Toxic woes after faulty hip implant

Photo above: Mrs Tan holding up the X-ray showing her husband's faulty hip implant. He had to get the implant removed and replaced but by then, he had already suffered metal poisoning.

SINGAPORE - More than 100 people here have been implanted with a faulty DePuy hip, which was voluntarily recalled in 2010 following numerous reports of early failure.

And at least seven people here have now undergone revision surgery, paid for by DePuy, a subsidiary of pharmaceutical giant Johnson & Johnson (J&J).

Aside from the hip wearing off much faster than expected, doctors have also warned of the faulty hip causing cobalt or chromium poisoning.

About 93,000 people worldwide have had this hip implanted since 2003. In the United States, irate patients have filed more than 8,000 lawsuits against DePuy.

After thousands of reports of early failure by March 2010, DePuy decided in August that year to stop what it calls "articular surface replacement" (ASR) implants and to replace faulty ones.

In Singapore, it informed the Health Sciences Authority (HSA), hospitals and doctors, and set up a helpline. In addition, it offered to pay for replacing the hip and out-of-pocket expenses related to the surgery.

A J&J spokesman said 115 people here were implanted with this hip between 2006 and 2010.

She told The Straits Times: "The company does not have access to data on all patients who have received an DePuy ASR hip implant and has therefore provided recall information to surgeons so patients can be notified."

One 63-year-old patient here who almost slipped through the recall process suffered high levels of metal toxicity in his blood.

Mr Tan, who does not want his full name used, had a DePuy hip transplant in 2007 but was not told by his surgeon about the recall. Although both DePuy and the HSA informed doctors in 2010 of the recall and the possible adverse effects of the metal-on-metal hip, Mr Tan said his surgeon did not inform him of this development.

It was by chance that he saw a news report early this year about the recall.

By then, he had experienced about three years of pain in his transplanted right hip. One of the first signs, about a year after the transplant, was a grinding noise whenever he moved his right leg.

His wife, Maureen, called his orthopaedic surgeon, who is in private practice. She said she was assured by the clinic staff that the DePuy hip had not been used. She added that it was only when she insisted on finding out the brand of hip used that they finally told her it was indeed a DePuy.

A blood test found that Mr Tan had extremely high levels of metal - both chromium and cobalt - in his blood. The level of cobalt was 18 times the safe level.

The original surgeon told him he had to remove the hip immediately. The longer the delay, the greater the danger, since the metal would continue shedding and poisoning his blood.

The metal debris, according to the HSA warning to doctors, "may cause pain and swelling around the joint and could damage some of the muscles, bones and nerves around the hip".

The Tans decided to consult another surgeon, who agreed that speed was essential.

In changing the hip, the second surgeon had to remove 44g of muscle from around Mr Tan's right hip joint. The muscle had turned grey from the high level of metal filings shed by the implant. As a result, there was not enough muscle to hold the new hip properly, and within the first two weeks, it popped out three times.

"He was screaming in pain, his face all white," recalled his wife. "I could see the ball bulging out from the groin. It was horrendous. I used both my hands and kept pushing down on it till it popped back in." His case might not be unique, because the worldwide failure rate of this hip implant is above 12 per cent.

J&J paid for Mr Tan's replacement surgery, pre- and post-surgery checks, as well as the cost of the Tans forgoing four trips as a result of the unplanned surgery. The total came to about $70,000.

salma@sph.com.sg


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