Insertion of an expandable cement restrictor reduces intramedullary fat displacement.

The insertion of an intramedullary cement restrictor can lead to the same pathophysiologic reactions that are well described as fat embolism syndrome after cement and stem implantation. Fat and marrow are forced into the draining veins of the femur. In this study, we compared the extrusion of intramedullary contents produced by the insertion of a commonly used gelatin (Biostop G/IMSET) and a new expandable cement restrictor (REX Cement Stop) in 7 paired, fresh-frozen femora. A further 9 pairs were used to evaluate the function of a custom-made application instrument, which allowed for suction during plug (Biostop G/IMSET) insertion. The oversized restrictor produced, on average, twice as much fat as the expandable restrictor (P = 0.0156). The gelatin plug with additional suction was not associated with reduced fat extrusion, because the suction device in its current design failed because of obstruction in most cases. The expandable restrictor showed favorable characteristics and has the potential to reduce the risk of fat embolism.