Long-term wear of dual mobility total hip replacement cups: explant study

Purpose Dual mobility THA implantations are increasing. THA survival of more than 15 years is considered long-term survival based on the Charnley prosthesis, which has a median wear rate of 39 to 98 mm(3)/year. What is the median wear rate of dual mobility THA cups and its repartition on the liner volume? What are the factors influencing dual mobility wear? Methods Thirty-five explants were analysed. The liners were entirely mapped with a fully automatic stripe light scanner that uses green LED light. Results The liners had a median wear rate of 38 mm(3)/year. The distribution of the wear between the two bearings varied greatly. No factor was found influencing wear volumes. Conclusions The median annual wear of dual mobility liners is at least as low as the wear of cemented polyethylene liners and lower than equivalent cementless liners. The two articulations of the dual mobility THA do not cause more wear.