Saturday, 18 August 2012

Placebo surgery #4: Knee arthroscopy in arthritis


An arthroscopy (key hole surgery to wash out, trim or clean up) in the knee joint is one of the most common procedures in orthopaedics, and one of the most common surgical procedures overall, with over one million performed in the USA each year. An overview of arthroscopy for knee osteoarthritis can be found in a previous blog; this post covers the sham surgery trial as part of a series on that topic.

In 2002, researchers from the USA published the results of a placebo controlled, sham surgery study of arthroscopy in patients with knee pain and osteoarthritis. They were older patients, mostly with mechanical symptoms. 180 study participants were randomised to one of three treatment arms: an arthroscopy with removal of loose bodies and torn cartilage and menisci, an arthroscopy and washout only, and a placebo only (just with the incisions). All patients had similar scars, and they were blinded to what treatment they received. Even the researchers doing the follow up didn’t know what treatment group they were in, eliminating any bias when assessing the outcome.

Over two years, there was no difference between the groups in pain or function. Patients in all groups got better; they just got better by the same amount.

The fact that patients in all groups improved is crucial. Many surgical procedures are performed on the basis that many patients get better after the treatment, and cause-and-effect is assumed (post hoc ergo propter hoc). Only comparison to a placebo can tell us whether or not the treatment has a specific effect on the patient.

Understandably, the study was criticised by surgeons who felt that the results did not fit with their experience. It has been supported by other randomised trials since, and there is some evidence that the rates of knee arthroscopy for osteoarthritis fell slightly after this study was published, but there are still many being performed, and the rates in my country are increasing. Why? Failure to accept the evidence, patient and referrer expectations, financial incentives, the desire to do something when nothing else is effective, and also because it works. It just doesn’t work any better than placebo.

17 comments:

  1. You are 100% correct about this. It needs to be more widely publicized. The orthopedist does make much money for treating knee arthritis with pills.

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  2. Sorry. Of course, I meant to say "The orthopedist doesn't make much money for treating knee arthritis with pills."

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    1. Funny, that's the way I read it anyway (not noticing the error). Must be my bias.

      Thanks for the comment.

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  3. Greenhorn Skeptic18 August 2012 at 23:22

    It would seem patients with knee pain fall into the 'disease-illness paradigm' you talk about in your post "I'm not sick but I'm not well". If their pain is complex and not completely organic which seems to be suggested by the above-mentioned study, it would be interesting to randomise patients presenting to an Orthopaedic surgeon with knee pain to arthroscopy, psychological counselling, or conservative treatment. Obviously the methodology is debatable but my point is that addressing the psychosomatic aspect of knee pain could potentially be be of value, could be no worse than placebo....or arthroscopy!
    Btw, great blog, I really enjoy the questions that this blog asks and the discussion that it stimulates!

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    1. Thanks Greenhorn Skeptic,

      For some patients with pain, you are probably right. Pain is such a complex concept, with so many factors feeding into the model, that there will always be some patients who have very little physical basis for their pain.

      For many in this group, however, they have a legitimate disease-illness: osteoarthritis. It's just that arthroscopy does help that much.

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  4. "the desire to do something when nothing else is effective"

    This is what I struggle with every day. As a patient, I don't know that these studies can conclude one thing or another. Each individual outcome is different and in my personal experience has far more to do with motivation than the skill of the surgeon. My OA pain is not organic but the product of 3 ACLs 2 infections and host of other complications. I can't fathom surgery number twelve but at 35 what are my options? I've been through them all and have come to the conclusion that while my pain management is in my own hands, my mechanical dysfunction I can not wholly fix on my own. We will see what happens.

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    1. Thanks Sarah,

      Readers should remember that I am a medical practitioner, and that there are many examples in medicine where we can improve patients (otherwise I would have to advertise on my blog). My aim is not to say that all medicine and surgery is ineffective, but to highlight how we tend to overestimate the benefit from medicine, and much of the time I do this by pointing out ineffective treatments that we think are effective.

      Your condition sounds fairly complicated; the kind of situation where you will need to rely on the opinion of an experienced, sensible orthopaedic surgeon. Or more than one if you have doubts. As long as the final decision on any intervention is yours to make, you will be more comfortable with the process and the outcome. Good luck.

