About half a million patients could be at risk from metal-on-metal hip implants. The problem stems from issuer relating to a release of metal ions leeching into the bloodstream at a high rate. In addition, there is a much higher failure rate than advertised. These issues led to a 2010 recall of Johnson and Johnson hip implants.
The problem with prosthetic devices is not a new one; it’s been more than ten years since Sulzer Orthopecis 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 problems appear to make that incident look like a minor stumble – problems are further compounded with increasing numbers of manufactures based outside the US, making them harder to police and even harder to pin down with law suits.
The FDA has released a draft of the issues it plants to discuss at its upcoming meeting, including assessment of patients with and without symptoms associated with hip replacement problems. This includes recommending examinations of metal ion levels in blood, urine, or serum, imaging assessments and physical examinations. They also intend to discuss proper labeling of prosthetic products to include the kinds of details normally found on pharmaceuticals including warnings, precautions, and directions for use.
Metal-on-Metal hip implants have peaked at about one third of hip replacement operations 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 for metal-on-metal hip replacements compared with other prosthetics including ceramics and polyethylene. The issue with metal-on-metal is that both the ball and socket are metal meaning that metal rubbing against metal can cause erosion, leading to metal particles in the bloodstream and a faster pace of failure.
As the technology improves and the plastic and ceramic material technologies progresses, some of the hip replacement issues will eventually pass. Manufacturers taking losses from lawsuits, combined with better FDA oversight and heightened patient awareness will likely aid in reducing future mistakes. The problem now is how to help the hundreds of thousands of people who have a deficient product implanted in their body.