During a knee replacement or knee arthroplasty surgery, doctors replace the knee joint with an artificial knee. In many cases, an artificial knee joint will last the rest of a person’s life.

During a knee replacement surgery, doctors remove worn-out surfaces of the joint, resurface the knee, and then replace it with metal parts.

People undergoing knee replacement surgery commonly report improvements in quality of life, functioning, and pain.

However, an artificial knee is not suitable for everyone, and some people experience significant relief with more conservative treatments.

A 2017 review argues that a knee replacement is more likely to improve quality of life in those with severe symptoms.

Read on to learn more about artificial knees and how they can help.

Person standing at an X-ray machine with an X-ray of a knee in the foregroundShare on Pinterest
BSIP/Getty Images

An artificial knee replaces a portion of the knee joint. Specifically, a surgeon removes damaged cartilage around the bone and small pieces of bone, replacing these with metal components and plastic spacers.

Doctors use artificial knees to repair knee joints in people who have arthritis.

An artificial knee is generally only appropriate when conservative treatments, such as lifestyle changes, medication, and physical therapy, do not provide relief.

The most common types of arthritis that can damage the knee and necessitate a knee replacement include:

A doctor may recommend a knee replacement when a person has severe pain or mobility difficulties and conservative treatments do not work.

An artificial knee, like the joint it replaces, can undergo damage from wear and tear. Carrying excess weight and high impact activities, such as contact sports and running, can shorten the life of an artificial knee.

However, for many people, an artificial knee lasts the rest of their life.

A 2019 study pooled data from 7,232 knee replacement surgeries. The researchers found that 82% of total knee replacements last at least 25 years and that 70% of partial knee replacements last 25 years or longer.

It is important to note that the study did not include revision surgeries. These types of surgeries modify a knee replacement when it does not provide sufficient relief or causes additional symptoms.

Before surgery, a doctor will examine the knee and ask the person whether they have tried other interventions.

They will also assess whether the individual is a suitable candidate for surgery. Surgery may be unsuitable if the person has:

  • difficulty following medical advice
  • peripheral vascular disease
  • unreasonable expectations for what to expect after surgery

Knee replacement surgery takes 1 to 2 hours, not including preparation and recovery time.

A person may receive general anesthesia and be completely unconscious during the procedure. Alternatively, they may receive a regional anesthetic, meaning they are awake but will not feel anything in the operation area.

During the surgery, a doctor shaves down the damaged cartilage and removes a small part of the bone. They then replace the joint with an artificial knee comprising metal. In some cases, a surgeon also resurfaces the patella or kneecap.

They will also put spacers between metal parts so the joint can easily glide.

It may take 3 to 6 weeks to recover fully from knee replacement surgery. A person needs to increase their intensity levels gradually when returning to their typical activities. Some individuals may also need physical therapy. For some people, it may take longer to regain full strength in their knees.

During recovery, it is important to avoid falling, which can injure the joint.

People also need to recognize the signs of a blood clot, such as pain, warmth in the leg, and sometimes, swelling of the foot.

Less than 2% of knee replacements cause serious complications such as infection or rehospitalization. However, all surgeries carry some degree of risk. The potential risks of knee replacement surgery include:

  • complications from anesthesia
  • an infection
  • injury to the blood vessels
  • a dislocated or fractured knee
  • stiffness and pain
  • nerve pain

In some cases, a knee replacement may worsen symptoms.

Older research suggests that ongoing issues after knee replacement surgery may be common. One 2010 study of 1,217 people suggests that as many as 20% of patients are dissatisfied with the results of their surgery.

The following are some questions people frequently ask about artificial knees.

Can I kneel on an artificial knee?

It is possible to kneel on an artificial knee without damaging it. Some people find it uncomfortable or notice that it causes unusual sensations.

Can doctors replace artificial knees?

Revision surgery involves replacing or fixing an artificial knee. A person may need a revision after many years or if the initial surgery does not provide relief.

What does an artificial knee cost?

The out-of-pocket cost of an artificial knee varies depending on where a person lives, whether they have insurance, what type of insurance they have, and whether they have met their annual deductible.

An artificial knee can replace a damaged knee joint. It can improve symptoms in most people, but the procedure may yield minor or no improvements in symptoms in some.

Discussing the risks and benefits of treatment with a doctor can help a person decide whether surgery may be right for them. In some cases, conservative treatment may be an option.