The Trident constrained acetabular (bipolar) component for recurrent dislocation. New mode of liner failure.

Recurrent dislocation after reconstructive hip surgery remains a challenging problem to treat. Constrained acetabular components can provide an excellent solution, in selected patients. Failure of constrained components may still occur despite excellent component implantation and occurs at the liner-shell and shell-bone interfaces usually as a result of trauma or aseptic loosening. We describe the failure of a Trident bipolar acetabular component at its bipolar/insert interface, a previously unreported mode of failure.