Knee Replacement Techniques

Knee replacement surgery is one of the largest and most complex surgeries an orthopedic surgeon can perform, yet it has become relatively common, with an excellent success rate. As the years have passed, surgeons have experimented and tried new methods and tools, always with the aim of trying to lessen the negative impact of the surgery--increasing recovery time and reducing the size of the incisions used to perform the surgery.

Total Knee Replacement (Standard)

• The most common type of knee replacement surgery is the standard midline incision joint replacement. This is where the surgeon makes an incision from a few inches above the kneecap (patella) all the way down the middle of the knee to a few inches below the knee (shin). The joint is then totally exposed and the work of joint replacement can be done with good visual guidance and gives plenty of room for the surgeon to use his tools and muscle power to secure the prosthetic joint into place. While this is the most common, it is also the most invasive, with an incision of anywhere from 6 to 10 inches, and the damage to surrounding tissues is substantial. It takes longer to heal from, with more rehab.

Total Knee Replacement (Minimally Invasive)

• The newer and more popular method of knee replacement surgery is minimally invasive knee replacement. This is where a smaller incision, from 4 to 6 inches, is made, and more of the work of the surgeon is performed using cameras and other small tools to see inside the joint where the skin is not open to view. Because technology has advanced so much, even in just the past 10 years, this method is becoming more common because the tools surgeons now have to use are better, smaller, and more effective than the larger, clumsier instruments they previously have been limited to. Minimally invasive surgery is not for everyone. And sometimes a surgery that starts as minimal must expand to a full size replacement, depending on what the surgeon finds in the joint.

Partial Knee Replacment

• This method, also called unicompartmental knee replacement surgery, only removes and replaces the part of the knee that is diseased. In the cases of injury, physical deformity, or other exception, only one side of the knee may be damaged. In these cases, the surgeon will make a 4-inch incision along that side of the knee, removing and replacing just the section of the joint that is degenerating or causing pain. This method is still rare, and has not had the overall success rate of a total knee replacement.

Common Ground

• What all these surgeries share as a common technique is the cutting and removal of parts of the leg bones, and the placement of a prosthetic joint, or compartment of the joint, into the knee space. Once the joint is exposed, the surgeon will take a bone saw and cut away the diseased bone. In the case of a total knee replacement, the upper part of the lower leg bone (tibia) and the lower part of the upper leg bone (femur) are cut away, along with removal of the kneecap. The living bone is shaped and covered with cement, and the prosthetic is pinned, hammered, and glued into place. In the case of a partial knee replacement, the area of diseased bone is cut out, and the prosthetic is set in the empty spot in the same fashion as a total knee replacement.

Misconceptions

• A common misconception is that a knee replacement will make the knee as good as new. This cannot be further from the truth. Although knee replacement surgery can vastly improve the quality of life of the patient, and restore them to a more normal lifestyle, no technology made by man can match the human body. Heavy activity, sports, running, jumping, and twisting are all out - for life. A knee replacement allows a resumption of normal day to day activities where pain will not be a constant issue - but it does not restore the knee to normal function. Take care of your knee replacement, because the harder you are on it, the shorter lifespan it will have. And in general, a person can only have two replacements in one lifetime.