DePuy Polyethylene Hip Implants? They Just Don't Know

In the wake of MoM (metal-on-metal) hip implant failures, several manufacturers – including DePuy – are coming out with new types of implants.

But are they any better?

Maybe not. The British Medical Journal (BMJ) recently published the results of a study which concluded that there is little difference between the various types of hip implants currently available. While evidence indicates that patients who receive metal-on- polyethylene inplants may have lower rates of revision surgery, there is not enough hard data to determine if they are necessarily safer.

Using a measurement known as the "Harris Hip Score," the clinical study compared metal-on-metal, metal-on- polyethylene, ceramic-on-ceramic and ceramic-on- polyethylene. These scores tended to favor metal-on- polyethylene over metal-on-metal and showed that patients who received the ceramic-on-ceramic implants had the lowest rate of revision surgery. However, data from a national registry in the U.K. (where the study was carried out) as well as records from the FDA dating back to 2009 failed to demonstrate any significant difference between these various implants and overall patient outcomes.

Dr. Peter Cram, who teaches at the University of Iowa Carver College of Medicine, was quoted on a National Institutes of Health website, commenting that "the study highlights a critical issue in joint replacement surgery, which is there is not a lot of good data," expressing shock at the fact that so many hip replacements are done every year when there is so little data available.

Cram also said that the surgeon's experience is more important than the type of device that is implanted: "You probably want an experienced surgeon, who does lots of these procedures, in a hospital that does lots of these procedures."

Why is there so little data? Could it possibly be due to the fact that our profit-driven, bottom-line health care industry is rushing these products to market in order to maximize profits – regardless of the risks to patients?

Is a cloudless sky blue? Does the Earth go around the sun?

Sources

Art Sedrakyan, et. al. "Comparative Assessment of Implantable Hip Devices With Different Bearing Surfaces: Systematic Appraisal of Evidence." British Medical Journal, 29 November 2011.

N/A. "New Hip Implants No Better Than Older Ones, Study Finds." MedilinePlus (http://www.nlm.nih.gov/medlineplus/news/fullstory_119188.html ). Updated 30 November 2011. Accessed 6 December 2011.

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