Osteoarthritis is a common joint disease often (incorrectly) thought of as “wear and tear” at a joint. It affects the whole joint but most of all it affects the articular cartilage (the cartilage covering the ends of the bones). This articular cartilage becomes thin and fragile. This can be due to healthy cartilage being exposed to heavy loads over a long period of time. (eg heavy manual labour) or unhealthy cartilage that for some reason cannot handle normal loads.
The 3 joints most often affected by osteoarthritis are the knee, hip and hands. But any joint in the body covered with articular cartilage can be affected. Around 5% of people between 35 and 54 years of age have osteoarthritis. Many of these folk have injured their joint earlier in life. Women are more likely to have osteoarthritis than men and more often in their knees and hands. Osteoarthritis often has a hereditary component and approximately 1/3 of the population between the ages of 50 and 70 years have problems related to osteoarthritis. The percentage increases as we age. By the time we hit our 80’s, 90% of us will experience some sort of hand/finger arthritis.
A joint is a connection between two bones. The ends of bones are covered with cartilage, which creates a smooth surface to allow for the bones to slide during movement. A capsule surrounds the joint. This capsule contains synovial fluid (a lubricant providing nutrition to the cartilage). Muscles and ligaments surround the joint and help to keep it stable. A healthy knee joint is pictured below.
Cartilage is solid but flexible, absorbing shock and spreading loads over its surface. It has no blood supply or pain sensors (so it cannot “hurt”).The cartilage instead relies on the movement of water in and out of it to feed it and keep it clean. Water is constantly being drawn into the cartilage by high amounts of molecules called proteoglycans that reside within it. The water is then squeezed out by the forces it experiences during movement and loading. Think of the cartilage as a wet sponge. When a load is applied, fluid is forced out. As the load is removed, fluid is sucked back in. If we are walking, for example, our body weight and gravity press down on our cartilage in our knee, pushing out fluid. Once we rest, the fluid is sucked back in.
Things tend to go a little awry when there is a breakdown in this transportation of water in and out of the cartilage. More often than not this is due to not enough water being squeezed out of cartilage – which means that waste products are not removed and the cartilages environment becomes a bit toxic. This then begins a chemical cascade and to put it simply begins to degrade the cartilage. The cartilage becomes thin, cracks, and may disappear. Bones can then start to rub against each other. This is osteoarthritis – when there is more degeneration than regeneration of the cartilage.
So exercise and joint loading is essential for cartilage health. It is often too little loading rather than too much that is the culprit! Cartilage needs a certain amount of load to regenerate. This is why healthy loads need to be applied on joints for cartilage recovery.
Rest is Rust, Motion is lotion. It is not “wear and tear” but better to think “load and adapt”.
The best way to diagnose osteoarthritis is via the reported symptoms. These might include
Scans such as X-rays and MRI are not necessary to diagnose osteoarthritis. You can have the above symptoms for years without changes evident on a scan. Similarly, a scan can show osteoarthritis changes such as decreased joint space and extra bony growths but you may not experience and pain or symptoms.
At the moment, there is no known way to prevent the cartilage loss described above. Instead treatment aims to reduce symptoms and improve the function of the joint. Importantly, this ‘treatment’ includes education or learning about osteoarthritis and exercise and weight loss.
Anyone with osteoarthritis should have some basic knowledge about how it affects their life so that they can feel less anxious and have confidence in their ability to use exercise to manage their pain. We also know that losing around 5% of body weight can lead to up to a 40% decrease in pain.
The scientific evidence demonstrating the positive effects of exercise in general for our health is indisputable. In most adults the benefits of exercise far outweigh the risks. In fact, exercise is medicine. Overwhelming amounts of research also point to the positive effect that exercise has on osteoarthritis. Exercise improves bone density and cartilage health. It also improves joint range of motion and joint stability and function. It helps you move better and with more confidence and reduces pain by increasing muscle strength and through the release of serotonin and endorphins (the ‘happy’ hormones released in the brain post exercise).
Strong muscles help to stabilise the joints and improve your confidence to complete the activities in your daily life (such as getting of the lounge, weeding the garden). Exercise also helps with your coordination ie using the right muscles at the right time with the appropriate force.
Specific therapeutic exercises, known as neuromuscular exercises, can particularly improve the brain muscle connection and can help you have better control over your movement. Physiotherapists are experts at prescribing these types of exercises. We start with simple movements that we get you to repeat and repeat and repeat. Practice makes perfect. We increase the load and complexity during the exercise to improve your strength and endurance.
Like any “medicine” or treatment, exercise also needs to be appropriately dosed. Therapeutic exercises such as neuromuscular exercises (or motor control exercises) are best performed at least 3x/week to be effective. If you were to commit to a therapeutic exercise program to improve your OA joints function, research shows that a 12 week commitment produces the best outcomes (source GLA:D Australia). Of course the best exercise is the exercise that gets done!
It is important to remember that pain ≠ damage. Pain is often a companion to osteoarthritis and it often hurts when you start exercising. So pain during exercise is acceptable and any pain during or after exercising should subside within 24 hours. Physios are experts at modifying exercises to suit the individual so that you can exercise at an acceptable level. Generally, the more exercise you do the less pain you will get. Remember pain is complex and does not necessarily originate in the knee. Our brains are responsible for our response to pain based on thoughts, feelings, beliefs and past experiences.
If your joints are noisy and you don’t have pain, you shouldn’t worry. If your knees are noisy for example, it is most likely due to the fluid behind the kneecap and is not an indicator of a problem that is developing. It may actually be a sign of a healthy, well lubricated joint. If you have a “clicky” knee, specific neuromuscular exercises can help with your knee cap alignment (generally the problem) and help to improve strength in your quads and gluteal muscles to decrease the click (perhaps read this recent @physioonaroll post on Instagram).
It is worthwhile pointing out that knee and hip problems and pain can often have a multifaceted cause. It can be due to a sudden increase in load- increase in mileage, repetitive movements, a longer walk than normal, more walking than normal. Don’t assume that because you have pain and are a particular age that you have osteoarthritis.
Another thing to remember is that the best solutions for knee and hip issues and your body in general, is exercise. If you are after particular exercises to create strong quads and glutes and a strong core try squats, lunges, bridges, planks, modified planks, bird dogs and sit ups- all of these are functional exercises that will also improve your activity in day to day life.
Most importantly, if you have any questions, talk to your Physio, they will be able to assess you and adapt exercises to suit your issues.