[Cement-free hip cups. Current status]

Important criteria for stable cup fixation are the type of anchor system and stabilizers,cup form and the material and surface structure. Different fixation systems are manifest in pressfit and threaded cups. Pressfit implants are oversized and lead to equatorial jamming. For additional fixation, and to improve stability, screws, pegs, rings, fins, spikes or hollow cylinders are used. In threaded cups, thread geometry is decisive for the cup's performance during the screw-in process and positioning. The hemispheric shape of the cups requires less bone resection and the position of the implant can be arbitrarily selected. The conical shape guarantees high tilting stability. Most implants are made of pure titanium or a titanium-aluminum alloy. A rough surface area - produced by corundum blasting, titanium-plasma spray, titanium balls, nets or other grid designs - is essential for osseointegration. The results of second generation pressfit and threaded cups with 10 year survival rates of 93-100% are persuasive.