Why Joint Replacements are Lasting Longer
When is the right time to have joint replacement surgery? The answer isn’t cut and dried.
A few years ago, the age of a potential joint replacement patient was an important consideration due to the relatively short life of implants. But the number of Americans choosing to have the procedure is increasingly moving toward a younger population thanks to medical advances in artificial joints ― and improvements continue to be made in the implant products in use.
“The current materials used for joint replacements have increased resistance to wear and tear so greater longevity of implants is being seen,” explains Karim Elsharkawy, M.D., an orthopedic surgeon on the medical staff of Texas Health Plano and with Texas Center for Joint Replacement, a Texas Health Physicians Group practice. “I use 15 to 20 years as a general guide when I’m talking with a patient about a possible hip or knee replacement. The down side here is that the longevity of artificial joints has yet to be fully evaluated in younger patients who often return to a greater level of physical activity after surgery.”
For this reason, the American Association of Hip and Knee Surgeons relies more on the annual failure rate in accessing how long a joint replacement will last. Current data suggests that both hip and knee replacements have an annual failure rate between 0.5-1.0 percent. This means that if a person has a total joint replacement today, they have a 90-95 percent chance that the joint will last 10 years, and an 80-85 percent chance that it will last 20 years.
Dr. Elsharkawy points to research reported in the medical journal Lancet in February 2019 for some added perspective. Researchers conducted an exhaustive review of joint replacements in Australia, Denmark, Finland, Norway, Sweden and New Zealand and found encouraging results:
- The researchers followed nearly 216,000 hip replacement patients for 15 years. They also tracked 74,000 for 20 years and more than 51,000 patients for 25 years. Nearly 60 percent of the hip replacements ― or nearly six in 10 ― lasted 25 years, 70 percent lasted 20 years and almost 90 percent lasted 15 years.
- Total knee replacements lasted even longer in the 300,000 patients tracked for 15 years. Of those who had a total knee replacement, 93 percent lasted 15 years. The same was true for about 77 percent of patients who had a partial knee replacement. They also followed 80,000 patients for 25 years and 92,000 patients for 20 years: 82 percent lasted 25 years and 90 percent lasted 20 years.
What Makes an Artificial Joint Last?
Orthopedic innovators are always looking for ways to improve the outcomes of total joint replacement surgery. What has changed over the past few years is that a better process has evolved for making the plastic (polyethylene) material from which artificial joints are made. “Plus, where we once solely used metal and plastic for the joints, we are now using ceramic materials (for total hip replacement) and much more durable polyethylene materials,” Dr. Elsharkawy adds.
“There have also been other improvements in hip and knee implants. We are now using ‘press-fit’ or ‘cementless’ implants, especially for hip replacements. It’s a process that allows the bone to grow onto the prosthesis for a much better hold than cement. For knee implants, cement is still more often used. However, the press-fit technology has been introduced over the last few years with promising results.”
Do Surgical Advances Account for Greater Longevity?
Elsharkawy says the answer is yes. Better technology, such as advanced imaging and robotics, is being used to measure replacement components. The capability to check the measurements of these components is especially useful for hip replacements.
“If components are in an awkward position, that affects the longevity of the implant,” he says. “Placing the implants in a more accurate, reproducible and balanced position has a positive effect on the durability of the replacements.”
How to Extend the Life of a Joint after Surgery
Although running a marathon soon after joint replacement surgery might not be the best thing to do, Dr. Elsharkawy recommends patients generally go about their daily lives. “We tell our patients to be careful in performing repetitive, high-impact activities immediately after surgery, especially if they are 50 years or older. This doesn’t mean that the recovering patient can’t play sports or move. Movement helps the body recover.”
“Joint replacement innovations are making artificial joints last longer over time. Better component technology and medical advances are two reasons why joint replacement surgery is one of the most popular procedures in medicine. It’s why more people, and younger people, are choosing to live with a new joint.”