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Complications of a knee replacement

Possible complications of a knee replacement

A knee replacement is a common and safe procedure. However, as with any operation there are risks. Your doctor will explain these to you.

Most people who have a knee replacement have no complications. If there are any, they are usually minor and can be treated.

The risk of having complications depends on your age and general health.

Blood clots or DVT (deep vein thrombosis)

Blood clots or DVT (deep vein thrombosis) are possible after a knee replacement because of how the blood flows and clots after surgery. This is often not serious.

If you have a blood clot that causes pain or swelling, your doctor can give you anticoagulant medicines to help.

A blood clot that forms in the leg can sometimes travel to your lungs (pulmonary embolism). This can cause serious complications.

To reduce the risk of blood clots your doctor might suggest wearing compression stockings or taking anticoagulant medicines.

Wound infection

There's a small chance that your knee wound could get infected after the operation. This is usually treated with antibiotics.

If the infection spreads deep into the knee joint, you may need further surgery.

Damage to nerves or tissue

During surgery, there's a chance that a blood vessel, nerve or ligament around the knee joint could be damaged.

This is not common and can either be repaired during surgery or will heal afterwards.

Problems with your new knee

Most people find their daily life improves after a knee replacement. However, it's possible that you may have ongoing issues with your new knee, including:

  • problems bending the knee
  • ongoing pain and stiffness
  • the knee being unstable when you stand up or walk

Physiotherapy and certain exercises may help with these problems.

Most knee replacements last for about 20 years or more. Depending on when you had the operation you may need another replacement later in life, but this is not common.

Urgent advice: Ask for an urgent GP appointment or get help from NHS 111 if:

You've recently had a knee replacement and you have:

  • throbbing or cramping pain in your leg
  • a high temperature
  • chills and feel shivery
  • oozing or pus from your wound
  • redness, tenderness, swelling or pain in your knee that is not getting better or is getting worse

These could be signs of an infection or a blood clot.

You can call 111 or get help from 111 online.

Immediate action required: Call 999 or go to A&E if:

You have pain and swelling in your leg and:

  • you're having difficulty breathing
  • you have chest pains

This could be a blood clot in the lungs (pulmonary embolism), which needs to be treated immediately.

Page last reviewed: 9 March 2023
Next review due: 9 March 2026