A hydrogel-metal assembly is provided. An intervening polymer network is used to bond together a water-swollen hydrogel layer and a biocompatible surface-modified metallic layer. The hydrogel layer is a water-swollen hydrogel layer of at least two interpenetrating polymers. The surface of the biocompatible surface-modified metallic layer is surface-modified with an inorganic material. The intervening polymer network has been chemically grafted to the inorganic material of the biocompatible surface-modified metallic layer through bi-functional linker molecules. The intervening polymer network is further physically or chemically cross-linked with the polymers of the water-swollen hydrogel. The hydrogel-metal assembly can be adapted to form a medical device, medical implant, an artificial implant, an orthopedic implant, or at least as part of a joint. The hydrogel-metal assembly is attractive for use as such implants or devices due to its characteristics such as, for example, low coefficient of friction, impact-absorption capacity or strength, and / or biocompatibility.