- Sep 5, 2011
Recall of DePuy Orthopaedics ASR hip replacement deviceAustralia was the first country in the world to take regulatory action to ensure the removal of the DePuy ASR hip replacements from the market.
There are two types of Depuy ASR hip prostheses. The DePuy ASR resurfacing hip prosthesis was first approved for use in Australia in 2004. The DePuy ASR XL femoral head prosthesis was first approved for use in Australia in 2005. These replaced some earlier models supplied by DePuy. It is common practice for manufacturers such as DePuy to change the design of their joint implants in response to clinical needs identified by orthopaedic surgeons. New designs are intended to offer improved performance, more flexibility for surgeons and their patients in the choice of implant, and the potential for less invasive surgery leading to quicker recovery times for the patient.
The ASR hip was included in the Australian Register of Therapeutic Goods (ARTG) after an evaluation by the British Standards Institute (BSI). BSI is an accredited European assessment body under the supervision of the British regulator, the Medicines and Healthcare products Regulatory Agency (MHRA). In August 2010 DePuy Orthopaedics, a subsidiary of Johnson & Johnson, recalled ASR hip replacement devices implanted in about 93,000 people worldwide, due to a high rate of repeat surgeries.
The ASR hip prosthesis was removed from the Australian market in December 2009 after intervention by the TGA. The TGA had acted upon data from the Australian National Joint Replacement Registry (NJRR) that showed an unacceptably high need for repeat joint replacement in patients who had received an ASR hip.
In 2007 analysis by the TGA of data reported by the NJJR first suggested that the DePuy ASR resurfacing hip implant (one of the two types of ASR hips) was associated with a higher than average replacement rate. The data from the NJRR and the TGA's analysis was put before the independent expert advisory committee, the Orthopaedic Expert Working Group (OEWG), which advised at the time that the higher rates of revision for this type of ASR hip prosthesis was most probably due to the technical complexity of correctly siting the device during surgery. It was recommended that additional training and education be provided to surgeons to fix the problem.
The OEWG also recommended ongoing monitoring through the NJRR to verify the effectiveness of this additional training. DePuy Orthopaedics agreed to provide additional training to surgeons on the correct insertion technique. These actions resulted in a large decline in the usage of the ASR implant in Australia over the next 18 months.
In 2009, after ongoing monitoring of the performance of both types of ASR hip prosthesis for a reasonable period to evaluate the effects of the enhanced training program, data from the NJRR revealed that the rate of hip revisions remained of concern. The TGA took immediate action with the sponsor regarding this ongoing, higher-than-anticipated revision rate and subsequently DePuy Orthopaedics agreed to remove the ASR resurfacing hip implant from the Australian market in December 2009.
Following removal of the ASR implant from the Australian market, the TGA worked with DePuy and the Australian Orthopaedic Association (AOA) to ensure that all Australian orthopaedic surgeons were aware of the recall and the appropriate advice provided to patients. A worldwide recall of the ASR implants followed in August 2010, several months after the Australian government's monitoring and regulatory systems had identified and acted upon the problem. The combination of data from the NJRR, appropriate advice from surgical experts on the OEWG and effective intervention by the TGA resulted in the ASR implant being withdrawn from the Australian market well before any other part of the world.
Unfortunately, however, some Australian patients who received the ASR hips have suffered considerable side effects related to their surgery, and some may require repeat surgery and insertion of a new hip prosthesis. Patients who believe they may have side effects related to their hip replacement surgery are advised to contact their surgeon for further clinical review as appropriate.
How are medical devices regulated?
Medical devices range from low-risk devices such as simple bandages, to high-risk products that are implanted in the body for long periods of time. There are more than a million individual varieties of medical devices available for use in Australia, all designed to improve Australians' quality of life, treat disease, or save lives. Some of these devices are things we take for granted every day like crutches or syringes, and others are potentially life-saving technologies such as pacemakers, heart valves and joint replacements.
To keep up with the demand for safe, reliable and potentially life-saving medical devices, therapeutic product regulators around the world use risk-based systems that apply different levels of pre- and post-market oversight depending on the risk of the individual device. For example, the level of evaluation and post-market monitoring applied to an application for a new type of bandage is substantially less than that applied to an application for a new heart valve.
At the time a new medicine or medical device is approved for use in clinical care it is not possible to know all the possible complications that may develop with its use. This is because some of these side effects are very rare and may only become apparent when the medicine or medical device is being used to treat large numbers of patients. To identify all rare side effects occurring at this rate would involve clinical trials involving tens of thousands of patients. Such large-scale trials would simply not be practical in a country with the population of Australia and would prevent life-saving technologies being made available within the Australian Health system.
In recognition of the need to achieve an appropriate balance between ensuring adequate safety and performance, while at the same time allowing the beneficial effects of new technologies to be available in a timely manner, governments have developed internationally accepted processes of approval for new medical devices. The mainstay of these processes is a framework developed by the Global Harmonisation Taskforce (GHTF), an international forum of representatives from Europe, the United States, Japan, Canada and Australia. This framework has established the basic principles by which regulators in these countries undertake evaluation and monitoring of medical devices.
