An alloprosthetic composite implant comprising includes a structural porous scaffold having a pore density profile corresponding to a density profile of bone to be replaced. A plurality of cells are seeded within pores of the porous scaffold and grown by incubation. The cells may include osteoblasts and/or stem cells to form the structure of the implant, and one or more cartilage layers may be grown on top of the scaffold. The pore density profile of the scaffold may be formed based on one or both of the bone density profile of the bone to be removed, and the bone density profile of the native bone that will be in contact with the alloprosthetic implant. A robot may be employed reo resect the native bone and also to shape the alloprosthetic implant to fit into place in the native bone.