Corrosion Expert Comments on Metallosis From Metal-on-Metal Hip Implant

Corrosion Expert WitnessThis case involves a patient from Mississippi who suffered from metallosis after receiving a hip implant. Several months after receiving a metal-on-metal hip implant manufactured by a leading medical device manufacturer, the patient began to suffer from a range of abnormal symptoms, including swelling, pain, a loosening of the implant, and cognitive dysfunction. It was discovered that the implant had corroded and degraded after being implanted into the patient due to friction between two metal surfaces on the implant.

Question(s) For Expert Witness

  • 1. Please explain why you're qualified to serve as an expert reviewer of this matter, specifically, your knowledge of tribology.
  • 2. Have you previously designed hip implants?

Expert Witness Response E-007816

Expert-ID: E-007816

What happened in this situation is called fretting corrosion, which destroys passive film and increases the corrosion rate causing the collection of debris. This sort of damage presents under load with repeated surface to surface motion. This motion causes material transfer at the surfaces that are in contact with one another, which can lead to oxidation and further corrosion. This degenerative process will increase the rate at which damage occurs, as well as the rate at which material can be transferred from the surface into the surrounding area. I helped to develop the modern theory on this as it relates to medical devices.


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