Broadly consistent approaches to medical device regulation apply in most developed economies based on guidance documents written by the GHTF. More recently, the framework developed by the GHTF has been adopted by groups such as the Asian Harmonisation Working Party for medical devices.
As a result of the similarity of arrangements applying to the regulation of medical devices it has been possible to establish mutual recognition agreements between some countries so that a device evaluation undertaken in one country can be used for regulatory approval in another country. Such arrangements apply between Australia and the European Union, and most medical devices available on the Australian market have undergone initial assessment by a European assessment body that is approved and monitored by European regulators.
Detailed description of the GHTF framework and the way medical device regulation operates in Australia can be found in the Australian Regulatory Guidelines for Medical Devices.
The regulation of joint prostheses in Australia
In 1999 the Australian Government funded the establishment of the National Joint Replacement Registry. The NJRR is a clinical registry that collects information from orthopaedic surgeons about joint replacement procedures performed in Australia. It was established in recognition of the need to actively monitor the safety and performance of medical devices once they are available in the Australian health system.
It is known that one of the limitations of joint replacements is that these devices have a limited lifespan and may require replacement. An important function of the NJRR is to monitor the lifespan of implants to determine whether there is an early and unexpected failure rate for a specific type of prosthesis relative to other similar devices. The TGA makes extensive use of the data collected by the NJRR in its monitoring programs and has established an expert advisory group, the Orthopaedic Expert Working Group (OEWG), to review the data arising from the NJRR and advise the TGA on the need for any regulatory action relating to a specific device.
This model, in which a comprehensive registry (the NJRR), managed by the peak professional body involved in providing data (the Australian Orthopaedic Association), linked directly to the regulator with the power to act on the data arising from the registry (the TGA) is regarded as a world's best practice model of post-market monitoring of medical devices. It is important that patients are aware that it is possible that a repeat joint replacement may be required with any type of hip prosthesis and that this is not an issue confined to the DePuy Orthopaedics ASR hip replacement prosthesis referred to in the 4 Corners program on 16 May 2011. Approximately 35,000 hip replacements are carried out in Australia each year, saving lives and adding substantially to the quality of life of people with hip fractures, chronic pain or arthritis.
Unfortunately, a small proportion of these hip replacements are accompanied by complications. These complications may be contributed to by the design or performance of the hip prosthesis, factors related to surgical technique or post-operative care, or factors relating to the clinical state of the individual patient. No joint replacement surgery is risk-free, and no joint prosthesis is free of the possibility of the need for future replacement surgery.
The Orthopaedic Expert Working Group
TGA established an Orthopaedic Expert Working Group (OEWG) in 2007. This group consists of orthopaedic surgeons with expertise in joint replacement surgery. It has a crucial role to play in advising the TGA on appropriate actions to take in the regulation of orthopaedic devices. It is called upon to review available clinical data and other relevant information and provide advice to the TGA on whether an early revision (replacement) rate for orthopaedic devices is acceptable for the identified implant of concern.
To date the OEWG has been called on 9 times and considered 76 orthopaedic implants that appear to have higher than expected revision rates. Of these, the OEWG have recommended no further action or ongoing monitoring in 50 joint replacements. Of the remaining 26 joint replacements, 15 have been removed from the market, 4 are under consideration following the OEWG's last meeting in November 2010, and 7 remain on the market after consideration by the TGA of further evidence provided by the manufacturer. These 7 joint replacements remain the subject of active ongoing monitoring by the TGA.
The ASR hip is one type of metal-on-metal (MOM) implant. The TGA has sought the advice of the surgical experts at the AOA regarding the scientific validity of reports with MOM technology. The AOA has advised that at this stage "current data supports avoidance of condemnation of all MOM implants, as such action would run the significant risk of removing appropriate and well-performing prostheses for specific target groups of patients."
The TGA will continue to closely monitor data coming from the NJJR regarding individual MOM prostheses and take regulatory action on an implant by implant basis as required, if the scientific data really does support higher rates of side-effects with this type of implant.
Changing the regulations
The TGA has recently released a consultation paper proposing reforms to the way medical devices are regulated in Australia. This consultation paper includes a number of proposals intended to enhance the level of clinical evaluation by Australian authorities for high-risk medical devices. It can be found at Reforms in the medical devices regulatory framework.
Hip protheses are currently classified as Class 2B devices. The 2010 Australian Government Health Technology Assessment review recommended increasing the regulatory oversight of higher risk devices (recommendation 8C). One proposal in the consultation paper is to upgrade all hip, knee and shoulder joint replacement implants from Class 2B to Class 3 Medical Devices. This would increase the level of scrutiny that occurs before these devices are made available within Australia as well as providing a more efficient way of monitoring them once they have been supplied. The TGA continues to work with international regulators to further improve the way medical devices are regulated globally.
Information for patients
About 5,500 Australians have been implanted with an ASR hip replacement system. Orthopaedic surgeons have been notified and advised by the Australian Orthopaedic Association to contact patients who have been implanted with an ASR hip replacement system to arrange assessment and regular follow-up. Surgeons have been advised to follow patients closely including annual review for at least 5 years following surgery. As well, your surgeon may recommend X-rays and blood tests. If revision surgery is required, DePuy Orthopaedics has recommended removal of all components and replacement with a different system. It is not expected that revision surgery will be needed in all patients.