Reasons for Having a Knee Replacement

A knee replacement may be recommended when knee pain is seriously affecting your quality of life and other treatments haven't provided enough relief.

Osteoarthritis

The leading cause is osteoarthritis, a condition that leaves joints painful and stiff. The knee normally moves smoothly thanks to a layer of cartilage covering the bone ends; once that cartilage wears away or is damaged, the bones grind against one another, causing pain and reduced movement.

Other Conditions

Less commonly, a knee replacement may also be used to treat:

• Gout — a form of arthritis caused by a build-up of uric acid crystals in the joint
• Sports-related injuries that have caused lasting joint damage

The Outcome

During the procedure, the damaged sections of the knee are replaced with metal and plastic components. Knee replacements are generally very successful, with most patients experiencing significantly less pain and improved movement afterwards.

Common Alternatives to a Knee Replacement

There are non-surgical treatments, and other surgical options, that may be tried before a full knee replacement is considered.

Treatments Tried First

Your doctor will usually discuss lifestyle changes and pain-relief options first, such as:

• Losing weight to ease the strain on the knee if you're overweight
• Low-impact exercise such as swimming, walking or cycling, along with strengthening exercises — a physiotherapist can help guide you
• Using walking aids
• Wearing supportive footwear or shoe insoles
• Pain relief medicines, gels or creams
• Hydrocortisone (steroid) injections into the knee joint to reduce pain and swelling

Other Types of Surgery

Where a full replacement isn't the right next step, your surgeon may discuss alternative procedures, including:

• Arthroscopy — a keyhole procedure to flush out loose bone or cartilage fragments from the joint
• Osteotomy — reshaping the shin bone to shift pressure away from the damaged part of the knee
• Microfracture — creating tiny holes in the bone surface to stimulate new cartilage growth
• Scaffold insertion — placing a patch or gel into the joint to encourage new cartilage to form

How to Prepare

Ahead of your knee replacement, your doctor will advise on steps that can help your recovery go smoothly. This often includes specific pre- and post-operative exercises, stopping smoking, eating a balanced diet, and managing your weight.

It's worth acting on this advice as early as possible, since waiting lists can be lengthy — the more prepared you are going in, the better your recovery is likely to be.

Pre-Admission Clinic

A few weeks before surgery, you'll likely be invited to a pre-admission clinic to confirm you're fit for the operation. This may involve:

• Blood tests
• Blood pressure checks
• A chance to meet the healthcare team involved in your care and ask any questions

Preparing Your Home

It's also worth getting your home ready for when you return after surgery. Things to consider include:

• Arranging help with everyday tasks
• Keeping frequently used items within easy reach
• Stocking the freezer with ready-made meals
• Organising transport, since you won't be able to drive for several weeks afterwards
• Talking to your employer about a plan for returning to work

What Happens During Surgery

You'll usually be admitted to hospital on the day of your knee replacement. Shortly before the procedure, a nurse will take you through to the operating theatre, where you'll have either a general anaesthetic (you're fully asleep) or a spinal anaesthetic (you're awake but numb from the waist down). The operation typically takes 1 to 2 hours, depending on factors like the extent of the damage, your age and your general health.

Total Knee Replacement

This is the most common form of the procedure, replacing the lower end of the thigh bone and the upper end of the shin bone with metal and plastic components.

The main steps are:

1. The surgeon makes a cut down the front of the knee and moves the kneecap aside to access the joint
2. The damaged ends of the shin bone and thigh bone are cut away
3. New metal and plastic parts are fitted to both bones to form the new joint
4. The underside of the kneecap may also be resurfaced if needed
5. The kneecap is repositioned back into place
6. The cut is closed with stitches or clips and covered with a dressing
7. You're moved to a recovery room until you're fully awake, where pain relief is given as needed

Partial Knee Replacement

Used when only one side of the knee is affected by arthritis, this option replaces just the damaged bones on that side. The cut is smaller than for a total replacement, and recovery tends to be quicker.

National Joint Registry

After the operation, you may be asked whether you're happy for your details and information about your knee replacement to be added to the National Joint Registry, which tracks outcomes to help improve patient safety and care.

Recovery in Hospital

After surgery you'll spend time in a recovery room where you'll be given pain relief as needed, continuing over the following days as your knee settles. Nurses and physiotherapists will help get you walking again as soon as it's safe to do so — you'll likely need crutches or a walking frame to begin with.

Recovery at Home

Most people are able to leave hospital 1 to 3 days after surgery, once their wound is healing well and they can move around safely. Before discharge, a physiotherapist or occupational therapist will talk you through daily activities and a home exercise plan — sticking with these early on really helps long-term strength and movement. Stitches or clips are usually removed around 10 days later, with a follow-up check at about 6 weeks.

Possible Complications

A knee replacement is a common and generally safe operation, but as with any surgery there are some risks, which your doctor will talk through with you beforehand. Most people don't experience complications, and where they do occur they're usually minor and treatable. Your individual risk depends partly on your age and overall health.

Blood Clots / DVT

Blood clots or DVT (deep vein thrombosis) can occur after surgery due to changes in blood flow, and this usually isn't serious. Compression stockings or anticoagulant medicines are often used to lower the risk. Rarely, a clot can travel to the lungs (pulmonary embolism), which is more serious.

Wound Infection

There's a small risk of infection at the wound site, usually treated with antibiotics. If the infection spreads deeper into the joint, further surgery may be required.

Nerve or Tissue Damage

Occasionally, a nearby blood vessel, nerve or ligament can be affected during surgery. This is uncommon, and can typically be repaired at the time or will heal naturally afterwards.

Ongoing Issues with the New Knee

While most people notice a big improvement in daily life, some may experience ongoing difficulties such as trouble bending the knee, persistent stiffness, or a feeling of instability when standing or walking. Physiotherapy and targeted exercises can often help. Most knee replacements last 20 years or more, though a further replacement may occasionally be needed later in life.