The role of knee arthroscopy

Recently there have been a number of high-profile articles published in two particular medical (note, not surgical) journals, commenting on the role of arthroscopy in degenerate knees. The first was in the British Medical Journal (BMJ). The second was in the British Journal of Sports Medicine; however, their article was simply just a regurgitation of the BMJ’s article, with no further scientific evidence but with some very strong conclusions and opinions. The crux is that some people are saying that “knee arthroscopy doesn’t work!”…

Knee arthroscopy simply means looking (‘scopy’) into a knee joint (‘arthro’) with a camera. It is nothing more than simply just a method for looking into a knee. The term ‘knee arthroscopy’ says nothing about why you might be doing the procedure, nothing about what you might actually find inside the knee and nothing about what the actual surgical procedure might be to fix the problem.

A list of just some of the things that one might find inside a knee joint at the time of an arthroscopy (and this list is not exhaustive) includes:

  • meniscal tears,
  • fissures, flaps or defects in the articular cartilage on the joint surfaces,
  • ACL tears (partial or total),
  • osteochondral loose bodies,
  • osteochondritis dissecans lesions,
  • thickening / inflammation of the fat pad and
  • medial and/or lateral and/or supra patellar plicae.

Looking just at ‘meniscal tears’: there are many various different types of meniscal tear, ranging from vertical peripheral circumferential tears to radial tears, to horizontal cleavage tears, to flap tears, to ragged degenerate tears, to complex tears and to bucket handle tears (which may be stable, unstable or displaced and locked). Each of these tears has different characteristics and tends to be treated in different ways, with a number of various different surgical techniques. So, a meniscal tear is not ‘just a meniscal tear’. The same applies for pretty much every other potential pathology that one might find inside a knee: each one needs to be considered carefully and with thought, on a case-by-case basis, according to the exact pathology in the specific context of that particular individual patient (in terms of their physiological age, their health, their job, their exercise/sport activities, their circumstances and their expectations and aspirations).

In terms of the technicalities of what potential surgical procedures might be undertaken in a knee joint at the time of an arthroscopy, the list (which again, is certainly not exhaustive) includes:

  • meniscal trimming,
  • meniscal repair,
  • meniscal replacement (e.g. meniscal transplantation),
  • radio frequency chondroplasty,
  • abrasion chondroplasty,
  • micro fracture,
  • arthroscopic articular cartilage grafting,
  • fixation of osteochondral / ossechondritis dissecans lesions,
  • arthroscopic ACL repair,
  • arthroscopic ACL reconstruction,
  • washout of debris,
  • removal of chondral / osteochondral loose bodies,
  • trimming of the fat pad,
  • excision of place,
  • lateral release and
  • synovectomy.

These are the actual procedures that can be performed, which can be performed either minimally-invasively through keyhole surgery or, potentially, through larger open incisions.

So, hopefully you can appreciate that genuinely, an arthroscopy is not just ‘an arthroscopy’, and the term ‘arthroscopy’ really is nothing more than term that describes a method for performing a wide variety of different surgical procedures without the need for having to open up a knee joint fully.

Good surgery is all about:

  • having deep as well as broad knowledge of your subject;
  • it’s about listening properly to your patients and giving them sufficient time;
  • it’s about making the correct diagnosis;
  • it’s about having a truly broad skillset, so that you’re able to offer the full range of appropriate available surgical solutions;
  • it’s about careful and appropriate patient selection and decision-making in close conjunction with the patient’s own wishes;
  • it’s about communication skills and patient education;
  • it’s about empathy and understanding of patients’ emotional needs;
  • and finally, it’s then about good technical skill as a surgeon.

It is therefore difficult to understand how people who do not have the relevant training, knowledge, qualifications or experience are able to make such bold statements out of their area of expertise.

Specifically with respect to the articles in the BMJ and the BJSM, there have been two truly excellent papers published in response to the recent negative press, both by Mr Steve Bollen, who is one of the UK’s leading knee surgeons. One of Bollen’s article was published as a lead article in the Bone and Joint Journal, and a copy of this article is available HERE. This is essential reading for anyone actually genuinely interested in the debate and in the subject of knee arthroscopy. The Journal of Arthroscopy then published an ‘Open letter to the Editor of the BMJ’: click HERE to read a copy of this letter, which again is essential reading.

A few very important specific issues have arisen from the recent debate in the literature. These are:

  • Some people now seem to be defining the cut-off for ‘old’ as 35!! … with some people stating that if you’re 36 or above then your knee must be degenerate and hence you’re not ‘worthy’ of even consideration for a knee arthroscopy. This is decision-making with no scientific basis. I’ve seen people in their 20s with knees that are severely worn and fully arthritic; but I’ve seen 70-year-olds with pristine knees who are still doing sport and running marathons.
  • Some people seem to think that ‘a degenerate knee’ is a full and proper diagnosis. To me (as an actual knee expert) this means very little indeed. Wear and tear, degeneration and osteoarthritis are often used interchangeably; however, these terms can cover an extremely wide range of different degrees of damage in a joint. There are a number of different grading systems available; some easy and simplistic, some more detailed and complex. However, in my opinion no-one should ever treat anyone’s knee without first seeing exactly what the extent of any damage might be and without knowing exactly which areas of the joint is affected, which is not something that can be described adequately or appropriately in just three words (“a degenerate knee”).
  • Next, some people seem to be lumping together the terms ‘knee degeneration’ and ‘degenerate meniscal tear’. The two are not the same. I’ve seen spontaneous degenerate tears in the posterior horn of the medial meniscus in a number of young people (in their 20’s); whereas I’ve seen acute simple traumatic tears in people over 60 where the meniscus has otherwise been in good condition, and where the tear has actually been repairable. Nobody sensible would advocate meniscal repair in someone with fully-blown arthritis in their knee, with exposed bare bone in that compartment of the knee rubbing on the meniscus; however, likewise, no-one sensible would (or perhaps I should now say ‘should’) simply ignore a persistently symptomatic meniscal tear in a patient’s knee just because they’re over 35 or just because they’ve got a small amount of minor partial thickness wear and tear of their articular cartilage.

