What is a Total Knee Replacement?

Often referred to as an "arthroplasty," knee replacement surgery is a procedure that removes the arthritic surfaces of the bones around the knee and caps the ends of the bones with smooth, polished, durable implants. Depending on what type of knee replacement you may be having, different structures in your knee may or may not have to be removed. For instance, in the case of a total knee replacement, the anterior and posterior cruciate ligaments, damaged joint cartilage, and menisci (shock absorbers) are removed and substituted by the implant. The medial and lateral collateral ligaments and tendons around the knee are typically left intact for all knee replacement procedures, except in unusual circumstances.

In the case of a patellofemoral replacement, the arthritic cartilage of the patellofemoral compartment of the knee is removed and resurfaced with a plastic button and metallic cap, leaving the menisci, cartilage of the healthy compartments, and cruciate ligaments intact.

In unicompartmental replacement, only the arthritic surfaces and meniscus of the involved compartment are removed, leaving the cruciate ligaments and other compartments intact. Due to the conservative nature of partial knee replacement options, these are often referred to as resurfacing procedures. For a more detailed explanation watch this animation.

Combining patellofemoral and unicompartmental resurfacing may be an option for patients suffering with arthritis in two compartments of the knee, including the patellofemoral compartment and either the medial or lateral compartments, when non-surgical treatments have failed to treat their knee pain. Typically this is reserved for a small group of young patients for whom a total knee replacement may be undesirable, although select elderly patients may also be candidates. Robotically assisted techniques are used for the procedure to enhance the accuracy.