Collagen matrix or granulate blend of bone substitute

A granulate blend comprising a mixture of:

• granules of a biphasic (CAP/HAP) bone substitute material (A) comprising a sintered CAP core and a closed epitactically grown layer of nanocrystalline HAP deposited on the external surface of the sintered CAP core, whereby the epitactically grown nanocrystals have the same size and morphology as human bone mineral, wherein the closed epitactically grown layer of nanocrystalline HAP deposited on the external surface of the sintered CAP core has a homogeneous coarse external surface comprising flat crystal platelets, wherein the % of HAP as measured by XRD is 2.0 to 6.0%, wherein the homogeneous coarse external surface comprises epitactically grown nanocrystalline hydroxyapatite platelets forming an interlocked network of platelets with sizes of 0.2 to 20 μm as determined by Scanning Electron Microscopy (SEM), and
• granules of a bone substitute material (B) selected from the group consisting of:
• a biphasic CAP/HAP bone substitute material comprising a sintered CAP core and at least one closed epitactically grown layer of nanocrystalline HAP deposited on the external surface of the sintered CAP core, whereby the epitactically grown nanocrystals have the same size and morphology as human bone mineral, wherein the % of HAP as measured by XRD is 10 to 40%, and
• a bone mineral derived from natural bone and retaining original crystal structure and mineral microstructure of natural bone, while having an organic impurity content below 150 parts per million and a protein content below 135 parts per million.