The main distinction between the two is that the ASR cup is made up of one solid piece of metal and the Pinnacle is made up of a cup and liner. The Pinnacle cups and liners are available in different types of materials, which allow for three different combinations:
The ASR’s metal-on-metal design is what sparked the injuries that lead DePuy to recall the device, as patients were experiencing pain and immobility when the femoral head could not move freely through the cup. The ASR’s cup was sub-hemispheric and it is theorized that it was too shallow for the head and thus the system would edge-load, causing the ball to hit the edge of the cup and pieces of metal to flake off.
The Pinnacle’s cup, on the other hand, was designed as a full hemisphere, giving it greater depth and allowing the femoral head to move more accurately within the socket.
Another major difference is that there is no way to visually determine if the ASR socket is completely seated in the pelvis, since it lacks any holes in the device. The Pinnacle includes a dome hole that allows surgeons to see how well it fits. The fitting is also facilitated by screws that allow the device to be permanently attached to the pelvic bone. The ASR did not require screws, which gave surgeons no way to fix the device to the body; the success of the design depended on the bone growing around and into the device.
As a result of DePuy’s poor design for the ASR, nearly one in every eight ASR hip replacement patient will experience severe pain, immobility and the need for a second surgery, which is why the device was recalled in August 2010. There are also reports of permanent disability, even after the second hip replacement surgery is performed.
If you are a DePuy ASR hip replacement patient who is facing a revision surgery or has questions about the DePuy ASR hip recall, contact Zoll, Kranz and Borgess toll-free at 888.841.9623 or via email at Michelle@ToledoLaw.com.
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ZOLL, KRANZ & BORGESS, LLC is an advocate for pharmaceutical drug/device safety and a recognized leader in nationwide litigation involving defective medical drugs and devices, as well as other types of Multidistrict (“MDL”) & Class Action Litigation.