Corrosion at the Head-Neck Junction: Why Is This Happening Now?

While mechanically-assisted crevice corrosion (MACC) at the head/neck junction of modular total hip arthroplasty (THA) femoral components was first described over two decades ago, it is only within the last few years that investigators have observed that adverse local tissue reactions (ALTRs) associated with MACC are an increasingly prevalent mode of failure of contemporary THAs. As yet, the incidence, etiology and pathogenesis of MACC-associated ALTR are not well understood. In this review, possible implant-, patient-, and surgeon-related factors are considered in the context of a small but growing body of evidence from laboratory simulations, implant and tissue retrieval studies and clinical case series. It is likely that MACC-associated ALTR is a multifactorial process and that ongoing research will lead to multiple strategies that will facilitate early diagnosis and ultimately prevention of the adverse clinical sequelae of this phenomenon.