New Twist on DePuy Hip Replacement Issue

Palo Alto, CAA new twist in the DePuy Hip Replacement story is the potential for neurological and cardiac issues relating to the failure of the now-maligned metal-on-metal hip replacement system. The DePuy ASR XL Acetabular and DePuy ASR Hip Resurfacing systems were recalled last year after they began failing in a large proportion of hip replacement patients far sooner than the normal 15- to 20-year lifespan of hip replacement devices.

The result has left a number of patients with severe pain and mobility issues, and potentially in need of revision surgery as a result of the Hip Replacement Recall.

But now there's a new wrinkle, according to the January 8 edition of the Irish Examiner—or at least an issue that has not seen much media ink until now. And that's the potential for neurological and cardiac impact stemming from the presence of metal cobalt in the bloodstream and body tissues.

Part of the fallout from the failed metal-on-metal devices is the introduction of metal particles in the joints that can be the basis for pain and swelling. But now there is a concern that the presence of metal cobalt in the bloodstream and body tissues can lead to forgetfulness and various other consequences.

The article 'Arthroprosthetic Cobaltism: Neurological and Cardiac Manifestations in Two Patients with Metal-on-Metal Arthroplasty' appeared in a recent issue of The Journal of Bone and Joint Surgery (JBJS). It should be noted that one of the two patients in the study is the author himself, Dr. Stephen S. Tower, MD. While Dr. Tower acknowledges "a study of a large group of patients with metal-on-metal implants will be required to define the prevalence and spectrum of arthroprosthetic cobaltism," there are nonetheless several conclusions that can be drawn now.

"Patients with metal-on-metal hips are at risk for cobaltism if the bearings wear excessively or if renal function declines," the report claims. "Most patients with metal-on-metal implants have higher serum cobalt levels than industrial workers and may be at risk for subclinical cognitive and cardiac impairment. A serum cobalt level of >20 ug/L is common in some groups of patients with metal-on-metal implants and may result in symptomatic neurological and cardiac cobaltism. Severe neurological and cardiac impairments have been reported in association with arthroprosthetic cobaltism when serum cobalt exceeds 60 ug/L"

Dr. Tower noted that both of the patients were "fit, well, forty-nine-year-old men at the time of metal-on-metal arthroplasty with Articular Surface Replacement implants" manufactured by DePuy, since recalled in a hip replacement recall.

The author noted as well that symptoms of cobaltism may be, in part, reversed in patients that have "timely revision surgery. Surgeons need to be aware that the high serum cobalt levels found in some patients with metal-on-metal hips may cause neurological or cardiac damage."

In Ireland, DePuy Hip patients undergoing MRI scans are having the procedures on areas not solely restricted to their hips. The Irish Examiner noted that some 100 patients have also had MRI scans of the brain. This latest revelation may inject a new avenue of offence for plaintiffs filing a DePuy Lawsuit.