Knee pain: causes, treatment and when to see a doctor

Arthritis UK says there are many possible causes, which can range from a simple muscle strain or tendonitis to some kind of arthritis, and that sometimes a cause cannot be found. The NHS says knee pain can be a symptom of many different conditions, and that you should not self-diagnose but see a GP if you are worried.

For most knee pain, the NHS suggests starting with self-care: put as little weight as possible on your knee (for example, avoid standing for a long time), use an ice pack or bag of frozen peas wrapped in a tea towel for up to 20 minutes every 2 to 3 hours, and use painkillers such as paracetamol or ibuprofen gel or tablets.

Arthritis UK adds that for the first 24 to 48 hours you could rest the knee but avoid long periods without moving, and move it gently for 10 to 20 seconds every hour. After 48 hours, try to use your leg more, because exercise can help with long-term pain, and stick to your normal routine if you can. Low-impact exercise such as cycling and swimming can be useful when recovering. It says heat is effective for most aches and pains but should not be used on a new injury.

If your pain does not go away, a doctor may suggest treatments for the underlying cause. The NHS says they might prescribe medicine or physiotherapy, or refer you to hospital for a scan or specialist treatment such as surgery. Arthritis UK says physiotherapy may include tailored exercises, taping of the kneecap or a knee brace, and that stronger painkillers such as codeine may be prescribed for severe pain, usually for a short time.

Arthritis UK says paracetamol may be taken regularly for a few days, and that anti-inflammatory painkillers (NSAIDs) such as ibuprofen can help with pain, inflammation and swelling but carry potential side effects, so ask a pharmacist or doctor if they are suitable. Rub-on (topical) anti-inflammatories get much less of the medicine into the bloodstream, with less risk of side effects.

It says carrying extra body weight makes joint pain more likely and can make existing pain worse, and that losing even a small amount of weight can make a big difference. Sensible shoes and arch supports if you have flat feet are listed as suitable footwear.

Arthritis UK says surgery or injections are not recommended for most types of knee pain, because people often recover as well or better with non-invasive treatments. If you have osteoarthritis of the knee causing a lot of pain and difficulty with everyday activities, your doctor may refer you to a surgeon to discuss knee replacement.

Arthritis UK describes two conditions that particularly affect children and young people. In Osgood-Schlatter disease, the bony lump below the kneecap becomes painful and swollen during and after exercise. Patellofemoral pain syndrome is a common knee problem, particularly in children and young adults, with pain behind or around the kneecap that is usually felt going up stairs, running, squatting, cycling or sitting with the knees bent. Exercise therapy is often prescribed for it.

The NHS lists Osgood-Schlatter disease as a possible cause for teenagers and young adults with pain and swelling below the kneecap. The NHS advice on a hot, red or badly swollen knee, and on knee pain that does not improve, applies to children too.

Arthritis UK says your doctor will often be able to diagnose your knee problem from your symptoms along with a physical examination of your knee. Occasionally they may suggest tests or a scan to help confirm a diagnosis, especially if more specialised treatment may be needed.

The NHS says a doctor can suggest treatment based on what is causing your knee pain and may refer you to hospital for a scan.

Arthritis UK says knee pain can develop gradually, come on suddenly or come and go, and that whatever pattern it has, it is most often not due to arthritis, but might be in some people. Osteoarthritis is the most common type of arthritis, can affect anyone at any age and is most common in people over 50.

With osteoarthritis of the knee, you might feel your knee is painful and stiff at times in one knee or both. The pain might feel worse at the end of the day or when you move your knee, such as going up or down stairs, and might improve when you rest. Morning stiffness usually does not last more than half an hour.

The NHS says to get advice from 111 now if your knee is very painful, you cannot move your knee or put any weight on it, your knee is badly swollen or has changed shape, or your knee locks, gives way or painfully clicks (painless clicking is normal).

It also says to get advice if you have a very high temperature, or feel hot, cold or shivery, and have redness or heat around your knee, as this can be a sign of infection. You can also go to an urgent treatment centre if you need to see someone now.

The NHS says to see a GP if knee pain does not improve within a few weeks. Arthritis UK says you might first see a physiotherapist or your GP, and that you may be able to access a physiotherapist on the NHS without seeing your GP, which you can check by asking at your GP surgery or local NHS organisation. You can also pay to see a physiotherapist privately without a referral.

On the NHS, community musculoskeletal (MSK) services in many areas accept self-referral for physiotherapy, and a GP can arrange scans or specialist referral where needed. Arthritis UK says counselling on the NHS usually consists of 6 to 12 sessions for people struggling with long-term pain, and that pain management programmes such as ESCAPE-pain are run in many locations across the UK.

Private physiotherapy and orthopaedic consultations are available and can offer quicker access to scans. Because most knee pain settles with non-invasive care, ask what a scan or injection would change before agreeing to it.