BUT that doesn’t account for the variation in knee osteoarthritis that we see..
From 90-year olds with no osteoarthritis
To mild changes in mid to later years
To completely destroyed younger knees
In
Newsletter #054 I covered the
3 obvious causes of osteoarthritis that also affect the Knee. Mainly:
1. Fracture 🦴
Trauma to a joint can cause secondary osteoarthritis.
Any step in the joint will usually heal..
BUT it disrupts the even spread of load across the joint.
Each and every time we take a step.. AND we take 1 to 3 million steps / year.
We can tolerate a broken shin bone well away from the knee joint. Treatment with a plaster cast will hold the bones more or less straight and get a good functional outcome.
However, if that same fracture extends into the knee joint, we want the two sides of the fracture lined up to the millimetre. Anatomical.
Cartilage does not like a step that leads to uneven load.That leads to shear forces, and inevitably..
Inflammation, more cartilage damage + osteoarthritis.
2. Ligament damage 🦵🏼
Perhaps this is where ‘I played too much football’ ⚽️ can play a part..
Not 'too much football' per se, but an ACL injury. That well known footballing injury..
Injury to the ACL (the Anterior Cruciate Ligament in the middle of the knee) leads to less stable everyday joint movement.
Again that instability leads to irregular shear forces that cartilage does not like.
Like a tyre skidding- rather than rolling- on a road, cartilage does not like sideways shear forces.
3. Joint infection 🦠
This is one of the orthopaedic emergencies that keeps us up at night.
Sudden onset of joint pain in anyone who is unwell gets any medics immediate attention.
Why?
Because infection damages cartilage.
That in itself is bad right there and then..
BUT it also leads to an irregular joint cartilage surface..
And that again leads to irregular loading and further damage, inflammation and long-term osteoarthritis.
With enough clinical suspicion we'll often..
Washout a knee joint with copious sterile saline fluid through a knee scope, and
Start antibiotics. All long before the microbiology results are in.
So Fracture, Ligament damage and Joint infection are 3 of the big causes of knee osteoarthritis.
I almost wrote 'common causes'. BUT, to be honest, although we do see those causes, they're not that common at all.
The common causes that underpin most Knee OA are far less obvious..
