(From the American Academy of Orthopedic Surgeons Patient Information initiative)
On May 6, 2011, the Food and Drug Administration (FDA) issued a postmarket surveillance studies of total metal-on-metal hip replacement devices. A postmarket surveillance study monitors adverse events after a device has been approved or cleared by the FDA
Although the vast majority of patients have not had any problems with MoM implants, orthopaedic surgeons and the FDA are concerned because a few cases reported in the peer-reviewed literature and through a British database have involved patients who had local hip symptoms (pain and swelling) as well as other medical concerns seemingly unrelated to the hip.
The following is the patient-education portion of the FDA’s patient health communication:
How often should I follow-up with my orthopaedic surgeon?
If you develop new or significantly worsening symptoms or problems with your hip, including pain, swelling, numbness and/or a change in ability to walk, contact your orthopaedic surgeon right away.
What symptoms might a metal-on-metal hip implant cause?
Symptoms may include hip/groin pain, local swelling, numbness or changes in your ability to walk. There are many reasons a patient with a metal-on-metal hip implant may experience such symptoms and it is important that you contact your surgeon to help determine why you are having them.
Are there other medical effects that can occur with my metal-on-metal hip implant system?
Metal-on-metal hip implants, like other types of hip implants, are known to have adverse events, including infection and joint dislocation. There are some case reports of the metal particles causing a reaction around the joint, leading to deterioration of the tissue around the joint, loosening of the implant, and failure of the device, as well as some of the symptoms described above. In addition, some metal ions from the implant may enter into the blood stream. There have been a few recent case reports of patients with metal-on-metal hip implants developing a reaction to these ions and experiencing medical problems that might have been related to their implants, including effects on the nervous system, heart, and thyroid gland.
What should I do if I am experiencing adverse events associated with my metal-on-metal hip implant?
1. If you are experiencing hip/groin pain, difficulty walking or a worsening of your previous symptoms, you should make an appointment to see your orthopaedic surgeon for further evaluation of your implant. Your orthopaedic surgeon may wish to perform a physical exam and an evaluation based on your symptoms.
2. If you experience any new symptoms or medical conditions in your body other than at your hip, you should report these to your primary physician and remind them that you have a metal-on-metal hip implant system during their evaluation.
What does it mean when I see that a hip implant system has been “recalled?”
A hip system may be recalled by the manufacturer for a number of reasons. If your device is recalled, this does not necessarily mean that the device needs to be removed and replaced. In some cases, the recall just calls for different or more frequent monitoring. It is important to discuss the reason for the recall with your surgeon to determine the most appropriate course of action. If you are unsure if your hip implant was recalled, consult with your orthopaedic surgeon. Additional information on the recall can be obtained from the manufacturer or from: FDA Medical Device Recall InformationFDA Medical Device Recall Information
With the risk of adverse reactions to metal-on-metal hip implant systems, why are these devices still being offered to patients?
It is known that every different type of hip implant system has its own set of risks as well as its own set of benefits. FDA’s assessment of medical devices such as metal-on-metal (MoM) hip implants is based on a risk-benefit ratio with the data available. MoM hip implants overall have been shown to provide significant benefits (e.g., high survivorship) in certain patient populations. Although the exact prevalence of adverse reactions to metal-debris is not known, current experience leads us to consider the adverse outcomes to be relatively low or equal to other types of hip implants. Thus, for many patients, currently available information supports a favorable risk-benefit ratio.