Porosity of neat and composite bone cement mantles

The effect of fiber additions to bone cement on femoral cement mantle porosity was determined. Eighteen porcine femurs were implanted with a cemented prosthesis. Three cement types were used: as-received cement, cement with untreated polyethylene terephthalate fibers, and cement with treated polyethylene terephthalate fibers. Radiographs revealed all cement mantles as grade B, with slight radiolucency at the cement-bone interface. The cement mantles were sectioned at 7 levels, and porosity was measured at each level. All specimens had similar porosities, with an overall mean percentage of porosity of 3.3% +/- 2.2% and a mean pore count of 208 +/- 160 per section. The high pore count and porosity were not visible on the standard clinical radiographs.