sacrifice of 2 sheep the proximal humerii proximal femora and distal femora were removed under sterile conditions cleaned of soft tissue and cut from their diaphyses to produce 500 g of cancellous graft these were then divided into two equal groups and passed through a small 3 mm diameter and large 6 mm diameter bone mill respectively one third of the graft from the large mill was mixed with all the graft from the small mill to produce a more uniform particle size distribution which represents an u2018 idealised u2019 mixture large mill graft idealised with bioactive glass idealised bone graft with idealised bwsg as used in example 1 in a 50 50 by volume mixture idealised bone graft alone idealised bwsg as used in example 1 alone group 1 was produced by previously determining the particle size distribution of sheep bone produced from the large mill then adding the correct amount by volume of bioactive glass of each particle size to produce a linear log particle size distribution group 2 was produced by the addition of bioactive glass with a linear log particle size distribution in a 50 50 ratio by volume volumes of bioactive glass compared to sheep bone were determined in the knowledge of mass and density at one standard impaction samples from the above four groups were then sent to microbiology for culture to ensure sterility before use 6 metaphyseal defects per limb in a sheep model 12 sheep were grafted using negative control impacted autograft as a positive control and the experimental groups prepared as described above with random placement of graft types along the.