The DePuy Orthopaedics company is a division of the worldwide pharmaceutical and healthcare products company, Johnson & Johnson. DePuy was the first orthopedics products manufacturer in the U.S. with estimated yearly revenue of $8 billion and has designed hundreds of joint replacement and other orthopedic medical devices. Most of the DePuy products have been very successful, but several of their joint replacement devices have caused severe medical injuries including three hip replacement devices.
The Pinnacle Hip Replacement devices, the ASR XL Acetabular System and the ASR Hip Resurfacing System have shown unexpectedly high failure rates and DePuy is facing serious legal problems due to the injuries. Both the Pinnacle device and the ASR line were intended for younger patient with a more active lifestyle. The devices were designed to be more stable and to last longer than other devices with an expected lifetime of over 15 years but many patients have experienced failure with serious medical complications far earlier than anticipated – many within 5 years of implantation.
This has resulted in thousands of complaints and lawsuits due to severe injury and the requirement for numerous additional surgeries.
In most hip replacement surgeries, the entire joint – including the “ball” and “socket” are removed and replaced with new, artificial joint devices. The ASR Hip Resurfacing products do not remove the “ball”, instead the boned is reshaped and capped with a metal prosthetic device to preserve bone tissue in patients that can benefit from bone preservation.
Traditional hip replacement with the removal of the entire joint has been thought to be a greater risk, causing more incidences of hip dislocation. Hip resurfacing was intended to reduce the chance of hip failure due to dislocation.
History of DePuy ASR Hip Resurfacing
The DePuy ASR Hip System was introduced in 2003 to markets outside of the U.S. It was never fully approved by the Food and Drug Administration (FDA) for use in the U.S. but a portion of the device was approved in 2005. By 2008, hundreds of serious adverse event reports had been received by the FDA and international health authorizes.
A British orthopaedic surgeon had presented a report to an international medical professionals meeting regarding the high failure rate and the Australian Health Authority warned DePuy a number of times regarding ASR failure rate. The ASR Resurfacing System was withdrawn from the Australian market in 2009 but did not recall the U.S. approved portion of the device until 2010. In addition, some patients may have received the full device system whose components were acquired outside of the U.S.
Like multiple hip replacement products, ASR devices approved in the U.S. were determined to be eligible for a device exemption known as the 510(k) process. The 510(k) process allows medical device manufactured to claim that their device is “substantially similar” to devices already on the market and to skip expensive clinical testing in humans before offering the device to the public. The DePuy ASR devices were never fully tested in human subjects prior to release on the U.S. market.
Design of ASR Hip Resurfacing Device
Like many of the DePuy hip replacement products, the ASR Hip Resurfacing system was designed with metal-on-metal (MoM) construction. MoM devices were intended to be longer lasting and more stable, resulting in a decreased failure rate due to solid construction.
It was believed that MoM devices would not “wear out” as easily and would not shed plastic fragments into surrounding tissue as other devices did. The metal construction has turned out to be dangerous as well due to the chance that the metals will grate against one another and release metal fragments into surrounding tissue. The alloy used in the ASR devices is comprised of chromium, cobalt, and molybdenum which can be toxic to tissues.
In addition to possible metal poisoning, some devices may have failed due to the device shape which may be too shallow and increase the risk of dislocation.
Side Effects of the ASR Hip Resurfacing System
The MoM construction of the ASR Resurfacing system may be the main cause of many serious side effects caused by the device. MoM devices have been shown to grate against one another and release metal fragments and metallic ions into surrounding tissue. As the devices are made of a cobalt, chromium, and molybdenum alloy, the metal ions are toxic and may be absorbed into the bloodstream. In addition, some patients have experienced device loosening and joint dislocation.
Severe side effects caused by the ASR Hip Resurfacing System have included:
- Dislocation of the hip joint from device loosening
- Localized metallosis or poisoning due to shed metal fragments
- Systemic metallosis or poisoning due to absorption of metal ions into the bloodstream
- Death or dissolution of bone and tissue (necrosis and osteolysis)
- Bone fractures due to damage caused by local tissue inflammation
Patients who have these side effects have experienced pain and inflammation causing mobility issues and a requirement for replacement of the joint. Some patients have required reconstruction surgeries to repair broken, split or necrotic bone tissue. Additional surgeries for reconstruction or replacement may be much more painful and require longer recovery times than the original joint replacemnt surgery. In addition, patients who absorb cobalt and chromium into the bloodstream may experience symptoms such as chronic headache, severe fatigue, rashes, and other inflammatory issues.
DePuy ASR Hip Resurfacing Lawsuits
DePuy and the parent company, Johnson & Johnson face thousands of lawsuits regarding the ASR devices, including the hip resurfacing system.
More than 90 thousand ASR devices have been implanted worldwide. Experts estimate that up to 40 percent of the devices may fail in the first five years – despite the expected device life of 15 years. More than 10 thousand lawsuits have been filed, including more than 8,000 federal lawsuits in federal courts which have been consolidated into multi-district litigation in the U.S. District Court for the Northern District of Ohio. Thousands of additional cases remain at the state and local levels.
The first ASR device trial, filed in California resulted in a judgment of $8.3 million and Johnson & Johnson, DePuy parent company has agreed to settle the federal lawsuits for a total of $2.5 billion but more lawsuits may be expected.