Early Intraprosthetic Dislocation in a Modern Dual Mobility Cup: a Case Report

Intraprosthetic dislocation (IPD) is a unique complication of dual mobility cup (DMC), and it is defined as the disassembly of the femoral head from a polyethylene (PE) liner. Current literature divides IPD into two main categories: the ones characterized by the wear of the polyethylene as the final common pathway, occurring approximately 10 years after the index surgery and the iatrogenically-induced. Different wear modes have been described, and thanks to the adoption of the new tribological solutions, IPD has notably reduced. Nonetheless, this case report describes an early IPD characterized by polyethylene wear occurring in DMC of modern design, focusing on the possible strengths and drawbacks of modern bearings. It outlines the importance of recognizing IPD, the surgical revision technique adopted, and it evidences the need to identify the cause of IPD, considering the tribological aspect of the implant used in order to avoid the recurrence of the same complication.