Knee prostheses, being made from metal alloys, are highly resistant to fracture. However, in the event of significant trauma, the bone surrounding the implant, particularly where it connects to the prosthesis, may be susceptible to fracture. In such situations, the weak link is generally the surrounding bone, not the prosthesis itself. The polyethylene (plastic) components located between the metal alloy parts of the knee prosthesis do not fracture but can experience wear over time.