Expert Health Articles

The Unicondylar Partial Knee

The unicondylar partial knee implant is a partial knee implant designed to repair only one side of the knee (the medial side), making it much smaller than a total knee implant.

In patients with only limited knee arthritis, known as medial compartment arthritis, surgeons may elect to perform a partial knee replacement. Unlike total knee replacement that removes all the knee joint surfaces, a partial knee replacement replaces only one side of the knee joint. Some advantages of the unicondylar partial knee replacement are that it removes 75% less bone and cartilage, is less painful, enables a more rapid recovery and provides more natural motion when compared to a total knee replacement. By retaining all of the undamaged parts, the joint may bend and function more naturally.

Knee osteoarthritis usually occurs first in the medial (inside) portion of the joint. In knees that are otherwise healthy, a partial knee implant procedure can preserve the healthy bone, cartilage and ligaments, potentially preventing or delaying the need for total knee replacement.

Some unicondylar implants, have a fully mobile bearing partial knee system available. Research has shown that partial knee replacements with moveable plastic bearing have low wear rates, potentially giving them even longer life expectancies. The free-floating nature of the device potentially provides for a more natural feeling knee and more natural motion. In a healthy knee, the meniscus serves as a shock absorber between the ends of the bones. The artificial meniscal bearing is designed to glide freely the knee's range of motion, more closely replicating normal movement.

Published long-term clinical results on unicondylar partial knee implants demonstrated a 98% success rate at 10 years and 95% at 15 years and beyond, equaling the results of the most successful total knee replacement thus far.

Not all patients are candidates for partial knee replacement. You should discuss your condition and treatment options with your surgeon. All provide the option of minimally invasive surgery.


Stanislaw Dajczak, MD

Blanchard Valley Orthopedics & Sports Medicine