Osteoarthritis is the leading cause of cartilage pathology. There are lots of other causes e.g trauma, infection, inflammatory joint disease, Rheumatoid Arthritis as well as other lesser known pathologies.

People usually think that it is “wear and tear” and part of ageing. To a certain extent that is true but if it was, then we’d all have arthritis in old age but that doesn’t happen. When you look at the difference in cartilage structure between ageing and OA, there is a difference. This is summarised nicely in the table below:

Essentially, what appears to be happening in OA is an up-regulation and increased activity of enzymes that break down cartilage (MMPs) and down-regulation of the tissue inhibitors of these enzymes (TIMMPs). This leads to a breakdown of the cartilage.

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The causes of OA are not fully understood but the main associations are:

- High BMI, occupation, age, genetics, sex (females more likely), Race (Afro-Caribbean less likely).

- Knee OA is most common at 240/100 000 incidence.

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The main symptoms are:

• Pain on walking and when severe, pain at night and disturbed sleep
• Swelling
• Reduced range of movement / stiffness
• Reduced ability to walk and exercise

Pain leads to less use of the joint, resulting in stiffness of the surrounding tissues and a worsening of the movement around the joint. The less the joint is moved, the weaker the muscles become, which means further load on a diseased joint and worsening of the vicious cycle.

You will be fully assessed with a thorough history and clinical examination.

X-rays are routinely carried out to look for the pathology in the joint.

The classic x-ray signs are:

• Joint space narrowing
• Osteophyte formation
• Sub-chondral cysts
• Sclerosis (hardening of the bone).

Sometimes, MRI scan is required to look at the joint in more detail to decide the best course of treatment.

Based on the findings, the correct treatment will be recommended.
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