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Unicondylar (Unicompartmental) Knee Replacement

In unicondylar knee replacement (also known as partial knee replacement or unicompartmental knee replacement), your surgeon will only replace the part of your knee that is damaged. This procedure has been around for decades, and partial knee replacement is often a good option for those with arthritis that affects only a portion of the knee. It also requires a smaller incision than total knee replacement, which can speed your recovery.

Am I a candidate for partial knee replacement?

Your surgeon will talk with you about your specific condition and the best procedure for you. In general, partial knee replacement is an option if:

  • You’re over 50 years old.
  • You have pain that limits your mobility or daily activities.
  • You only have damage in one compartment of your knee.
  • You do not have rheumatoid arthritis, severe angular deformity, or an unstable knee.
  • You do not participate in contact sports or a high-impact job.

What does partial knee replacement involve?

Because every case is different, your surgeon will customize your partial knee replacement to you. You may need a different size implant or different pieces than someone else.

Typically, partial knee replacement takes approximately two hours. Your surgeon will make an incision on your knee that’s about 7 centimeters. From there, the ends of your thigh bone (femur) and shin bone (tibia) will be prepared. Your surgeon will carefully fit your artificial knee components until they fit well and are secure. After your new knee components are in place, your knee will be closed up.

When you wake up from surgery, you’ll have a bandage around your knee, an IV in your arm, and a tube in your bladder. You will also be attached to monitors to keep track of your vital signs.

What recovery is needed after partial knee replacement?

After partial knee replacement, you will stay in the hospital for three to five days. During your stay, your care team will help you control your pain. In some cases, you may have a patient-controlled analgesia (PCA) pump for pain. You’ll also have measures in place to prevent blood clots and lung congestion.

Within a day or two of your surgery, you’ll be encouraged to get out bed, move around, and begin to walk. Getting out of bed and working with your physical therapist will help you have a smoother recovery.

When you leave the hospital, you may have a walker or cane. With physical therapy, you should be able to bend your knee some, walk more comfortably, and drive at six weeks. It may take up to three months to resume all of your normal activities.

What are the advantages and disadvantages of partial knee replacement?

In the right patients, partial knee replacement has some advantages when compared to total knee replacement. These may include:

  • A smaller incision
  • Less bone removal
  • Less blood loss
  • Shorter hospital stay and recovery
  • Better knee movement

On the other hand, because only a portion of the knee is replaced, partial knee replacement may not be as effective at eliminating all pain. The benefits also may not last as long as a total knee replacement. That’s why it’s important to discuss all of your options with your doctor to understand the right choice for you.