Unicompartmental Arthritis

Arthritis of your knee can cause both significant pain as well as limit your ability to move about freely.   Degenerative or osteoarthritis is caused either by progressive wearing away of the smooth, resilient bearing surface (articular cartilage) which “treads” the bone, or by an injury which damages that surface.  When the articular cartilage is lost, the knee joint bearing surfaces become “bone-on-bone”.  Arthritis, however, does not always involve your entire joint uniformly and can be relatively localized.  The knee is considered to have three compartments, medial (along the inside), lateral (along the outside) and the third, your kneecap (or patellofemoral) joint.

Partial Knee Replacement

The goal of knee replacement is to alleviate pain and restore function.    Most of your knee may be healthy, in which case, it would be unnecessary to replace the entire joint.  A unicompartmental (UNI)  or partial knee replacement resurfaces the worn thigh bone (femur) with a metal runner, and the lower leg (tibia) surface with a high density plastic material only in the compartment which has degenerative arthritis.  Minimally-invasive surgical techniques facilitate a quicker recovery and enable restoration of more normal  range-of-motion.

Am I a candidate for a “UNI”?

Your knee arthritis pain should be significantly affecting your quality of life before any surgical procedure is appropriate.  Certain prerequisites are necessary for an optimal result from a partial knee replacement.  Your history and examination should confirm that your pain is localized to one compartment, that your knee is stable and not ligamentously lax, and that any loss of knee motion is relatively small.  In general, significant bone deformities are not amenable to correction with a partial knee replacement.

What could I expect from a partial replacement?

When performed using a minimally-invasive technique and compared to a complete knee replacement,  a partial replacement generally result in a quicker recovery as well as less pain and blood loss.  Because all of your normal ligaments are preserved (unlike complete knee replacement which sacrifices the anterior cruciate ligament or ACL), patients with a partial knee replacement tend to have a more normal feeling and function of their knee.  UNI knee replacements using a minimally-invasive surgical technique have been shown to perform well over extended periods of time (12 – 15 years).   A very active lifestyle with relatively few limitations can be resumed although repetitive, high impact activities should be avoided.  Find out if a partial knee replacement might be able to offer you a “new lease on life”!