Cementing technique of the femur in primary THA: the French paradox.

The French paradox cementing technique encompasses a canal filling highly polished stem with a thin (<1 mm) cement mantle. The technique has been developed by Pr Marcel Kerboull in the late 1960s after he observed the patterns of debonding of the original Charnley stem. The key point of the technique is based upon removal of the metaphyseal cancellous bone (with hollow reamers or aggressive broaches) especially at the supero-medial region. Only two stems have been validated with this technique: the Charnley-Kerboull (CK) and the Ceraver Osteal stem, both of which are collared. This technique is neither a taper slip (the stem does not subside at long-term follow-up) nor a composite beam (a highly polished stem is used). A 12% shortened stem CK has shown similar results to the standard-length stem, including the absence of stem subsidence. Combined with the Hueter anterior approach, this technique has demonstrated one of the lowest femoral PPF rate in elderly patients in the literature.