Scientists are working on this very problem. They’ve found graft material can be strengthened by washing it. The pieces of bone are put through a multi-level sieve (strainer). Fat, debris, and other non-bone particles are rinsed out. After washing, the pieces of bone fit together more closely and can accept more pressure.
Researchers in Scotland have discovered that different particle sizes and shapes also make bone graft stronger. The uneven edges allow for tighter interlocking pieces. The graft is more compacted when a broad range of particle sizes are used.