Arthritis is one of the most common of all ailments: there are thought to be around 10 million sufferers in the UK. In fact the term ‘arthritis’ is a catch-all for several different forms of the condition, from rheumatoid arthritis to lupus, psoriatic arthritis and gout. The most common form of all is osteoarthritis – a type with particular relevance to our knees, which sustain so much impact during everyday life. So what exactly is this condition, and what can we do about it? Here’s a quick primer.
What does ‘osteoarthritis’ mean?
The word ‘osteoarthritis’ comes from the Greek terms for bone, joint and inflammation. That’s not a bad description. Osteoarthritis is a bone-related condition where the joints become damaged, inflamed and painful. It’s quite different from rheumatoid arthritis, which is a disease of the immune system.
How does it affect the joints?
The bone endings in joints are covered in a layer of protective material called cartilage. Cartilage is what enables them to slide smoothly against each other. Osteoarthritis is what happens when the cartilage covering wears away. When worn away, the bone endings grind painfully against each other. The condition is sometimes colloquially known as ‘wear-and-tear’ arthritis.
What actually causes osteoarthritis?
The exact cause isn’t clear, but we do know that certain things increase our risk of developing it. These include an injury to the joint, a pre-existing condition (such as rheumatoid arthritis), obesity and a family history of the condition. Although osteoarthritis can affect people of all ages, it’s more common as we get older – it’s the biggest reason for knee pain above the age of 50.
What does osteoarthritis feel like?
It affects people in different ways. In the early stages, it can start as a dull background ache, rather like toothache. Sometimes the discomfort becomes more noticeable after activity, and it’s often worse at night (this may be related to an increase in inflammatory ‘mediators’ during sleep, and possibly to a decrease in the anti-inflammatory hormone cortisol). In later stages, the pain can be quite severe and ongoing. Osteoarthritis can also cause stiffness, bony spurs (osteophytes) and swelling.
Will the pain eventually become unrelenting?
Not necessarily. Many people actually find their discomfort comes and goes. Even severe pain that lasts for a week, or several weeks, can settle down again; it won’t automatically mean that you need major surgery. Osteoarthritis doesn’t always get worse – in fact some people find their symptoms can improve over time.
Does osteoarthritis lead to osteoporosis (fragile bones with decreased density)?
No – in fact in can often result in harder and stronger bones; this is known as Wolff’s Law, which states that bone rehardens in relation to the load that is placed upon it. Osteoporosis is sometimes a problem below hip joints, but it’s rarely an issue where knees with osteoarthritis are concerned.
How do you diagnose osteoarthritis?
We are normally able to diagnose it with a physical examination of your knee, though we may sometimes request an x-ray to confirm the condition. During the assessment we’ll ask about your symptoms, history and when you tend to get the pain or stiffness; is it persistent, or does it come and go? Do you normally experience it after rest or activity? And so on.
What treatments are available for the condition?
In the early stages, the best course of action is lifestyle-related management. That means avoiding high-impact activities where possible, using ice packs for swelling, and taking simple pain relief during flare-ups (perhaps even an anti-inflammatory like ibuprofen, if you are able to take it). Physical therapy, guided exercises and in some cases weight loss can also be helpful. A further stage might involve inflammation-reducing steroids or hyaluronic acid injections (hyaluronic acid is the main component of synovial fluid in joints). If the arthritic damage and pain becomes severe and ongoing so that it places a significant burden on everyday life, we may consider a knee replacement procedure.
Is it possible to replenish joint cartilage?
Unfortunately not. Natural cartilage is an amazing biological material. Its co-efficient of friction (friction-reducing capacity) is greater than wet ice sliding against wet ice – that’s a pretty smooth (not to mention strong) material, and it’s very difficult to replicate artificially. Another problem with osteoarthritic joint pain is that it usually also involves a ‘biomechanical failure’ – a deformity or misalignment in your leg that’s causing those joint-bone surfaces to rub against each other. Place any material inside this space and it will experience the same grinding, unless the whole joint is realigned (ie with a knee replacement). Having said that, recent scientific investigations into regrowth in salamanders suggests there may one day be hope for regenerating natural cartilage. But, as yet, a medical application for painful knees seems a long way off.
Looking for more information about osteoarthritis?
Read about osteoarthritis in our Treatments section
Find out more about how knees work
Discover some common conservative treatments for knee pain