Who is right for a knee replacement and who is not? And what actually happens during the surgery?
Orthopaedic surgeons, Alexander R. Orem, MD, MS, and Wayne E. Moschetti, MD, MS, answer the questions people ask before knee replacement surgery and about the surgery itself.
Do I need to lose weight before knee replacement?
Most patients with a body mass index (BMI) between 18 to 40 will not need to lose weight prior to having a joint replacement surgery. BMI is a ratio of weight to height that estimates body fat percentage and can indicate a person's risk of certain health problems. Patients who have a BMI greater than 40 have some increased BMI-related risks. Those risks can be significant, including the risk of what's called a deep infection. If you have a BMI greater than 50 or 60, it is highly recommended that you work on weight reduction prior to surgery to lower the chance of complications.
Who should get a knee replacement?
The best candidates for knee replacement surgery are people who have severe osteoarthritis or osteonecrosis of their knee. It is important to set expectations. If you are really hurting and disabled by knee arthritis, you will likely be more satisfied with the results of a knee replacement. But if you are looking to get a few extra miles from a knee that is already very active, you may want to think twice about getting knee replacement surgery.
“I can't give you the knee that you had when you were 20 or 30 years old, but we can give you an artificial knee that will hopefully hurt less, move better than your arthritic knee, and allow you to return back to activity,” says Moschetti.
Why do my knees sound like Rice Krispies?
When your knees crunch, the fluid becomes pressurized in one part of the knee and pops into another. This movement also happens when you crack your knuckles. You are pressurizing fluid in one area that then pops into another, creating that sound.
Will I have to stay overnight in the hospital?
Maybe. The decision will be made based on your ability to get up and walk around, and how well you're doing after surgery. “If you can get up, walk around, feel well, we're happy to send you home the same day,” Moschetti says.
What happens during the surgery?
Knee replacements are actually a knee resurfacing more than a removal. The surgery is done by making an incision in the skin and next to the kneecap.
“We open up the knee by moving the kneecap to the side, and that exposes the cartilage inside the joint and meniscus,” Orem explains.
The cartilage is then scraped off so that the bone can take on a shape that matches the back of the implant. The implant is grouted, or in some cases attached to the bone, in a manner that allows the bone to heal onto it. The same process is repeated on the undersurface before the entire knee is put back together.
Learn the answers to questions people ask about recovering from knee surgery.
Watch the full interview with orthopaedic surgeons, Alexander R. Orem, MD, MS, and Wayne E. Moschetti, MD, MS, as they answer questions people ask about knee replacement surgery.