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Unicompartmental knee arthroplasty

Contents of this page:


Knee joint
Knee joint
The structure of a joint
The structure of a joint
Partial knee replacement - series
Partial knee replacement - series

Alternative Names    Return to top

Partial knee replacement; Knee replacement - partial; Unicondylar knee replacement; Arthroplasty - unicompartmental knee; UKA

Definition    Return to top

Unicompartmental knee arthroplasty (UKA) is surgery to replace either the inside (medial) or outside (lateral) compartments of the knee.

Because only part of the damaged knee is replaced, it is often called a partial knee replacement.

See also: Total knee replacement

Description    Return to top

You may receive either general anesthesia (asleep, no pain) or local anesthesia (awake but no pain). The surgeon will make a small cut about 3 inches long over the knee that is damaged.

The damaged bone is removed and replaced with an implant (prosthetic) made of plastic and metal. The thigh and shin bone may be slightly shaped to fit the implant. Once the implant is in the proper place, it is secured with bone cement, and the wound is closed with stitches.

The operation takes about 1 - 1 1/2 hours.

UKA has gone under significant changes since first performed in the 1970s. Today, the procedure offers many benefits over total knee replacement, including:

Pain relief is the same for both procedures.

Why the Procedure is Performed    Return to top

Certain diseases and conditions can affect knee function. The most common reason for UKA is arthritis.

This procedure may be considered in patients with the following conditions:

Patients age 60 and up who are not physically active and who have no history of inflammatory arthritis are good candidates for this procedure. UKA is not recommended for patients who:

Risks    Return to top

Risks for anesthesia include:

Risks for any surgery include:

Risks for UKA include:

After the Procedure    Return to top

Most patients have a rapid recovery and have considerably less pain than they did before surgery. 

Outlook (Prognosis)    Return to top

Most patients go home the day after surgery (unlike the 3 or 4 days required by a total knee replacement). You can put your full weight on your knee immediately. There is usually less rehabilitation or physical therapy required compared to total knee replacement.

Most forms of exercise are acceptable after surgery, including walking, swimming, and biking. However, you should avoid high-impact activities such as jogging.

References    Return to top

Berger RA, Meneghini RM, Jacobs JJ, et al. Results of unicompartmental knee arthroplasty at a minimum of ten years of follow-up. J Bone Joint Surg Am. 2005;87(5):999-1006.

Patil S, Colwell CW Jr, Ezzet KA, et al. Can normal knee kinematics be restored with unicompartmental knee replacement? J Bone Joint Surg Am. 2005;87(2):332-338.

Update Date: 5/5/2008

Updated by: Andrew L. Chen, MD, MS, Orthopedic Surgery and Sports Medicine, The Alpine Clinic, Littleton, NH. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

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