Unicompartmental Partial Knee Replacement

ER - Madison

12 min Average
UnityPoint Health - Madison

Unicompartmental Partial Knee Replacement

The unicompartmental partial knee replacement is a procedure that removes one damaged compartment in the knee and replaces it with an implant.

Who is a Candidate?

Patients who have:

  • Difficulty with normal everyday activities
  • Not had any success using the non-surgical treatments
  • Medial knee pain (arthritis)
  • Pain on one side of the knee

Good candidate for partial knee replacement over a total knee replacement if:

  • The patient has anterior and medial knee pain
  • The patient has an almost normal range of motion in their knee (90 degrees).
  • The patient's knee is stable

Benefits of this Procedure Compared to a Total Knee Replacement

  • A 3-4 inch incision compared to an 8-12 inch incision for total knee replacement
  • No disruption of the knee cap, which is vital to rapid rehabilitation
  • Minimal amount of blood loss
  • Decrease post-operative pain
  • Greatly reduce hospitalization time
  • Faster rehab/recovery time (2-5 weeks, but may vary)
  • Able to walk within 3-4 hours after surgery
  • Better range of motion
  • Enabling more natural postoperative knee function.
  • More flexibility in the knee

What is a Unicompartmental Partial Knee Replacement?

The unicompartmental partial knee replacement is performed when only one of the three compartments of the knee is damaged. The healthy compartments then remain untouched.

To perform the surgery, the surgery will make a 3-4 inch incision in the front of patient's knee. The surgeon will properly balance the patient's knee. The damaged bone is removed and the end of the femur and top of the tibia are reshaped to properly position and align the new implant.

The implant is made up of a tibial component that replaces the top surface of the lower tibia bone and the femoral component that replaces the end of the femur bone. The new implant in then positioned into place. The surgeon will close the incision and place a bandage over the wound. For most patients, the implant lasts about 10-15 years.

Since the normal knee kinematics is changed by having knee replacement, it may feel different to perform daily activities. The shape and motion of the knee will be different than with the natural knee, so the muscles and ligaments will need to adapt. At first, this may lead discomfort and fatigue for the patient.

The Allergic Alternative

If a patient is allergic to a type of metal that the implant is made of, then the surgeon will change the type of metal to make it possible for the patient to have the procedure.


After the surgery, ice and elevation of the knee will be needed to reduce pain and swelling in the knee. Once the patient is stabilized, a physical therapist will help the patient use crutches and a walker for the first day after surgery.

Call Your Surgeon If You Have

  • Increased swelling in the knee or lower leg
  • Persistent pain not relieved by pain medication
  • Abnormal side effects from anesthesia or medication
  • Changes in the incision site