The effect of bone porosity on the shear strength of the bone–cement interface

This study investigated the relationship of bone porosity and bone–cement interface shear strength. One hundred forty-six samples were taken from the distal metaphysis of 20 bovine femora. After cementation, the shear strength of the bone–cement interface was tested. According to the porosity, the samples were divided into four groups. Group I (porosity <80%) had a median interface shear strength of 4.03 MPa, group II (80% ≤porosity <85%) 7.06 MPa, group III (85% ≤porosity <90%) 9.44 MPa, and group IV (porosity ≥90%) 14.85 MPa. The differences between the four groups were statistically significant. Greater porosity yielded a stronger bone–cement interface shear strength under the identical cementation technique. The optimum porosity of cancellous bone is more than 90% which can be found by reaming or drilling to deeper bone in cemented acetabular fixation.