Intra-prosthetic dislocation of dual-mobility cups after total hip arthroplasty: potential causes from a clinical and biomechanical perspective

摘要

Introduction Recurrent dislocation of total hip arthroplasty is a frequent indication for revision surgery. Hip joint stability depends on implant design, cup position and crucially on femoral head diameter. Due to an effective ultra-large diameter femoral head, dual-mobility cups are considered an attractive solution to prevent dislocation in unstable conditions. Although patients obviously benefit for many years in terms of mobility and pain, an increase of intra-prosthetic dislocation reports using dual-mobility cups has been recently observed. However, the failure mechanism of this implant-specific complication, which is characterized by the loss of the positive-locking between the femoral head and the mobile liner, is not yet completely understood.