Current state of cement fixation in THR.
The author surveys important landmarks in the development of total hip arthroplasty, with an accent on implant fixation using acrylic cement. He explains why he personally opted for hybrid prostheses, combining a cemented stem and a cementless socket, in patients over sixty years. Excellent cementless, sockets have been available for a long time; on the femoral side, the first steps were difficult, but several cementless, stems were subsequently developed, which provided excellent long term results. This historical evolution resulted in a very uneven use of cemented versus cementless stems from one country to another in Europe. Cemented implants have enjoyed a renewed popularity over the past few years as a result of several factors, including economical factors. The author discusses the conditions for optimal fixation of a cemented stem; these conditions are not always met satisfactorily, as a number of surgeons obviously stick to a crude cementing technique. The author describes the role of the stem geometry and surface finish, as well as the possible influence of a centralizer; he explains why, based on a correct analysis of the available data, discredit has been unduly cast on cemented stems made of titanium alloy. He insists on one important although often disregarded factor: the specific type of cement used, as better results have clearly been achieved with certain cements than with others. He insists on the necessity to take into account all the elements involved, in order to avoid making erroneous conclusions. He also insists on one very important variable, the quality of the surgical technique. Total hip arthroplasty is likely to make further progress in the future, although we are likely now in the asymptotic portion of an ascending curve. Further improvement in clinical results will result from improvement of currently existing systems and optimization of surgical technique, rather than from the continuous designing of new implants.
Morscher
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EW
Laboratory of Orthopaedic Biomechanics-LOB, Orthopaedic Department, University of Basel, Felix Platter-Spital, CH-4012 Basel/Switzerland.
Wirz
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D000497:Alloys; D019644:Arthroplasty, Replacement, Hip / Q000379:methods* / Q000592:standards; D002484:Cementation / Q000379:methods*; D006801:Humans; D008422:Materials Testing; D019904:Polymethyl Methacrylate; D019919:Prosthesis Implantation / Q000379:methods; D011786:Quality Control; D014025:Titanium
D000497:Alloys; C031462:titanium alloy (TiAl6V4); D019904:Polymethyl Methacrylate; D014025:Titanium