Acetabular cup for polyethylene or ceramic liners Maximum security concept The hard-on-hard friction couples require a thorough conception of the shell. The conical surface on which will be seated the liner, needs to be as smooth as possible and free of any peak stress inductors. The fitting of the liner into the shell need to be secured by a proper "taper entry" design, and the cup should prevent from micro-deformation under impaction stress, yet optimizing the head to cup diameter ratio. On the contrary, the polyethylene liner will not be securely fixed based on a tapered connection alone. The polyethylene stability against rotation and pull-out stresses, need to be completed with mechanical devices such as ring locks and anti-rotational fins. In addition the liner needs to be protected from cold-flow deformation, and thus be perfectly adapted to the concavity of the cup. Captiv OTM succeeds in combining both opposite requirements. Design rationale primary hip arthroplasty elliptic acetabular cup moderately crosslinked PEXEL polyethylene or pure alumina or composite ceramic (Delta) choice of friction couple mechanical devices for polyethylene locking dissociated from the taper connection initial equatorial over-sizing increased by macrostructured design and 8 pairs of anchoring teeth hydroxyapatite coating 155 µm factory sealed screw holes to prevent wear particules migration apex hole plug included in packaging