Knee replacement surgery is one of the most complex surgeries that an orthopedic doctor performs. The knee joint is the largest in the human body, and the procedure calls for its removal and replacement with a prosthesis. Knowing about the surgery, the parts used to replace the natural knee, and the recovery process can help patients who are facing this surgery.
Types
There are several types of knee replacement surgery. In traditional replacement surgery, a six-to-nine-inch incision is made midline across the kneecap, the entire knee joint exposed, and the lower part of the upper leg bone (femur) as well as the upper part of the lower leg bone (tibia) and the entire kneecap (patella) are removed. A prosthetic, pre-made to fit the specifics of the patient, is then inserted into the knee joint and pinned, cemented, and screwed into place. The incision is closed, and the rehab begins.
In minimally invasive knee replacement surgery, the procedure is the same, but it is done through a smaller incision and uses cameras and other equipment to help the surgeon "see" inside the joint.
A third type is unicompartmental knee replacement. Here, only part of the knee is removed and replaced. Generally, this happens when only one side of the knee has been damaged or diseased.
Replacement Parts
Generally the same replacement parts are used for any knee replacement surgery. A prosthesis is made for the tibia, one for the femur, and a prosthetic kneecap. In the case of unicompartmental knee replacement, only half of the standard prosthetic is required. The differences lie in what they are made of and how they are applied to the bones of the leg.
Differences
Knee replacements are made of ceramic material or oxidized zirconium. The ceramic materials greatly improve the longevity of the prosthesis; they allow the joint to function smoothly without the friction that occurred in metal parts, which eventually caused them to break down. The zirconium parts are made with a process that allows oxygen to be absorbed into the material, creating a ceramic surface. These prosthetics pieces can outlast the older, all metal and plastic prosthetics. The average life of a traditional implant is 15 years, while the average life of these advanced implants is around 25 years.
Cementing or Not
Standard knee replacements are usually secured with cement, and pins are also driven into the human bone to hold the prosthetic in place. In the newer replacements, the prosthetics are made with spaces in them for the living bone to grow into. In the case of older patients or patients whose bones may have other issues, the cement procedure is still the best choice. But in younger patients with healthy bones, the newer type is a great choice, as the body actually incorporates the replacement into the human bone as it heals.
Misconceptions
A common misconception about knee replacement surgery is that the new knee is the same as a normal knee. This could not be further from the truth. While in many cases pain relief is huge and activities can be practiced that have not been done in some time, the replaced knee can never be as strong, durable, or flexible as the original it replaced. Knee replacements give a patient back quality of life, but they do not give back sports careers.
Tags: replacement surgery, knee replacement, knee joint, average life, human bone, into human