When head and mobile cotyle have different centers of rotation they tend to spontaneously align themselves under load along the longitudinal axis of the neck, which coincides with the line of action of the force weight.
The result is that in a bicentric bipolar the mobile cup will never slip out of line and will always stay well centered with respect to the line of load. This means less risk of dislocation, reduced distribution of load on the natural cotyle, less likelihood of seizure and, last but not least, enhanced radiography acceptability.
Minimum wear on natural cotyle
The tapered profile of the metal edge of the cup stops it coming into contact with the cotyle’s articular cartilage, even in extreme positions. The “grating” effect is thus avoided and the cotyle wear typical of endo-prosthesis is minimized.
Reduced load distribution on the natural cotyle
Less likelihood of seizure
Enhanced radiography acceptability
AISI 316L remelted stainless steel to ISO 5832-1 standard
High nitrogen content stainless steel to ISO 5832-9 standard
Chromium cobalt molybdenum alloy to ASTM F75-92 standard
Ultra high molecular weight polyethylene (UHMWPE) “Super Pressed” IMP 2000-4 Medical Grade to ISO 5834-2 and BS 7253 part V 1990 standards