knee osteoarthritis

What is OA?

Osteoarthritis (OA) is the most common chronic joint disease in which the cartilage which lines the end of your bones wears away. Cartilage is a smooth material which cushions the bones in your joints, and allows them to move smoothly. With OA, as the cartilage in the joint starts to thin, its ability to withstand stress worsens, and this can lead to pain, swelling, stiffness, and sometimes the development of bone spurs.

What causes OA?

Within our joints, tissue such as bone and cartilage are constantly being broken down and repaired. Chemicals within the joint are released to ensure that old or damaged tissue is removed, and new, healthy tissue is synthesised to replace it. In healthy joints, the balance between break down and repair is well balanced. In OA, however, the breakdown of joint tissue exceeds its repair. This leads to a loss of cartilage, which leads to increased stress on the underlying bone and subsequent issues such as bone spurs. 

Although OA has traditionally been thought of as a mechanical 'wear and tear' disease, the onset of OA is a complex interplay of many different factors. These include things such as genetics, metabolic diseases, past injury or obesity related inflammation. Research now suggests that OA can be caused by a chronic, low grade inflammation, the same type of chronic inflammation that seems to contribute to other chronic diseases such as type 2 diabetes and heart disease. 

What does knee OA feel like?

Knee OA is most common in people over the age of 50, and symptoms normally develop gradually over a period of time. The most common symptoms of knee OA are:

• Pain - this may range from a dull, aching pain, to sharper pain around the knee. The pain may be worse after activity, or after periods of inactivity, such as when you first get up in the morning, or after long periods of sitting.
• Stiffness - your knee may feel stiff, especially after prolonged inactivity. You may experience decreased movement in the knee, which along with the pain, may make it difficult to perform activities such as climbing stairs.
• Swelling - you may notice the knee looks or feels puffy due to inflammation or fluid in the joint.
• Crepitus - you may notice grinding or clicking noises as you move your knee.

Can I exercise with knee OA?

Yes! Research has shown that exercise is beneficial for many people with knee OA. Walking and even running are not associated with an increased risk of structural worsening in OA. In fact, research has shown that in recreational runners, up to 40km of running per week is NOT associated with OA worsening. However, if your OA pain is severe, then options other than exercise may have to be considered.

Why exercise if you have knee OA?

• OA is not primarily due to wear and tear! Many other factors such as genetics, metabolic diseases, obesity and previous trauma/injury contribute to OA.
• Exercise does NOT wear away your cartilage. In fact, it may even improve cartilage health! Note that this does not mean exercise will not cause any pain - too much or too intense of an exercise can exacerbate some symptoms.
• Exercise can have anti-inflammatory effects.
• Exercise can improve your overall health and prevent or improve many different health conditions such as heart disease, muscle loss, obesity and osteopenia.

What sort of exercise should I be doing and how much?

• The World Health Organisation (WHO) recommends at least 150 mins of moderate intensity physical activity per week, or 75 mins of vigorous activity. This level of activity will NOT lead to a risk of structural worsening of OA. 
• Aerobic, balance and resistance training are some of the best forms of exercise you can do. Exercise should be done according to pain tolerance. A little bit of discomfort during exercise does not mean the knee is being damaged further, however, exercise does not need to be done into intolerable or high pain levels.
• Aerobic exercise can be as simple as walking. If this is too painful, walking in the pool, cycling or the elliptical machine can be great alternatives.
• Balance training helps you feel more stable, and is great in helping prevent falls. Examples of this can include standing on one leg, or standing with both feet touching. Holding these positions for 15-30s, 2-3x a day is a good start.
• Resistance training helps strengthen the muscles around the knee, which helps support the joint and also allows you to perform daily tasks such as using stairs or standing up from a chair easier. A great exercise to begin with is simply sitting and standing from a chair. 

What can I do to feel better in the short term if I have knee OA?

• Heat - moist heat works well in particular
• Non steroidal anti inflammatory drugs (NSAIDs)- please consult your doctor to make sure that any medication use is appropriate for you.
• Compression sleeves
• Knee taping

What about cortisone injections and surgery?

Corticosteroids, or cortisones, are injections with strong anti inflammatory properties that can help provide pain relief for some people who have not responded well to first line treatments. Studies have shown that although cortisones are able to provide pain relief in the short term, the effects are normally temporary, and the duration can vary from person to person. Repeat cortisone injections have also been found to be less effective, and also potentially harmful for joint health in the long term. 

Surgery for knee OA is often considered as a last resort once all other options have been tried. Although surgery can provide significant pain relief and be very effective, it also comes with risks and potential complications, and the post surgical rehabilitation process can be long and painful. 

Overall, the decision to use cortisone injections or proceed with surgery should be made after a thorough discussion with a qualified physiotherapist or medical professional about the potential benefits and risks, your overall health, the severity of your OA, and your personal preferences and goals for treatment.