The US Food and Drug Administration (FDA) on Wednesday announced the issuance of a final order requiring manufacturers to submit a premarket approval (PMA) application for two types of metal on metal (MoM) total hip replacement devices.
The new PMA requirement for the two types of devices -- the hip joint metal/metal semi-constrained with a cemented acetabular component and the hip joint metal/metal semi-constrained with an uncemented acetabular component -- comes as FDA believes there is “insufficient evidence and information to conclude that general controls in combination with special controls would provide reasonable assurance of the safety and effectiveness of these devices.”
By 18 May 2016, the agency says PMA applications must be filed with the agency if a manufacturer wants to continue marketing these two types of Class III MoM total hip replacement devices and/or market new versions of such MoM total hip replacement devices.
According to FDA, the PMA applications for such devices should include: (1) any known risks, or risks that should be reasonably known; (2) the effectiveness of the device; and (3) full reports of all nonclinical and clinical information from investigations on the safety and effectiveness of the device for which premarket approval is sought.
FDA also previously directed five manufacturers currently marketing MoM total hip implants in the US to conduct postmarket surveillance study plans.
Other MoM Work
The new final order comes as back in April 2015, FDA raised concerns about MoM hip implants, including that the metal ball and the metal cup in the device can slide against each other during walking or running.
“Metal can also be released from other parts of the implant where two implant components connect. Metal release will cause some tiny metal particles to wear off of the device into the space around the implant. Wear and corrosion at the connection between the metal ball and taper of the stem may also occur,” FDA said.
The agency is also monitoring published medical literature, adverse event reports, post-approval study reports and data from several orthopedic device registries around the world to better understand possible adverse events associated with metal debris from MoM hip implants.
The launch of the International Consortium of Orthopaedic Registries (ICOR), an international collaboration looking to address the differences in global orthopedic registries and harmonize and utilize the data available, will also help to track the safety of the devices.
FDA is also working with MoM hip implant manufacturers to evaluate the devices in a magnetic resonance imaging (MRI) environment and to develop device specific labeling for MR conditions, which would help ensure safe scanning of patients with MoM hip implants. Improving the image quality around metal implants is important, FDA says, because the metal in the devices can prevent doctors from monitoring bone and soft tissue around the implant for signs of problems.
In addition, FDA is requesting and reviewing device retrieval analyses from the manufacturers of certain hip systems distributed in the US to further understand how and why certain MoM implants fail over time.
Effective Date of Requirement for Premarket Approval for Total Metal-on-Metal Semi-Constrained Hip Joint Systems
Overview of FDA MoM Activities