What is Total Knee Replacement Surgery

Knee replacement surgery involves removing all or part of a knee joint that is diseased and replacing it with an artificial knee joint or prosthesis. Frequently a knee replacement is performed when a person’s knee becomes damaged and painful from arthritis. If abnormal biomechanics from knock knee deformity (genu valgus) or bowlegged deformity (genu varus) are present, then the surgery must also correct these abnormal biomechanics.

Knee replacement surgery is generally performed when limitations and painful symptoms can no longer be controlled with non-operative treatments. Ultimately it is the patient who decides within their our heart when they are “ready”.

In Total Knee Replacement surgery (TKR), the bone and cartilage on the bottom end of the thigh bone (femur) and top of the shin bone (tibia) are removed. This is performed using precise instruments to create surfaces that will accommodate the implant perfectly. Computer navigation and robotic technology have wonderfully improved our precision and made the results even more predictable.

A metal implant that is shaped like our natural femur is placed on the femur. A metal tray and plastic insert are implanted on top of the tibia. The underneath surface of the patella or kneecap is also removed and replaced with a plastic button. Now as the new knee moves, only specialized plastic moves against the new metal femoral component and pain is relieved. The “art” is balancing the soft tissue sleeve and recreating more normal knee movements or kinematics. My ability to accomplish this reproducibly has been greatly enhanced using kinematic sensor technology. Prior to implanting the definitive plastic insert, a trial insert made with a micro-computer chip with pressure sensors and shaped exactly like to definitive plastic insert is implanted. Using a different computer, I measure precise inter-compartmental loads (measure the load between the inner and outer compartments of the knee) and the location of these loads which now provide a “road map” to optimally aligning the components and balance the soft tissue sleeve for optimal knee kinematics and function. I share with my patients that in my experience this technology is proving to be a game changer.