Knee arthritis: symptoms, treatment and when surgery is needed

Arthritis UK says there is no cure for osteoarthritis of the knee, but there are treatments and things you can do for yourself that can make a big difference to your symptoms and how the condition affects you. The NHS says mild symptoms can sometimes be managed with simple measures: regular exercise, losing weight if overweight, suitable footwear and special devices to reduce strain on the joints. If symptoms are more severe, you may need painkillers and a structured exercise plan with a physiotherapist, and in a small number of cases surgery.

Arthritis UK says symptoms can be different from person to person but the most common are pain, either all around the knee or in a certain place; stiffness or problems moving the knee; creaking, grating or crunching sounds when moving; weakness in the leg; and the knee giving way when you put weight on it. Symptoms can develop quite rapidly, but more often it is a slow process over many years. One or both knees may be affected.

The knee can look swollen, either from hard swelling caused by bony spurs (osteophytes) or soft swelling when the joint becomes inflamed and produces extra fluid, sometimes called water on the knee. Symptoms usually vary from day to day. Pain may be worse at the end of the day or when moving the knee and improve with rest, and some people have pain that wakes them at night. Stiffness in the morning usually does not last more than half an hour. It can be worse going up or down stairs or getting up from a chair.

Arthritis UK also notes that osteoarthritis can make people feel depressed or anxious and can affect relationships and sleep, and that the level of change in the joint does not always match the level of pain.

Arthritis UK explains that osteoarthritis develops when the joint's ability to repair itself becomes less effective, so the cartilage thins, the surfaces become rougher and bony spurs may form. There is no single cause, but factors include being overweight, genes inherited from parents, previous injuries to the joint, and other conditions that affect the joints, such as rheumatoid arthritis or gout.

The NHS adds that your risk increases with age, that osteoarthritis may run in families, that it is more common in women than men, and that overusing a joint that has not had enough time to heal after an injury or operation can contribute. It says the exact cause is not known.

The NHS says a GP will ask about your symptoms and examine your joints, and may suspect osteoarthritis if you are aged 45 or older, have joint pain that gets worse the more you use the joint, and morning stiffness is absent or lasts less than 30 minutes. Prolonged morning stiffness can be a sign of rheumatoid arthritis. Further tests such as X-rays or blood tests are not usually necessary but may be used to rule out other causes such as rheumatoid arthritis or a fractured bone.

Arthritis UK says rarely your doctor will do an X-ray or blood test to rule out other causes. It adds that symptoms are sometimes evaluated in stages from stage 1 (minor) to stage 4 (severe), which can help decide the best treatment plan.

Arthritis UK says it is very important to keep moving: joints need to be moved regularly, and exercise strengthens the muscles around the knee, improves posture and helps weight loss. You need to find the right balance between rest and exercise, because too much activity can sometimes increase pain while too little can make joints stiffen up. A physiotherapist can advise on the best exercises. Good gentle options include swimming and water-based exercises (hydrotherapy) and walking.

To reduce strain on your knees, Arthritis UK suggests pacing your activities, choosing shoes with thick soles and enough room for your toes, using a walking stick, using a handrail on stairs and going up one step at a time with your good leg first, making changes at home, in the car or at work, and asking about insoles. Some people find knee supports or braces help.

On weight, Arthritis UK says being overweight increases the risk of developing osteoarthritis and of it progressing, and that there is no special diet, but a balanced, reduced-calorie diet with regular exercise helps if you need to lose weight.

Arthritis UK says surgery is only needed in a small number of cases because exercise, treatments and a healthy weight usually improve symptoms and quality of life. About 1 in 10 people with knee osteoarthritis go on to have a knee replacement. Surgery might be suggested if your pain is very severe or you have problems getting around or moving your knee. Discuss with your healthcare team what you can expect to gain and the possible risks.

The most common operation is knee replacement, where some or all of the joint is replaced; Arthritis UK says research has shown up to 8 in 10 knee replacements could last as long as 25 years. Arthroscopic (keyhole) surgery can remove damaged cartilage or repair tears, but washing out the knee (lavage or debridement) is not usually available for knee osteoarthritis unless there are clear mechanical problems such as the knee locking.

Osteoarthritis is the commonest, but not the only, cause of an arthritic knee. The NHS says prolonged morning stiffness can be a sign of rheumatoid arthritis, and that osteoarthritis can happen secondary to conditions such as rheumatoid arthritis or gout. Arthritis UK lists rheumatoid arthritis and gout among conditions that can contribute to osteoarthritis of the knee. The NHS knee pain page also lists gout or septic arthritis for a knee that is hot and red with sudden attacks of very bad pain.

Arthritis UK lists complications including the knee joint changing shape, which can make it feel unstable and painful; a Baker's (popliteal) cyst, a lump from joint fluid bulging through a small tear in the joint capsule; and changes in posture or the way you walk, which can affect the hips or back.

If knee osteoarthritis leaves you low or anxious, speak to your doctor, who may recommend psychological therapies such as cognitive behavioural therapy. For sleep problems, Arthritis UK suggests a sleep diary, regular sleep times and avoiding screens in the bedroom.

The NHS says to see a GP if you have persistent symptoms of osteoarthritis, so they can confirm the diagnosis and prescribe any treatment needed. NHS 111 advice on knee pain says to get advice now if your knee is very painful, you cannot move it or put any weight on it, it is badly swollen or has changed shape, it locks, gives way or painfully clicks, or you have a very high temperature (or feel hot, cold or shivery) with redness or heat around the knee, which can be a sign of infection.

On the NHS, a GP assesses your knee, can prescribe medicines and refer you to physiotherapy, occupational therapy or a hospital orthopaedic team if surgery is being considered. Arthritis UK says hyaluronic acid injections are not generally available on the NHS, though you may get them privately or through a trial.

Some people choose private physiotherapy, injections or consultations for faster access. If you are considering a knee replacement privately, ask what non-surgical options have been tried, and make sure your GP is kept informed so that follow-up is joined up.