What is knee replacement surgery?

If you undergo knee arthroplasty, you've had a partial or total knee replacement. During this operation, doctors remove damaged cartilage and bone in your knee. Then, the surgeon replaces the damaged material with a metal implant to rebuild the joint. Plastic spacers reduce friction and enhance smooth movement in the joint.

Your knees are your body’s largest joint. They’re responsible for your comfort and mobility while you move. To understand your knees better, let’s look at the basic anatomy. Your knee contains several parts, including:

  • The kneecap
  • The upper part of the shin bone
  • The lower end of the thigh bone
  • Cartilage between the ends of all three bones
  • Menisci, which are the joint’s shock absorbers
  • Ligaments that keep the thigh bone and shin bone together
  • Synovial membrane, a thin lining that provides lubrication for your knee cartilage

What to expect from knee replacement surgery

Before you have the surgery, your doctor will want to do an exam. You might have to have bloodwork or other testing done to make sure you're healthy enough for the operation. You'll also have to avoid eating or drinking anything for about eight hours before your operation. 

In most cases, you’ll receive general anesthesia and you'll be asleep for surgery. Some patients get an epidural to numb them from the waist down instead. This surgery takes between one and two hours. 

Your surgeon might choose one of two methods. Minimally invasive surgery requires a small cut between 4 and 6 inches. The traditional method involves making a cut between 8 and 10 inches in the front of the knee. This surgery has three basic steps: 

  1. Preparation, when your surgeon removes the damaged bone and cartilage
  2. Positioning the implants, your doctor replaces what they removed with metal implants to "rebuild" the joint
  3. Inserting spacers, plastic spacers go between the metal parts so everything moves smoothly

After the operation, your doctors and nurses will get you up within the first day or so. Expect to use crutches or a cane for a while. You should also expect to have physical therapy to strengthen your knee and learn exercises to help keep it flexible. 

Common conditions requiring knee replacement

Doctors often recommend this operation for people with moderate to severe pain and stiffness. This operation might be for you if your pain prevents you from being able to enjoy your normal activities. Examples include walking, getting up and down from a chair or climbing steps.

Common conditions that require this operation include:

  • Obesity
  • Trauma or repeated injury
  • Arthritis, a group of degenerative joint diseases that damage the joint and limit movement

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