Overview
Osteoarthritis is the most common type of arthritis, and the knee is the joint it affects most often. The smooth that cushions the ends of the bones gradually becomes thin and rough, and the other tissues of the joint change too. The knee becomes painful and stiff.
It usually develops slowly, over years, and ranges from mild aches to pain that limits daily life. Many people manage well with simple measures.
Symptoms
- Knee pain that is worse with activity, such as walking or climbing stairs, and eases with rest
- Stiffness after rest or first thing in the morning, usually easing within half an hour
- Swelling around the knee, often after activity
- A grating or crackling feeling or sound when the knee moves
- Difficulty bending or straightening the knee fully
- The knee giving way or feeling unstable
- In later stages, pain at rest or at night
When to see a doctor
See a doctor if knee pain or stiffness lasts more than a few weeks, keeps coming back, or limits walking, work or sleep.
Causes
Osteoarthritis is not simply wear and tear. It develops when the and other tissues of the joint break down over time. The exact cause is not fully understood, and several factors usually act together.
As cartilage is lost, the bones may rub against each other, and bony growths (bone spurs) can form at the edges of the joint.
Risk factors
- Older age
- Being overweight, which puts more load on the knees
- A previous knee injury or knee surgery
- Being female
- A family history of osteoarthritis
- Work or activities that put repeated stress on the knees
- Knees that are not well aligned, such as bow legs or knock knees
Complications
- Long-term pain and disturbed sleep
- Difficulty walking, climbing stairs and doing daily tasks
- Weakness of the muscles around the knee
- Falls, if the knee gives way
- Becoming less active, which can affect weight, general health and mood
Prevention
Osteoarthritis cannot always be prevented, but these steps lower the risk and help protect the knees:
- Keeping to a healthy weight
- Staying active with regular exercise that keeps the leg muscles strong
- Avoiding knee injuries, and having injuries treated properly
- Taking breaks from long periods of kneeling or squatting
Diagnosis
A doctor can usually diagnose knee osteoarthritis from the symptoms and an examination of the knee. An X-ray may be taken, and can show narrowing of the joint space and bone spurs.
There is no single blood test for osteoarthritis. Blood tests, a sample of joint fluid or an are sometimes used to rule out other causes of knee pain, such as rheumatoid arthritis, gout or infection.
Treatment
There is no cure, but treatment can reduce pain and keep the knee working. The main treatments are:
- Regular exercise, including muscle strengthening and low-impact activity such as walking, cycling or swimming
- Losing weight if overweight
- Physiotherapy
- A walking stick, knee brace or supportive footwear
- Heat or cold packs
- Pain relief, such as anti-inflammatory gels for the knee, paracetamol, or anti-inflammatory tablets if suitable
- Steroid injections into the knee, when other treatments have not helped enough
Surgery is considered when pain and disability remain severe despite these measures. The options include knee replacement, where part or all of the joint is replaced with an artificial one, and in some cases an operation to realign the bones ().
Myths and facts
Things people often say about this. Open each one to see what is true.
Myth“Using the knee wears it out further, so the best thing is to rest it.”What is true?
Fact
Exercise is one of the most important treatments. Activity that keeps you moving and builds up the muscles around the knee usually improves pain, stiffness and movement. Build up gradually rather than doing too much too soon, and a physiotherapist can suggest exercises that suit the knee.
Myth“It is just old age and simple wear and tear, so nothing can be done.”What is true?
Fact
Osteoarthritis is not an inevitable part of growing old, and it is not caused by simple wear and tear on the joint. It can affect younger people too. There is no cure, but exercise, weight control and pain relief reduce the symptoms for most people.
Myth“Anyone with knee arthritis ends up needing a knee replacement.”What is true?
Fact
Surgery is needed only in a small number of cases, where other treatments have not helped enough or daily life is seriously affected. Most people manage with exercise, keeping to a healthy weight and pain relief.
Myth“Pain tablets are harmless, so they can be taken every day for years.”What is true?
Fact
Anti-inflammatory tablets do not suit everyone. They can break down the lining that protects the stomach from acid, which is why a doctor sometimes adds a stomach-protecting medicine alongside them, and they may not be suitable for people with a stomach ulcer, asthma, angina, or a previous heart attack or stroke. It is best to check with a doctor before taking them regularly.
Questions to ask your doctor
Tick the ones you want answered and take them with you.
Common questions
Should I rest my knee or keep moving?
Keeping active is one of the most important treatments. Regular exercise strengthens the muscles that support the knee and helps reduce pain and stiffness. A physiotherapist can suggest exercises that suit the knee.
Do glucosamine or chondroitin supplements help?
Research has not shown a clear benefit. The World Health Organization describes glucosamine as not effective for osteoarthritis, and the NHS no longer prescribes glucosamine or chondroitin. It is sensible to discuss any supplement with a doctor first.
Will I need a knee replacement?
Not necessarily. Many people manage their symptoms with exercise, weight control and pain relief. Knee replacement is considered when pain and loss of movement stay severe despite these measures and are affecting quality of life.
