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What Are the Risks of Knee Replacement Surgery?

Undergoing any surgical procedure comes with potential risks and complications. If you’re considering a knee replacement, here are a few things you should know.

Millions of people who have suffered from knee pain and arthritis have experienced relief and restored mobility through total knee replacement. Globally, hundreds of thousands of knee replacement procedures are performed each year. However, as with any major surgery, knee replacement involves potential complications and risks both during and after the procedure. Your care team takes many precautions to prevent and manage the following possible risks.

Reaction to anesthesia

Your anesthesiologist is a specialist in giving the medications that will help relax you and manage your pain during and after surgery. You will meet with your anesthesiologist before your hospital admission or surgical procedure to determine the type of anesthetic that is most appropriate for you. Strictly follow your doctor’s guidelines regarding food and drink before surgery. The more common side effects related to anesthesia include nausea, vomiting, and headaches (all of which can usually be relieved with medication). Please ask your doctor and anesthesiologist about all risks associated with anesthetic.


Surgical incision sites and/or bone and tissue around the knee implants can become infected, which can delay recovery and even require additional surgery to remove and/or replace the implants. Talk to your surgeon about the potential risks and complications of infection. After your knee replacement, your doctor may require you to take preventive antibiotics before dental or surgical procedures that could allow bacteria to enter your bloodstream. Before other procedures, speak with your surgeon and your dentist to see if you still need preventive antibiotics.

Blood clots

The risk of blood clots in the leg veins is related to alterations in blood flow that occur during knee surgery. Blood thinning drugs prescribed by your doctor are typically used to improve blood flow and reduce the risk of clot formation. During your initial exam, your doctor will assess factors such as your weight and cardiovascular history to select the best blood thinner for you. In the hospital, elastic stockings or compression stockings may be used to further reduce this risk. After surgery, you will be encouraged to move and exercise to prevent blood clot formation.

Damage to nearby blood vessels, bones or nerves

To help minimize damage that may occur to blood vessels, bones and nerves in and around the incision, surgeons use precision tools, guides and highly refined surgical techniques. Nerve damage, although rare, can cause irritation and pain following your surgery.

Persistent pain

There is no guarantee that knee replacement will make you pain-free.

Loosening, wear or breakage of the artificial knee

Knee implants can loosen, parts can wear and rarely, a device does break. Such occurrences are typically accompanied by pain and/or loss of function, and may require additional surgery.


Pneumonia is a risk with major surgery, especially in older patients. Postoperative pneumonia is related to immobility and the tendency of patients to use less of their total lung capacity following surgery. Therefore, respiratory rehabilitation is a key component of your recovery. A respiratory therapist will work with you while you are in the hospital to show you how to cough, perform breathing exercises and use devices such as the incentive spirometer to help keep your lungs clear.

You will be given a consent document to sign before your surgery. This document typically explains in detail, the known risks, both major and minor. Review the document carefully and discuss any questions or concerns you have with your doctor before signing.

Knee replacement surgery is your decision based on the advice of your surgeon, input from family and friends and a careful consideration of the facts, benefits and risks involved.

When knee replacement surgery is not appropriate

Given the risks, your doctor may decide that knee replacement surgery is not appropriate if:

  •  You have an infection or a history of infection
  •  You don't have enough bone or the bone is not strong enough to support your new knee
  • You have injured nerves in your knee area
  • You have injured or nonfunctional knee muscles
  • Your knee is severely unstable
  • Your bones are not fully grown or developed
  • You have noticeable bone loss or a severe decrease in bone mass (osteoporosis)
  • Your knee joint has been previously fused and is stable, functional, and painless
  • You have rheumatoid arthritis and active/history of skin lesions (because of increased risk of infection)
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