Knee Pain: Causes, What You Can Do at Home and When to See a Doctor
By Rolandas Janušas, MD, Specialist in Orthopaedics and Trauma Surgery · Updated: October 2026
Your knee hurts – but the cause is often somewhere else. In my practice I regularly see people who have focused on their knee for weeks, only for the examination to show that the hip, the lower back or the way they walk and sit plays a big part. Others arrive with an MRI report and a lot of worry, although the findings only partly explain their pain.
This guide will help you understand common knee pain causes, what you can sensibly do yourself and when you need medical help.
Important: This article does not provide a diagnosis and does not replace a medical examination.
Where exactly does it hurt?
- Front of the knee, around or behind the kneecap: often patellofemoral pain or irritation of the patellar tendon. Typically worse going downstairs, squatting or after sitting for a long time.
- Inner knee pain, just below the joint line: often pes anserinus irritation, where several tendons attach. Osteoarthritis and meniscus problems also frequently show up on the inside.
- Outer knee: in runners, often iliotibial band syndrome (“runner’s knee”).
- Pain behind the knee: sometimes a Baker’s cyst – a fluid-filled swelling that is usually the result of another problem inside the joint.
What causes knee pain from an orthopaedic point of view?
- Overload: too much, too soon, too one-sided – for example after suddenly increasing running or hiking.
- Osteoarthritis: more than “wear and tear of cartilage”. It affects the whole joint – cartilage, bone, capsule, ligaments and muscles – and involves inflammatory processes. Typical are stiffness and pain when you start moving, easing after a few steps, and phases of swelling.
- Meniscus: in younger people tears usually follow a twisting injury. From about 40–50, degenerative tears without any injury are common – and often not the actual cause of the pain.
- Ligament injuries: after accidents, with instability or the knee giving way.
- Inflammatory causes: such as rheumatic conditions, gout or pseudogout (CPPD, calcium crystal deposits). The knee is then often suddenly warm, red and swollen.
- Knee pain from the hip or back: hip osteoarthritis often shows up first as knee pain. Irritation of the L3/L4 nerve roots in the lower back can also radiate to the thigh and knee.
- In children and teenagers: knee pain with a limp can come from the hip, for example a slipped capital femoral epiphysis (SCFE). This needs prompt assessment.
In my experience, a good conversation and a careful examination are usually the most important part of the assessment. Imaging is not always needed, and not every finding on a scan explains the pain.
What other perspectives are there?
Lucerna deliberately combines several viewpoints. Alongside the orthopaedic view, my specialist field, Lucerna also describes perspectives from Traditional Chinese Medicine (TCM) and observations of the face and tongue. TCM asks, for example, whether pain gets worse in cold, damp weather or how sleep, digestion and energy are.
These observations add to the conversation by drawing attention to lifestyle and general wellbeing. They are not a diagnosis and do not replace an examination of the knee.
What can you do at home?
- Keep moving, in doses. Walking on level ground, cycling with low resistance or swimming are usually well tolerated. Mild pain during exercise is fine if it is not worse the next day.
- Strengthen your thighs. Straighten your leg while seated and hold for five seconds; stand up slowly from a chair and sit down again; hold a shallow wall squat – only within a pain-free range.
- Include hips and feet. Side-lying leg raises and stable footwear take load off the knee.
- Watch your weight. Each kilo you lose reduces the load on the knee by about 4 kg with every step.
- Mostly warmth – with exceptions. In most cases warmth is more comfortable and more useful, for example an infrared heating pad. Warmth improves blood flow and relaxes the muscles. Exceptions: briefly cool a fresh acute injury; do not warm a hot, red, swollen knee (e.g. gout, flare-up of osteoarthritis, infection) – have it checked instead. After surgery, follow your treatment team’s instructions.
- Adapt your day. Avoid prolonged kneeling and deep squats for a while; get up regularly after sitting.
- Take sleep and stress seriously. Poor sleep and pressure make pain feel worse.
Only take painkillers short term and after speaking to a pharmacist or doctor.
When should you see a doctor immediately?
