How Long Do Knee Replacements Last?

Knee replacement surgery is a treatment for severe knee arthritis. Most patients understand that knee replacements can wear out over time, but exactly how long is a knee replacement supposed to last?

Doctor holding knee replacement implant
Peter Dazeley / Getty Images

Knee replacements eventually wear out. Because the knee replacement implants are made of metal and plastic, over time, these materials begin to wear, just like the rubber on your car tires. While knee replacements are designed to last a long time, they will not last forever.

What Studies Show

The good news is that studies show that common types of knee replacements can last more than 20 years. One study on long-term outcomes of a commonly used knee and hip replacements published in 2017 found the implant to still be functioning in about 90% of patients 20 years after being implanted. This is certainly one of the better reports, and other studies have not necessarily shown that level of success. However, the goal of a knee replacement should be to achieve several decades of a functioning knee.

You should remember that while some patients may have knee replacements that last several decades, other patients may require a repeat knee replacement just a handful of years after their surgery. Revision knee replacement (a second knee replacement) can be a major undertaking that can have less predictable results than an initial knee replacement.

An older report from 2001 found that only about 2% of knee replacement surgeries required a second surgery within five years of the initial knee replacement. More recent data shows a 10-year revision rate of 6.2% for a total knee replacement and 15.5% for a unicondylar (partial) knee replacement.

Factors Affecting the Longevity

Many studies have been done to determine how long a knee replacement will last. With hundreds of different types of knee replacements and countless different types of patients, there is no rule to how long a knee replacement will last in a particular individual.

Implant manufacturers are constantly striving to create a "better" implant that will last longer. Some of these implants have only been used for a handful of years, and determining whether or not they will last longer is a question only time can answer.

Some of the factors that seem to influence the longevity of knee replacement implants include:

  • Age of the Patient: Younger patients require more years out of their knee replacement. On top of that, younger patients tend to be more active. Therefore, patients who have knee replacement in their 50s or younger can usually expect to require a revision knee replacement in their lifetime.
  • Patient Activities: Some activities may not be appropriate for patients with a knee replacement. While these activities may not be painful or difficult, they may be placing excessive stress on the knee replacement, causing the parts to wear out more quickly.
  • Patient Weight: The more an individual weighs, the more stress that is placed on the joint replacement implant. Maintaining a normal body weight is critically important when trying to make a joint replacement last. Appropriate exercises can be helpful in maintaining a healthy knee replacement.
  • Avoiding Complications: This may sound obvious, but there are some specific medical conditions that can lead to complications affecting the joint replacement. Patients having invasive medical procedures (including dental work) may require antibiotic treatment to prevent bacteria from getting into the joint replacement. Patients with osteoporosis should ensure they are being adequately treated as a fracture in the bone around a joint replacement can affect the functioning of the implant.

A Word About the Newest Knee Replacement Implants

One temptation of patients and surgeons alike is to be attracted to the newest knee replacement on the market. Undoubtedly, this implant will claim to function better and last longer than other knee replacements. While these newer implants may be better, it is also important to understand they do not have long-term data on how well these implants will function over time.

Ask any orthopedic surgeon about the implants they have seen come and go over the course of their career. Just because an implant is newer does not necessarily mean it is better.

Patients and surgeons should try to find an appropriate balance between modern design and not being a 'test' patient. Your surgeon can help guide you to an appropriate knee replacement that is best for you.

Frequently Asked Questions

  • What are knee replacement implants made from?

    Knee replacement implants are made of metal and plastic. The metal used is typically titanium- or cobalt-chromium-based alloys. The plastic is usually medical-grade polyethylene. Ceramics or ceramic and metal mixtures, such as oxidized zirconium, are sometimes used as well. 

  • Can a knee replacement last 30 years?

    It is possible that a knee replacement can last 30 years. However, the typical lifespan of a knee implant is 15 to 20 years. Newer materials and designs of artificial knee joints make it possible for the replacement joint to last longer. Devices made with a combination of oxidized zirconium and highly cross-linked polyethylene have been shown to have a longer lifespan than original knee replacement designs. 

  • How can you tell if a knee replacement is wearing out?

    Signs that your knee replacement is wearing out include pain, decreased joint function, swelling or stiffness in the area, and joint instability. If you have an artificial knee and experience any of those symptoms, talk to your doctor.

3 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Bayliss LE, Culliford D, Monk AP, et al. The effect of patient age at intervention on risk of implant revision after total replacement of the hip or knee: a population-based cohort studyLancet. 2017;389(10077):1424–1430. doi:10.1016/S0140-6736(17)30059-4

  2. Daly CG. Antibiotic prophylaxis for dental proceduresAust Prescr. 2017;40(5):184–188. doi:10.18773/austprescr.2017.054

  3. Smith and Nephew. 30 year wear performance of Legion Primary Knees with Verilast technology.

By Jonathan Cluett, MD
Jonathan Cluett, MD, is board-certified in orthopedic surgery. He served as assistant team physician to Chivas USA (Major League Soccer) and the United States men's and women's national soccer teams.