Knee Replacement (Knee Arthroplasty)

About the Procedure

Knee replacement surgery (or Knee Arthroplasty) is a form of orthopedic surgery in which the interlocking surfaces of the knee joint are replaced with metal and polyethylene prostheses. These prosthetic elements are designed to give the patient a range of movement that is comparable to an organic knee joint, though even in the best case scenarios, approximately 20 degrees of motion is lost. Knee arthroplasty is most commonly performed on patients suffering from severe arthritis pain or who have sustained physical damage to the knee joint due to some kind of trauma.

The procedure is performed under general anesthesia and begins with a vertical incision over the front of the knee. This incision is typically 8 to 12 inches in height. Then, the quadricep muscle is partially cut from the patella (the knee “cap”) so that the patella can be moved aside in order to grant access to the actual knee joint. Any damaged or diseased bone or cartilage is removed from the joint at this point. The bottom of the femur is then shaved down to accept a metallic, rounded prosthetic. The top of the tibia is then shaped and some of the base of the tibia is hollowed out to receive a metal anchor, in which a slightly cupped, polyethylene prosthetic is placed. The patella is then moved back into position and the incision is sutured shut.

As in other forms of prosthetic surgery, polymethylmethacrylate (PMMA) bone cement is generally used to affix the metal prostheses to the surrounding bones in most cases. This may not be the best option for patients with particularly weak bones and, in some cases, cementless prostheses can be used. Such prostheses have porous surfaces designed to allow the surrounding bone to grow into them, binding together over time. Recovery times are typically longer when these cementless prostheses are used since it takes some time for the bone to start growing into them.

What to Know Before the Procedure

Knee arthroplasty is a major form of surgery that should be considered only once less radical options, such as physical therapy, have been explored. If the patient suffers from obesity they should consult their doctor before undergoing the surgery. The extra weight such a patient carries can put undue strain on the prosthetic joint, resulting in catastrophic failure. As such, obese individuals should consider weight loss before having the surgery. Since many candidates for knee arthroplasty have physical difficulty with exercise, bariatric (weight loss) surgery is often suggested to achieve this. Consult your doctor to determine the healthiest option for you.

Due to the fact that your knee will be weaker and less able to support your weight for some time after the surgery, other parts of your body will be put under more strain, including your hips thighs and calves. It is quite common for patients who plan to have a knee arthroplasty to go into physical therapy before hand to perform strengthening exercises on these parts of the body. This is done to prepare the body to be able to handle the excess strain it will be under. Such exercises are typically started up to a month prior to the operation.

What to Know After the Procedure

The average hospital stay after the operation is three to seven days. As early as the first day, the patient will be able to move their new joint and walk with the assistance of a walking aid. After they are released from the hospital the patient then undergoes about 6 weeks of intense physical therapy to rehabilitate the muscles around the knee joint. At about the same time frame, patients should be able to put their full weight on their new joint with minimal assistance from a walking aid. It may be as long as 3 months or more before they are able to return to fully resume normal activity.

Infection is the most potentially severe risk after any form of arthroplasty. In addition to pain medications your doctor will most likely prescribe antibiotics to minimize the risk of infection. Inspect the surgical area regularly for discharge, or discoloration. The patient should also monitor their temperature periodically, as a rise in temperature can be an indication of infection as well. Contact your doctor should any of these occur.

If you Need to Travel Outside of your Local Hospital

Knee arthroplasty has been performed for decades and there are many qualified surgeons throughout the United States who can perform it properly. However, there are cost benefits to having it done overseas. Travelling after such an intensive procedure can prove difficult, but is safe if you have people to assist you properly. Follow up procedures are not common unless there is some kind of unforeseen complication, so that is not a limiting factor. Physical therapy is done on an out-patient basis and does not require a return visit to your doctor. Consider the cost reducing factors against the challenges of travel to determine which options is right for you.