Partial (Unicompartmental) Knee Replacement

Surgery for advanced arthritic changes of the knee has traditionally been a total knee replacement. Thanks to many advances in technology, surgical techniques, and implants, partial knee replacement surgery was developed to offer a specific subset of patients a less invasive approach.

A partial or unicompartmental knee replacement is intended for someone who has cartilage wear in only one of the three compartment of the knee. In order to be a candidate for this type of procedure, certain attributes must be met. First, patients with rheumatoid arthritis are usually not candidates for this type of surgery as rheumatoid disease is an inflammatory condition that will affect the entire joint. This surgery is also not recommended for those who are morbidly obese or those who have significant deformity to their knee. The ligaments and supporting structures in the knee must be intact to be able to support the partial replacement. Only an orthopaedic surgeon who specializes in joint replacement surgery can determine if a partial knee replacement is an appropriate treatment for a given patient. The outcomes of this surgery are highly dependent on patient selection and meeting all of the necessary criteria for this surgery.

The procedure involves making a relatively small incision over the affected knee. As with a total knee replacement, the diseased cartilage and bone is removed off of the femoral and tibial surfaces. In the case of a partial knee replacement, this resection is limited to one side of the knee. Once the joint surface is prepared, a metal prosthesis is placed. The prosthesis is cemented in place. There are several different types of partial knee replacements on the market based on the surgeon’s preference and patient’s anatomy.

This surgery is usually performed in a hospital setting. The technique involved in performing this procedure has progressed to a point where this surgery is performed on an outpatient basis for some patients. Regional anesthesia (numbing lower half of the body or leg) is commonly used.

Post-operatively, patients are normally started on a rehabilitation program right away. The goal is to be able to resume walking without the use of an assistive device. Most patients can get back to daily and recreational activities faster with this procedure than a total knee replacement. This type of surgery is not intended for those looking to return to high impact activities and certain sports.

Complications from this type of surgery are relatively low. There is minimal blood loss. Other potential risks include infection, nerve injury, blood clots, problems related to the prosthesis, and other risks associated with anesthesia.