[Endoprosthesis of the knee joint: current status and trends]

Knee joint endoprosthetics has proved to be at least as successful as hip joint endoprosthetics, although the total implantation rate has risen to only about 15%, which ignores its widespread unpopularity. There is a great variety of artificial knee joints, although according to ISO standards all models can be reduced to four basic ones. Deciding to use a stabilized, semi-constrained or unconstrained artificial knee prosthesis requires careful consideration especially if the possibility of its removal is taken into account. The main reason for unsatisfactory clinical results is still retropatellar pain. Intensive basic research is necessary in this area as well as in the development of new materials that might be used for new prosthetic designs. Designers as well as surgeons should aim at regaining the natural function level with no pain for the patient.