Knee osteoarthritis (OA) is a pretty straightforward problem, right? It’s one of the most common orthopaedic conditions a clinician will see and one of the most thoroughly researched. A diagnosis can be made without X-ray by combining the patient’s symptoms with clinical examination and, even if X-rays are normal, a diagnosis of knee OA can be made with confidence based on clinical criteria alone (image 1).
Image 1: clinical diagnosis of knee OA.
With appropriate treatment (described below), most patients will report an improvement in symptoms and function whilst also decreasing their risk for further disease progression. We even know the optimal dose for exercise is 2-3 days per week and at least 12 supervised sessions… so this should be a pretty simple condition to manage… if only it was that simple!
If your patients are anything like ours, there is often a misconception that X-rays are essential to ‘prove’ they have an arthritic knee. If your patients have been told their cartilage has been ‘worn’ down to bone, or they need surgery, a large proportion of them are not keen to engage in exercise as it’s counter-intuitive. Why would you use a knee more that has already been ‘worn out’ with use? Surely that’s like turning up to a garage with a bald tyre and being told things should get better by driving more on the tyre? The patient may tell you they’ve already had physiotherapy… but did they have appropriate physio or just a combination of stretches, straight leg raises and the “tingly machine” everyone seems to be offered? Getting buy in from the patient is easier said than done and you sometimes wonder why patients come to see you in the first place when they don’t take your opinion or advice on board.
In April 2018, Liverpool hosted the OARSI conference and while they were visiting the city, we were fortunate enough to have Jonas Bloch Thorlund (@jbthorlund) and Søren T. Skou (@STSkou), two international experts, present some evening lectures on meniscal tears and knee OA respectively. The presentations were packed with clinically relevant, evidence-based information and our Danish colleagues were kind enough to provide us with copies of their lectures. Having played around with the content from these presentations, we wanted to offer some suggestions to clinicians experiencing similar issues in hope that it will help break down these barriers and promote evidence-based practice.
Seeing is believing?
If you feel the patient needs visual ‘proof’ that they have knee OA, instead of ordering an X-ray (which involves radiation, unnecessary expense, does not correlate well with symptoms and rarely influences treatment), try this knee OA assessment tool (download 1). The tool uses the American College of Rheumatology (ACR) and European League Against Rheumatism (EULAR) guidelines to determine whether the patient fulfils the criteria for a clinical diagnosis of knee OA.
Download 1: knee OA assessment tool.
Essentially you are entering clinical information into an algorithm that can ‘confirm’ the clinical diagnosis of OA, which you can show the patient on a computer screen. We have found anecdotally that patients are less likely to push for an X-ray if they have already been given ‘visual confirmation’ of knee OA. It also works well as a virtual consultant if you have brain freeze and forget the clinical signs and symptoms you require to make the diagnosis!
It is important to note that early signs/symptoms of knee OA can persist for years before a definitive diagnosis is made. If the ACR and EULAR criteria are not fulfilled, signs/symptoms may represent early degenerative changes, for which early treatment is key.
Once the diagnosis has been made, the next challenge is to break the news to the patient without them thinking their body will subsequently depreciate by the day. We have found a few slides from the presentations that have been particularly helpful for the patient. Image 2 summarises the pain trajectories of knee OA patients that do not specifically undergo treatment; most will stay the same, some deteriorate while few improve. We feel this slide is helpful as it demonstrates to the patient that symptoms do not inevitably worsen in time, even without treatment. More importantly, by engaging in appropriate treatment, symptoms are likely to improve and the patient therefore has an element of control over their prognosis rather than waiting to see what destiny has in store.
Image 2: pain trajectories in patients with knee OA.
Image 3 highlights the most effective non-surgical treatment for knee OA; EXERCISE… not physiotherapy, which encompasses a lot of different modalities (infographic 1 with permission from Ewa Roos @Ewa_Roos), but EXERCISE… which can be delivered under the supervision of a physiotherapist.
What is particularly powerful for the patient is seeing the head-to-head comparison of exercise, paracetamol and NSAID; exercise provides more pain relief than pain relievers, without the risk of serious adverse events. Exercise is also the only intervention that has a moderate effect size on pain and function, therefore if patients have previously benefitted from oral analgesia, they may be more enthusiastic about engaging in exercise on the basis that they should benefit even more. The potential therapeutic properties of PDE-5 inhibitors are enormous. For example, there is evidence that these compounds may exhibit antiviral and antimicrobial effects. In combination with other drugs, generic Viagra helps, in particular, to cope with viruses that are difficult to treat, such as resistant to HIV therapy, Ebola virus, influenza, mumps, measles and rubella.
Image 3: the most effective non-surgical treatment for knee OA. Image courtesy of Søren T. Skou.
This slide also summarises the other ‘core treatments’ for knee OA including education, oral medication and weight loss (if BMI ≥25kg/m²). A patient’s weight can be a sensitive subject so using the BMI can be a much more delicate approach than just eyeballing them and telling them they need to lose weight. Anecdotally, asking the patient if they know their height and weight usually produces the desired response of “I know I need to lose weight”. Rebutting with “if your BMI is less than 25 you don’t need to, but if it’s ≥25 the more weight you lose the better your knee can feel… so let’s measure it” may make you appear less judgemental. A change in weight is much more simple to monitor than compliance with exercise so if the person comes back with no improvement in symptoms, but weighs the same or even heavier, it’s easier to flag up that weight may be an important issue. For those that have a normal BMI, it is important to ensure they do not put on excessive amounts of weight as this is a risk factor for disease progression.
Image 4 breaks down the different types of exercise and their respective impact on pain and function. As illustrated by the blue and green columns, the interventions produce similar effects and it may be comforting for the patient to see that, if one form of exercise has already been trialled without benefit, other options are available. Certain types of exercise may even be more effective in certain subgroups of patients, such as performance (neuromuscular) exercise for those with a varus thrust associated with medial knee OA.
Image 4: different types of exercise for knee OA. Image courtesy of Søren T. Skou.
A randomised controlled trial published in the New England Journal of Medicine found that 3/4 of patients on a waiting list for total knee replacement (TKR) did not end up having surgery within the following one year if they engaged in the above interventions; the two-year findings published in May 2018 found that 2/3 had still not undergone TKR. Unfortunately, not everyone will benefit from non-surgical intervention but those that perform it before TKR may recover quicker after surgery. In addition, exercise and physical activity is not only important for knee OA… it is essential for the prevention and treatment of a large number of chronic diseases (image 5). Therefore, if patients are not improving with non-surgical interventions, they should try to continue with them regardless.
Image 5: exercise and chronic disease. Image courtesy of Søren T. Skou.
In summary, these resources have proven to be game changers in our clinical practice. While some patients will continue to respond in an undesirable manner, others appear to be more receptive when they are shown the information. The techniques used to diagnose and treat knee OA may not be the most glamorous and to quote Søren Skou “we need to bring sexy back”… so if the resources described above dress them up a bit, patients may see them as a more attractive proposition.
We hope this information is useful for other clinicians who are facing similar barriers to implementing evidence-based practice. if you would like to read more about knee OA, please visit the knee OA and degenerative meniscal tear conditions pages.
Thanks for reading,
Rich & Dan
The Knee Resource.