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    2. It is complicated. And I do know that some medical procedures are beneficial. My knee experiences are of the extreme and I know that. I mean really, who gets Serratia Marcesans and Staph? I also know that times change and what people thought was once true, may no longer be the case. I don't think there is an Ortho out there now who would replace an ACL in 240 lb 15/f with no hopes of proper rehab.
      My current orthopedic surgeon has been the best one yet. When we met in '09 he told me he didn't want to see the inside of my knee for 5 years. After having a surgery every year and half or so since I was 15 this was a blessing. But also hard. I had fallen into mindset that I could be fixed. When I attempted the 3rd ACL I was at my lowest weight ever having lost 185 pounds through diet and exercise. I was unstable... but fine, strength was all I needed. That is still the case but I can't fix the scar tissue building up or the osteophytes on my own... One of these days I will have to go under the knife again, but this time with my eyes wide open.

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  5. Michael Mirochna, MD20 August 2012 at 07:25

    This is one of the reasons Medicare can "save" money or be "cut." We as taxpayers are spending so much money on procedures that clearly are as effective as placebo. Thanks Dr. Skeptic. Good Read.

    @DocRockne

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    1. You are not alone. Check out this NY Times opinion piece on how to save money in health - cut out the stuff that doesn't work. http://www.nytimes.com/2012/08/20/opinion/testing-standard-medical-practices.html?smid=tw-nytimeshealth&seid=auto

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  6. This is like what is done with people that come to the hospital all the time just for the pills. So they start giving them sugar pills but they still seem to get the same effect

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  7. osteoarthritis symptoms can range from mild to severe.They may include Pain,Stiffness,Muscle weakness,Swelling,Deformed joints,Reduced range of motion and loss of use of the joint,Cracking and creaking

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    1. Thanks. Knee arthroscopy is usually done for "mechanical symptoms" and the trials are criticised (incorrectly) as just choosing patients with 'arthritis', rather than mechanical symptoms. In fact, these trials did include patients with mechanical symptoms and they still didn't do any better.
      Deformity and instability can be a problem with severe arthritis, but this is best dealt with by a knee replacement, not arthroscopy.

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  8. This comment has been removed by a blog administrator.

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  9. Knee arthroscopy is a kind of keyhole surgery, used to look inside and treat the knee joint. It is one of the most frequently used procedures for the diagnosis and treatment of knee injuries. This minor surgical procedure is done using an instrument called an arthroscope. While the knee is the joint most often viewed and operated using the arthroscope, other joints such as the shoulder, elbow, ankle, hip and wrist can also be viewed using this instrument.

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    1. Thank you for this description of an arthroscopy. I guess my point though, is that it doesn't work. At least for arthritis anyway.

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  10. Current Med J Aust 2013; 199 (2): 100.:
    Wayne Adams, Manager, Safety and Quality in Health Care
    Benefits Management, HCF, Sydney, NSW.

    "In their editorial, Buchbinder and Harris conclude that “The use of arthroscopy for knee osteoarthritis has been allowed to continue, exposing patients to an intervention that is at best ineffective, and at worst, harmful”

    "It would be fair to say that the patient’s view of the benefits of the procedure is a leading indicator and should form an integral part of assessing the success of knee arthroscopies for osteoarthritis."

    Rachelle Buchbinder and Ian A Harris, Med J Aust 2013; 199 (2): 100.
    "In reply: We thank Adams for providing private health insurance data that confirm the continued use of arthroscopic surgery for patients with osteoarthritis."

    "We do not doubt that many patients are happy with the results of arthroscopic knee surgery, but this does not necessarily imply that the surgery has had any specific effect, as satisfaction rates are high after many ineffective placebo treatments. Indeed, high-quality randomised controlled trials have consistently failed to demonstrate clinically relevant self-assessed benefits of arthroscopy compared with sham surgery1 or non-surgical comparators.2-4 Potential risks of arthroscopy are also an important consideration."

    An interesting, and revealing exchange. I am still baffled by Mr Adam's managerial position at Safety and Quality in Health Care. He is not working at the Headquarters of Placebo, so... yeah. Baffled.

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