Partial Knee Replacement
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 cartilage surface. When the articular cartilage is lost, the knee joint bearing surfaces become “bone-on-bone” contact. 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. 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. Minimally invasive surgical techniques facilitate a quicker recovery and enable restoration of more normal range-of-motion. To be a candidate, your pain should be localized to one compartment, your knee stable, and have reasonably normal alignment. In general, significant bone deformities and restrictions of motion are not amenable to correction with a partial knee replacement. When performed using minimally invasive techniques and compared to a complete knee replacement, a partial replacement generally results 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 when compared to a total knee replacement.