Efficacy of cement restrictors: Experimental study and development of a classification

Cement restrictors (CRs) are devices that allow occlusion of the femoral canal in order to obtain greater interdigitation of the cement between the bone and a better pressurization, which generates an increase in the survival of cemented stems. The aim of this study was to evaluate the efficacy of the different CRs used and propose a classification of this device. An experimental study was carried out, where 7 CR references of different designs and manufacturers were taken. Later, tests were carried out on 9 chlorinated polyvinyl chloride tubes for each reference, to achieve a total of 63 tests. In our study, 34.9% of the CRs in ultra high molecular weight polyethylene failed, presenting migration and allowing cement to leak while none of the gelatin RC failed. The RC with an umbrella design proved to be the less effective, presented a higher incidence of migration and cement leakage, while the gelatin CRs were the best performers. Based on the results of this study, an analysis of the CR design was carried out and a classification was proposed that divides these devices into 2 types.