Knee Pain: What is Osteoarthritis?

Spoiler: Osteoarthritis is the Knee Pain Bogeyman. Let me explain…

The first thing I would like to make clear to any reader that has been diagnosed with osteoarthritis as a cause of their knee pain, is that the pain you feel is absolutely real, in many cases it can be severe, causes an awful lot of disability and most importantly, it deserves an explanation.

It is my strong belief that osteoarthritis is one of the most over-diagnosed, and mis-understood conditions that I see. A simple diagnosis of osteoarthritis can change someone’s life, and not for the better.

So let’s put osteoarthritis in the dock, charged with meaninglessness and creating undue fear, and partake in a bit of cross-examination.

The Word Osteoarthritis is Meaningless

Let’s start this investigation with some definitions.

We’re are looking at the most common form of arthritis; Osteoarthritis. “Osteo” means related to bones. “Arthro” means related to joints and “itis” means inflammation.

So the term literally means bony / joint inflammation. Now the problem I have with this word is two-fold:

1. Bone/joint inflammation is more of an observation than a meaningful diagnosis. It doesn’t tell us anything about WHY the person is in pain.
2. It creates fear. The word osteoarthritis is synonymous with getting older, wearing out, crumbling away, disability, decreasing mobility and progressing e.g. it only gets worse.

The mainstream information on osteoarthritis is outdated, fearful and needs to change.

So let’s move on from the word itself and start looking at what the current consensus is about osteoarthritis. Let’s start where many of our clients do, in asking wise old Doctor Google.

What does Dr Google have to say about all of this?

I searched for the term: What is osteoarthritis? I immediately got a Google definition:

• “a disease causing painful inflammation and stiffness of the joints”

A disease?! That sounds a bit strong…

It makes it sound like arthritis is like some bacteria or cancer eating away at my joints. And hang on a minute… osteoarthritis ’causes’ painful inflammation and stiffness of the joints?

Let me just go back to that word again; Osteoarthritis = bone / joint inflammation.

So you’re saying, bone / joint inflammation ’causes’ joint inflammation? That doesn’t sound like the most plausible explanation I’ve heard.

Let me put one thing to bed at this moment in time. Knee pain and inflammation are outputs. They are a reaction of the brain to a credible threat to your bodily tissues. They are symptoms of a condition, not the cause.

Ok. So what does Google know anyway? The NHS will know better, they treat the condition all the time. Let’s see what they’ve got to say:

• “Osteoarthritis is a common condition that causes pain and inflammation in a joint”

There’s that word again: ’causes’! How can joint inflammation cause joint inflammation. Lets read on:

• “Osteoarthritis initially affects the smooth cartilage of the joint, the cartilage between the bones gradually erodes, causing bones in the joints to rub together”

What! Where do they get this stuff from?

Come on Arthritis research UK, I trust that they will surely have the answer. Nope! were back to the cartilage again:

• “The main problem is damage to the cartilage that lines the bones”.

A couple of important points to note here:

1. Articular cartilage is aneural and avascular, which basically means it cannot be involved in the pain response because there are no nerve endings there.
2. I agree that bones rubbing together sounds horrible, but do bones rubbing together cause the problem?

Ok, if all of these respectable organisations are saying that joint degeneration, cartilage damage and bone rubbing on bone is the issue, let’s see how well that argument stacks up in the literature.

Figure 1 below is from Adam Meakins’ blog and shows the results of a study by Guermazi et al.

This group looked at the knees of participants that did NOT have knee osteoarthritis. So basically asking the question: if osteoarthritic knees are caused by abnormalities of the cartilage, what do good knees look like.

72 participants showed signs of osteophytes (extra lips of bone) and had absolutely NO pain, 25 had meniscal lesions and absolutely NO knee pain.

Let’s look at the good old cartilage, 68 participants showed signs of cartilage damage but absolutely NO Knee Pain!

If damage to the cartilage was the cause of knee osteoarthritis, these findings would show that everyone that had damage to their cartilage would have knee pain, and that’s just not true. There is much more to this condition than what you see on a scan.

Figure 1: Prevalence of abnormalities detected by MRI in adults without osteoarthritis

The thing that I want you to take away from this graph, is that it is clear, that our bodies change as we get older, but how our body looks, does not correlate well with pain.

So would it not be better to change the terminology we use and stop scaring the life out of patients. Let’s ditch these fear inducing diagnoses and explanations and just use the term knee pain, and set about working out why the individual has knee pain.

This is 2015!, come on, surely we know that degeneration, and changes seen on imaging, are not well linked to knee pain.

Understanding Osteoarthritis Knee Pain

To understand joint pain, especially in runners, you have to understand both pain itself, and the law of adaptation:

Pain

We know so much more about pain in 2015, we’re still a long way from knowing the full picture, but we are certainly far enough down the road to leave the current explanation of osteoarthritis in the ditch.

