What is arthritis?

Arthritis is a group of conditions that cause damage to one or more joints.

The most common type of arthritis is osteoarthritis, where there is gradual wear and tear of a joint.

Arthritis eventually wears away the normal cartilage covering the surface of the joint and the bone underneath becomes damaged. This causes pain and stiffness in your knee, which can interfere with normal activities. If only part of your knee is damaged by arthritis, you can sometimes have a partial knee replacement instead of a total knee replacement.

What are the benefits of surgery?

You should get less pain and be able to walk more easily. A partial knee replacement may bend better and feel more like a normal knee than a total knee replacement.

Are there any alternatives to a partial knee replacement?

Simple painkillers such as paracetamol and anti-inflammatory painkillers such as ibuprofen can help control the pain of arthritis.

Using a walking stick on the opposite side to the affected knee can make walking easier. Wearing an elasticated support on your knee can help it feel stronger.

Regular moderate exercise can help to reduce stiffness. Physiotherapy may help to strengthen weak muscles.

A steroid injection into your knee joint can sometimes reduce pain and stiffness for several months.

An operation called a tibial osteotomy changes the shape of your leg and can take the load off the worn part of your knee.

If you decide not to have a partial knee replacement, you can usually have a total knee replacement instead.

What will happen if I decide not to have the operation?

Arthritis of your knee usually gets worse with time. Arthritis is not life-threatening but it can be disabling.

What does the operation involve?

Various anaesthetic techniques are possible. The operation usually takes an hour to 90 minutes.

Your surgeon will make a cut on the front of your knee and will check that your knee is suitable for a partial replacement.

Your surgeon will remove the damaged joint surfaces. They will then insert an artificial knee joint made of metal, plastic or ceramic, or a combination of these materials.

The implant is fixed to the bone using acrylic cement or special coatings on your knee replacement that bond directly to the bone.

How can I prepare myself for the operation?

If you smoke, stopping smoking now may reduce your risk of developing complications and will improve your long-term health.

Try to maintain a healthy weight. You have a higher risk of developing complications if you are overweight.

Regular exercise should help to prepare you for the operation, help you to recover and improve your long-term health. Before you start exercising, ask the healthcare team or your GP for advice.

Speak to the healthcare team about any vaccinations you might need to reduce your risk of serious illness while you recover. When you come into hospital, practise hand washing and wear a face covering when asked.

What complications can happen?

The healthcare team will try to reduce the risk of complications.

Any numbers which relate to risk are from studies of people who have had this operation. Your doctor may be able to tell you if the risk of a complication is higher or lower for you. Some risks are higher if you are older, obese, you are a smoker or have other health problems. These health problems include diabetes, heart disease or lung disease.

Some complications can be serious and may even cause death.

General complications of any operation

• Bleeding during or after the operation.
• Infection of the surgical site (wound).
• Allergic reaction to the equipment, materials or medication.
• Acute kidney injury.
• Difficulty passing urine.
• Blood clot in your leg (deep-vein thrombosis – DVT).
• Blood clot in your lung (pulmonary embolus), if a blood clot moves through your bloodstream to your lungs.
• Chest infection — your risk will be lower if you have stopped smoking and you are free of Covid-19 (coronavirus) symptoms for at least 7 weeks before the operation.
• Heart attack — a heart attack can sometimes cause death.
• Stroke — a stroke can sometimes cause death.

Specific complications of this operation

• Damage to nerves around your knee, leading to weakness, numbness or pain in your leg or foot.
• Damage to blood vessels behind your knee, leading to loss of circulation to your leg and foot. You will need surgery straight away to restore the blood flow.
• Bearing dislocation, where the piece of plastic in the middle of your knee replacement comes out of place. You will need another operation.
• Infection in your knee, which can result in loosening and failure of your knee replacement.
• Wear or loosening without infection. You may need another operation to do your knee replacement again.
• Continued discomfort in your knee.
• Severe pain, stiffness and loss of use of your knee. Your knee can take months or years to improve. Sometimes there is permanent pain and stiffness.
• Difficulty passing urine.

Consequences of this procedure

• pain
• unsightly scarring of your skin

How soon will I recover?

You can go home when your pain is under control, you can get about safely, and any care you may need has been arranged.

You will need to use walking aids until you can walk well without them.

Regular exercise should help you to return to normal activities as soon as possible. Before you start exercising, ask the healthcare team or your GP for advice.

Most people make a good recovery, have less pain, and can move about better. An artificial knee never feels quite the same as a normal knee.

A partial knee replacement can wear out with time.

Summary

Arthritis of your knee usually happens without a known cause. It can sometimes affect only part of your knee. If you have severe pain, stiffness and disability, a partial knee replacement should reduce your pain and help you to walk more easily.

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