Metal On Metal Hip Implants Causing Big Problems Again
Some half a million patients could be at risk from the metal-on-metal hip implants, with Johnson and Johnson being the biggest manufacture; others in the field include Zimmer Holdings Inc and Wright Medical Group. The problem stems from studies that led to the 2010 recall of the J&J products, after research showed metal ions leaching into the bloodstream at a high rate. The failure rate also seems to be a lot higher than advertised.
The process of recalling hip replacements is far from easy however, with the surgery being extremely aggressive on the patient and an operation costing thousands. A recent article in the NY Times pegged the cost of replacing failed hip replacements to tax payers and medical insurers into the billions. They cite the appalling example of Thomas Dougherty who spent five months without a left hip, due to a failed replacement operation. He ended up confined to a recliner, with nearly half a million dollars in medical bills.
The problem with prosthetic devices is not a new one, it's been more than ten years since Sulzer Orthopedics paid a record $1 billion to settle claims by 6,800 patients who received artificial hips and knees that were contaminated with industrial oil during the manufacturing process. However, the current situation looks set to make that incident look like a minor glitch - problems are compounded with increasing numbers of manufactures based outside the US, making them harder to police and even harder to chase with law suits.
The FDA has released a draft of the issues it plans to discuss at its meeting this week, including assessment of patients with and without symptoms associated with hip replacement problems. This includes recommending analyses of metal ions levels in blood, urine or serum, imaging assessments as well as physical examinations. They also intend to discuss properly labeling of prosthetic products, to include the kinds of details normally found on pharmaceuticals. This would include: Contraindications, Warnings, Precautions, Directions for Use, Outcomes Data and any other relevant information for patient and doctor.
Metal-on-Metal hip implants peaked at about one third of hip replacement procedures back in 2007, and have since dropped off to represent only 10% of the market today. A 2011 report showed twice the number of revisions (ie. where the prosthetic device must be surgically replaced), for metal-on-metal hip replacements than other varieties that include ceramics and polyethylene. The issue with metal-on-metal is that both the ball and socket are metal, meaning that metal working against metal can cause erosion, leaching of metals particles and more rapid failure.
Although metal on metal joints are common in cars and other machinery, the ease of manufacture, as well as the possibility of oiling the joints and replacing them with spare parts, obviously makes them a good choice. Once inside the body however, something more durable and able to withstand the abrasion and stress and strain of day to day life, without maintenance is necessary.
The same problem with over use of metals, has largely been overcome in dentistry, with less and less metal products being used in the mouth. The days of having to persuade the dentist not to fill your teeth with a horrible gray amalgam, laced with toxic mercury are long gone in most countries. As the technology progresses and the plastics and ceramic material technologies improve, some of the hip replacement issues will obviously pass. Manufacturers taking losses from lawsuits, combined with better oversight from the FDA, and more demanding patients who are aware of the issues will certainly help to reduce future mistakes. The problem is what to do with the hundreds of thousands of people who have a deficient product installed.
Anyone with a metal on metal hip replacement or those seeking advice or details on the matter should visit the FDA page that lays out all the issues in depth.
Written by Rupert Shepherd