By Mayo Clinic Staff
Knee replacement surgery — also known as knee arthroplasty (ARTH-row-plas-tee) — can help relieve pain and restore function in severely diseased knee joints. During knee replacement, a surgeon cuts away damaged bone and cartilage from your thighbone, shinbone and kneecap and replaces it with an artificial joint made of metal alloys, high-grade plastics and polymers.
The first artificial knees were little more than crude hinges. Now, you and your doctor can choose from a variety of designs that take into account your age, weight, activity level and overall health. Most knee replacement joints attempt to act like your knee, with its ability to roll and glide as it bends.
The most common reason for knee replacement surgery is to relieve severe pain caused by osteoarthritis. People who need knee replacement surgery usually have problems walking, climbing stairs, and getting in and out of chairs. Some also have moderate or severe knee pain at rest.
As with any surgery, knee replacement surgery carries risks. For knee replacement surgery, these risks are low. They include:
- Blood clots in the leg vein or lungs
- Heart attack
- Nerve damage
Signs of infection
Although the risk of infection is low, notify your doctor immediately if you notice:
- Fever greater than 100 F (37.8 C)
- Shaking chills
- Drainage from the surgical site
- Increasing redness, tenderness, swelling and pain in the knee
An infected knee replacement usually requires surgery to remove the artificial parts and antibiotics to kill the bacteria. After the infection is cleared, another surgery is performed to install a new knee. Your chances of a good or excellent outcome that reduces pain and improves function lessen with each additional surgery.
Artificial knees can wear out
Another risk of knee replacement surgery is failure of the artificial joint. With daily use, even the strongest metal and plastic parts eventually wear out. Joint failure risk is higher if you stress the joint with high-impact activities or excessive weight.
An orthopedic surgeon performs knee replacement procedures. Before the procedure, the surgeon takes your medical history and performs a physical examination to assess your knee's range of motion, stability and strength. X-rays can help determine the extent of knee damage.
Knee replacement surgery requires anesthesia to make you comfortable during surgery. Your input and personal preference help the team decide whether to use general anesthesia, which makes you unconscious, or spinal or epidural anesthesia, which leaves you awake but unable to feel pain from your waist down.
Your doctor or anesthesiologist might advise you to stop taking certain medications and dietary supplements before your surgery. You'll likely be instructed not to eat anything after midnight before your surgery.
Plan for your recovery
For several weeks after the procedure, you might need to use crutches or a walker. Make arrangements for transportation home from the hospital and help with everyday tasks, such as cooking, bathing and doing laundry. If you live alone, your surgeon's staff or hospital discharge planner can suggest a temporary caretaker.
To make your home safer and easier to navigate during recovery, consider making the following improvements:
- Create a total living space on one floor since climbing stairs can be difficult.
- Install safety bars or a secure handrail in your shower or bath.
- Secure stairway handrails.
- Get a stable chair with a firm seat cushion and back, and a footstool to elevate your leg.
- Arrange for a toilet-seat riser with arms if you have a low toilet.
- Try a stable bench or chair for your shower.
- Remove loose rugs and cords.
During the procedure, your knee is in a bent position to expose all surfaces of the joint. After making an incision about 6 to 10 inches (15 to 25 centimeters) long, your surgeon moves aside your kneecap and cuts away the damaged joint surfaces.
After the joint surfaces are prepared, the surgeon attaches the pieces of the artificial joint. Before closing the incision, he or she bends and rotates your knee, testing and balancing it to ensure that it functions properly. Expect knee replacement surgery to last about two hours.
After knee replacement surgery
After surgery, you're wheeled to a recovery room for one to two hours. You're then moved to your hospital room, where you typically stay for a couple of days. You might feel pain, but medications prescribed by your doctor should help control it.
During the hospital stay, you're encouraged to move your foot and ankle, which increases blood flow to your leg muscles and helps prevent swelling and blood clots. You might need to receive blood thinners and wear support hose or compression boots to further protect against swelling and clotting.
The day after surgery, a physical therapist shows you how to exercise your new knee. During the first few weeks after surgery, a good recovery is more likely if you follow all of your surgeon's instructions concerning wound care, diet and exercise. Your physical activity program needs to include:
- A graduated walking program — first indoors, then outdoors — to increase your mobility
- Slowly resuming other household activities, including walking up and down stairs
- Knee-strengthening exercises you learned from the hospital physical therapist, performed several times a day
For most people, knee replacement provides pain relief, improved mobility and a better quality of life. Talk with your doctor about what you can expect from knee replacement surgery.
Three to six weeks after surgery, you generally can resume most daily activities, such as shopping and light housekeeping. Driving is also possible at around three weeks if you can bend your knee far enough to sit in a car and if you have enough muscle control to operate the brakes and accelerator.
After you've recovered, you can enjoy a variety of low-impact activities, such as walking, swimming, golfing or biking. But you should avoid higher impact activities — such as jogging, skiing, tennis and sports that involve contact or jumping. Talk to your doctor about your limitations.
Sept. 22, 2015
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