Traditionally, artificial hip devices have had a ceramic component. In fact, some DePuy Pinnacle devices have either ceramic or poyethelyne liners. Recent concerns about hip devices, however, are focused on those that are metal-on-metal, meaning that the lining of the cup and the ball joint are both metal. In the case of the DePuy Pinnacle, the metal-on-metal device is sold as the Ultamet.
The problem with metal-on-metal devices is that metal debris can reportedly come loose, resulting in metals being absorbed by the patient's surrounding tissue and causing excess levels of chromium and cobalt in the patient's blood. Furthermore, patients may experience pain, inflammation and soft tissue damage in the area around the hip, making mobility difficult if not impossible.
Earlier this year, the US Food and Drug Administration (FDA), concerned about the potentially high failure rate of the hip replacement devices, ordered makers of the all-metal artificial hips to conduct studies of patients who received the implants to determine whether the implants are causing metallic debris.
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Unlike the Pinnacle, the DePuy ASR was recalled due to a high failure rate. At the time of the recall, estimates put the failure rate at between 12 and 15 percent within five years of implant. A report from the British Orthopaedic Association issued in March 2011, however, argued that the ASR failure rate could be as high as 50 percent within six years of implant.
Failure rates of the Pinnacle Ultamet have so far not been shown to be as high as those of the ASR.