Metal Hip Implant Suffers Catastrophic Failure

This case takes place in Utah and involves the sudden and dramatic failure of a Biomet hip prosthesis while the Plaintiff was exercising. Months before the incident in question, the Plaintiff underwent a total DePuy Pinnacle ceramic left hip replacement, at which time the device, which was manufactured by a leading orthopedic implant producer, was installed. She completed a course of physical therapy following the procedure, and was instructed that she could return to her normal level of activity. The Plaintiff, who was an avid yoga practitioner, and she had been cleared to participate in yoga classes by her doctor before the date of the incident in question. During her yoga class, the Plaintiff performed a move that she had done countless times before when she suddenly heard a popping sound and felt extreme pain. She presented to the hospital, where it was discovered that the neck of her hip implant had failed catastrophically. Months after the incident, the manufacturer had a Pinnacle hip recall. An expert witness on biomaterials was sought to opine on the issue.

Question(s) For Expert Witness

1. Please discuss your background working with artificial hip implants.

2. Have you ever done research on these devices?

3. Have you previously designed such devices?

Expert Witness Response E-007593

My research focuses on tribology, which covers friction, wear, and corrosion of orthopedic implants. I work at the cutting edge of designing new devices, and my work in orthopedics is currently funded by the National Science Foundation and the National Institutes of Health. I also have experience working as an expert witness on several cases related to failure of hip implants. I have worked on a case with simple and multi-modular designs, as is the case with the device in question here, and I am intimately familiar with the failure modes of these devices and interfaces. The facts of this case seem to indicate that wear was the cause of failure here, which is indeed a significant problem in modular devices. In particular "fretting wear", caused by reciprocating micro-motion, is of primary concern in these types of devices. The case description mentions "fracture" of the head, which may or may not be the result of wear, however it is likely that wear was at the heart of the issue here. Currently, my research is on designing orthopedic implants. My background is "mechanical design", and I am the Chair of the Design and Manufacturing division within the Department of Mechanical Engineering at a major university. I am one of the few people who do rigorous academic research on design of orthopedic hip implants, as opposed to clinical trial-error based "research".