Saturday, 13 February 2016

Knee arthroscopy for "mechanical symptoms"

I have previously written about the (non) role of arthroscopy for osteoarthritis or degenerative meniscus tears in the knee (here, here and here). Surgeons have continued to operate, based on a belief that (now) centres on the presence of mechanical symptoms. An analysis of the recent sham surgery trial of arthroscopic partial meniscectomy (APM), which showed APM to be no better than sham for patients with meniscus tears without arthritis, has shown that this procedure is no better than sham surgery for patients with mechanical symptoms.

I spend a lot of my time complaining that we don’t have enough high level evidence for many of the procedures we do. For knee arthroscopy, however, we have multiple high level studies, including the recent randomized trial of APM versus sham surgery for degenerative meniscus tears – a study that has been rated as having the least risk of bias of any study in this area, or just about any area. Yet knee arthroscopy is still one of the commonest orthopaedic procedures in the world, with about a million performed each year in the US alone, mostly in middle aged or older patients and patients with degenerative changes in the knee.

Surgeons used to perform this procedure for arthritic knees, and many still do. After the sham surgery study by Mosely in 2002 (and other studies), surgeons changed their tune. They continued to operate, but said it was for the meniscus tear, not the arthritis. Then the study by Sihvonen et al showed that it was not effective for degenerative meniscus tears without arthritis. Surgeons continued to operate, arguing that they were operating for ‘mechanical symptoms’ – a group of symptoms difficult to define and, depending on how you define it, present in most arthritic knees. In fact, nearly all of the patients in the first sham surgery study (by Mosely) had mechanical symptoms.

So Sihvonen and colleagues re-analysed their famous APM sham surgery study in patients with meniscus tears without arthritis, looking at who had mechanical symptoms and who did not, and whether surgery or sham treatment changed that (article is here). They decided to use catching or locking as the definition of mechanical symptoms, which is what most people would use, and this was present in nearly half of the patients. Patients with a knee that would not straighten (a true ‘locked’ knee) were excluded from the initial study.

For those having the real APM surgery, the proportion of patients with mechanical symptoms ROSE from 46% before surgery to 49% afterwards.

For those having sham surgery, the proportion of patients with mechanical symptoms FELL from 49% before, to 43% afterwards.

This means that APM is worse for mechanical symptoms than sham surgery, but the difference is not statistically significant so I cannot conclude that it is worse. Importantly, however, NO ONE can conclude from this that APM makes people with degenerative meniscus tears and mechanical symptoms better.


  1. Interesting that you advertise yourself as an arthroscopic knee surgeon Dr Ian Harris and yet here you are saying it doesn't work! You have to be kidding yourself to say that a patient with locking symptoms doesn't improve with direct curative treatment of the cause of those symptoms. Maybe you never had a torn meniscus? Maybe you can't really do arthroscopy well and therefore assume no one else can? Whatever the case is, your statements of arthroscopy being unhelpful for knee arthritis that are taught in first year medical school are now being used to debunk arthroscopy as a whole! They are being used to convince patients that they should spend their money on laser treatments instead!! All I can say is that you need to retire and stop your whining because we are all sick of seeing your face on abc and reading your name in the paper. Worst of all is that you don't even appear to be an elected representative of orthopaedic surgery yet you are being quoted as the chief. Maybe the abc and Medicare review panels should actually talk to a knee sub specialist and see what the actual truth is?

    1. Hi Sam, I hope I can clear up matters somewhat. I perform arthroscopy for certain indications, but not for indications for which it has shown to be ineffective compared to placebo, like osteoarthritis and degenerative meniscus tears (with or without mechanical symptoms), which are the conditions I have restricted my comments to. If people are using that evidence to ban arthroscopy altogether, or using it to justify some kind of other ineffective treatment, then they need to be corrected. I am not responsible for their interpretation of the evidence.

      The argument that I am not a good arthroscopist is not a valid one. Firstly, I was not involved int he trials and the surgeons that did the trials were experienced knee athroscopists. Secondly, the argument for expertise warrants a comeback: if you think the procedure works in your hands, then show me the evidence and do a trial. Otherwise, we can only base our decisions on the best available evidence.

      I understand that you may be sick of seeing my face, but consider my position: I have to see it every morning in the mirror.

      Regarding my 'elected' position in orthopaedic surgery, I do actually hold a very senior elected position in orthopaedics, but I do not claim to represent any individual organisation in my communications with the media or in the book. If I have, then please let me know and I will correct it but in the book I specifically state that I am NOT representing any professional body.

      Regarding the Medicare review panels, they have not spoken to me and I am not involved in that process. I know some other surgeons that are involved in that process.

      Regarding retirement and whining, I am actually happier than I have ever been and usually optimistic about the future. I still believe that surgeons are the ones that can correct the current problems with surgical practice and I also believe that they are doing so. I have considerable support in the surgical community in my attempts to achieve that goal and I am buoyed by that support. The first step in correcting the problems of surgery is to acknowledge them, and to carry out this process in an objective, scientific and unemotional manner.

  2. Hello Sir,

    Is there any certain and proven research about the relationship between partial menisectomy and early osteoarthris. What is the rate of the patient who is suffering from osteoarthris becuase of the partial menisectomy removed in early ages ?

    Is there difference between partial menisectomy and partial synovectomy ?

    Thank you,

    1. Although there is some evidence that partial meniscectomy increases the risk of OA, there is also evidence that it doesn't. Traditionally, we used to see severe OA occuring 15 years after complete (old fashioned) meniscectomy. It makes mechanical sense, but I don' thave strong evidence to support it.
      Meniscectomy and synovectomy are two very different things and are done for different reasons.

  3. I think this whole debate would be settled if we knew the mechanism behind the pain. If correcting the bones, or cleaning up a joint doesn't work to reduce pain, than what is really causing the pain? This question needs to be answered.

    There seems to be a growing body of thought that a lot of this chronic pain is a movement/muscle (and a possible role of nutrition) problem rather than a bone or joint problem.

    Why are people still immobile or in pain after hip replacement, discectomy, etc...? Why do people who exercise get the same pains as sedentary people? what causes arthritis anyway?

    I have been using the techniques of Kelly Starrett, Katy Bowman, Matt Hsu, and Shane Dowd to treat my FAI pain and my knee pain post ACL and meniscus surgeries.
    It seems to me that the muscles/movement problem hypothesis explains everything better than a bone/joint problem hypothesis or a "just getting older" hypothesis, but I would like to see more research in this area.

    1. You ask a very important question. There is some debate about what actually causes the pain in osteoarthritis. I don't think I can answer it. I know from experience that some people with severe arthritis don't have much pain, and vice versa.