Knee replacement surgery is common. The latest tally by the American College of Rheumatology estimates nearly 800,000 total knee replacements are done every year in the U.S.
Who is the right candidate for knee replacement surgery?
Cody Sessions, M.D., is an orthopedic surgeon at Sanford Health in Bemidji, Minnesota. He said knee replacement surgery, or knee arthroplasty, is most common in patients over the age of 50 who have been diagnosed with arthritis.
He says everyone’s first question to him is if they need surgery.
“The answer is oftentimes, well, how much pain are you in? What have you tried short of surgery? And if the answer to those questions is that I’ve tried everything, and I still have uncontrolled pain, then probably a knee replacement is your solution,” said Dr. Sessions.
Schedule a visit: Knee replacement at Sanford Health
Dr. Sessions said surgeons may favor non-operative treatment in younger patients, due to concern about the duration that a knee replacement may last.
Who isn’t a good candidate for knee replacement?
As mentioned earlier, having arthritis is an important prerequisite for knee arthroplasty. If someone is having knee pain, and it’s not stemming from a previous diagnosis of arthritis, “you’d be a very poor candidate for knee replacement,” according to Dr. Sessions.
However, there are also certain risk factors that would increase a patient’s chances for complications:
- Diabetes
- Neuropathy (nerve damage)
- Obesity
- Kidney disease
- Smoking
- Medications that weaken the immune system
“I think nobody is zero risk,” said Dr. Sessions. “I don’t like people to go in thinking that it’s a guarantee that they’re going to do excellent because they went and had a knee replacement. That’s simply not the case. You have to gauge some of that risk.”
Full vs. partial knee replacement
When it comes to full vs. partial, Dr. Sessions compares the two to a tricycle (full) and unicycle (partial).
Dr. Sessions said a knee has three surfaces:
- Medial side: The inside of the knee, where the femur and tibia meet.
- Lateral side: The outside of the knee, opposite of the medial side.
- Patella femoral component: The front of the knee, where the kneecap at thigh bone meet.
Essentially, you’re replacing all three wheels on a tricycle. The surgical term for this is tricompartmental arthroplasty.
A partial knee replacement, or a unicompartmental arthroplasty, would be like replacing one part, “like a unicycle is just one wheel,” said Dr. Sessions.
He said more total knee arthroplasty surgeries are performed than partial knee replacements.
“People are often wearing out multiple surfaces as they age,” according to Dr. Sessions.
Location of pain matters
Knowing if surgery is right for you also depends on where the pain is at in the knee, he said.
“If you are not having pain consistent with arthritis – than maybe another diagnosis needs to be considered.”
He explained arthritis within the knee usually results in pain over the medial side of the joint.
“If you’re kind of classically painful over the medial side of the joints, and your X-rays demonstrate that it’s worn out on the medial side of the joints, and you’ve had a cortisone shot and it made the pain better for a temporary time, I think we can say that your clinical exam, your imaging, your cortisone shot, with improvement, all would indicate your knee pain is from arthritis. And, if you’re the right age, I think replacing (the knee) is very reasonable,” explained Dr. Sessions.
Surgery and recovery
Dr. Sessions said the surgery is always completed in one day.
“But the real question is when do you return home? And, for many patients, they can return the same day.
“For certain patients, because of some underlying health risks, we encourage them to stay an additional night for close monitoring. For other patients, it’s based off of their home and family structure – who is available to help them recover? How many stories is their house? Things of that nature can all play into whether or not you should spend the night,” he said.
He said knee replacements can take longer to recover from, and the first two weeks can be pretty challenging for some patients.
“In the first two weeks, you are doing physical therapy every day despite the fact that the knee is stiff, swollen, painful, and you’re taking narcotic pain medication. Usually by six weeks people feel like they’re getting better, but certainly not at the position of full recovery,” he explained.
To borrow from “The Tortoise and the Hare,” slow and steady wins the race.
“We’ve found that if you study patients long-term, they’re actually doing better at one year than six months. So, I usually tell people you’re probably 80% better at four months, but it’s going to take you another eight months to get the last 20%,” said Dr. Sessions.
Can a knee replacement eventually wear out?
Dr. Sessions said knee replacements can last for differing amounts of time.
“We often estimate 20 years, but there are certainly scenarios of knees lasting longer or in some cases shorter than this amount of time,” he said.
He said when a knee wears out and it must be replaced again – it’s called a revision.
“In general, the data would support that outcomes are not as good with these revision knees. The level of involvement of a revision knee can depend on what is wrong with the knee.
There’re a few different scenarios that would warrant a revision knee replacement.
Sometimes the plastic within the knee, or polyethylene, is wearing out.
“There might be a situation where we can just do an isolated exchange of the plastic in the knee, however, sometimes the problem is more involved and the entire knee will need to be replaced again,” said Dr. Sessions.
“If it seems like the cement mantle, which is holding the knee in, has loosened – or there’s been contact of the metal tibial component with the femoral components and now there’s metal debris in there – then you might have to have a whole new knee,” he added.
By and large, he said, “most people are really happy with their knee replacement. So, I think that if you are chronically suffering from knee pain, it can be a very good solution.”
Learn more
- New knee like ‘night and day’ after farmer’s years of pain
- Total knee replacement with a new robot assistant
…
Posted In Bemidji, Orthopedics, Sports Medicine
