When a worn knee starts to give you trouble, nonsurgical treatments are the first line of defense. Weight loss, physical therapy, or injections may help reduce your pain. If your knee doesn't respond to those approaches, it's time to consider a joint replacement. And you'll need information to make a decision about the surgery, which is a big commitment.
Here are some questions to ask, and a sneak peek at what your doctor might say, courtesy of Dr. Antonia Chen, an orthopedic surgeon and director of research for the Division of Adult Reconstruction and Total Joint Arthroplasty at Harvard-affiliated Brigham and Women's Hospital.
Q: What should I look for in a knee replacement surgeon?
Dr. Chen: Ideally your surgeon would be someone who is board-certified in orthopedic surgery, fellowship-trained, and a specialist in knee replacement. But that type of expert might not be available in your community. If not, look for an orthopedic surgeon who's been performing knee replacements for at least two years and make sure the surgeon you choose performs at least two knee replacements a month.
Q: What type of prosthetic is best?
Dr. Chen: The gold standard knee replacement is made of cobalt chromium with polyethylene (plastic) in between the metal pieces. Sometimes, the bone behind the kneecap will be replaced with polyethylene (see "Anatomy of a knee replacement"). There are additional materials, such as titanium or zirconium, that can be used in knee replacements. The best prosthetic will be the one your surgeon is comfortable implanting, unless you have a metal allergy, which you should discuss with your doctor.
Anatomy of a knee replacement
The knee is a hinge formed by the bottom of the thighbone (femur) and the top of the shin bone (tibia). In front of them is the kneecap (patella). The ends of the bones are cushioned by cartilage. As cartilage wears out over time, the bones rub against each other, causing pain.
In a knee replacement, the surgeon removes the damaged ends of the thigh and shin bones and replaces them with artificial parts. The prosthetic on the thighbone is made of metal (typically cobalt chromium). The prosthetic on the shin bone is made of metal (typically cobalt chromium or titanium) and has a plastic piece on top. The plastic is polyethylene, a strong, slippery material that acts as cartilage.
The kneecap may also need to be lined with plastic to glide over the other two bones.
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Q: How should I prepare physically for a knee replacement?
Dr. Chen: Pre-surgery physical ability predicts your post-surgery physical ability. So work on bending, straightening, and strengthening the knee as much as possible before surgery. Physical therapy can help, and so can exercises that you can do at home.
Q: How should I prepare my home for recovery?
Dr. Chen: Remove anything that might cause you to slip and fall, such as throw rugs, floor clutter, and furniture that blocks your path. It will help to have certain types of equipment at home, including a walker and a cane. You can also consider getting a raised toilet seat and a bedside commode, but not every patient will need these.
Q: Which surgical approach will you take?
Dr. Chen: There are three main approaches. One goes around the kneecap, one goes through the middle of the quadriceps muscles, and one goes underneath the quads. There are pluses and minuses for each one, and it mostly depends on the approach your surgeon is most experienced with.
Q: Will you use robotic tools?
Dr. Chen: Some studies have shown that robotic surgery is more precise than traditional surgery. I personally use robotic tools, but robotics are not available at every hospital.
Q: What are potential surgery complications and what will you do to reduce them?
Dr. Chen: Knee replacement risks include bleeding, blood clots, and infection. We use devices to stop bleeding at the time of surgery and we may apply a tourniquet. You will likely get an antibiotic before surgery to prevent infection and a blood thinner after surgery to prevent clots.
Q: Will I have to stay overnight in the hospital?
Dr. Chen: Most people go home on the day of their surgery or stay overnight in the hospital for one night. Home health services can provide visiting nurses or physical therapists who go to a patient's home after surgery.
Q: How much pain will I have and how will you treat it?
Dr. Chen: The first two to six weeks after surgery will be very painful, and we have an extensive plan to treat it. We start right before surgery, giving the patient painkillers such as acetaminophen (Tylenol) and celecoxib (Celebrex), as well as spinal anesthesia. During surgery, I'll inject a number of different analgesics and anti-inflammatory medicines into the knee. After surgery, we use narcotics such as oxycodone (OxyContin) only sparingly. If necessary, we can prescribe low-level narcotics such as tramadol (Ultram). But we prefer that you use acetaminophen around the clock. It may not work well on its own, but adding a nonsteroidal anti-inflammatory drug such as naproxen (Aleve) or a nerve medication called gabapentin (Neurontin) can improve pain relief.
Q: What do you do to ward off stiffness and swelling?
Dr. Chen: These side effects can happen right after knee surgery. It's important to get right into physical rehabilitation to prevent stiffness. To reduce inflammation, I like my patients to use ice or an ice machine that circulates cold fluid around the leg.
Q: What will rehab look like?
Dr. Chen: If you are deconditioned or undergo surgery in both knees at the same time, you might need to go to an in-house rehab facility after surgery and stay for a week or two. If you're stronger, you can go home and have a physical therapist visit the home, or go to an outpatient facility for physical therapy. The rehab process can last up to three months. And it's a year for a full recovery.
Q: When will I be active again?
Dr. Chen: You might have to walk with a walker or crutches for one or two weeks, and then walk with a cane or one crutch for another two to four weeks. It can take three to six months to get you back to brisk walking, six to nine months for activities such as tennis or golf, and nine months to one year for skiing.
Q: How long will the prosthetic last?
Dr. Chen: The plastic part of the prosthetic knee will wear out in about 15 to 20 years, and you might need surgery to replace it.
Q: What if I want to wait before considering surgery?
Dr. Chen: It's your choice: you'll be limited by your pain, and the pain is unlikely to improve. The good news is that waiting won't make your knee much worse. So if you don't want to go through a major surgery and a long recovery, don't do it. Wait until you're ready.
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