The knee is a fascinating joint with little evolution. It hinges, rotates and slides in different directions. A rounded thigh bone and relatively flat shin bone makes it inherently unstable in design. It relies on the interaction between different tissues, such as cartilage, ligaments, tendons and muscles. It is supposed to last and function longer than engineered bearing surfaces, despite increasing demands of intense leisure activities at increasingly younger ages. With an ageing population and the fact that cartilage is a tissue without healing or regeneration abilities, the scene is set for the challenge a knee surgeon faces.