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Answers to Common Questions About Total Knee Replacement

Medically reviewed by William Morrison, MD on October 23, 2017Written by Samuel Greengard

1. When is the right time to undergo a knee replacement?

There’s no precise formula for determining when you should have a knee replacement. But if you’re having trouble getting up to answer the phone or walk to your car, you may be a candidate. A thorough examination by an orthopedic surgeon should yield a recommendation. It might also be beneficial to receive a second opinion.

2. Is there a way to avoid surgery?

For some, lifestyle modifications, physical therapy, medication, or alternative treatment methods such as acupuncture and prolotherapy (which involves injecting fluid to strengthen connective tissue) can help manage knee problems.

Also, you may want to speak to your surgeon about other procedures that are commonly recommended before resorting to knee replacement surgery, including steroid or hyaluronic acid injections and arthroscopic surgery that addresses the damaged cartilage.

However, delaying or declining a necessary knee replacement could result in a less favorable outcome. Ask yourself: Have I tried everything? Is my knee holding me back from doing the things I enjoy?

3. What will occur during surgery and how long will the knee replacement operation take?

The surgeon will make an incision on the top of your knee in order to expose the damaged area of your joint. The standard incision size can be as long as 10 inches, but a minimally invasive procedure can result in incisions as short as 4 inches.

During the operation, the surgeon moves your kneecap aside and cuts away damaged bone and cartilage, which are then replaced with new metal and plastic components. The components combine to form a synthetic (but biologically compatible) joint that mimics the movement of your natural knee.

Most knee replacement procedures take 1.5 to 2 hours to complete.

4. What pieces are used in a knee replacement and how are they kept in place?

Implants are comprised of metal and medical-grade plastic. To seal these components to your bone, two methods are used: application of bone cement, which typically takes about 15 minutes to set, and a cement-less approach that uses components with a porous coating that grows into tissue or attaches to bone. In some cases, a surgeon may use both techniques in the same surgery.

5. Should I be concerned about anesthesia during surgery?

Any surgery with anesthesia has risks. However, complication rates and mortality for general anesthesia are extremely low. An anesthesia team will determine whether general anesthesia or spinal, epidural, or regional nerve block anesthesia is best.

6. How much pain will I experience after surgery?

Although you’ll experience some pain after surgery, it should diminish quickly — within four or five days max. You may receive a nerve block the day of surgery, or your surgeon may use a long-acting anesthetic during your surgery to help with pain relief postoperatively.

Your doctor will prescribe medication to help you manage the pain, which may be administered intravenously (IV) immediately after surgery or taken orally. After you’re released from the hospital, you’ll switch to painkillers taken in a pill or tablet form.

After you’ve recovered from surgery, you should experience significantly less pain in your knee, but there’s no way to predict exact results — some will have knee pain for a full year after the surgery.

Your willingness to engage in physical therapy and make lifestyle modifications can have a significant impact on your postsurgery level of pain and adjustment to the implant.

7. What should I expect immediately following surgery?

You will wake up with a bandage over your knee and, possibly, a drain to remove fluid from the joint. You may wake up with your knee elevated and cradled in a continuous passive motion (CPM) machine that gently extends and flexes your leg while you’re lying down, but you may wake up with just your knee elevated.

A doctor might also insert a catheter so you don’t have to get out of bed to get to a toilet. The catheter will usually be removed the day of surgery or the following day.

In addition, you may wear a compression bandage or sock around your leg to improve blood circulation or foot pumps to reduce the odds of a clot.

Your doctor will administer antibiotics intravenously, and you may receive anticoagulants (blood thinners) to reduce the odds of a clot.

Many experience an upset stomach during the immediate postsurgery period. This is normal, and your doctor or nurse can help provide medication to ease stomach pain.

8. What can I expect during recovery and rehabilitation from knee replacement?

Most people are up and walking the day of surgery or the next — with the aid of a walker or crutches. A physical therapist will help you bend and straighten your knee a few hours after your surgery.

After you return home, therapy will continue regularly for weeks, and you’ll be asked to engage in specific exercises designed to improve the functionality of the knee. If your condition is more severe, or if you don’t have the needed support at home, your doctor may recommend you first stay at a rehabilitation or nursing facility.

During the weeks after surgery, your doctor will wean you from pain medication.

9. What do I need to do to prepare my home for recovery?

If you live in a multiple-story house, prepare a bed and space on the ground floor so that you can avoid the stairs when you first return.

Make sure the house is free of obstructions and hazards including power cords, area rugs, clutter, and furniture. Focus especially on pathways, hallways, and other places where you’re likely to walk through.

It’s wise to make sure that handrails are secure and a grab bar is available in the tub or shower you plan to use. You may want to add a bath or shower seat.

10. Will I require any special equipment?

Your doctor may recommend that you use a CPM machine at home while lying on a flat surface or bed. You may be sent home from the hospital with this device, but if you aren’t, your doctor or physical therapist will arrange for one to be delivered to you. A CPM machine helps to increase your knee motion during the first few weeks after surgery, and is usually prescribed to slow the development of scar tissue and to help you achieve the maximum range of motion from your implanted knee. It’s crucial to use the device as prescribed. However, doctors are finding that it isn’t as necessary as it has been in the past and often isn’t utilized any longer.

Additionally, your doctor will prescribe any mobility equipment that you need, like a walker or crutch.

11. What activities will I be able to engage in?

You should be able to resume normal daily activities — such as walking and bathing — within several days.

Low-impact exercise should also be doable after your rehabilitation period, typically 6 to 12 weeks. Consult with your physical therapist about introducing new activities during this rehabilitation period.

You should avoid running, jumping, bicycling up and down hills, and other high impact activities.

Discuss with your orthopedic surgeon any questions concerning your activities.

12. How long will the artificial knee joint last, and will I ever require a revision (a second knee replacement)?

Studies show that upward of 85 percent of people who undergo this surgery still have a functioning artificial joint 15 to 20 years after receiving it. However, wear and tear on the joint can adversely affect its performance and lifespan. Younger people are more likely to have the joint wear out and require a revision during their lifetime. Consult with a doctor about your particular situation.

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