Polyethylene liner dissociation in a DePuy pinnacle cup with a manufacturer analysis of the failed component.

A 74-year-old patient presented to the emergency department with acute atraumatic hip pain 9 years after her primary left total hip arthroplasty (THA). Plain radiographic imaging demonstrated lateralisation of the femoral head within the acetabular shell-indicating an issue with the polyethylene liner. The patient required revision of the acetabular component and the femoral head, as well as a new polyethylene liner. A detailed analysis of the components removed was performed by DePuy Synthes Engineering. Between 2009 and 2020, 8 publications have documented 52 cases of liner dissociation with the Pinnacle acetabular component and Marathon polyethylene liner. Various theories have been proposed in the literature as all of these components appear to fail in the same way, with shearing of the locking tabs in the polyethylene liner. In spite of a manufacturer analysis of the components, no root cause was identified as to why the polyethylene liner failed.