Monday, June 4, 2012

Smith and Nephew Withdraws Metal Hip Liner

Business Week reports that London based medical device company Smith & Nephew PLC is withdrawing a metal liner used in its R3 Acetabular Metal-on-Metal hip replacement system. The company stated that it pulled the device because it was "not satisfied with the clinical results" of the liner, and some patients needed an additional surgery to have the liner removed. The company reports that this device is an optional metal liner for its R3 Acetabular System hip device and current patients needing surgery will use a different plastic liner. Smith & Nephew claims that the pulling of this device is a precautionary move. These metal liners were developed with the hope of producing longer lasting results than the traditional plastic liner, but unfortunately, did not live up to expected standards.
The primary reason for recall is that the device produced a higher than desired level of patient problems or a higher than expected failure rate. Patients using this Smith & Nephew metal liner experience problems including infections, fractures and dislocations. There have been no reported instances of this particular device causing  "metallosis" or the build up of other metallic debris in the body, as reported in problems with other Metal-on-Metal hip implants. This liner was introduced in 2009 and 7,700 of the devices have been implanted in patients.
This is not the first time metal-on-metal hip implants have been subject to scrutiny. Metal-on-Metal hip implants generally have been linked to high rates of revision surgery and systemic complications, apparently because of component erosion and leaching of metal ions both locally and into blood circulation. In 2010, DePuy Companies issued a recall of its ASR metal-on-metal hip due to early failure rates. Problems surrounding the ASR device include increased blood levels of chromium and cobalt ions and possible necrosis, intense hip, thigh, and groin pain, a loss in overall mobility, and component misalignment and loosening.

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