J&J Expert Grilled on Calculation of Hip Placement Device

A witness for Johnson & Johnson miscalculated in testifying that a Montana man’s metal hip device failed because of the angle at which it was implanted, the man’s lawyer said in cross-examination.

Avram Edidin testified at a trial about a lawsuit by Loren Kransky that claims J&J defectively designed his ASR hip device and failed to warn of risks. Kranky’s lawsuit in Los Angeles is the first of 10,000 to go to trial. Analysts say J&J may pay billions of dollars to resolve cases over the devices, which the company recalled in August 2010.

Edidin, a professor at Drexel University’s School of Biomedical Engineering in Philadelphia, described the metal cup placed in a hip, and the metal ball placed atop a femur that rotates in those cups. The ideal angle of cup placement, he said, is 45 degrees. Kransky’s surgeon placed his cup at an angle of 63 to 65 degrees, causing the metal to wear, he said.

Kransky’s cup “was implanted at a high inclination angle,” Edidin told state court jurors. Higher angles are “associated with higher wear. If you put any component in that position,” he said, “you are going to see the kind of wear that you see on Mr. Kransky’s component.”

On cross-examination, Kransky lawyer Michael Kelly showed the jury the X-ray on which Edidin had drawn the angle. Kelly superimposed a protractor on the image and showed the actual angle was 57.5 degrees, not the 63 to 65 degrees calculated by Edidin.


“You are aware you can find a protractor at Walgreens, are you not?” Kelly asked.

“I am,” said Edidin, who testified as an expert.

He offered no explanation of the discrepancy. On his redirect testimony after a lunch break, Edidin said he reviewed several images of Kransky’s ASR before the revision surgery, re-measured the angle and determined it was 63 degrees. Kelly didn’t ask about the matter again.

J&J, the world’s largest seller of health-care products, recalled the hips when their failure rate hit 12 percent in the U.K. Since then, the failure rate hit 40 percent in Australia. J&J, based in New Brunswick, New Jersey, denies that it defectively designed the device or failed to warn of the risks.

Edidin, who has spent much of the past 13 years working as an expert on the spine, told the jury that he analyzed the design file of the ASR hip and found no flaws. He said J&J’s DePuy unit had done “an extraordinary amount” of testing before selling the device in the U.S. in 2005.

Steep Angle

Edidin told the jury that his analysis showed that because of the steep angle of implantation, Kransky’s ASR was “sub-luxing,” a phenomenon where the metal ball joint slightly dislocated when Kransky walked.

Kransky’s hip was implanted in December 2007 and removed, or revised, in February 2012.

Edidin conceded that none of the several surgeons or other doctors who examined Kransky prior to his revision ever determined that such dislocations were occurring.

Kelly showed him a DePuy document from the Health Hazard/Risk Evaluation Executive Review Board at the time of the recall. Under “market action strategy” were three possible explanations for the recall. The company checked Class A for “defective product that would affect product performance and/or could cause health problems.”

Among those who signed the document was DePuy’s former president, David Floyd.

‘Know Better’

“Do you believe you know better than the president of the company?” Kelly asked.

“Based on the evidence I see, yes,” Edidin testified.

“Have you called them and asked them to put it back on the market?” Kelly asked.

“No,” Edidin said.

Kranksy’s lawyers have faulted DePuy for doing no clinical testing on the ASR before it was first sold. Asked about the dichotomy between his testimony that DePuy did extensive testing and the high revision rates, Edidin said, “The tests don’t speak to revision rate. There’s no test that predicts revision rates.”

He said that “clinical trials will do that.”

In 2009, DePuy finally did some testing at implantation angles other than 45 degrees. Tests at 55 degrees showed from an increase in wear ranging from fivefold to tenfold, while the increase in wear at 60 degree ranged from nine-fold to 17-fold.

The case is Kransky v. DePuy, BC456086, California Superior Court, Los Angeles County (Los Angeles).

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