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  6. Metal-on-Metal Hip Implants: Information for Patients
  1. Implants and Prosthetics

Metal-on-Metal Hip Implants: Information for Patients

Metal-on-Metal Hip Implants: Information for Patients

Information for Patients who have Metal-on-Metal Hip Implants

Information for Patients Considering a Metal-on-Metal Resurfacing Device


Information for Patients who have Metal-on-Metal Hip Implants

How do I know if I have a metal-on-metal hip implant?

Patients are usually told about the type of implant they are receiving prior to the surgery. If you are uncertain about which type you have, you should contact the orthopaedic surgeon who performed your procedure.

How often should I follow-up with my orthopaedic surgeon?

You should follow-up with your orthopaedic surgeon as recommended. There are some cases where your orthopaedic surgeon may recommend more frequent follow-up based on the type of hip implant, the outcome of the surgery and your recovery and the results of blood tests or imaging procedures.
If you develop new or significantly worsening symptoms or problems with your hip including pain, swelling, numbness, weakness, noise (popping, grinding, clicking or squeaking of your hip), and/or a change in ability to walk, contact your orthopaedic surgeon right away.

What should I discuss with my orthopaedic surgeon at each follow-up appointment?

It is critical that you talk to your surgeon about any new or worsening symptoms related to your hip, groin or legs since your last visit. This may include pain, swelling, numbness, noise, and/or change in ability to walk. It is also important that you discuss:

  • Changes in your general health.
  • Whether you are being seen or treated by another physician for a new condition since receiving your metal-on-metal hip implant.

What symptoms might a metal-on-metal hip implant cause?

Local symptoms may include hip/groin pain, weakness, swelling, numbness, or changes in your ability to walk. There can also be systemic symptoms involving the skin, kidney, heart, thyroid, and nervous system. 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 adverse effects that can occur with my metal-on-metal hip implant?

Metal-on-metal hip implants have the same adverse effects as other types of hip implants, including infection, loosening, bone loss, device or bone fracture, and joint dislocation.

In addition, metal particles from a metal-on-metal implant may cause a reaction around the joint, leading to deterioration of the tissue around the joint, loosening of the implant and failure of the device. Metal ions from a metal-on-metal implant will enter the bloodstream. There are case reports in which patients with metal-on-metal hip implants may have developed an adverse reaction to these metal ions and experienced medical problems that could have been related to their implants.

These problems included:

  • General hypersensitivity reaction (skin rash)
  • Cardiomyopathy
  • Neurological changes including sensory changes (auditory, or visual impairments)
  • Psychological status change (including depression or cognitive impairment)
  • Renal function impairment
  • Thyroid dysfunction (including neck discomfort, fatigue, weight gain or feeling cold)

What are my chances of developing a reaction to my metal-on-metal hip implant and having these types of medical problems?

The FDA does not know at this time how to predict adverse reactions that may occur in patients with metal-on-metal hip implants.
Part of the difficulty in answering this question is that individuals vary in how they react to metal ions in their bodies. For example, one patient may develop a reaction in response to a very small amount of metal ions in their body, whereas a different patient may have a much larger amount of metal ions in their bodies and yet not react to these ions. Certain patients may have an increased risk of device wear and subsequent local or systemic – reaction and therefore should follow-up with their surgeon more frequently. These patient groups include (but are not limited to):

  • Patients with bilateral implants (hip replacements on both the right and left sides)
  • Patients with resurfacing systems with small femoral heads (device sizes less than or equal to 44mm)
  • Female patients
  • Patients receiving high doses of corticosteroids
  • Patients with evidence of renal insufficiency (kidney problems)
  • Patients with suppressed immune systems
  • Patients with suboptimal alignment of device components (device components not placed in the ideal positions)
  • Patients with suspected metal sensitivity (e.g. cobalt, chromium, or nickel)
  • Patients who are severely overweight
  • Patients with high levels of physical activity

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, noise, hip weakness, 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 other evaluations 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 during their evaluation.
  3. Report any adverse systemic events which are believed to be related to your metal-on-metal hip implants to the FDA through MedWatch, the FDA Safety Information and Adverse Event Reporting Program.

What should I do if I am not experiencing adverse events associated with my metal-on-metal hip implant?

If you are not having any symptoms and your orthopaedic surgeon believes the metal-on-metal hip implant is functioning appropriately, there is no evidence to support the need for additional tests. You should continue to routinely follow-up with your orthopaedic surgeon every 1 to 2 years for a physical examination and radiographs.

