An Abnormal Liner Fracture about 4 Consecutive Cases

Abstract

The experience of Alumina ceramic liner fixed in a metallic shell is not new ; From 1983 to 1999 , 555 components of this type with a titanium screw in shell design were implanted . Recently a review of the first 117 cases with a mean follow up of 12 years were presented. No ceramic fracture were recorded. In 1989 a new press fit shell fixation system replaced the screw in design; This material was implanted from 1989 to 1997. The shape of the liner was an angle of 5°40’ , a liner in excess of 2 mm .A centraliser to insure the correct setting. The shell thickness was limited in order to allow the grid fixation One fracture of the rim (Shipping) was discovered during revision surgery performed elsewhere for acetabular loosening; This revision was performed 4 years after a trauma with fracture of the patella in a fore board trauma. No other fracture was recorded with this design (over more than 1500 implanted). Starting in 1997 a new press fit socket was introduced with a sand blasted surface covered with HA. To be able to retain the same liners , the thickness of the shell were increased resulting in a thin Alumina component for the small sizes (50 mm for a 32 mm head.) . In 1999 a slight modification of the design were made. Recessed liner of 1 mm , ancillary material with a system to insure as well polyethylene or alumina liner fixation. At the moment 5 fractures of this design were recorded (one coming from another institution).