Osseointegration is a biological process allowing for a stable connection between living bone tissue and an implant, which becomes a functional body part. Osseointegrated implants are commonly used for internal joints and teeth replacement since the sixties of the last century but have been more recently introduced in the treatment of people with amputation, to directly connect the external prosthesis to the residual bone as alternative to socket-based anchoring. Over the last six years, the Centro Protesi Inail promoted a variety of research projects aiming at developing custom-made 3D-printed osseointegrated implants for lower limb, upper limb and hand fingers with the aim to offer its patients a choice of treatment options. The presentation provides an overview of the research projects promoted by the Centro Protesi Inail related to the treatment of people with amputation with osseointegrated implants, from the development of the custom-made device to the post-surgery outcomes.