A group of patients who all allegedly suffered complications after the use of Zimmer products in their total hip arthroplasty procedures decided to file a class action against the device manufacturer. Each patient had suffered Metallosis, or the buildup of metal particles in soft tissue, and claimed it was due to the corrosion of the head-neck taper in Zimmer’s products. They each required revision surgery, and the case sought an expert who could speak on the design of Zimmer devices and opine on the alleged corrosion of the head-neck taper.
Question(s) For Expert Witness
- 1. Please discuss your background working with artificial hip implants.
- 2. Have you ever done research on the head-neck taper as it pertains to metallosis?
Expert Witness Response E-007593
My research group at my university works at the leading-edge of artificial hip implant design and analysis. I have done research on the head-neck taper as it pertains to metallosis The critical aspect of the head-neck taper is failure due to fretting corrosion, which is a combination of fretting wear and a corrosive medium, such as joint fluid. Fretting corrosion generates wear particles that may get absorbed into soft tissue and the blood flow, causing inflammation, high Carbon Monoxide and or Creatinine levels in case of a metal femoral head, and ultimately tissue necrosis. This failure mode stems from the modular design of present day hip implants, which allows micromotion to occur between the different components. I understand the application of artificial hip implants, and the science/engineering that is involved. In addition, I have the track-record through my tenure-track academic position and publication and funding record to be considered an expert in this field.
Expert Witness Response E-007633
I am an ex-FDA medical device reviewer and I have worked on multiple hip implant cases previously as a Forensic Expert. I am very familiar with metallosis or the inflammation reaction to metallic particles released during wear of the hip implants.The previous hip implant cases I have worked on as a Forensic Expert involved evaluation of the design and failure of the implant or medical device.