The History of Total Knee Replacement
Knee replacements have been performed for about 30 years, and until recently, patients were told that knee replacements were probably as successful as hip replacements, but the follow up was not that long. We have now collected data from tens of thousands of knee replacement cases and we know that knee replacement offers excellent relief of pain with improved function, and a longer lifetime of use than some joint replacements in the hip.
Total knee replacements have undergone several advancements since they were first introduced. The early design flaws of the artificial knee or “prosthesis” have been modified and improved to provide greater durability, improved stability, and increased motion for the patient. In addition, the difficulty with loosening of the prosthesis has also been addressed. Improvements in cement techniques, better instrumentation, and greater attention to leg alignment have resulted in improved long term results.
Today, prostheses are designed to be used with or without bone cement. Improvements in the bone cement itself and the techniques used to insert it are far better today than in past decades. In some circumstances, the metal parts of the prosthesis are coated with special surfaces designed to allow bone to grow directly into the metal, thus anchoring the prosthesis and eliminating the need for cement. The decision to use cement or not is made by the surgeon based on the patient’s age, expected activity level, the quality of the bone, and the individual’s weight.
Prostheses design and materials have continued to change and improve, and will continue to do so. However, we can safely assume the average life span of a prosthesis implanted today should be 15 to 20 years or more.
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