Cement Anchors With Screw Holes For Liner Cementation Into Cementless Acetabular Metal Shells.

This mechanical study was conducted with the shellcement interface in order to construct an acetabular metal shell, and to fix a polyethylene liner with bone cement. Six types of models were tested, with all cementations performed under similar conditions. The "lever out" test was conducted 3 times for each group in order to measure the dissociation strength. The average dissociation strength values were 11.5 N• m for those without screw holes; 33.6, 34.7, and 78.7 N• m for those with single holes at 1, 3, and 6 mm depth, respectively; and 41.3 and 101.1 N• m for 2 different configurations with 3 holes at 3 mm depth. The strength of adhesion increased with the use of a cement anchor, and with an increasing length and number of anchors. The application of a cement anchor with a screw hole is clinically useful for increasing the mechanical strength of the shellcement interface.