Titanium for sure. Not sure about what kind of plastics.
Artificial knees don't bend sideways at all. So it's not a full replacement of function, but it should last the rest of your life.
See #3546.
Assuming that the artificial variety does not come standard with built in sound effects and the accompanying features mentioned it would be an improvement..
UHMWPE is actively used material for fabrication of sliding element in biomedical application. It is the material of choice for the loading bearing surfaces in the tibial plateau component in the total knee and acetabular cup one in the total hip prostheses due to wear resistant and low coefficient of friction over extended periods of time. The high molecular weight, between 2 and 6 million g/mol, results in a high resistance to mechanical stresses