This is a picture of bone powder. This powder, made from bone of a tissue donor, has been embedded into a natural (fibrin) glue and placed into a gap between two pieces of a broken bone. Why?

First the powder acts as a filler material so the recipient's own, healing cells (seen here as blue dots) can find their way to the other side.

Second, the powder can release specific growth factors and other materials which the recipient's cells can use to heal faster and lay down their own, new bone substance, seen here in purple.