Differences Between the Pinnacle and the ASR Hip Implant: The Metal On Metal Hip eBook Part 14

While both the Pinnacle and the ASR have caused significant amounts of harm to patients who were implanted with the devices, there are noteworthy differences between the two models including:

·         The ASR gained FDA approval five years after the Pinnacle’s approval in 2000

·         The ASR was recalled in August, 2010; the Pinnacle has not been recalled

·         While the Pinnacle uses a separate liner, either plastic or metal, the liner was not included in FDA approval; the ASR liner is machined inside the cup

·         After numerous complaints were received regarding the Pinnacle, Depuy shortened the taper and added grooves to the Pinnacle in 2004

·         The Pinnacle is attached with screws, while the ASR implements a porous coating through which the femur bone will grow into and attach

·         The 2004 changes—along with a larger head diameter—increased the failure rates because of additional metal-on-metal wear

·         The ASR revision surgery requires replacement of the metal acetabular cup with a ceramic or plastic cup

·         The Pinnacle revision surgery generally requires only replacing the metal liner with a plastic liner

·         Both the Pinnacle and the ASR failure rates are as high as 12% after five years

·         Over 90,000 ASR hips were sold during their first five years on the market

·         The Pinnacle device incorporates a monoblock design while the ASR is a hybrid monoblock

·         The Pinnacle cup has an outer shell while the ASR cup is made of a solid section of cobalt and chromium

·         The ASR cup is thinner than the Pinnacle which has led to misshapen cups and excessive wear

It is theorized that the thinner ASR cup is also too shallow for the head which causes edge-loading when the ball hits the edge of the cup. Doctors who have done their own tracking of patients with DePuy Pinnacle hip implants believe an additional ten percent of these devices will fail in the next 1-2 years in addition to the devices which have already failed. A study of 1000 patients in the UK showed the Pinnacle had a failure rate of 8% at five years and 16% at 6.5 years. The lower failure rate of the Pinnacle—as opposed to the ASR—is believed to be largely due to the smaller head size.