Abstract: The invention pertains to the use of mesenchymal stromal cells (MSC) in the treatment of bone disorders or injuries. The invention provides MSC and preparations of specifically pooled MSC for use in the manufacturing of bone graft material for implanting into or attaching to bones in order to enhance bone regeneration after surgery or injury, or to treat various bone disorders, such as osteonecrosis. The invention provides bone graft material, a method for its production, bone graft implants, and medical methods and uses of the inventive products.