Joint pain is complex, multi-factorial, individual, and it changes over time. But just because it’s complex, doesn’t mean it’s complicated, or should be seen as such.

It just needs to be understood. Figure 2 below is a list, not exhaustive, of some of the things that can influence pain, it will serve the purpose of illustrating that pain is multi-factorial and can be influenced by many things.

Figure 2: Multi-factorial nature of knee pain

I think that most people have a good understanding of the ‘physical’ and ‘damage / trauma’ factors, and can easily associate them with pain.

But I don’t think the general public, and more importantly, many health professionals, have a good grasp of the psychological and social aspects of pain.

The other thing to bear in mind, is, that on first glance, that list of things looks pretty overwhelming, but no-one will have all of those things going on. The skill of diagnosis is to evaluate which of those things are playing a part in this individuals pain.

Intuitively, to get a good outcome you have to address every element that is effecting that pain experience.

So to return to one of our original questions; what causes Osteoarthritis Knee Pain? I would say the answer is: it depends on the individual.

It is a complex picture, but can be worked out with the right tools. Go back to the diagram in figure 2.

It could be all of those things and more, but it’s likely to be a few. There is an obsession in medicine on trying to zoom further and further into the joint itself, looking for answers, when we should be zooming right out…goodbye joint, hello person…put the scan / x-ray to one side for a moment and engage.

Tell me what you’ve been up to…
What’s going on in your life…?
How much load have you put through that knee recently…?
Are you worried about anything…?
Let’s watch you move…

Stop worrying solely about cartilage, inflammation, degeneration etc.

Red flags aside (red flags are serious pathologies) your knee pain is caused by what you have been doing, how you have been doing it, plus or minus psychosocial factors, not this mythical entity osteoarthritis!

Osteoarthritis is not something you contract, it doesn’t eat away at your joints, it’s just a posh word to describe knee pain!

But wait, I hear you cry! I’m a runner, we are a special group. We spend hours pounding the pavement and putting more stress through our joints, than the average person in the street. This has to have an effect, no?

Yes, it does. A positive one:

Check out this snippet from Cymet & Sinkoc (2006) entitled Does long-distance running cause Osteoarthritis?

“Although there are not currently enough data to give clear recommendations to long distance runners, it appears that long-distance running does not increase the risk of osteoarthritis of the knees and hips for healthy people who have no other contraindications for this kind of physical activity. Long distance running might even have a protective effect against joint degeneration”

And there’s more: Chakravarty et al (2008) took 45 long distance runners and 53 controls (mean age of 58) and took serial X-rays from 1984 to 2002. They found that runners did NOT have more prevalent Osteoarthritis on radiographs compared to control subjects.

Adaptation

In runners with joint pain, I cannot emphasis enough, the importance of understanding loading and adaptation.

So what do I mean by adaptation:

It’s important to understand, that your body is not like an old pair of slippers, that wears out over time, or the more you use it. It is an intelligent, living organism, constantly adapting to the environment. This means that:

1. If you don’t put any stress through a joint, it will de-condition. So, if you then decide to use this de-conditioned joint, it will not take much to overload it, and injury / sensitisation can occur.
2. If you put too much stress through a joint, it will overload it, and injury / sensitisation will occur.
3. If you put an adequate amount of stress through a joint, and then give it an adequate amount of recovery, and you do this consistently – that joint will strengthen! It will adapt and be able to cope with the demands you are placing on it.

The below graph is taken from Blaise Dubois of the Running Clinic, who illustrates the adaptation process nicely here.

The premise itself is very simple, but the reality is far from straightforward. Knowing how much stress, is the right amount of stress, to put us in the ‘adaptation zone’, is very difficult.

The ‘adaptation zone’ will be different from person to person, and just to make it even harder, will change from day to day (probably from hour to hour).

Is the exercise stress needed to hit the ‘adaptation zone’ the same following a day of intense training, compared to an easy day?

Is it the same following a week of stress and no sleep?

What if my athlete turns up and says they’ve had an argument with their boss and haven’t slept all night worrying about it, should we do the same programme I had planned? or do we adjust?

Unfortunately, I don’t have all the answers, but it illustrates the difficulty in getting it right. Prescribing the right dose of exercise, to get the desired adaptation, is often seen as much an art of coaching, as a science. It takes trial and error, understanding of your body, or understanding your athlete, and understanding all the factors that can change where the ‘adaptation zone’ is.

Having said that, to offer some simple, practical advice, I think the guideline of pain during running, pain after running, or excessive morning stiffness is a really nice, simple marker, to know if you may be pushing things too hard and in danger of injury.

Pay attention to these things in your training programme.

