The surgeon makes an incision over the front of the knee and removes the damaged cartilage and bone surfaces from the end of the thighbone (femur), the top of the shinbone (tibia), and usually the underside of the kneecap (patella). These surfaces are replaced with precisely shaped metal and high-grade plastic components that recreate the shape and movement of a healthy knee. The components are usually fixed with bone cement. The wound is closed with stitches or clips and a dressing is applied. The operation typically takes between one and two hours.
Total knee replacement is usually recommended for people with significant knee arthritis that causes persistent pain, stiffness, and difficulty with everyday activities such as walking, climbing stairs, or getting up from a chair. It is generally considered when non-operative treatments have been tried and are no longer providing adequate relief.
Before considering surgery, most patients will have tried some combination of weight management, physiotherapy and exercise, pain medication, walking aids, activity modification, and injections (corticosteroid or hyaluronic acid). These remain valid options, and the decision to proceed with surgery is always made jointly with your surgeon.
You will attend a pre-assessment clinic where blood tests, heart tracing, and other investigations may be arranged. Discuss your regular medications with the surgical team. Maintaining good dental health before surgery reduces infection risk. Strengthening exercises for the leg muscles can aid your recovery. You will be asked to fast before the operation.
The primary aim is to relieve pain and improve knee function. Most patients experience significant pain relief and are able to return to everyday activities including walking, gardening, and light recreational activity. The artificial joint typically lasts 15 to 25 years. The goal is a well-functioning, pain-free knee rather than a completely "normal" knee.
Swelling and stiffnessExpected
Normal in the early weeks and gradually improves with physiotherapy.
Wound infection (superficial)Common
Occurs in roughly 1–2 in every 100 patients. Usually treated with antibiotics.
Blood clots (DVT)Common
Can occur despite preventive measures such as blood-thinning medication and compression stockings.
Numbness near the scarCommon
A patch of numbness on the outer edge of the knee is relatively common and usually improves over time.
Deep joint infectionUncommon
Occurs in roughly 1 in 100 patients. May require further surgery or prolonged antibiotics.
Nerve or vessel injuryRare
Rare, but could cause weakness or altered sensation in the lower leg.
Periprosthetic fractureRare
Fracture of the bone around the implant.
Implant looseningLong-term
The components can loosen over time, eventually requiring revision surgery.
Pulmonary embolismRare
A blood clot travelling to the lungs. Rare but potentially life-threatening.
Persistent stiffnessUncommon
A small number of patients require manipulation under anaesthesia.
Usually performed under spinal anaesthesia combined with sedation, or under general anaesthesia. Your anaesthetist will discuss the most suitable option. A nerve block may be used for pain relief after surgery.
Most patients stay in hospital for one to three days. Physiotherapy begins on the day of surgery or the day after. Walking with crutches or a frame is encouraged immediately. Most people return to driving at around six weeks. Full recovery continues for up to 12 months.
Typically seen at two weeks, six weeks, three months, and one year. X-rays are taken to monitor the implant.
How long will my new knee last?
Modern knee replacements typically last 15 to 25 years.
Will I set off airport security?
The metal components may trigger scanners. You can request a card from your surgeon.
Can I kneel after a knee replacement?
Many patients find kneeling uncomfortable, though it is generally safe.
When can I drive?
Most patients can return to driving at around six weeks.