Significant Defects in Metal-on-Metal Hip Implants
An investigation by the New Zealand Herald newspaper reveals significant defects in about half of the metal-on-metal (MoM) hip implants received by thousands of New Zealanders about a decade ago.
There is no official record of the injuries suffered by people who received the faulty hips because the recall and monitoring of the devices are done by medical companies and surgeons, not by the government health agency, the Herald reports.
In its investigation, the Weekend Herald found that about 2,500 of 5,000 metal hip devices implanted in New Zealanders were subject to safety notices, health warnings, and recalls. The most recent safety warning came in February of this year for a device manufactured by Smith & Nephew. Zimmer and Stryker hips have also been subject to warnings. Of the devices under question, about 200 caused medical problems serious enough that the hips needed to be removed and replaced.
In 2012, an article in the British Medical Journal questioned the regulatory systems and the high chromium and cobalt readings in the blood of patients who had metal-on-metal hips. An article in The Lancet that same year indicated a higher than normal revision rate for MoM hips. Hip-replacement surgeon Peter Devane, who advised Australia’s regulatory body, said the government had to play catch-up because the risk rating for MoM devices was upgraded after the devices became popular. Peak use occurred in 2007, about the same time the risk was upgraded, according to the Herald.
The Herald obtained documents from Medsafe, the government regulator for medical devices, showing that 2,551 devices were subject to safety or hazard notices from the agency. A Medsafe spokesman said the agency had no role in approving the devices but looked to overseas regulators for guidance. Metal-on-metal hips have been a problem worldwide and have been subject to warnings and recalls by a number of regulatory agencies. Recipients of the hips have suffered injuries including pain, loosening of the joint, hip dislocation, difficulty walking, cysts around the joint, and metal poisoning. Thousands of hip recipients in the U.S. have filed lawsuits against hip-device manufacturers and in 2014 Stryker announced a settlement program for patients who suffered injuries from the hips.
New Zealand’s health minister, Jonathan Coleman, has stood by the regulatory system’s handling of the hip issue but said the system needs to be overhauled. “Officials are currently working on developing a new comprehensive regulatory scheme that includes medical devices, medicines, and cell and tissue therapies.” Coleman said the government needed to look at how legislation to better support the “rapidly changing” area of health, according to the Herald. The proposed new law would regulate the quality, safety, and effectiveness of all therapeutic products. Professor Tom Faunce of the Australian National University’s College of Law and College of Medicine said each country needs its own proactive medical device regulator when dealing with large, multinational corporations. Faunce said New Zealand should not outsource device regulation to other countries.
