Knee Pain: Common Causes and When to See a Doctor
Medically Reviewed by Dr. Pedro Yelamo Vera, MD
Licensed Physician No. 484814280 · Official Medical College of Bizkaia (Spain)Last reviewed: 31 October 2026
Knee pain is usually a strain, a torn meniscus, arthritis or gout. What helps at home, when you need an X-ray, and when to get urgent care.
You don't have to figure this out alone
Dr. Pedro Yelamo Vera is an independent, bilingual GP licensed in Spain. Book a 15-minute video consultation in English or Spanish for €50, with a private electronic prescription issued under Spanish law when clinically appropriate.
Most knee pain comes from a strain, overuse or wear and tear. It usually eases with rest, ice and simple painkillers, and many people feel better within days. See a doctor if it is not improving after a few weeks. Get help today for a hot, swollen knee or a fever, and go to an emergency department after a bad injury.
- Common causes are sprains, tendon strain, a torn meniscus or ligament, osteoarthritis, bursitis and gout.
- Start with home care: ease the load, use ice, and try a painkiller gel or tablets.
- The NHS advises seeing a GP if knee pain does not improve within a few weeks.
- A hot, red, swollen knee, or a fever, needs a doctor today. It can be gout or a joint infection.
- After an injury, go to an emergency department if the knee looks deformed, cannot take weight, or swelled up fast.
- In people aged 45 or over, NICE says osteoarthritis can usually be diagnosed without an X-ray.
Dr. Pedro Yelamo Vera is a GP licensed in Spain (Colegiado No. 484814280).
For a medical emergency, call 112 or go to the nearest local emergency department. Do not wait for a video consultation or an online reply.
What are the most common causes of knee pain?
The way the pain started, and where it hurts, give the best clues. The NHS links these patterns to likely causes:
- Pain after a twist, overstretch or overuse: a sprain or strain.
- Pain between the kneecap and shin after running or jumping: tendonitis, often called jumper's knee.
- The knee gives way or will not straighten, sometimes after a pop: a torn ligament, tendon or meniscus (the knee cartilage).
- Stiff, aching knees, often both, and more common with age: osteoarthritis.
- Warm swelling at the front, worse when kneeling: bursitis.
- A sudden hot, red, very painful knee: gout or a joint infection (septic arthritis).
- Pain below the kneecap in a teenager: Osgood-Schlatter disease.
Pain can also spread to the knee from the hip or lower back, says the MSD Manual. In Spain you will hear menisco (meniscus), ligamento cruzado (cruciate ligament), artrosis (osteoarthritis) and gota (gout).
Why does my knee hurt on stairs or after sitting?
Pain at the front of the knee, around or behind the kneecap, is often patellofemoral pain. It is sometimes called runner's knee. MSD Manuals notes that it often hurts after running, especially on hills, and after sitting for a long time. Stairs, squats and kneeling load the same area.
It is common in runners and other active people. Strengthening the thigh muscles (quadriceps) is the main treatment. A physiotherapist (fisioterapeuta) can show you how.
How can I ease knee pain at home?
If there was no big injury and you can still get about, home care is a good first step. The NHS and Mayo Clinic advise:
- Ease the load. Avoid standing for long periods. Swap running for swimming or cycling for a while.
- Use ice. Wrap an ice pack or a bag of frozen peas in a tea towel. Hold it on the knee for up to 20 minutes at a time, a few times a day.
- Support and raise it. A light elastic bandage can help. Do not wrap it tight. Rest with the leg up on pillows.
- Pain relief. Mayo Clinic suggests trying a gel or cream first, such as diclofenac gel. The NHS mentions paracetamol or ibuprofen gel or tablets.
Ask a pharmacist (farmacéutico) which painkiller suits you. This matters if you have stomach, kidney or heart problems, or take blood thinners.
Knee pain that is not settling, or you are not sure what caused it?
You can book a video visit with a GP licensed in Spain, in English or Spanish. He asks how it started, watches you move the knee on camera, and helps you plan the next steps.
Is my knee pain arthritis?
Osteoarthritis is the most common long-term cause in older adults. The UK guideline from NICE says a doctor can diagnose it without a scan if you:
- are 45 or over, and
- have joint pain linked to activity, and
- have no morning stiffness, or stiffness that lasts no more than 30 minutes.
