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Shifting paradigms
  1. C Niek Van Dijk
  1. Correspondence to Professor C Niek Van Dijk, Academic Medical Center Amsterdam, Meibergdreef 9, Amsterdam 1105AZ, The Netherlands; C.NiekvanDijk{at}

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It was Thomas Kuhn, a philosopher of science, who taught us about paradigms.1 A paradigm is defined as an intellectual perception accepted by an individual or a group of individuals as a fact of truth. It is accepted as a model of how things work for that person. And yes, the members of a given scientific community share a paradigm at any one time. And they all share it contently as long as it works. As long as there aren’t too many anomalies, that is, deviations which it can’t solve.

But once the inconsistencies grow, they begin to threaten the paradigm and then you have a period where the ‘old guard’ defends it against a new generation who are promoting a new paradigm. A new paradigm which they think can explain and overcome the anomalies. In the transition period, we see some scientists who try to prove by all means that their assumption is right: forcing a square peg in a round hole or trying to reshape the hole.

We pride ourselves on our ‘evidence-based medicine’. But does the evidence apply to this particular patient who’s sitting opposite you, in your outpatient clinic? Hmmm, not necessarily so….

In this issue, we have several articles about challenging existing paradigms.

One example is that we don’t need robots to successfully and reliably perform our surgeries, including implants for total knee prosthesis. And, yes, the urologists have seen a paradigm shift towards robots for most of their surgeries. But we can rely on our craftsman’s eye! Computer-assisted surgical systems have demonstrated more consistent alignment with fewer outliers. Patient-specific instrumentation has shown a potential for better efficiency and accuracy. But the reality is that most surgeons still use conventional implant systems.

How long can we hold on to this paradigm? In their state-of-the-art article on unicompartmental knee arthroplasty (UKA), the authors observe that, compared with conventional UKA, robotic-assisted systems have an improved surgical accuracy, and better lower leg and component alignment.2 Correct alignment gives better functional outcomes and survivorship of UKA. The authors foresee a shift towards robotic-assisted surgery. I believe they are correct, and that robotic-assisted surgery will become the gold standard for UKA knee implantation, whatever the present paradigm.

Another paradigm, for generations of orthopaedic surgeons, has been arthroscopic meniscectomy. For decades this has been—and it still is—the most common orthopaedic procedure. We know it has long-term drawbacks. Ten to 20 years after meniscectomy there is a 10-fold increase in osteoarthritis, compared with controls. And there is mounting evidence that arthroscopic treatment of degenerative meniscal tears in arthritic knees does not substantially alleviate pain or function, whether short-term or long-term. In spite of this, many surgeons have defended the paradigm of arthroscopy for this population, and even for arthroscopy in symptomatic osteoarthritic knees.3

In this issue, Stone et al publish a consensus statement on degenerative meniscal tears, in which they argue that treatment of degenerative meniscal tears should be nuanced. They propose a treatment algorithm in which patients without mechanical meniscal symptoms should be treated conservatively, and with a minimum of 3–6 months supervised physiotherapy. Patients with mechanical symptoms, in which the MRI demonstrates a degenerative meniscal tear, must likewise be treated conservatively, with a minimum of 3–6 months supervised physiotherapy. Once surgical treatment is considered, the burden lies on the surgeon to ensure that the patient’s pain really does come from meniscal pathology.

To ensure a correct shift in paradigm, it is important for the authoritative organisations—ISAKOS, ESSKA, AOSSM and ANAA—to publish guidelines. The consensus statement across three continents can serve as an important cornerstone for these guidelines. It could set the parameters for a new paradigm, one which sees preservation of the meniscus as its priority. Present and future improvements in meniscal repair techniques, and biological enhancements such as fibrin cloth, biological scaffolds and stem cells may enable us to extend our indications for surgical intervention.

So what about my own paradigms? Well like all of you, I also have many! And yes, I still try to squeeze in my round scope in square openings. One of my leading paradigms is ‘keep it stupid simple’. And then I have my theories on cartilage repair and on treatment of tendinopathies.

In this issue, I coauthored a review on lateral ankle ligament reconstruction.4The paradigm here is that anatomical reconstruction is the best treatment for chronic lateral ankle instability. Over the years my group has published extensive research on the topic. Because of this research, I try to convince my audience to adopt the same paradigm. According to Kuhn, it is my way of looking at the world, based on one dominant idea and backed up by science.1

In this systematic review, for example, we compare anatomical reconstruction with tenodesis, but find no difference in the rates of recurrence. There is, however, a difference in complication rates, which favours anatomical reconstruction. Am I biased? Of course, I am. My bias is my paradigm! So please bear it in mind, as you read the article.

And finally, let us keep an open mind for new technology. Early reports of the suture bridge technique in lateral ankle ligament repair are promising, and arthroscopic reconstruction will find its way. But it’s also important to remain critical. An idea like ligament reconstruction for microinstability must expect to be criticised. The same applies to so-called ‘anatomic reconstructions with tendon grafts’. Does a free graft restore the original anatomy? Hmmm, it’s stretching the point. We can only restore the ‘true anatomy’ by using the original insertion remnants of the ligament (regarding its insertions, that is to say, because obviously we don’t restore the original anatomy of the ligament itself by using a tendon for its replacement). But when we start to drill tunnels for a tendon graft, we demand a concession from the original anatomy. How much deviation can we accept, and still call it ‘anatomic’?

This raises an important issue. We do not, so far, have a proper definition of ‘anatomic’ reconstruction. This is yet another task for ISAKOS. We need definitions based on evidence and consensus, which will guide us in our paradigms in total knee prosthesis, joint disorders, arthroscopy and orthopaedic sports medicine.


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  • Contributors CNVD is the sole contributor.

  • Competing interests None declared.

  • Provenance and peer review Commissioned; internally peer reviewed.

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