A state-of-the-art knee replacement implant built from oxynium, which is much more resilient, was done for the first time in Kolkata. Oxynium is a derivative of titanium, with a special coating that is black in colour, giving the implant its name. Unlike knee implants made of cobalt chrome, which last around 15 years and need to be replaced, oxynium knee replacements can survive without any hassles for around 35 years. It is much better for younger people, there is no debris like is noticed in ceramic implants, and the lubricating surface is much better, causing minimal abrasion.