Primary Differences between the DePuy ASR and the DePuy Pinnacle Hip Implant

Like many of the metal-on-metal hip implant systems, the DePuy ASR and the DePuy Pinnacle have had their share of problems. The Pinnacle gained FDA approval in 2000, and has not been recalled despite adverse reports of failure and metal toxicity. The ASR was approved in 2005 and spent only five years on the market prior to being recalled in August of 2010.

The Pinnacle was the predecessor for the ASR’s 510(k) approval by the FDA, and was intended to provide increased mobility and reduce pain in those with damaged hip joints. Both the Pinnacle and the ASR are considered monoblock designs although the ASR is a hybrid monoblock. This means that, unlike modular hip systems such as the Stryker Rejuvenate, monoblock implants are designed as a single ball and cup which is then fitted onto the top of the stem. The Pinnacle additionally implements a separate plastic or metal liner placed on top of the femoral head.

Monoblock acetabular components such as the ASR do not use screws, rather are pushed into the hip socket while the Pinnacle is fastened to the bone using screws. The idea behind the ASR’s external fixation design is to allow the femur bone to grow into the device through its porous coating. This is likely the reason many ASR cups have loosened and failed. The ASR’s construction machines the liner into the inside of the cup while the Pinnacle system allows the surgeon the choice of using a metal or plastic liner. Some studies show that the built-in-liner has less metal debris build up because there are fewer moving parts. The metal liner used in the Pinnacle is called the Ultamet, however the FDA never approved the Pinnacle hip system to be used with a metal liner.

In 2004, after receiving numerous complaints about the Pinnacle hip implant system, DePuy shortened the taper and added grooves which would allow surgeons to choose between a ceramic or metal femoral head. Unfortunately, those changes, along with a larger femoral head only resulted in higher rates of failure due to the increased metal-on-metal wear. Patients who have experienced severe pain, inflammation or failure of the Pinnacle or ASR or any type of cobalt andchromium toxicity problems will likely undergo revision surgery. The Pinnacle revision surgery is relatively simple in that the metal liner is simply replaced with a plastic liner. The ASR revision surgery requires replacement of the metal acetabular cup with a ceramic or plastic cup. Unless the bones have grown into the cup, the surgery, like the Pinnacle revision surgery, is relatively straightforward. Should the bones have grown into the ASR’s acetabular cup, the surgeon will be required to grind the bone away from the cup in order to remove it, making the surgery more complex and potentially dangerous.

Both the Pinnacle and the ASR have suffered extremely high failure rates—at least 12 percent of recipients were required to undergo revision surgery within five years. While the ASR and the Pinnacle have differences in design, they both have many of the same problems. If you or a loved one has undergone hip replacement surgery with an ASR or Pinnacle it is important to have your doctor run tests to determine whether you have higher-than-normal cobalt and chromium levels. If you are having undue pain you will likely have to undergo revision surgery and should contact an attorney to protect your future and ensure you are compensated for your damages.