Dual mobility acetabular cup for total hip arthroplasty: use with caution.

INTRODUCTION: Dual-mobility cups were introduced to reduce the incidence of dislocation after total hip arthroplasty (THA). The biomechanics of dual-mobility cups allow for greater range of motion, jump distance and better stability when compared to conventional cups in THA. These cups can be very beneficial in THA particularly when the hip instability is a concern such as elderly patients, obese, hip fracture patients, those with neuromuscular diseases, or patients undergoing revision THA for instability. Areas covered: An extensive search is conducted in PubMed and Google scholar to find past five years publications relevant to dual-mobility cups in THA. 225 articles were found which many of those were excluded because of: written in other languages, nearly same cohort in different journals, unavailable full text, and were not covering main fields of this article. We categorized the articles to four different aspects of the biomechanics, outcomes in primary, revision, and after hip fracture THA. Expert commentary: While the important role of the dual-mobility in addressing recurrent instability and reduction of instability in high risk patients undergoing primary THA has been demonstrated, the concern regarding the release of metal ion release, particularly in the younger and active patients, and prosthetic malfunction are worrisome.