Seek medical help straight away or go to the emergency department if:
- you heard a pop at the time of injury and the knee swells quickly (possible cruciate ligament tear),
- you cannot bear weight after a fall or the leg looks deformed,
- the knee is hot, red and swollen, especially with fever or chills,
- the knee suddenly locks,
- one calf is swollen, warm and painful (possible thrombosis) – if you also have shortness of breath or chest pain, call emergency services immediately (144 in Switzerland, otherwise your local emergency number, e.g. 112 in the EU, 999 in the UK),
- you notice numbness, tingling, weakness or coldness in the lower leg or foot,
- a child or teenager is limping and complains of knee or hip pain.
Get it checked if the pain does not improve after two to three weeks of self-help, keeps coming back, gets worse at night or comes with unexplained weight loss.
What if self-help is not enough?
A medical assessment comes next: history, examination of knee, hip and back, and imaging or blood tests if needed. For most knee pain, the most important step is targeted physiotherapy with strength and coordination training – guidelines on knee osteoarthritis also put exercise first.
Depending on the findings, regenerative procedures may also be an option. Today it is possible to treat with the following approaches – always only after an individual assessment:
- PRP (platelet-rich plasma): a concentrate is made from your own blood and injected into the joint. Of the regenerative methods, PRP for knee osteoarthritis has the most studies; however, the results are not consistent.
- Exosomes: tiny vesicles that cells use to exchange signals. They are being studied as a possible support for tissue healing. Research is still at an early stage, and large long-term studies are lacking.
- Stem cells: cells that can develop into different tissues and influence healing processes. Early results are interesting, but the evidence is still limited and inconsistent.
To be honest: no method works equally well for everyone, and none is a miracle cure. Whether a regenerative approach makes sense for you can only be judged after an individual assessment. Discuss the benefits, limitations, risks and costs openly with your doctor. Surgery only makes sense for specific findings.
Frequently asked questions
Should I exercise with knee pain?
Usually yes, adapted to your symptoms. Joint-friendly movement and strength training help most people. Rest if warning signs appear and after a fresh injury.
Do I need an MRI?
Not always. History and examination are often enough. An MRI makes sense when the result would change treatment, for example after an injury or if the knee locks.
Can knee pain come from the hip?
Yes. Hip osteoarthritis and nerve irritation in the lower back often radiate to the knee. In children with a limp, the hip must be examined promptly.
Should I use ice or heat on my knee?
In most cases warmth is more comfortable and more useful, for example an infrared heating pad. Exceptions: briefly cool a fresh acute injury; do not warm a hot, red, swollen knee (e.g. gout, flare-up of osteoarthritis, infection) – have it checked instead.
Does losing weight really help?
Yes. Each kilo you lose reduces the load on the knee by about 4 kg with every step.
What is the Lucerna analysis?
Lucerna is an online analysis I developed. You answer a short questionnaire about your symptoms and can upload medical reports and photos of your face and tongue if you wish. The analysis is generated with artificial intelligence (AI) and summarises your information in about 6 minutes from several perspectives – the orthopaedic and conventional medical view, plus descriptive TCM perspectives and face and tongue observations – together with questions for your doctor.
- Cost: the analysis is paid, from CHF 6, EUR 6.50 or USD 7.50 depending on your country; further perspectives can be added.
- No medical review: your information and the analysis are not personally reviewed by a doctor.
- Privacy: photos of your face and tongue and details of your symptoms are health data. See our privacy policy.
Please note: the Lucerna analysis and this article do not provide a diagnosis and do not replace seeing a doctor.
Sources
- German Society for Orthopaedics and Trauma Surgery (DGOU): S3 guideline “Prevention and Therapy of Gonarthrosis” (knee osteoarthritis), AWMF register no. 187-050, version 5.0, status 12 July 2024, valid until 11 July 2029. https://register.awmf.org/de/leitlinien/detail/187-050
- National Institute for Health and Care Excellence (NICE): Osteoarthritis in over 16s: diagnosis and management (NG226), published 19 October 2022. https://www.nice.org.uk/guidance/ng226
- Swiss League Against Rheumatism (Rheumaliga Schweiz): Arthrose (in German). https://www.rheumaliga.ch/wissen/diagnosen/arthrose.html
Conflict of interest: the author developed Lucerna and offers the regenerative procedures mentioned in his practice.
