How long does a hip or knee replacement last?

Undergoing a hip or knee replacement is an undertaking. All aspects of such a procedure need to be discussed thoroughly with an orthopedic surgeon to gain understanding of what is involved. One thing most people do realize is that hip or knee replacements can wear out over time, but exactly how long are they supposed to last?

Each in the U.S., surgeons perform more than 600,000 knee replacements and about 330,000 hip replacements. Granted, for most people, these operations will provide a major improvement in their quality of life.  The pain and discomfort they felt before the surgery will be significantly reduced while their ability to ambulate and move around will be improved.  But, even if everything goes well, the road to recovery is long and tedious and may have setbacks. That’s why anyone needing a hip or knee replacement will want that first surgery to go as well as possible to avoid a second or even third operation.  These ‘revision’ surgeries are usually technically more difficult, with a longer recovery time, and the success rate may not be as good as the first surgery.

How many years will a hip or knee replacement last?

This is the million dollar question that at best, doctors can give an estimate but not a completely accurate answer. No one can be 100% certain if a hip or knee replacement will be the last one needed in a person’s lifetime. There are many factors that can help determine an approximate time length of their durability, which includes surgical technique and surgeon experience, how many operations a particular hospital or surgeon performs each year, and factors that involve the patient such as their age, weight, physical fitness, and overall health at the time of surgery. Each of these factors can have powerful effects on how long a replaced joint lasts.

Based on data of hip and knee replacements done decades ago, medical technology has gotten better on improving the length each lasts. The standard answer as to how long a hip or knee replacement will last is approximately 15-20 years. A more accurate way to think about longevity of a joint replacement is via the annual failure rates. Most current data suggests that both hip and knee replacements have an annual failure rate between 0.5-1.0%.  This means that if you have your total joint replacement today, you have a 90-95% chance that your joint will last 10 years, and an 80-85% chance that it will last 20 years.  As technologies improve, these numbers may also improve.

Despite such improvements, it is important to maintain long-term follow-ups with your surgeon to assure your joint replacement is functioning appropriately.

New data on longevity of hip and knee replacement

A study published in the April 2017 edition of the journal The Lancet, found the following of the durability of joint replacements affected by the age of a person at the time of surgery:

·      Among more than 60,000 people who had a hip replacement, only 4.4% required revision surgery in the first 10 years after surgery, but by the 20-year mark, 15% required revision.

·      Among nearly 55,000 people who had a knee replacement, only 3.9% required revision surgery within 10 years of surgery; by 20 years, 10.3% required revision.

·      Age did matter. Of those over 70 having hip or knee replacement, the lifetime risk of having a second operation on the replaced joint was about 5%. But this risk was much greater in younger individuals, especially for men. Up to 35% of men in their early 50s required a second operation.

Factors affecting longevity of joint replacements

While there is no guarantee that a joint replacement will last the 15-20 years that most do on average, there are certain factors that seem to influence the longevity of joint replacement which include the following:

·      Age of the patient – Younger patients in their 50s or younger having either hip or knee replacement surgery will need that implant to last much longer than someone having the surgery done at an older age. Because younger patients tend to be more active, most can expect to require a revision hip or knee replacement in their lifetime.

·      Patient activities – Because some activities may not be appropriate for individuals who’ve had hip or knee replacement, it is important to have a thorough discussion with their surgeon as to what activities are allowed and which are not. Even if the activity is not painful or difficult, certain ones may be place excessive stress on the joint 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 as long as possible. Appropriate exercises can be helpful in maintaining a healthy joint replacement.

·      Avoiding complications – There can be specific medical conditions that can lead to complications affecting the joint replacement and how long it may last. Patients having invasive medical procedures (including dental work) may require antibiotic treatment to prevent bacteria from getting into the joint replacement. Any patient with osteoporosis should make sure they are adequately treated as a fracture in the bone around a joint replacement can affect the functioning of the implant.