Total Knee Replacements
By: Dale J. Buchberger, PT, DC, CSCS, DACBSP
The total knee replacement is becoming as routine as arthroscopic knee surgery. Patients suffering from arthritic knees are improving their quality of life everyday through the innovation of total knee replacement surgery. Despite the routine nature of a total knee replacement many patients with arthritic knees are still apprehensive when they are told that they need one. Some of this apprehension is driven from a lack of information. Hopefully this article will answer some common questions about the process of having a total knee replacement.
According to the American Academy of Orthopedic Surgeons approximately 90% of the patients that have a total knee replacement experience a significant reduction in pain and are able to return to recreational activities such as golf and walking. Almost 85% of replacements last up to 20 years. The most common age group having knee replacements is the 50 to 80 year old age group with the average being 70 years old.
Women have a slight edge over men with 60% of knee replacements going to women. Keep in mind that while there are some alternatives to having a total knee replacement, joint replacement is the only treatment that will come close to restoring the natural architecture of the joint. Alternatives are merely ways to put off the inevitable of having a joint replacement assuming you have been diagnosed with advanced arthritic development or osteoarthritis. Seeing a physical therapist for pain control treatment and to learn strengthening exercises can help reduce pain and increase function. The results will be limited based the severity of the degeneration. Injections of synthetic joint fluid such as hyaluronic acid can help provide some temporary lubrication that may reduce pain and increase range of motion. These injections are expensive and the outcomes are highly variable. There are a variety of anti-inflammatory measures that
can be taken such as oral medications and cortisone injections. Again these also provide temporary reduction in pain.
Weight loss and exercise can be very effective for delaying the replacement. Merely losing 10 pounds can reduce the force on the knees by 60 pounds per step. A recent study showed patients that lost a minimum of 15 pounds had a significant reduction in pain and an increase in quality of life.
Since the first total knee replacement performed on 1968, knee replacement surgery has advanced to become one of the safest procedures performed today. The procedure starts out with a 6-10 inch incision. The surgeon will then move the kneecap over to
improve their field of vision. The damaged surfaces of the knee joint are then removed and the knee joint is resurfaced with the prosthesis. The knee prosthesis is made up of metal and plastic. The prosthesis is generally made up of 3 components: the tibial component (to resurface the top of the tibia, or shin bone); the femoral [thigh bone] component (to resurface the end of the thighbone; and the patellar component (to resurface the underside of the kneecap that glides along the thighbone).
The early post-operative stage (0-7 days) is extremely important for several reasons. The first is to get the new knee moving. Early movement will improve your outcome and help prevent blood clots. Keeping your wound clean and dry will help reduce the chance of developing an infection while the incision is healing. Even though you will experience some early post-operative pain, performing the prescribed exercises is critical to not only the recovery process, it will extend the longevity of your new knee.
One of the biggest reasons for needing a revision procedure on a total knee replacement is the failure to continue the exercise program you learned during the rehabilitation and recovery process. The rehabilitation process will start with simple basic exercises and progress to more challenging exercises over a period of weeks that
you are in physical therapy. When you reach the point that your physical therapist discharges you from supervised physical therapy you will have a very comprehensive program of strengthening exercises. It is important to discuss your “maintenance” program with your physical therapist at the time of your discharge. This is the minimum program that you will perform the rest of your life.
If you allow the supporting muscles around the knee to get weak, the joint will then rely on the architecture of the new replacement for stability. This added stress will cause premature wear and tear on the synthetic materials. Ultimately the replacement will wear out and need to be revised. If you maintain the strength of the surrounding
muscles this will reduce the stress on the replacement parts and ultimately increase the time it will take to wear those parts out. Remember, when you sign up for a total knee replacement, you sign up for a lifetime of exercise to protect your investment.