Dual Mobility Implants

Introduction

Total hip arthroplasty (THA) represents one of the most safe and effective medical procedures, being cited as the intervention of the century. However, with an unchanged incidence of 3% in primary THAs and up to 28% in revision THAs, despite alleged surgical technique and implant design improvements, dislocation continues to be a matter of concern, with important functional and financial consequences. As an alternative to standard sockets, a French surgeon from Saint Etienne, Gilles Bousquet, in association with engineer André Rambert, introduced in 1976 unconstrained tripolar cups, so-called dual mobility sockets or mobile bearing hips . The concept of dual mobility, by increasing the effective femoral head diameter, has been proposed in the prevention of dislocation in both primary and revision THAs as well as in the treatment of recurrent dislocation. Since this early period, a number of cemented and cementless designs have emerged in Europe, some of which have been recently approved by the US Food and Drug Administration. The dual mobility socket has gained popularity in Europe since the early 2000s, currently representing one-third of the sockets implanted in France, with some surgeons using dual mobility for the vast majority of their patients undergoing primary THA even in the absence of known risk factors for dislocation.

This chapter will review the dual mobility concept; detail intraprosthetic dislocation, which is a specific complication; provide the reported results in both primary and revision THAs; and propose new directions for such implants.