Fabrication of 1-dimensional porous hydroxyapatite and evaluation of its osteoconductivity.

Porous HA ceramics with 1-dimensional pore channels were fabricated to obtain controllable microstructure. 1-dimensional porous HA was objected to find out the optimum condition of bone ingrowth and also to facilitate the observation of osteocondutive behavior in porous HA. The porous structure was formed by burnt-out of polymeric fibers and the size of pores was determined by the diameter of polymeric fibers. The porosity could be varied by the thickness of HA slurry coated on polymeric fiber and by the thickness of HA tapes inserted between fiber layers. As result, 1-dimensional porous HA ceramics of this study have the uniform interconnection size (50-500 microm) and the linearly open pore structure. The compressive strength of 1-dimensional porous HA was 6-10 MPa similar to that of human cancellous bone. On the in vivo test, oteon-like osteoconduction in pore channel of 1-dimensional porous HA was observed, like what had been found in cortical bones. This osteon-like new bone grew from the surface to the center of pore channels. The 1-dimensional porous HA ceramics prepared in this study were very useful as a model system to observe bone ingrowth in the porous HA implants.