NICE calls exercise and, if needed, weight loss the core treatments. It advises offering a painkiller gel (a topical NSAID) for knee osteoarthritis. It does not recommend glucosamine, because there is no strong evidence that it helps. Steroid injections can be considered when other treatments do not work, but their relief is short, about 2 to 10 weeks.
NICE also advises against keyhole surgery to wash out or clean the joint in osteoarthritis. In Spain the condition is called artrosis.
Do I need an X-ray or MRI for knee pain?
Often not. For typical osteoarthritis, NICE advises against routine imaging. For other knee pain, a doctor first asks how it started and examines the knee.
A scan helps when a broken bone, a torn ligament or a torn meniscus is likely. It also helps when the pain does not fit a usual pattern. Locking, giving way or a large swelling after an injury are reasons for an in-person exam.
What causes knee pain in children and teenagers?
In active children aged about 10 to 15, the usual cause is Osgood-Schlatter disease, says the Spanish Association of Paediatrics. A tendon pulls on the growing bone just below the kneecap. It hurts during or after running and jumping. A tender bump may appear there.
It settles with less sport for a while, ice and simple painkillers. The pain fades as the bone matures.
Knee pain in a child can also come from the hip. A child who limps, has a fever, has pain at night, or pain not linked to sport should see a doctor. If the child cannot put weight on the leg or has a fever, do not wait.
When should you see a doctor about knee pain?
Book a GP visit if:
- The pain has not improved within a few weeks.
- It disturbs your sleep or daily tasks.
See a doctor today if:
- The knee locks, gives way or clicks painfully.
- The knee is hot, red and swollen, or you have a high temperature. This can be infection or gout.
- The knee is very painful and you cannot move it.
- Your calf is swollen, throbbing and painful. A blood clot (DVT) needs checking.
Go to an emergency department (urgencias) if, after an injury, the knee looks bent or deformed, you cannot put any weight on it, or it swelled up quickly after a pop.
Call 112 if leg pain or swelling comes with sudden breathlessness or chest pain. This can be a clot in the lung.
Talking it through with a doctor by video
Dr. Yelamo is a GP licensed in Spain. He sees adults, children and pregnant patients by video, every day from 07:30 to 20:30 (Spain time). In the visit he will:
- Ask how and when the pain started, and what makes it worse.
- Watch you walk, bend and straighten the knee, and point to the sore spot on camera.
- Agree a plan for load, ice, pain relief and exercises.
- Tell you if you need an X-ray, a physiotherapist or an in-person exam.
He does not promise any test or prescription before the visit. Where clinically appropriate, following a genuine evaluation. Treatment and prescriptions are issued solely at the doctor's discretion based on evidence-based clinical guidelines.
A prescription is never guaranteed: it is issued only where clinically appropriate after a genuine evaluation, as a private electronic prescription under Spanish law. This service is for urgent, non-emergency care. In an emergency, call 112.
See how the Urgent Care video visit works. It lasts 15 minutes and costs €50.
This guide is general information. It does not replace a consultation with your doctor.
Frequently asked questions
When should I worry about knee pain?
Get help today for a hot, red, swollen knee or a fever. Go to an emergency department if the knee looks deformed or cannot take weight after an injury. See a GP if pain lasts more than a few weeks.
Does ice help knee pain?
Yes, for a sore or swollen knee. Wrap an ice pack in a towel and hold it on the knee for up to 20 minutes at a time.
Should I keep walking with knee pain?
If there was no big injury and you can bear weight, gentle movement is usually fine. Cut down long standing and swap running for swimming or cycling for a while.
Is knee pain a sign of arthritis?
Not always. In people over 45 with pain on activity and little morning stiffness, osteoarthritis is likely. Younger people more often have a strain, tendon problem or injury.
Why does my knee hurt going down stairs?
Pain at the front of the knee on stairs is often patellofemoral pain. Strengthening the thigh muscles usually helps.
How long does knee pain take to get better?
Many strains feel better within a few days. If the pain is not improving after a few weeks, see a GP.
Sources
- NHS: Knee pain
- Mayo Clinic: Knee pain, when to see a doctor
- NICE NG226: Osteoarthritis in over 16s
- En Familia (AEP): Osgood-Schlatter disease (in Spanish)
- NHS: Deep vein thrombosis
Related guides
Medical Citations & Sources
This content is written and reviewed by a licensed physician with reference to the following official health authorities.
