Metal implants used to repair fractures are also more resilient than bone, which can be problematic since they absorb external forces. The bone that forms around them therefore doesn’t experience strain during exercise and so can start to die. Kumar and his colleagues therefore also wanted a metamaterial that had the same shape and properties as can be found at the joint ends of long bones, for example those in our arms and legs. Here, the internal bone has a porous and honeycomb-like structure, known as trabecular bone, that provides strength and the ability to absorb shocks.
