The DePuy ASR Metal-on-Metal Hip Implant: A Scientific Analysis of its Problems

The last ten years have seen surgical replacement of hip joints with an artificial prosthesis increase significantly. The main reason for this surge in hip replacement surgeries is our aging population. With people living longer, more active lives, degenerating hip joints can put a halt to that activity. From 1997 through 2004, the number of hip replacement surgeries increased nearly 50% and if the trend continues it is estimated that the annual number of hip replacements in the United States will reach 600,000 by 2015.

Factors in Hip Replacement Surgery

Primary reasons for patients undergoing hip replacement surgery include chronic pain, impairment of daily functions and severe arthritis in the hip joint. The most common type of arthritis leading to total hip replacement is osteoarthritis and is generally seen with aging or trauma to the hip joint. In some instances necrosis of the hip can be present, usually caused by a fracture, alcoholism, lupus, or taking steroid drugs such as prednisone. Patients may experience progressively worsening chronic pain which prohibits them from walking, climbing stairs or even getting up from a sitting position.

Types of Hip Implants

There are many different types of hip replacement implant including the metal-on metal, metal-on-polyethylene and metal-on-ceramic as well as the implants which are 100% ceramic or polyethylene. Other than the materials the implant is constructed with, the only other major difference is in how the implant is affixed—it can be cemented to the bone or attached in such a manner that it grows into the patient’s remaining bone. The idea behind the cobalt and chromium metal-on-metal hip implant was to create an implant which would not have to be re-done for fifteen to twenty years—unlike the ceramic and polyethylene hip implants which last approximately 8-12 years.

First Three DePuy Cases settled by Johnson & Johnson for over $600,000

The DePuy metal-on-metal hip implant, approved by the FDA a mere seven years ago—has been inundated with over 8,000 lawsuits claiming the implant is inherently defective and can lead to costly and painful revision surgery as well as a myriad of other serious health issues. DePuy initially claimed the failure rate of the ASR metal hip implant to be between 4-5%. When DePuy voluntarily recalled the implant in 2010, they upgraded the failure rate to approximately 12% within the first five years. Studies independent of DePuy or Johnson & Johnson place the failure rate of the ASR metal implant at 50% within six years and 80% within eight years. These staggering numbers almost guarantee that this particular metal-on-metal hip implant will fail at some point in the majority of recipients.

Nearly a hundred thousand ASR devices were implanted worldwide prior to the recall with nearly forty thousand in the United States alone. The propensity of the implant to loosen and detach as well as the thousands of reports regarding adverse health effects from high levels of chromium and cobalt have led to over 6,000 lawsuits filed in federal court an another 2,000 filed at the state level in Maryland, California, Nevada and other states. Johnson & Johnson recently settled three Nevada cases for $600,000—an amount considered to be at the low end of the expected $200,000-$500,000 to settle each case.

These three lawsuits were expected to go to trial in late 2012 and came from three women, all over the age of sixty, whose surgeries were performed by the same surgeon. Each woman had no choice but to undergo revision surgery—a procedure which is not only extremely painful, but can require months of recuperation and time away from work. One of the women reported excessive amounts of damage to the surrounding hip bone as a direct result of the implant yet Johnson & Johnson countered that the implants were not responsible for any of the developing life-threatening illnesses. The research regarding the potential of chromium and cobalt in the bloodstream to cause serious and life-threatening illnesses is sadly lacking at this point in time.