Many geriatric patients need total joint replacements; these prosthetic devices have problems including aseptic loosening of the implants. To prevent the loosening, we propose a new concept, which is to coat joint prostheses with osteogenic cells or their precursors. Fresh bone marrow would be collected from the patient, and the mesenchymal stem cells (MSCs) isolated, expanded in number in culture, and subsequently cultured on the surface of the prostheses under osteogenic conditions. The surface of the prostheses would be covered with bone (osteoblasts and bone matrix) derived from the patient's own cells. This bone would possess the capability for bone bonding as well as new bone formation. Due to this biologic surface reconstruction, loosening can be avoided, while the post-operative rehabilitation program can be shortened due to early and secure bone formation around the implanted prosthesis.