what and how it works, whether this is ethical or not, well that’s another question best saved for another time.

As always, thanks for reading




  1. Hey there Adam, I see the same for surgery on acetabular impingement. I have wondered what would what would happen if people just backed off for 6 weeks like they actually had surgery, let things calm down and then add back a “post surgical” rehab program like you gave this guy. Problem is, most would never do this without surgery.

  2. Your 36yo triathlete —> 1. Did the pre op MRI show a thickened cuff or thickened CAL? 2. Why the weakness detected by dynamometry, and did this change on post op testing? 3. Does the traumatic muscle breach of arthroscopy result in a persistent fractional weakening of deltoid, and was there a change in deltoid power pre versus post op?

  3. Maybe the triathlete just needed a period of dedicated rest? And the post surgery time period supplied that? A coach I respect uses this as his sole means for injury management. Take down-time only when you are injured… you don’t need it any other time.

  4. So in this instance why is it the surgery appeared to work? If he seemingly had a shoulder with full range of movement and strength. Could we (sorry Adam) criteque the physio – was it not specific enough to the aggravating movement (swim stroke). Is there a need to focus on biomechanics in this type of patient. where does the role of biomechanics sit it the treatment of conditions. Was it that the patient had in the back of his mind ‘a get out of jail free card’ and so although tried physio because he knew of the benefits, surgery was still an option and so the benefit of the surgery is related to expectation/belief? Not procedure?!

    • Hi Kate… you can critique all you like, im used to it … ;0)
      But to answer your points… This patient has swum for years without any issues, so why would his biomechanics adversely affect him now? Also as I said he worked with an experienced swim coach whilst he was rehabbing with me (on my request) and he was told nothing major amiss with his technique apart from some minor adjustments. Still didnt make any difference.
      And yes maybe there was some expectation to fail despite him thinking and hoping otherwise.

  5. Excellent review and assessment of this problem. In my experience 60% (at least) of patients with ‘impingement’ will get better with time, quality rehab and maybe an injection or two (especially if the scans show a predominantly inflammatory picture with no structural issues). And none should have surgery unless all that has failed. Why it works (when it works) – now that’s magic!!!

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