Today, I want to talk about testimony that was received at trial from an expert witness that was put on by the plaintiffs. His name is Albert Bernstein and he is a bio-mechanical engineer. He has 30 years of experience designing and inventing prosthetic devices and surgical tools. He spoke about the process of developing medical devices and what a prudent manufacturer is supposed to do when they develop those devices. He testified that a prudent manufacturer will test the device in human beings before they release it to the public. Before the Pinnacle was released, it was not tested in individuals.
He also indicated that when a manufacturer discovers problems with the medical device that they have an obligation to disclose those problems to doctors as soon as they become aware of them. This is sort of a common sense opinion and I think most people agree. Now, he also went through the “end game memo” that has come up repeatedly in the case. This memo was drafted by DePuy executives and engineers back in the 90s before they designed metal-on-metal hips. The “end game memo” discusses the problems with metal on metal hips back in the 70s. The person who drafted this memo thought that DePuy focus on metal-on-plastic hips and making them better instead of going back to a metal-on-metal design. He discussed language in the memo concerning metal and plastic particles.
He states even though plastic particles can cause osteolysis (destruction of bone tissue), the problem with metal particles is different, and that metal particles can cause more problems in the soft tissue than plastic particles. He described that when you have wear on a prosthetic hip, specifically a metal-on-plastic hip, there will be a certain volume of plastic that will wear on the device and enter the hip joint. It is a very small amount but there is a volume that is measurable. However, when you take the same volume of metal that enters the hip joint you end up with 1.23x10^15 more particles with metal than plastic, an enormous number. This means that when you have plastic wear you will have a few, large particles but when you have metal wear you will have many more, smaller particles. He gave an example with two jars in the courtroom: one was filled with marbles and the other with sand. This demonstrated the difference between plastic wear and metal wear. He also indicated that metal wear is more unpredictable, that DePuy’s testing showed that it was unpredictable, and that the metal particles cause more problems in the hip joint than the plastic particles because the metal particles can enter cells and destroy them.
He also mentioned the defense’s position that back when they were developing metal-on-metal hips there was a debate in the orthopedic community regarding how to eliminate the problem of plastic wear and osteolysis. This is supposedly the reason why DePuy went with metal-on-metal. Dr. Bernstein refuted this contention. He said at the time the Pinnacle was released there was no debate in the orthopedic community. He states the plastic they were using at the time were advanced and they had essentially solved the problem of osteolysis. He pointed to various marketing brochures released by DePuy promoting their metal-on-plastic hips. In these marketing brochures, which were released in 2000, DePuy announced they solved the problem of osteolysis. Dr. Bernstein’s opinion was that the problem of plastic wear was essentially solved but DePuy decided to go with metal-on-metal.
He also discussed specific patients. Defense took the position that the reason two of the patients’ hips had failed was because the cups were put in at an extreme angle. Dr. Bernstein explained that when you are a surgeon and you are putting a prosthetic hip in that you want to put the cup in at the same angle that the natural hip socket was before the surgery. The reason you want to do this is that the muscles, tendons and tissues that surround the hip are designed to deal with a hip at a certain angle. He talked about how 45 degrees would be ideal but not everyone’s natural hip joint is at 45 degrees. There is a variance in the population and as a result hip manufacturers need to design hips that are variable and can match the patients. If they can’t, they need to tell the doctors. He looked at two of the patients’ x-rays and the angles the cups were put in, and he said they were put in at the appropriate angles for that patient. So, it may not have been 45 degrees but if they put it in at 45 degrees it may not have worked. His opinion was that the hips were put in at the right angles, and DePuy, with respect to the metal-on-metal hips, were negligent with the design of the hip and never should have gone with metal-on-metal because that caused the patients’ problems not the angles the cup was put in.
There will be more testimony. The defense will cross examine Dr. Bernstein. We will provide another update when we get this testimony.