Measuring the volume fraction of bone ingrowth: a comparison of three techniques.

The need for quick, accurate, and reproducible methods to measure the amount of bone within porous metals has increased as the use of these materials has become more common within orthopedics. The purpose of this paper is to compare measurements of bone ingrowth using microradiography, stained histology, and backscattered electron imaging-scanning electron microscopy (BEI-SEM) in cementless, porous-coated acetabular components retrieved from human patients. BEI-SEM of bone ingrowth into porous metal provided excellent images for quantitative analysis. The stained sections and BEI-SEM images provided very comparable results, while microradiography consistently underestimated the porosity of the porous coating and overestimated the amount of bone ingrowth.