Biomechanical evaluation of bone‐porous material interfaces

Abstract

Abstract An investigation was undertaken to correlate mechanical strengths of various bone‐porous material interfaces with the type and degree of osseous ingrowth. Intracortical cylinders of porous and nonporous metals, ceramics, polymers, and carbon were implanted into canine long bones and examined at 3, 6, and 12 weeks. Reflected and transmitted light microscopy were used to study bone ingrowth. Electron microprobe analysis and tetracycline labelling were used to characterize the degree of mineralization of the ingrowth. Shear strengths of bone‐porous material interfaces were measured on cylinders forced out in compression. Microhardness traverses were made across the interfaces. Readily identifiable bone was shown by histology in many porous specimens. Mineralization was found to various depths in all the porous specimens. The porous metals displayed the greatest interfacial shear strengths and hardnesses, with values from one‐ to two‐thirds that of cortical bone. Changes occurred in the ingrowth region, a bone‐metal composite, which suggest a reduction of elastic mismatch.