- Knee pain
- Osteoarthritis
- Joints
Knee pain: common causes, home care and warning signs
The knee is the joint most affected by osteoarthritis worldwide. We explain what may be causing your pain, what to do at home, and when you need urgent care.
PainManagement ER Published 3 min read
Climbing stairs, getting up from a chair, going for a walk. Your knees are involved in almost everything you do, which is why you notice so quickly when one hurts. The pain can come from a recent injury or appear with no clear cause, and each case is handled differently.
Knee osteoarthritis in numbers
One of the most common causes is osteoarthritis. According to the Global Burden of Disease 2021 study, published in The Lancet Rheumatology:[2]
- 595 million people had osteoarthritis in 2020, about 7.6% of the world’s population.
- The knee is the most common site.
- Osteoarthritis is more common in women than in men.
- High body-mass index contributed to about 20% of the disability burden from osteoarthritis.[2][3]
And cases are expected to keep rising:
Projected increase in osteoarthritis cases from 2020 to 2050, by site
- Other sites
- Hip
- Knee
- Hand
What could be causing your pain?
The NHS gives guidance on possible causes based on how the pain started and how it shows up:[1]
| How it shows up | Possible cause |
|---|---|
| After an injury | |
| After overstretching, overusing or twisting the knee, often during exercise | Sprain or strain |
| Pain between the kneecap and shin, from repetitive running or jumping | Tendonitis |
| The knee gives way, can't straighten, or popped during the injury | Torn ligament, tendon or meniscus |
| The kneecap changes shape after a collision or sudden change of direction | Dislocated kneecap |
| With no obvious injury | |
| Pain and stiffness in both knees with mild swelling, more common in older people | Osteoarthritis |
| A warm, red knee that is worse when kneeling or bending | Bursitis |
| A hot, red knee with sudden attacks of very bad pain | Gout or septic arthritis |
| Pain and swelling below the kneecap in teenagers and young adults | Osgood-Schlatter disease |
Source: NHS, "Knee pain" (2023).[1] This is general guidance; a professional should make the diagnosis.
What to do at home for recent pain
For recent knee pain, the NHS recommends:[1]
- Putting as little weight as possible on the knee and avoiding standing for a long time.
- Applying ice or a bag of frozen peas wrapped in a towel, for up to 20 minutes every 2 to 3 hours.
- Using pain relievers such as acetaminophen, or ibuprofen gel or tablets, following the label.
You should start to feel better in a few days. If it doesn’t improve within a few weeks, see a doctor.[1]
If it’s osteoarthritis, moving helps
Rest works for a recent flare, but osteoarthritis is managed differently. For knee osteoarthritis, the CDC’s 2022 clinical guideline lists exercise (aerobic, aquatic or resistance) and weight loss, plus topical NSAIDs for joints near the skin such as the knee.[4] The CDC adds that low-impact activity such as walking, biking or swimming can improve pain and function, and that even a small amount of weight loss can help people with overweight.[5]
No medication should be taken without medical advice: each one has contraindications and side effects.
Warning signs
The NHS advises getting urgent same-day care if:[1]
- Your knee is very painful.
- You can’t move it or put any weight on it.
- It is badly swollen or has changed shape.
- It locks, gives way or clicks painfully (painless clicking is normal).
- You have a very high temperature or chills with redness or heat around the knee, which can signal an infection.
If knee pain isn’t improving or limits what you do each day, an assessment can identify the cause and help you choose the right treatment.
Sources
- Knee pain . NHS (UK National Health Service) , reviewed December 21, 2023.
- Global, regional, and national burden of osteoarthritis, 1990–2020 and projections to 2050: a systematic analysis for the Global Burden of Disease Study 2021 . GBD 2021 Osteoarthritis Collaborators. The Lancet Rheumatology 2023;5(9):e508–e522 , August 2023.
- Nearly 1 billion people likely to live with osteoarthritis by 2050 (study press release) . EurekAlert!, The Lancet Rheumatology , August 2023.
- CDC Clinical Practice Guideline for Prescribing Opioids for Pain — United States, 2022 . Dowell D, et al. MMWR Recomm Rep 2022;71(No. RR-3):1–95, CDC , November 2022.
- Talking to Patients About Self-Management (Arthritis) . Centers for Disease Control and Prevention (CDC) , June 10, 2026.
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