Abstract
Gross trunnion failure (GTF) leading to dissociation at the femoral head-trunnion interface is an uncommon complication after total hip arthroplasty (THA). The incidence of this complication is currently unknown due to the limited number of reported cases but it is significantly more common in the context of a recalled femoral head. This report details the case of a gross trunnion failure and secondary polyethylene failure of a non-recalled metal-on-polyethylene primary THA from a taper type previously reported to be associated with an increased prevalence of mechanically assisted crevice corrosion (MACC). This case describes a 77-year-old man who was 10 years status post right THA presenting with acute-onset right hip pain after trying to rise from a seated position. Radiographs showed that the right femoral head was dissociated from the femoral component. At the time of surgical revision, there was extensive dark metallic debris in the hip joint. A revision THA was performed using a modular revision system. Clinicians must be aware that MACC can eventually lead to GTF, which can result in dissociation at the femoral head-trunnion interface in metal-on-polyethylene primary THA. Further research is needed to determine patient and implant factors that make patients susceptible to MACC/GTF so that adequate screening and patient counseling can be performed.