The trapezoimetacarpal prosthesis, from single to dual mobility

The principle of dual mobility has been developed for the total hip replacement. Hip prostheses (THP) suffer from instability as well as bone fixation and wear problems, they were developed in the last century, two concepts emerged in the 1960s: The Charnley prosthesis, with a thick poly-ethylene (PE) cup and a small head size to reduce wear shows a high rate of dislocation, Mac Kee's prosthesis with a head of size closer to anatomy shows fewer dislocations but problems of faster wear. The size of the prosthetic head is decisive for the risk of dislocation. In search of a compromise, Professor G. Bousquet in Saint Etienne with the help of C. Magnin, an engineer from the SERF company, invented in 1975 the concept of double mobility, consisting of a metal cup, a PE insert that is mobile free in this cup and mobile on the prosthetic head. After years of development, the concept proved to be a success, particularly with regard to the risk of dislocation, and was widely disseminated from the 2000s onwards. Trapezoimetacarpal prostheses have gradually adopted a design close to those of the THPs. Simple mobility, they suffered from the same type of complications and from 2012 onwards they benefit from dual mobility. With this evolution, the complication rate and in particular the risk of dislocation is significantly reduced. The combination of two French inventions: the trapezoimetacarpal prosthesis and dual mobility is proving to be a great success.