Medical device maker Smith & Nephew has reported a drop in sales of its metal-on-metal hip implant devices. According to the company, hip implant sales were down 2 percent during the first quarter of 2012, largely because its Birmingham Hip Resurfacing System suffered from an association with other metal-on-metal hip replacement devices.
Metal-on-metal hip implants have been the subject of safety concerns since the August 2010 global recall of DePuy Orthopaedic’s ASR hip implants. It is believed that all-metal hip replacements, which consist of a metal acetabular cup and metal femoral head, can shed minute particles of cobalt and chromium into surrounding tissue, and even into a patient’s blood stream. This can result in a condition called metallosis, which causes the death of tissue around the implant, including bone and muscle. Metal ions can also cause irreversible damage to DNA in cells, and have been found in many organs following hip replacements, including marrow, blood, liver, kidneys and bladder.
In May of last year, the U.S. Food & Drug Administration (FDA) asked 21 makers of metal-on-metal hip implants, including Smith & Nephew, to conduct safety studies of their devices. In June, the agency will convene a panel of outside advisers to discuss the problems related to metal-on-metal hip replacements.
The controversy surrounding metal-on-metal hip implants has sparked a wave of litigation. Thousands of DePuy ASR hip implant lawsuits are currently pending in a consolidated litigation in federal court in Ohio. In February, a multidistrict litigation was established in the U.S. District Court for the Northern District of Georgia for lawsuits involving the all-metal Wright Conserve Hip Replacement System. Hundreds of claims involving a metal-on-metal version of DePuy’s Pinnacle hip implant have been consolidated in a multidistrict litigation in Texas. Several lawsuits are also pending in the U.S. over Biomet metal-on-metal hip implants.
In February, Smith & Nephew announced a study it conducted to follow the progress of the first 400 Birmingham Hip Resurfacing patients in the U.K. had found that after 10 years, 99% were either satisfied or extremely satisfied with their procedure. Among other things, the company touted the study’s finding of an “implant survival rate according to the Kaplan-Meier analysis was 95.9% – well exceeding the 10-year survivorship threshold of 90% for implants as established by the National Institute for Health and Clinical Science.” Smith & Nephew said that a the study also found a “radiographic success rate of 99.7% was observed by independent radiographic review.”
In 2007, Smith & Nephew recalled about 185 Birmingham hip resurfacing system implants over improper packaging by a subcontractor. As a result of the packaging error, it was reported that different sizes of acetabular cups were mixed and mislabeled. A number of patients complained of having received wrong-sized hips, which forced some to undergo a revision surgery to remove and replace the poorly fitting device.