Expert Witness in DePuy ASR Trial Says Metal Hip has Multiple Design Defects

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Expert Witness in DePuy ASR Trial Says Metal Hip has Multiple Design DefectsOverview: The DePuy ASR hip implant has multiple design defects that cause it to fail more than other hip replacements, according to an expert witness testimony this week in Los Angeles state court. Bloomberg reports that Dennis Bobyn, a McGill University professor testified yesterday on behalf of Loren Kransky in the first DePuy ASR lawsuit to go to trial.

  • Yesterday an expert witness testified that the DePuy ASR has multiple design defects that cause it to fail
  • Professor Dennis Bobyn also said he thought the risks of the metal-on-metal hip implant outweighed the benefits and that the ASR shed excessive amounts of cobalt and chromium ions
  • Loren Kransky’s lawsuit is the first of 10,000 to go to trial in Los Angeles state court

Product: DePuy ASR Hip Implant

Manufacturer: DePuy Orthopaedics/ Johnson & Johnson

Side Effects & Complications

  • High failure rate
  • Necrosis (tissue death)
  • Increased levels of cobalt and chromium ions
  • Pain at the implant, sometimes spreading to the groin and back
  • Osteolysis (bone loss)
  • Fluid collections/solid masses around the hip joint

DePuy ASR Design Defects

According to Bloomberg, Bobyn testified yesterday on behalf of Loren Kransky, whose DePuy ASR lawsuit is the first of 10,000 to go to trial. When asked whether he thought that the recalled hip implant had multiple design defects that, whether alone or together, caused a failure rate higher than other hip implants, Bobyn agreed. Bobyn also confirmed that, in his opinion, the risks of the ASR far outweighed any claimed benefits. He said that he thought that Kransky’s implant had defects that caused it to fail, shedding excessive amounts of chromium and cobalt.

According to Bobyn’s testimony, cup shape is at least part of the reason why the DePuy ASR hip implant is defective and can lead to injury. He said that the one-piece cup, which is less than half a circle and has thin walls, contributed to the defective nature of the device. “Because it has the geometry that it does, it is susceptible to changing shape as it is forced into a patient’s pelvis,” Bobyn stated. “If I have a larger object that has to go into a smaller hole, something has to move.”

DePuy ASR Background

Johnson & Johnson’s DePuy unit recalled the ASR hip implant in 2010. At the time, the company said that the implant failed in 13 percent of patients within five years. During the trial, Kransky’s attorneys have stated that an Australian national registry indicated a failure rate higher than 40 percent. Kransky’s lawsuit is one of 2,000 filed in California state court. Meanwhile, some 7,000 are pending in federal court in Ohio as part of the DePuy ASR multidistrict litigation.