Joints
Knee pain
Knee pain is discomfort in or around the knee joint, often from wear, injury or inflammation, and is very common at all ages.
Education and reference only. This explains the common causes of knee pain and the warning signs that need urgent help, in plain language — it is not a diagnosis or a substitute for advice from a clinician. If you feel very unwell or are worried, seek medical help.
Quick answer
What is knee pain?
The knee is a large, hard-working joint that carries the body's weight and bends countless times each day, so pain here is common. It can come from the joint surfaces wearing over time, from a sudden twist, fall or sporting injury, or from inflammation in the joint or the soft tissues around it.
- Get urgent help: A hot, swollen, very painful knee with a high temperature or feeling unwell — this can be a joint infection (septic arthritis) and needs urgent same-day assessment. Being unable to put any weight on the leg, or an obvious deformity after an injury — get urgent assessment.
- Self-care: For everyday knee pain, it helps to keep moving gently while avoiding activities that make it much worse, as too much rest can stiffen the joint.
About knee pain
The knee is a large, hard-working joint that carries the body's weight and bends countless times each day, so pain here is common. It can come from the joint surfaces wearing over time, from a sudden twist, fall or sporting injury, or from inflammation in the joint or the soft tissues around it. The pain may be felt at the front, sides or back of the knee, and may come with stiffness, swelling, clicking or a feeling that the knee might give way. Most knee pain settles with simple measures, but a hot, swollen joint with fever, or a knee that cannot bear weight after an injury, needs prompt attention.
When to get help
Call 999 or go to A&E if knee pain comes with any of these warning signs:
- A hot, swollen, very painful knee with a high temperature or feeling unwell — this can be a joint infection (septic arthritis) and needs urgent same-day assessment.
- Being unable to put any weight on the leg, or an obvious deformity after an injury — get urgent assessment.
- A knee that locks or gives way repeatedly — get this checked.
When to see a doctor
See a doctor if knee pain is not improving after a couple of weeks of self-care, is getting worse, or is stopping you doing everyday activities. It is also worth being seen if the knee is swollen, keeps giving way or locking, or if the pain followed an injury and is not settling. If both knees are affected, or the pain comes with stiffness in other joints, an assessment can look for inflammatory causes that benefit from earlier treatment.
Not sure how urgent it is? It is always OK to call NHS 111 for advice, day or night.
What can cause it
Common causes of knee pain
Knee pain has many possible causes. Each links to a full, plain-language guide to that condition — what it is, how it's treated and when to seek help.
What helps
Self-care and what you can do
For everyday knee pain, it helps to keep moving gently while avoiding activities that make it much worse, as too much rest can stiffen the joint. Simple measures such as resting a flared-up knee, using a cold pack on a swollen knee, and supporting it with a comfortable position can ease pain. Strengthening the muscles around the knee through gentle exercise improves support over time, and keeping to a healthy weight reduces the load on the joint. Supportive, cushioned footwear and avoiding prolonged kneeling or deep squatting can also help while the knee settles.
Answers
Knee pain: frequently asked questions
Should I rest or keep moving with knee pain?
Gentle movement is usually better than complete rest, which can stiffen the joint and weaken the supporting muscles. Avoid activities that sharply worsen the pain, but try to keep the knee moving within comfort.
When is knee pain an emergency?
A hot, swollen, very painful knee with fever may be a joint infection and needs urgent same-day assessment. Being unable to bear any weight, or an obvious deformity after an injury, also needs prompt help.
Does being overweight affect my knees?
Yes. Extra weight increases the load on the knees and can worsen pain and wear. Losing even a modest amount of weight often eases knee pain and protects the joints over time.
Can I exercise with knee pain?
Usually yes, with low-impact activities such as swimming, cycling or gentle strengthening, which support the knee without heavy pounding. If pain is severe, swelling is marked, or the knee gives way, get it checked first.
Sources
Where this is drawn from
- NICE CKS: Knee pain (assessment).
- Versus Arthritis (charity)
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