Osteoarthritis and Cartilage problems

February 2018

Osteoarthritis and Cartilage problems

So… in the last blog we discussed the beauty and complexity of human cartilage. It is an amazing tissue that achieved evolutionary perfection millions of years ago. Unfortunately, despite its amazing load bearing properties, things can still go wrong, as is the case with all living things.
The structure of the cartilage can get damaged and this can lead to degeneration and subsequent loss of function of the cartilage. This leads to load transmission to the underlying bone and this registers as pain. As mentioned previously, cartilage doesn’t have a nerve supply so can’t feel pain, and no blood supply so can’t heal. Once a joint has cartilage damage and starts to feel pain, then a cascade of events starts which causes a downward spiral.
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.
We’ll discuss Osteoarthritis (OA) today due to time constraints.
So, what is osteoarthritis? What causes it? What happens in OA? What is the best way to treat it?
People usually think that it is “wear and tear” and part of aging. 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 cartilage structure between aging and OA, there is a difference. This is summarised nicely in the table below:

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 and hip OA at 88/100 000.
Essentially, what appears to be happening is an upregulation and increased activity of enzymes that break down cartilage (MMPs) and downregulation of the tissue inhibitors of these enzymes (TIMMPs). This leads to a breakdown of the cartilage.
Once this starts, pain is experienced and the cycle begins. 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. At the same time, the body knows that there is a problem with the joint and tries its hardest to heal the problem. Unfortunately, the body can only make more bone and can’t produce cartilage. And so small spikes of bone start to form around the joint. These are called osteophytes. These make the whole situation worse and irritate the surrounding tissues causing more pain. As things progress, the ability to walk any significant distance is affected and when it’s getting severe, there is pain in the joint at night time.
When a patient presents with arthritis, they are fully assessed and then x-rays carried out as a first port of call. The classic x-ray signs are: joint space narrowing, osteophyte formation, sub-chondral cysts, and sclerosis (hardening of the bone).

The best approach is to try and address anything that is exacerbating the problem. People think that surgery is the solution to everything but this comes with risks. Replacing a joint is a big operation and deserves the appropriate respect. Because it is now routinely done, people sometimes forget the enormity of the situation. I would avoid surgery until it is unavoidable and the risk to benefit ratio well in your favour.
Usually, the things that can save your joint for a prolonged time are lifestyle changes. This is easier said than done for a lot of people but must be done. Lose weight, eat healthily, do non-impact exercise. Once people lose some weight, their joints automatically feel a lot better.
The next step is injections. Previously steroid injections were the only option available. These are ok for symptomatic pain relief and reduction of swelling but do harm the cartilage. We live in exciting times and biological treatments are now coming to the fore with treatments like PRP injections and more recently stem cell injections which are being shown to help in OA. Amazing stuff. I’ll tell you more about biological treatments in another blog.
The surgical options are many. And depend on a number of factors. These range from limb re-alignment surgery, partial and total knee replacements.
The surgical treatments are also a blog topic for another day!
Till next time……