The self-locking Balgrist hip socket for cementless fixation: biomechanical principles and clinical results.

The Balgrist hip socket, initially made entirely of HDPE (high molecular weight polyethylene), now made of outer titanium alloy shell that faces the bone of the acetabulum has been in clinical use for 10 years. The purpose of this presentation is to illustrate the biomechanical principles that have governed this unique design and to present the clinical results that we have obtained until the end of 1991 with 717 implants. From 1982 to 1987 Balgrist HDPE sockets had been implanted for 346 hips, from 1984 to 1991 Balgrist Titanium alloy sockets have been implanted for 371 hips. The number of revision are 55 of 717 hips. 48 hips out of 55 were with Balgrist HDPE sockets. On the contrary, only 7 hips were with Balgrist titanium socket. The greatest benefit of Balgrist Titanium socket is the excellent mechanical lock with subchondral bone of the acetabulum.