Risks and benefits of knee replacement
Informed by recognized medical guidance
Overview
Knee replacement is a surgery where a damaged knee joint is removed and replaced with an artificial joint made of metal and plastic. It is done to relieve severe pain and improve movement when other treatments have not helped.
Key facts
- Knee replacement can greatly reduce pain and improve quality of life for many people.
- The artificial joint usually lasts 15 to 20 years or more.
- Recovery takes several months and includes physical therapy to regain strength and movement.
Yes, knee replacement is one of the most common joint replacement surgeries. In the UK, over 100,000 knee replacements are performed each year.
It is most often done in people aged 60 and older, but younger adults with severe joint damage from injury or arthritis may also be candidates.
Symptoms
- Sudden, severe knee pain with redness and heat – could be a sign of infection or blood clot.
- Inability to move the knee or bear any weight on the leg after surgery.
- Signs of a blood clot in the leg (calf pain, swelling, warmth, redness) that travel to the lung (chest pain, trouble breathing).
- ⚠Swelling that gets worse over a few days.
- ⚠Fever with shivers after surgery.
- ⚠Wound drainage that is yellowish or foul-smelling.
Common symptoms
- Severe knee pain that limits daily activities like walking, climbing stairs, or getting up from a chair.
- Knee stiffness, especially in the morning or after sitting for a while.
- Swelling and tenderness around the knee.
- A feeling that the knee is giving way or locking.
Symptoms in older adults
- Pain that wakes you up at night.
- Difficulty walking without a cane or walker.
- Need help with tasks like bathing or dressing.
Causes
Main causes
- Osteoarthritis – the most common reason, where cartilage wears down over time.
- Rheumatoid arthritis – an autoimmune condition that inflames the joint lining.
- Injury – a broken knee bone or torn ligaments that lead to long-term damage.
Risk factors
- Age over 50.
- Being overweight or obese.
- Previous knee injury or surgery.
- Family history of knee arthritis.
When to see a doctor
See a doctor urgently if:
- Sudden, severe knee pain with swelling and fever.
- Inability to walk or move your knee after a fall.
Book a routine appointment if:
- Knee pain that does not improve with rest, ice, over‑the‑counter pain relievers, or physical therapy.
- Pain that stops you from doing everyday activities.
- Knee that feels unstable or locks.
Diagnosis
Your doctor will ask about your symptoms and examine your knee. They may order imaging tests to see the damage inside the joint.
Tests that may be done
- X‑rays to look for bone spurs, narrowed joint space, and alignment issues.
- MRI to get a detailed view of soft tissues like cartilage and ligaments.
- Blood tests to rule out inflammatory arthritis or infection.
What to expect at your appointment
Your doctor will discuss your pain level, activity goals, and whether non‑surgical treatments have been tried. They will explain the benefits and risks of knee replacement so you can make an informed choice.
Treatment
Treatment for knee pain starts with non‑surgical options. If these do not help enough, knee replacement may be considered. The surgery has both benefits (pain relief, better movement) and risks (infection, blood clots, stiffness).
Self-care at home
- Rest and ice the knee after activity.
- Do gentle exercises to maintain strength and flexibility.
- Use a cane or walker if needed.
- Lose weight if you are overweight – every pound matters.
Medical treatments
Non‑surgical treatments include pain relievers (such as acetaminophen or nonsteroidal anti‑inflammatory drugs), prescription creams, physical therapy, and joint injections with steroids or a lubricant. These treatments can help but do not fix the underlying damage.
When is surgery considered?
Surgery is usually considered when knee pain is severe enough to affect sleep, work, or daily life, and when non‑surgical options have not worked. Your surgeon will explain the specific benefits (pain relief, improved mobility) and risks (infection, blood clots, nerve damage, implant failure) so you can decide together.
Living with this condition
After knee replacement, you will need to do physiotherapy exercises to regain strength and range of motion. Most people can walk without support within 6 to 12 weeks and return to normal activities in 3 to 6 months. Full recovery may take up to a year.
Lifestyle tips
- Avoid high‑impact activities like running or jumping.
- Take stairs one at a time for the first few months.
- Use a pillow between your knees when sleeping on your side.
Diet and exercise
A balanced diet helps with healing and weight control. Include plenty of protein, fruits, and vegetables. Low‑impact exercises like swimming, cycling, and walking are good for long‑term joint health.
Mental health and emotional wellbeing
Recovery can be frustrating. It is normal to feel down or anxious. Talk to your doctor or a counsellor if you feel overwhelmed. Staying active and connecting with others can help.
Prevention
Knee replacement itself cannot be prevented, but you may reduce your risk of needing an early replacement by maintaining a healthy weight, exercising regularly, protecting your knees from injury, and managing conditions like arthritis early.
Complications
If left untreated
- Chronic pain that becomes constant and limits independence.
- Muscle weakness and joint stiffness that make walking difficult.
- Increased risk of falls because the knee is unstable.
Long-term outlook
For most people, knee replacement leads to significant pain relief and a better quality of life. The surgery has risks, but serious complications are uncommon. With proper care and follow‑up, the new knee can work well for many years.
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Always verify with your doctor
Health guidelines vary by country and region. The information in this article is based on international clinical guidelines but may not reflect the specific guidelines, medications, or practices in your country. Always discuss your health concerns with your own doctor or healthcare provider, and refer to your local national health guidelines where available.
Important notice This information is for educational purposes only. It does not replace professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider about your specific situation. If you are experiencing a medical emergency, call your local emergency services immediately.
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Sources and guidance
This article is educational and is prepared with reference to recognized health information and clinical guidance sources where available. Specific source links may vary by topic.
Last updated: July 17, 2026
Educational note: This information is for education only and is not a diagnosis.
Use it to support, not replace, advice from a licensed clinician.
If symptoms are severe, worsening, or urgent, call your local emergency number or seek emergency care.
Guidance may differ by country or region. Confirm local recommendations with a qualified healthcare provider.