Another Study Sees Danger in Metal-on-Metal Hip Replacement DevicesMay 7, 2012 | Parker Waichman LLP
More bad news for recipients of metal-on-metal hip replacements, as yet another new study has confirmed the serious dangers associated with these devices. The study, which compared 36-mm diameter metal-on-metal hip replacement, compared to those with the same size metal-on-polyethylene device, found that corrosion in the head taper junction was more likely to occur in the all-metal devices. The research also revealed that the corrosion in metal-on-metal hip replacement devices was associated with local tissue reactions in patients with the implants. The study’s findings were published May 4 in the Journal of Arthroplasty.
The research used a five-point grading system to evaluate corrosion in metal-on-metal hip implants and metal on polyethylene hip replacements. A total of 8 all-metal heads (42%), compared to only 1 metal-on-polyethylene head (7%), demonstrated corrosion outside of the taper zone. The study also found that metal-on-metal patients who had undergone revisions following adverse local tissue reactions had greater corrosion scores than patients without reactions. Adverse local tissue reactions in metal-on-metal hip replacements were also likely to exhibit corrosion outside of the taper junction. The corrosion score increased with implantation time, and at all time intervals, the corrosion score for the all-metal group was greater, the study found.
Because corrosion worsens with time, the study authors wrote that metal-on-metal hip implant failures due to adverse local tissue reactions will increase with longer follow-up.
As we've reported previously, thousands of people fitted with new metal-on-metal hip implants have suffered complications soon after getting off the surgeon’s table. Most often, pain and inflammation caused by the shedding of metal debris eventually results in patients undergoing revision to replace the defective metal-on-metal hip implant. This has led to increased medical costs for recipients and leaves them at risk of permanently losing full mobility in the future after believing the implant would restore some normalcy in their lives.
Several previous studies have found that all-metal hip implants are more likely to fail prematurely. In March, a large study published in The Lancet showed that there is a 6.2 percent chance patients with all-metal hips will need a replacement within five years, prompting the study authors to call for an end to their use. The month prior, a report in the British Medical Journal warned that hundreds of thousands of people around the world may have been exposed to dangerously high levels of toxic and potentially cancer-causing metals from failing metal-on-metal hip implants.
The U.S. Food & Drug Administration (FDA) is currently investigating complications linked to metal-on-metal hip replacement devices, and has scheduled a meeting of outside advisors next month to look into their issues.