Concept and material properties of a cementless hip prosthesis system with Al2O3 ceramic ball heads and wrought Ti-6Al-4V stems.

A cementless total hip system of modular design is presented. The design of the stem provides for a firm seating on the cortical bone over a large area. Therefore primarily stable fixation is accomplished. The stem in seven different sizes is made of hot forged Ti-6Al-4V Protasul-64 WF alloy of high corrosion fatigue strength. The Biolox ceramic ball with three different neck lengths is connected to the high strength stem by means of a special selflocking conical spigot with a structured surface. The ceramic ball is combined with a polyethylene screw socket in four different sizes, designed by Endler and anchored in the acetabulum without acrylic cement. This hip prosthesis system has proved itself in clinical application since 1979.