Who Needs a Total Knee?
By James J. McCoy, Jr., MD

The real question is who needs a total knee replacement when half a total knee would do. As most people realize today, a total knee replacement is a treatment option for painful degenerative arthritis in the knee. When the articular cartilage of the weight-bearing joint degenerates and an individual is left with bone-on-bone contact in the knee, pain with weight bearing results. Degenerative arthritis can follow infection in a joint or injury or it can be a slow insidious process that progresses with age. All of us experience degenerative wear and tear in our weight-bearing joints but some are affected sooner than others.

In the early stages of degenerative arthritis, the discomfort can usually be alleviated with lifestyle changes and anti-inflammatory medicines. It is easier on the knees to bike or swim rather than jog or play tennis. Later as the degeneration progresses and anti-inflammatories have less pain relieving effect, many patients find relief with periodic cortisone injections into the knee. Eventually the pain may become so severe that conservative measures are exhausted and a total joint replacement surgery is often employed. This usually involves the resurfacing of the end of the femur, the thighbone, with metal and the top of the tibia, the shinbone, with a plastic surface. The back of the kneecap is frequently resurfaced as well. The resulting metal-on-plastic weight-bearing surfaces relieve the pain. This is a big operation and usually necessitates a good deal of physical therapy to rehabilitate the knee to get back to as normal a gait as possible.

Many individuals, because of an injury or their particular body architecture, will wear out one side of the knee faster than the other. If both knees are involved and the outer sides wear out, a knock-kneed deformity will result. Contrary-wise, if the inner aspects of both knees wear out, a bowed deformity will result. Many patients, and indeed many physicians, are unaware that in these cases, a unicompartmental knee replacement may be sufficient to give the patient many years of pain relief. This is essentially half a total knee replacement and the procedure can be done through a much smaller surgical incision and the rehab involved is much easier than with the total knee replacement.

So who needs a total knee replacement? The answer is many patients who have knee pain with weight bearing that have exhausted the benefits of anti-inflammatory medicines and cortisone shots but there is also a large part of that population that can find relief in a simpler operation that can buy them some time as well as pain relief.