Limitations of Total Knee Replacement
- Age of patient (Not designed for the lifestyle of 40 year-olds)
- Limited longevity (15 to 20 years with current designs)
- Some loss of ROM
- Clicking or other noises
- Lifelong precautions
As good as a prosthetic joint may be, it is not the same as a normal, healthy joint. Total knee replacement functions well, if subjected to an activity level of an average 70-year old person. Naturally, a 40-year old will, on average, be much more active, and would possibly subject the prosthesis to loads for which it was not designed, causing premature failure of the implant. Avoiding excessive loading of the artificial joint is especially important in younger patients because of their longer life expectancy.
Knees can be successfully replaced in younger people, but the patient must accept the limitations.
A typical artificial knee will last about 15 to 20 years in 80 to 90% of the cases. The more it is used (and abused) the faster it will wear out. Re-do replacement surgery is possible but is a much more difficult operation.
Artificial joint does not function exactly like a normal, healthy joint. There is always some loss of the range of motion; there may be some clicks or other benign noises. Some aching and discomforts may also be occasionally felt.
Because of the inherent limitation of the design of artificial joints, some life-long precautions have to be observed. One needs to restrict high-velocity, high-impact activities (running, jumping, water skiing, etc.).