A partial or total knee replacement can be a benefit to people who suffer from degeneration of the knee joint due to such things as osteoarthritis and rheumatoid arthritis. The disease-related damage impedes normal functioning of the knee, including the ability to flex and extend. Typically, a person considering knee replacement has already tried nonsurgical treatments such as medication, physical therapy, or injections into the joint. Surgery is often a last resort.
While knee replacements don’t last forever, experts say that 90 percent of them do last for at least 10 years. A meta-analysis of studies involving knee replacements among patients with osteoarthritis, published in The Lancet in 2019, found that the estimated 25-year success rate for partial knee replacement was between 70 percent and 72 percent, while the 25-year success rate for total knee replacement was a little more than 82 percent.
The longevity of a knee replacement depends on how well the implant—the artificial components that compose the new knee—holds up over time. One issue that younger knee replacement recipients may face is more wear and tear on the implant as they’re likely more active than older recipients. In fact, a 2017 study evaluating the likelihood of lifetime knee replacement failure in different age groups showed that those who were at least 70 years old when they had the procedure had a revision risk of just 5 percent, while men between the ages of 50 and 55 had a lifetime revision risk of 35 percent.