How Long Do Knee Replacements Last?

By Rebecca Boardman

Knee replacement surgery is not for the faint of heart. It is a major operation that takes months of rehabilitation and therapy. Once recovery is completed, many patients are more than happy they made the decision to have the surgery, as the reduction in pain is almost instantaneous. But it is important to realize that the new knee is not as perfect as the knee the patient was born with. There can be no running, no jumping or strenuous sports activities that might re-injure the joint. A common question patients have is how long will the new knee last. This article will give you some information on the surgery and the recovery, as well as information on how to care for your new knee long-term, making it last as long as possible.


The significance of knee replacement surgery is huge. The surgeon will remove a section of the lower and upper leg bones, completely remove the kneecap, and replace all these with prosthetic pieces made to fit the patient. The knee goes from being diseased or severely injured, to being totally without disfunction on the inside of the joint. This is a huge difference, as in many cases, the patient has been dealing with long-term pain and declining quality of life. When a patient received a new knee, it is like she has a whole new leg, that functions as it should. This can often lead to a much happier life for the patient. The pain of the surgery, and the rehabilitation are tough, but the end result is usually spectacular. The immediate improvement in pain management, and the restoration of quality of life makes the surgery a good option for those with end stage osteoarthritis.


The function of knee replacements are to completely replace the entire knee joint in the human knee. The entire lower section of the femur and the upper section of the tibia, as well as the entire patella and all its connective tissues, and replace it with man-made materials. The prosthetic joint will then work smoothly, imitating the human knee as it worked before it was damaged by disease, arthritis or injury. When a knee replacement is done, and physical therapy has been successfully completed, the joint will work without causing dislocations, pain or instability. This is the function of knee replacement surgery, and--for most patients--it can truly be the solution to a terrible problem. As with anything man made, the parts making up the new joint will not last forever. The human body puts an incredible amount of abuse on the knee joint, and even with today's best technology, the prosthetic knee will wear out.


The return to normal activities, such as walking, climbing, kneeling, etc. are what a patient can look forward to once he has this surgery. There is not a return to professional sports, and even light sports will be severely curtailed, as the knee is easily injured during sports activities. And although the replacement is a wonder, it is not as perfect as the original human knee it replaced. Generally, most patients who receive a knee replacement are over the age of 50. Even the best knee replacements do not usually last more than 20 years, tops. If the patient is active and young, it will wear out quicker. There is no way to tell exactly how long the prosthetic knee will last, but it is safe to say that if a brace is worn during exercise, care is taken in using the knee, and proper body weight and fitness are maintained, the joint will last much longer than if it is abused or overused.


Prevention can be the patient's best medicine. Once she has received a knee replacement, it is important to begin by completing physical therapy. This is a process that will take many months, and require work and dedication. When done successfully, the muscles around the patient's new knee are properly strengthened and able to handle activity. The patient needs to maintain physical activity and use the joint, and needs to strive for a healthy weight. Both these things will keep the joint moving and keep it from wearing out too soon. Adding some dietary supplements, such as glucosamine, may help, but check with your doctor before you begin any medicines.

When Does It Wear Out?

The question remains of how long the knee replacement will last, and it is a question with a different answer for every patient. Depending on health, size, weight, strength, pain tolerance and a multitude of other factors, patients will vary from person to person on how long the prosthetic knee will last. Generally, the more heavily active a patient is, the more stress they place on their joint. Yet it is a fine line. The joint needs to remain active to have it move smoothly. So, a middle ground is an important area to find for each patient. Generally, a knee replacement will last about 15 years. And a patient can have only have two replacement surgeries on the same knee. That is why a total knee replacement is not something that doctors do immediately.

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