5 Signs It Might Be Time for a Knee Replacement

According to Eytan Debbi, MD, PhD, a hip and knee replacement surgeon at HSS, here are a few signs that you might want to consider knee replacement surgery in the near future, and some things to know about the process.

Your pain is bone on bone. 

The hallmark of knee osteoarthritis is bone-on-bone knee pain, which results from the deterioration of the cartilage that protects the bones in the leg from rubbing against each other. To diagnose the cause of bone-on-bone knee pain, physicians must examine the knee and take x-rays of the joint to make sure that another problem isn’t causing the discomfort—one that wouldn’t be solved with knee replacement surgery. 

People often wonder why they developed knee arthritis, Dr. Debbi says. Was it because they played football in high school, or ran marathons in their 20s and 30s? The answer, he says, is no one knows. Although some people who were very active in their youth develop knee arthritis, others who led equally active lives do not—just as some people who were sedentary get bad knees while other couch potatoes do just fine. 

“We believe that the risk is likely due to a combination of genetics, activity level, and a history of prior injuries to the knee, which are known to increase the risk of arthritis,” he says. Another important factor is being overweight. “Unfortunately, weight has a significant effect on the loads across the knee joints and can increase the wear rate of the cartilage and exacerbates pain in the knee,” he says.   

You’re having trouble performing daily tasks. 

“I think the most important thing that we try to figure out when we meet our patients is how much is this affecting their function and their quality of life,” Dr. Debbi says. That means asking people how much the pain intrudes on their ability to do the things they love—walking, riding a bike, playing with their grandchildren. If a person is no longer able to do those activities, Dr. Debbi says, “then usually they would do better with a knee replacement than trying to function with their arthritis.” 

Not everyone experiences arthritis pain the same way, which means the level of pain isn’t necessarily a good indicator of the extent of the damage to the joint. “Sometimes a person can have severe damage on an x-ray but not be in terrible pain, whereas some patients may have mild damage on x-ray but be in severe pain,” Dr. Debbi explains. “These changes can sometimes take as little as a few months, but sometimes they can take several years or even decades to develop.” 

You’ve exhausted conservative approaches. 

Knee replacement is major surgery, so Dr. Debbi recommends that people try less invasive strategies first to manage their pain. Your primary care physician can recommend pharmacologic options, including non-steroidal anti-inflammatory medications and joint injections—such as corticosteroids and hyaluronic acid—as well as physical therapy.

Some alternative therapies, including glucosamine, might also provide relief, although Dr. Debbi notes that the evidence for these treatments isn’t strong. If you’ve already gone this route and still haven’t found relief, a knee replacement may be a good option, and you’ll want to consult a specialist to talk about the procedure in detail.

You’re prepared to commit to your recovery. 

Although knee replacement surgery increasingly is an outpatient procedure, recovery times vary from person to person. Generally speaking, most people spend the first two weeks after the procedure focusing on healing and pain control.

As the pain and swelling subside, the focus turns toward physical therapy and exercises that improve the range of motion. These can continue for several months, Dr. Debbi says. “If you’re highly active, you can probably start using a stationary bike within a few weeks, but it’s recommended to recover for several months to regain balance and strength before going out on the road or doing any high impact activities.” 

For runners, knee replacement might mean it’s time to hang up the sneakers and find another sport. “While some people do run after the surgery, the concern is that they will experience extra wear and increased stress at their implant, which can possibly lead to increased wear and potential earlier failures,” Dr. Debbi says.  

Recommendations are changing, however, as a growing number of younger people seek knee replacement surgery. “Some are able to return to very high impact activities and are able to tolerate them well,” he says. 

You’re an active person looking for a long-term solution. 

One of the questions patients ask most often about knee replacement is how long the new joint will last, Dr. Debbi says. In the past, his answer was roughly 15 to 20 years. But newer versions of the prostheses appear to be much more durable than their predecessors. 

“The rates of wear that we’re seeing today with modern hip and knee replacements are very low,” he says. “So while we usually think of the longevity of the replacement knee to be approximately 20 years, we’re seeing joints that last significantly longer than that.” 

As a result, he adds, people should be less concerned with the prospect of requiring a revision surgery down the road than with how much their arthritis is affecting their daily activities. “It’s more important that they enjoy themselves now than they worry about what happens to the replacement 20 to 30 years later.”