Interpreting scientific studies is a complex thing that requires an understanding of scientific process and methodology, an understanding of statistical analysis and an understanding of context. It also requires one to have an open mind. Importantly, however, it is vital that one appreciates the significant limitations that are inherent in much of the published medical scientific ‘evidence’.

If one is to quote a medical study, and even more so if one is to cast opinions and recommend formal guidelines and policies, then it is essential that one reads the actual papers in full. The recent BMJ paper by Thorlund et al. was simply a review article that based its conclusions on just a very small number of the papers that have actually been published on the subject of degenerate meniscal tears. However, has the Editor of the BMJ or the Editor of the BJSM actually gone back and read in full all of the individual papers that Thorlund has selectively chosen to quote? Almost definitely not.

By way of what should hopefully be a clear enough analogy …. Let’s set up a study looking at the use of sutures for stitching cuts vs just covering the cut over with an Elastoplast. If we were to take 1000 people from the general population with a cut, then the very large majority of these cuts (from paper cuts to catching oneself on a rose thorn) would not need stitching. If we were to prospectively randomise 1000 people so that 500 of them had their cuts stitched and 500 didn’t, and they simply had a sticking plaster instead, and if we were to then look at healing rates, we’d see no difference between the two treatments (stitching vs just plasters). So, one might then conclude that stitching doesn’t work, or that it’s pointless, or that it’s ‘wrong’. However… if we then consider that of those 1000 cuts, a very small number were deep cuts, all the way through the skin, or cuts that exposed fat, muscle, bone or tendons, or even a surgical ‘cut’ (because ‘a cut is just a cut’, isn’t it?!) – then for some of these ‘cuts’ the stitches are essential, and trying to cover a large or deep wound with just a simple Elastoplast would be nonsensical and really quite crazy. However… according to the scientifically robust prospective blinded randomised study that was published on the subject (incidentally, by people who, let’s say, have never actually stitched a wound in their lives), no-one should ever be allowed to have their ‘cut’ stitched!!?!

Yes, this may seem like an over-exaggeration of the point. However, the basic concepts here are valid. Clinical trials can only ever give a limited snapshot of information about a subject, which should only be applied with great caution to particular patient groups and actual specific individual patients.

In one of the main quoted studies against the use of arthroscopy for degenerate meniscal tears, about 30% of patients in the conservative treatment (the physiotherapy arm) of the study actually ended up having to go for an arthroscopy anyway, because of persistent ongoing symptoms. The authors of this study concluded that there was no difference between knee arthroscopy and conservative management; however, the reality was that in their study group 30% of patients failed conservative management and did actually end up needing surgery after all! So, the correct conclusion ought really to have been perhaps that a majority of the patients selected for this particular study did well enough with conservative management not to need surgery, but that a significant minority (one third!) did actually need surgery. One really has to question why the authors failed to emphasise this, and why the various people quoting just the headline conclusions neglected to present any proper analysis or evaluation of the true findings of the study.

Recently, the BJSM published a set of guidelines about knee arthroscopy. These guidelines go completely against the formal advice published by the British Orthopaedic Association and the British Association for Surgery of the Knee, and the BJSM guidelines also completely contradict the formal published guidelines of ESSKA (the European Society for Sports Traumatology Knee Surgery and Arthroscopy). So, one has to question who exactly it was that was behind the BJSM’s guidelines? The answer is that not one single knee expert was actually involved; instead, the authors included a part-time GP, a physiotherapist from a spinal unit (who has no association at all with their local specialist knee unit) and somebody affiliated to a Chilean Dentistry University!!?!

The UK Biological Knee Society is an academic study group set up by a number of leading specialist soft-tissue knee surgeons in the UK who have a particular specialist interest in the latest techniques for complex reconstructive surgery of the knee. The UK BKS has issued its own position statements on the role of knee arthroscopy, and I would strongly urge you to read these:

If you want a proper opinion on a specific knee issue then this requires a proper full face-to-face clinical assessment, which needs to include one taking a full and detailed clinical history, performing a detailed clinical examination, reviewing all necessary and appropriate imaging (such as X-rays and MRI scans) and then having a proper detailed discussion about the actual diagnosis, a discussion about the various potential appropriate treatment options available and the pros and cons of each, a discussion about the potential risks involved with any particular treatment, a discussion about the rehab that might be required afterwards, and then a discussion about the anticipated outcomes and success rates, and the longer-term prognosis.

This is simply called: proper medicine!

If you have any questions or comments on any of the above then I would be more than happy to hear from you:


Mr Ian McDermott MB BS, MS, FRCS (Orth), FFESM(UK)
Consultant Orthopaedic Surgeon specialising purely in Knees, London Sports Orthopaedics
Honorary Professor Associate, Brunel University School of Sport & Education
President of the UK Biological Knee Society
Vice Chairman of the Federation of Independent Practitioners Organisations



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Written by Mr Ian McDermott Consultant Knee Surgeon, London

Last updated 6-1-19