Firm knew of dangers of flawed replacement hips: probe

PARIS — Hundreds of thousands of people have been fitted with replacement hips whose flawed design may be exposing them to toxic metal, according to a probe by the BBC and the British Medical Journal unveiled Tuesday.

The risk comes from “metal on metal” joints that grind against each other, with the risk of leaking cobalt and chromium into the body, it said.

The probe said Depuy Orthopaedics, a subsidiary of the U. S. medical conglomerate Johnson & Johnson, continued to sell the hips even after it knew of the risk.

The risk of leakage from cobaltchrome implants has been known since 1975, when doctors discovered that local tissue reacts to ions, or charged atoms, from these metals, the investigators said.

Lab research has also linked cobalt to a heart condition called cardiomyopathy and identified chromium ions as a probable carcinogen, the journal said.

The BMJ and the BBC news program Newsnight said they had seen a Depuy internal memo from 2005.

“In addition to inducing potential changes in immune function, there has been concern for some time that wear debris may be carcinogenic,” the memo reportedly said.

Despite this, “Depuy’s marketing of metal- on- metal hips continued unabated, with promotional material failing to reflect internal company concerns,” the BMJ- BBC probe charged.

There was no immediate response from Depuy.

The investigation heaped blame on U. S. and European health regulators for failing to respond to concerns or even requiring monitoring of patients who had received hips capable of producing toxic debris.

“Patients have been kept in the dark about their participation in what has effectively been a large uncontrolled experiment,” said BMJ investigations editor Deborah Cohen.