Separation of the apex hole eliminator screw in four failed hybrid total hip arthroplasties.

Advancement or separation of the apex hole eliminator screw in uncemented Duraloc 100 cups (DePuy, Warsaw, Indiana, USA) has been recently reported as a radiographic finding without clinical effects. We report 4 patients with a separation of the apex hole eliminator screw in Duraloc 300 uncemented cups and aseptic failures of a hybrid total hip arthroplasty (acetabular osteolysis and femoral stem loosening). Revision surgery was performed when disabling pain and radiographic signs of loose components were present. Although difficult to determine, a relationship between the screw migration and the failure could have existed in these cases. Migration of the screw might not only be interpreted as a radiographic, clinically irrelevant finding. Its presence should alert the orthopaedic surgeon that the prosthesis is exposed to high intraarticular fluid pressures.