Conclusion & Take Home Points

• I propose we need a change in the way osteoarthritis is viewed and discussed.
• Your pain is real and it deserves an explanation.
• The word Osteoarthritis means bony/joint inflammation.
• Osteoarthritis is more of a description than a meaningful diagnosis.
• Pain and inflammation are symptoms and not causes.
• The proposition that damage to a joints cartilage as the cause of osteoarthritis is at worst refuted by the literature and at best just a very small part of a multi-factorial problem.
• Joint abnormalities are seen in people with no pain and are more prevalent the older we get.
• Diagnoses such as osteoarthritis, spondylosis, spondylitis, wear and tear, degenerative joint disease do not describe the condition well. They can be seen as threatening and, in my opinion, should be discontinued as a way of explaining joint pain.
• Joint pain is multi-factorial, individual and can change over time
• Running does not cause osteoarthritis and is likely very good for your joints.
• Diagnosing the cause of knee joint pain means evaluating all elements of the pain response and working out which ones are at play in this individuals pain state.
• The body will adapt and get stronger if the applied stress is not greater than it’s capacity to adapt. Use this information to pace your training.

So runners… don’t stop running, enjoy every minute of it.

Running is not only good for your joints, but just about every system in your body. But before you going bounding out the door, remember to have knowledge of the multi-factorial nature of pain and have a healthy understanding of the law of adaptation.

Resources such as the NHS website and Arthritis UK: Update your information!

I believe with all my heart that the information placed on your sites is there to help people, but it’s becoming part of the problem and strengthening negative, mis-informed beliefs, that is in turn, creating poorer outcomes for patients, not better. It has to change.

And for those that think I’m just one person saying this, and maybe have cherry-picked a few articles, here’s a snippet from the NICE guidelines on osteoarthritis, published in 2014.

For those of you that don’t know, NICE stands for the National Institute for Health Care Excellence, and provide national guidance and advice on health and social care. What do they have to say on osteoarthritis?

“Osteoarthritis refers to a clinical syndrome of joint pain accompanied by varying degrees of functional limitation and reduced quality of life. It is the most common form of arthritis, and one of the leading causes of pain and disability worldwide. The most commonly affected peripheral joints are the knees, hips and small hand joints. Pain, reduced function and effects on a person’s ability to carry out their day-to-day activities can be important consequences of osteoarthritis. Pain in itself is also a complex biopsychosocial issue, related in part to a person’s expectations and self-efficacy (that is, their belief in their ability to complete tasks and reach goals), and is associated with changes in mood, sleep and coping abilities. There is often a poor link between changes visible on an X-ray and symptoms of osteoarthritis: minimal changes can be associated with a lot of pain, or modest structural changes to joints can occur with minimal accompanying symptoms. Contrary to popular belief, osteoarthritis is not caused by ageing and does not necessarily deteriorate. There are a number of management and treatment options (both pharmacological and non-pharmacological), which this guideline addresses and which represent effective interventions for controlling symptoms and improving function.”

Some key the phrases from this to remember: “complex biopsychosocial issue” “poor link between changes on X-ray” “not caused by ageing” “doesn’t necessarily deteriorate”.

The prosecution rests, your honour.

FREE DOWNLOAD: Runner’s Knee Rehab Resources [PDF]

Exercises in Osteoarthritis Knee Pain

It’s always difficult giving general exercise advice, in a condition that’s so individual. But in order to give you some guidance I would say exercises for knee Osteoarthritis pain should be based on SI factors. SI stands for your severity and irritability.

The severity of your pain can be placed on a simple 10 point scale, 0 = no pain, 10 = excruciating pain.

Intuitively, the higher the number, the more severe your pain. Irritability, basically means, that if your pain is brought on, how long does it take to settle.

If the pain goes immediately, it is of low irritability. If it takes hours or days to settle, it is of high irritability.

The higher your SI factors the gentler, and less stressful, the exercise should be, to begin with. I say to begin with, because if you respect the law of adaptation and understand pain you should be able to progress through to more challenging exercises.

There are no ‘bad’ exercises for knee pain, or any condition for that matter. It’s just about understanding that some exercises are more stressful on the joint, than others, and additional factors such as adding weight, increased repetitions, duration, speed, surface, footwear will also effect the stress going through the joint.

Exercise-wise, it appears that a combination of strengthening, around the knee and hip, along with cardiovascular (CV) exercise works well.

For me, I also like to look at your painful movement as well. So, if you get your pain when you run, then I want to see you run, and see if there are any changes we can make, to make it less stressful for your knees.

In terms of pain when exercising. Ideally I would like the exercises to be pain free. Some discomfort is OK, but my general cut off is nothing over a 3-4/10 on a pain scale and that settles within 24 hrs. If it’s more than that, do not stop, adjust the exercise to make it easier so you fall within the above parameters.

Below are some examples of exercises. This is not an exhaustive list, but may give you an idea of where to start based on your SI factors.

Cardiovascular Exercise

Choose whichever makes you happy and is pain free. Examples include swimming, water aerobics, cycling, cross trainer and walking. Start at a low level of intensity/duration and build from there.

Knee Rehab Exercises

Last updated on March 2nd, 2021.