[Total hip prostheses, friction lever and wear].

The increased number of joint prostheses now being implanted into younger and active patients has made wear on polyethylene more apparent. This wear is the consequence of the bearing surface of polyethylene against metal. Research into the problem of wear is complex and other models such as metal-on-metal implants, ceramic-on-ceramic implants are tried to decrease the amount of particles accumulated after wear and avoid inflammatory reactions leading to bone lysis and implant loosening between 10 and 20 years.