In vitro pressurization of the acetabular cement mantle: the effect of a flange.

A model was developed to assess the effect of an acetabular flange on pressure within different zones of the cement mantle during insertion. Two prosthetic designs were assessed in 3 different sizes. Flanged components produced significantly higher mean pressures than unflanged ones (P < .01). The effect of a flange was more pronounced at the rim than at the pole. Delayed insertion resulted in a further significant rise in mean pressure (P < .01), but this did not compensate for the lack of a flange. This experimental model supports the use of a flange to increase pressure within the cement mantle on component insertion. The beneficial effect is more marked in the area that is most likely to show deficiency in the cement-bone interface on postoperative radiographs.