Knee Replacement Surgery

About knee replacement surgery

One of the most important orthopedic surgical advances of this century, knee replacement was first performed in 1968. Improvements in surgical materials and techniques since then have greatly increased the procedures effectiveness. According to the American Academy of Orthopaedic Surgeons. about 267,000 total knee replacements are performed each year in the United States.

Most Common Causes for Knee Replacement

• Arthritis: Arthritis is a wearing away of the surfaces (articular cartilage) of the joint, caused either by aging or disease. As the cartilage wears away, the raw bones rub together whenever the joint moves. This rubbing causes pain and a roughening of the surfaces of the bone.
• Osteonecrosis: If the blood supply to the thigh bone is decreased, part of the bone will die and break from weight-bearing activity. The result is a very painful joint.
• Injuries: Injuries include trauma and accidents, or continue abuse from sports injuries.

If medications, changing activity level, and using walking supports are no longer helpful, you may want to consider total knee replacement surgery. By replacing the knee's damaged and worn surfaces, total knee replacement surgery may relieve pain, correct leg deformity, and helps many patients to resume their normal activities.

The physicians at Cedars-Sinai Orthopaedics are consistently striving to develop new technologies, instrumentation and more minimally invasive techniques for knee replacement surgery. This leads the way to more accurate outcomes, shorter hospital stays, faster recovery and less pain. Knee replacement surgery procedures include the following.

Total Knee Replacement: Traditional Procedure

Total knee replacement surgery is very effective, relieving nearly all pain in most cases. Approximately 90 percent of replacement joints last 10 years, while 80 percent are good for 20 years, depending on patient activity levels. Outcomes vary from patient to patient.

It is important to realize that a knee "replacement" is actually just a "resurfacing" of the knee joint. The femur or thighbone is covered with a metal covering and plastic is placed on the tibia so that instead of irregular arthritic surfaces, one has metal and plastic articulating which produces a smooth nonpatent surface. In most cases the undersurface of the kneecap is also replaced with a plastic surface so that this articulates with the femoral surface.

The actual procedure involving knee replacement involves a three to six day hospitalization. Weight bearing begins immediately the first postoperative day. Post-operative care after hospital discharge usually consists of a combination of home health care, physical and occupational therapy and other forms of rehabilitation. Patients usually use a walker for a period of one to two weeks, going to crutches and then a cane. People are off all walking aids anywhere from three weeks to two months.

Activities after knee replacement that should produce no difficulty are simple walking, bicycling, golfing, and swimming. The prosthesis is not designed for impact loading sports such as skiing, basketball, and racquetball. People have been known to play doubles tennis with bilateral knee replacements. To prepare you for surgery, Cedars-Sinai Orthopaedics has developed an extensive surgery education class and daily recovery guide for your hospital stay so you understand all aspects and anticipations prior to surgery. This will help lead you to a faster recovery and an easier transition.

Partial Knee Replacement

A partial knee replacement or unicompartmental knee replacement involves replacing only the part of the knee that is arthritic. Traditionally, this procedure was reserved for older and more sedentary patients. Now, a partial knee replacement is recommended more often for younger individuals. Benefits include:

• A smaller, more minimally invasive incision
• The removal of less bone leads to preservation or normal, healthy bone
• Less pain
• Less blood loss
• A faster recovery and return to work within a couple of weeks versus up to a month or more.
• Much easier transition to a total joint replacement (if it is needed later)

Mini-Incision Knee Replacement

In traditional knee replacement surgery, the surgeon makes a long incision over the middle of the knee and cuts muscles, tendons and ligaments to get to the knee joint. When more tissues, muscles and tendons are cut during surgery, the recovery is more painful and the healing process takes longer.

Cedars-Sinai offers a minimally invasive knee replacement surgery technique that significantly reduces overall surgery trauma and recovery time. The procedure is called the mini-incision total knee replacement and involves a smaller incision that the traditional total knee replacement. By doing a smaller incision using special instrument to approach the knee from the side, there is minimal trauma to the soft tissue, muscles and tendons.

Even the kneecap does not have to be moved as far to get to the knee joint. The same types of joint prosthetics are used as the total knee replacement; however, it is more precisely and carefully placed through the muscle and tendons.

This careful placement of the knee replacement usually leads to the following benefits:

• Less pain after surgery due to less manipulation and more precise placement.
• Eliminates the amount of cutting done to replace the knee joint, for an overall faster recovery.
• Typically reduces hospital stays from one to two days versus four to six days.
• Most commonly, less time is need for rehabilitation therapy.
• Generally allows patients to return to work and normal activities within a couple of weeks versus up to a month or more.

Revision Surgery

The longevity and performance of any joint, whether it is an original joint or a replacement one, depends on a person's activity level, weight and general health. Just as wear in the natural joint contributed to the need for a replacement, wear in the implant may eventually require a second surgery, known as a revision.