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Adam S. Bright, MD

Knee Replacement: Knee FAQ's

When do I need a knee replacement?

On the end of your bones, you have cartilage. The cartilage is smooth and frictionless, allowing your knee to bend and straighten freely. The cartilage has no nerves in it, so the pain free function of our knee is something we take for granted until the cartilage wears out and becomes thin. When the cartilage is too thin, we start feeling pain from the exposed nerves in our bone. Exercise, medication, braces, and shots such as cortisone or viscosupplementation can relieve relieve pain. However, when the pain is uncontrolled, then you probably need a knee replacement. When your walking and exercise start to become limited, then you should have a knee replacement. If you wait too long, research has shown that you might not ever be able to regain the strength and flexibility of your knee.

How does a knee replacement work?

A knee replacement removes the diseased and worn out surface on the end of your bones (usually about 1/4 inch) and resurfaces it with metal and a very durable plastic. Because the knee replacements are shaped like a normal knee, patients can return to an active and healthy lifestyle with a dramatic reduction in their pain. To see a video of a knee replacement, click here.

How long will the knee replacement last?

Knee replacements usually last more than fifteen years. Patients who are overweight or are very active may wear out their replacement faster. Also, despite the newest advances in technology, a very small number of knee replacements do fail very early.

How is my knee replaced?

If you and Dr. Bright decide that knee replacement is best for you, then Dr. Bright will arrange for you to have a detailed MRI of your knee with additional limited views of your hip and ankle. These images will then be loaded into a complex software program. Dr. Bright will then develop a surgical plan to restore your normal anatomy. This plan is then transmitted electronically to the knee implant manufacturer, and a custom guide is produced for your knee. During surgery, the custom guide is placed onto your knee. The custom guide process eliminates 21 steps of the traditional surgery, improves the accuracy of the surgery, and decreases the blood loss and surgical time. The custom guide is then used to remove 1/4 inch of diseased bone from the surfaces of your knee. The anatomically designed knee replacement is then glued onto the bone surfaces, so you can immediately start your rehabilitation.

Custom Knee Guide Custom Knee Guide

How long will I be in the hospital?

My patients nearly always stay for three days, which means a Monday surgery goes home on Thursday, and a Thursday surgery goes home on Sunday. Patients who experience some difficulties, such as fever or pneumonia or other complications, sometimes need to stay longer in the hospital.

How long will it take to recover?

Generally, most patients experience more pain than they had before surgery for the first one to two months. After two to three months, they typically experience better function and less pain than before surgery. Patients continue to get stronger and more flexible for nearly a year after the surgery.

Do I need to go to a rehabilitation hospital after my surgery?

Patients who live alone, or who have other medical problems such as obesity or severe heart disease frequently benefit from going to a rehabilitation hospital for a few weeks after they leave the hospital. Patients who are more active and have someone at home to help them for the first week or two usually go home. Overall, about 80% of my patients go home. Research has proven that there is no statistical benefit to going home and having home physical therapy (which is cheaper) than going to a rehabilitation hospital. The decision is mainly based on medical need, and patients who can get out of bed and walk several feet without help are usually able to go home where they are more comfortable.

How can I keep my replacement working well and lasting long?

Staying thin and exercising will likely make the replacement last longer. Following up with Dr. Bright every few years for a checkup can also help to avoid any long term problems, and allow you to keep informed of any changes or advances in knee replacements.

What can I do to avoid a complication with my surgery?

See your medical doctor for a complete physical exam to make sure you are as healthy as possible. Do not take any herbal remedies the week before and after your surgery since they might interfere with your anesthesia or even cause excessive bleeding. See a dentist before your surgery for a cleaning and checkup to make sure there are no infections that could spread from your mouth to your knee replacement. Smoking increases the chances of blood clots and infection, so plan to stop smoking now. For women, avoid hormone replacement therapy for one to two months after your surgery to decrease your chances of a blood clot. Lastly, begin a modest exercise program for both your arms and your legs, such as going for a short walk or bike ride and lifting small hand weights. After your exercise, stretch your joint gently to improve its flexibility.

What sports will I be able to do with a knee replacement?

Speed walking, cycling, elliptical trainer, golf, horseback riding, skiing, and many other sports are healthy for you after your knee replacement. Contact sports such as basketball, football, lacrosse, and soccer should be avoided since these sports carry significant risk of injury, and a metal and plastic knee replacement would not be able to heal like a normal knee might.

Will I be able to kneel or squat?

The advanced knee replacements that Dr. Bright uses permit knee flexion of up to 150 degrees, which would allow kneeling and squatting. However, most patients have found that prolonged or repeated kneeling or squatting is difficult after a knee replacement. With excessive flexion of the knee during kneeling and squatting, there is also a very high mechanical load on a very small area of the plastic part of the knee which could cause it to fail earlier than expected. Most patients are able to kneel and squat better than before surgery, but not all patients. To summarize, you may be able to kneel or squat with your knee replacement, but you may not, and it is not recommended to do this repeatedly (but is permitted occasionally).

Will my knee replacement set off the airport metal detector?

Yes, almost certainly. The new transportation safety administration guidelines require very sensitive metal detectors which will detect the titanium knee replacement that I use. I used to give all of my patients plastic cards to hand to security. However, since security personnel are now required to perform a secondary screening with a metal detecting wand, the card is completely unnecessary and will only result in a further delay to you in security since the TSA official will then pause to look at your card. My advise is to wear loose clothing so you can show the security personnel your scar, and be courteous as you explain that you do have an excellent knee replacement from Dr. Bright.

Am I too old for a knee replacement?

Only your medical doctor can determine if knee replacement surgery is safe for you. Your physician can inform you of your relative risk of a complication, but unfortunately there is no guarantee that something cannot go wrong. As we age, so does our heart and lungs, and with our aging our risk of surgery increases. However, knee replacement is still just as rewarding and successful for a ninety year old patient as it is a forty year old patient. The main difference is that the 90 year old patient has a greater risk of medical complications, such as heart attack or stroke. In the end, it should be your personal decision if you can accept the risk of the surgery and the few months of recovery for the reward of pain relief and improved function.

How do I avoid MRSA infection?

Patient's who smoke and patients who are overweight are at higher risk, so stopping smoking and losing weight helps. I also screen my patients before surgery for MRSA, and if you are one of the 10% of Americans who is a carrier, we pre-treat you before your surgery to kill the MRSA bacteria. I also preform my joint replacement surgeries in a glass chamber called a laminar flow room with highly filtered air, and I and my surgical team wear space suits so we cannot breath near the replacement. The custom guide that I use also eliminates 22 steps of the surgery. Because my surgeries are faster and take slightly less than an hour, there is statistically a lower chance of infection.

How do I avoid a blood transfusion?

Dr. Bright's research has shown that using a custom guide to perform the knee replacement diminishes the blood loss. Having surgery under spinal anesthesia has also been shown to lower blood loss. My patient's are not given blood unless their blood count is very low AND my patient has symptoms. Research has shown that patients who are arbitrarily given blood transfusions for an arbitrary number when they are NOT symptomatic gain no benefit from the blood transfusion. Receiving someone else's blood affects their immune system. Although blood transfusion do not have bacteria, simply receiving someone else's blood during a major surgery affects us and increases the chances we will develop infection at our surgery site, or pneumonia or urinary tract.