The use of mesenchymal stem cells cultured in the presence of HS-2 for the treatment of bone fracture. Repair of bone fracture using such cells is enhanced compared with the treatment of bone fracture using mesenchymal cells cultured without HS-2. These mesenchymal stem cells may be formulated in a pharmaceutical composition and injected directly into tissues surrounding the fracture or used in a biocompatible implant or prothesis.