Knee pain: “do I have osteoarthritis?”
“Do I have osteoarthritis?” is a question many people ask fearfully when they come to my clinic with knee pain. This post is to prompt some thinking around a common problem, to help give back ownership (it’s your knee) and gain some understanding of a very common complaint.
The knee: a highly functional but highly complex hinge joint
Most go through life subjecting knees to excessive loads on a daily basis without even batting an eyelid. Many people develop knee pain, only really taking notice when it to affect their function. This may prompt a visit to the GP and in the absence of a traumatic injury, said GP will notice that the patient is pointing to the inner side of their knee and give a general diagnosis of ‘wear and tear’ or ‘normal for age’, the formal diagnostic label being osteoarthritis.
Osteoarthritis (OA) is reported to be a huge global problem, a study in 2019 estimated it affects 527.8 million cases globally. According to Versus Arthritis (2023) knee OA affects over 5.4 million people in the UK. Another study (Yu, 2015) stated 3.5 in every 1000 adults in the UK are diagnosed with knee OA. Reading these statistics, OA appears to be a common diagnosis. But when you consider that for many clinicians in the UK, the diagnosis of OA is based upon guidance from the National Institute for Clinical Excellence (NICE), it is not surprising the numbers are so high.
The NICE guidance states:
anybody over the age of 45 years old, with activity based joint pain, who has pain or stiffness that last for no longer than 30 minutes has osteoarthritis (OA) of the joint
X-rays are not encouraged, as the majority of investigations will demonstrate a knee that has had a life of experiences. It will most likely show structural change that one could expect, “wear and tear”.
Osteoarthritis is a failed healing process and could be described as “wear and lack of repair”
Instead of begrudgingly accepting that it is ‘old age’ and ‘not a lot can be done about it’, take another look at the 2 cars above. Both the vehicles are at least over 60 years old. One of the vehicles shows signs of degeneration that you may expect for its age. Whilst the other vehicle, apparently the same age, is in much better condition. Take a moment to notice that there are differences. Perhaps question “if everybody ages and gets old, why is knee pain not universal?”
And whilst you’re at it, why is the right knee and not the left one (or vice versa)? Why does it hurt now?
Biomechanics – the what
To help you understand, let’s start with the role of the joints of the body.
The body is a series of linkages, each linkage (joint) designed to share forces through the body. Structures of the body are subjected to and manages physical forces all of the time. Newtons 3rd law of motion states that in nature, every action (force) has an equal and opposite reaction (force). Ground reaction force (GRF) is generated by gravity, bodyweight and physical contact on a solid surface whilst walking, standing or rising from chair. In quiet standing, GRF is equal to body weight, yet in dynamic activity GRF increases significantly: 2-3 time body weight when walking and 3 to 4 times when running.
The when
All joints of the body with a normal range of movement (ROM) have clear and functional communication and the ability to a sensory message that recruits muscles attaching to the joint. Any joint movement or mechanical stimulus creates a sensory message called proprioception (joint position sense).
And potentially, the why
If a joint doesn’t have a normal ROM, it doesn’t communicate with its muscles, resulting in the joint becomes a ‘stiff link’ in the chain, demanding more movement (therefore increasing loading) on adjacent joints above or below.
The knee being a (very complex) hinge, is designed to share and take a certain amount of load when all of the links in the chain work together. The cumulative links all stimulating global reflexive muscular contractions when rising from a chair, standing, walking, running or jumping.
However, ‘stiff links’ anywhere throughout the chain such as the foot and ankle, hip, spine, even neck can reduce global contributions, subjecting major joints such as the hip or knee to increased loading.
But why does it hurt?
Knee pain is a response to tissue loading, strain and swelling. It is the brain’s attempt to modify behaviour (“stop loading that knee!”). Unfortunately the brain does not speak a verbal language, or any language that we understand. But we do take notice, we slow down, develop a limp or use a walking stick to decrease knee pain.
And don’t forget that OA is a progressive, age-related pathology. Consider the actual cause for physical degeneration: the longer you’ve been alive, the longer you will have had to pick up bad habits, get by with ‘stiff links’ and use altered loading strategies that work, until they don’t work any longer.
Your knee is the victim, not the perpetrator
Essentially, your knee could be hurting because as a joint, it is continually being forced to take more load than it can handle. It is the victim, not the perpetrator.
There is evidence to support exercise as the main form of rehabilitation for knee joint OA. The NICE guidance states that knee rehab can be painful but must be maintained for a long time. However, unless the perpetrator pattern is dealt with, the knee will continue to be the victim. If you’d like to find out more aout your knee pain, click on the contact form to tell me your story and we can discuss where to begin.
My clinic is in Blackwell (DL3 8QF) in Darlington. Click on the contact form below to arrange a discovery call, to discuss how I can help you.
Nick Watson physiotherapist
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