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Unicompartmental Knee Replacement

What you should know

Unicompartmental knee replacement (UKR) is surgery to remove part of the knee joint damaged by wear, injury, or disease. The knee is made up of 3 compartments (sections). The middle and side sections are where the femur (thigh bone) meets the tibia (large lower bone or shin bone). The third section is where the patella (kneecap) meets the femur. During UKR, only the damaged section is removed and replaced with a knee implant.

Knee Anatomy

Care Agreement

You have the right to help plan your care. Learn about your health condition and how it may be treated. Discuss treatment options with your caregivers to decide what care you want to receive. You always have the right to refuse treatment.


  • You may be allergic to the anesthesia and have trouble breathing. You may bleed more than expected or get an infection. Nerves, muscles, or tendons may be damaged during surgery. After surgery, your knee may be stiff or numb. Your legs may not be the same length.
  • You may get a blood clot in your leg. This can cause pain and swelling, and it can stop blood from flowing where it needs to go in your body. The blood clot can break loose and travel to your lungs or brain. A blood clot in your lungs can cause chest pain and trouble breathing. A blood clot in your brain can cause a stroke. These problems can be life-threatening.
  • Your implant may get loose or move out of place. The implant may get worn out over time and need to be replaced. If you do not have this surgery, your knee pain may get worse. You may have trouble walking, moving, or doing your usual activities.

Getting Ready

The week before your surgery:

  • Write down the correct date, time, and location of your surgery.
  • Ask a family member or friend to drive you home after your surgery. Do not drive yourself home.
  • Bring your medicine bottles or a list of your medicines when you see your caregiver. Tell your caregiver if you are allergic to any medicine. Tell your caregiver if you use any herbs, food supplements, or over-the-counter medicine.
  • Ask your caregiver if you need to stop using aspirin or any other prescribed or over-the-counter medicine before your procedure or surgery.
  • You may need x-rays, a CT scan, or an MRI. This will help your caregiver plan your surgery. Ask about any tests you may need. Write down the date, time, and location of each test.

The night before your surgery:

  • Ask caregivers about directions for eating and drinking.

The day of your surgery:

  • Caregivers may insert an intravenous tube (IV) into your vein. A vein in the arm is usually chosen. Through the IV tube, you may be given liquids and medicine.
  • An anesthesiologist will talk to you before your surgery. You may need medicine to keep you asleep or numb an area of your body during surgery. Tell caregivers if you or anyone in your family has had a problem with anesthesia in the past.
  • You or a close family member will be asked to sign a legal document called a consent form. It gives caregivers permission to do the procedure or surgery. It also explains the problems that may happen, and your choices. Make sure all your questions are answered before you sign this form.


What will happen:

You knee will be cleaned. Your caregiver will make an incision over your knee joint. The damaged section of your knee will be removed. Your caregiver will place the knee implant in your knee joint. He will secure it with screws or medical cement. A drain may be placed to remove extra blood and fluids from the surgery area. Your incision will be closed with stitches or staples and covered with a bandage.

After your surgery:

You will be taken to a room where you can rest until you are fully awake. Caregivers will monitor you closely. Do not try to get out of bed. When caregivers see that you are okay, you will be taken to your hospital room. The bandage covering your incision helps keep it clean and dry to prevent infection. A caregiver may remove the bandage soon after surgery to check your wound. You may need to use a continuous passive motion (CPM) machine. This machine will slowly bend and straighten your knee for you as you lie in bed.

Contact a caregiver if

  • You cannot make it to your surgery.
  • You get a cold, the flu, or have a fever.
  • You have infected skin or a wound near your knee.
  • You have questions or concerns about your knee surgery.

Seek Care Immediately if

  • The problems for which you are having the surgery get worse.
  • You have severe knee pain.
  • You have more trouble walking or moving your knee.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.