What should I discuss with my other health care providers including my general internist or family practice doctor?

There are case reports of patients with metal-on-metal hip implants who experienced medical problems in areas of the body away from their hip implant. It is possible that these problems may be related to the metal ions released by the metal-on-metal hip implant.

If you see a health care provider for the evaluation of any new or worsening symptoms outside the hip/groin area, including the symptoms related to your skin, heart, nervous system, kidneys, or thyroid gland, it is important that you tell that clinician that you have a metal-on-metal hip implant. This information may affect the types of tests that are ordered to further evaluate the cause of your symptoms.

When would a hip revision surgery be needed?

There are multiple reasons why a surgeon may recommend a device revision (a surgical procedure where your implant is removed and another is put in its place). Many of these reasons, including infection, dislocation, loosening, and device fracture, apply to any type of hip implant. Your surgeon might also consider revision if you develop evidence of local or systemic reactions to the metal from your hip implant. In that case, the surgeon will take several factors into account in considering if and when revision surgery is advisable.

What are the risks of revision surgery?

Any surgical procedure, including revision surgery, has risks associated with it, including reaction to the anesthesia, infection, bleeding, and blood clots. The revision surgery may be more difficult if you had a local reaction to the implant that may have affected your soft tissue and/or bone quality. Post revision hip dislocation has been more prevalent with revision of metal on metal hip replacement.

If I have a revision, what happens to the original implant?

In a revision surgery, your existing hip implant is removed and replaced with another device. Your surgeon may ask you to allow that the implant that was removed to be sent back to the manufacturer for analysis. If you agree, the manufacturer will perform a thorough examination and analysis of the device to better understand how the implant worked and why it may have failed. The analysis is particularly informative in cases where there is no obvious cause of implant failure. Analysis can often lead manufacturers to improve an implant's design and update device labeling for future patients.

In addition to sending the implant, your surgeon will also provide non-personal information about you, the date of the procedure, observations from the revision surgery, and any reports or analysis on the tissue collected during surgery to the hospital pathologist.

There is typically no cost to you for this analysis and you will not be compensated for returning your implant. You may not be notified of the results of the analysis. If you do not want the implant returned to the manufacturer, you may decide what happens to the device.

What does it mean when I see that a hip implant has been "recalled?"

A hip implant 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 recommends 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 Recalls

Where can I get additional information regarding metal-on-metal hip implants?

Information for Patients Considering a Metal-on-Metal Hip Resurfacing Implant

What types of questions should I ask my orthopaedic surgeon about metal-on-metal hip implants?

When discussing your options for hip surgery with your surgeon, some questions you should ask include:

  • What are the benefits and risks of each type of hip implant system (metal-on-metal, metal-on-polyethylene, ceramic-on-polyethylene, ceramic-on-ceramic, and ceramic-on-metal total hip systems, as well as, resurfacing versus total hip replacement implants)?
  • Why is a metal-on-metal resurfacing hip implant the best for your situation?
  • What are the surgeon's results and personal experiences with the recommended hip resurfacing system?
  • What are the surgeon's outcomes and personal experience in performing surgical procedures with other types of hip systems?
  • What symptoms can you expect to experience after surgery and for how long?
  • What types of activities, if any, should be limited or restricted with a metal-on-metal resurfacing hip implant?
  • What results can you expect after surgery with a metal-on-metal resurfacing hip implant?
  • Which specific symptoms should you report after the surgery?
  • What types of reactions may occur due to the implant and/or metal ions and how would they be evaluated and treated?
  • If you have a complication related to the metal-on-metal resurfacing hip implant, how likely is it that the implant would need to be removed and what would be the consequences?

Which patients should not have a metal-on-metal hip resurfacing device implanted?

Each type of hip implant has its own set of benefits and risks. Metal-on-metal hip implants are not for everyone. You should discuss your situation with your orthopaedic surgeon to determine whether you are a candidate or not. In general, metal-on-metal hip systems are not meant to be implanted in patients:

  • Who have kidney problems
  • Who have a known allergy or sensitivity to metals
  • Who have a suppressed immune system
  • Who are currently receiving high doses of corticosteroids such as prednisone
  • Who are women of childbearing age

What personal information should I share with my orthopaedic surgeon if I am considering a metal-on-metal hip resurfacing implant?

It is critical that your orthopaedic surgeon know your complete medical history including any problems you may have with your kidneys and any known sensitivities or allergies to metal, for example, tell the surgeon if you have allergic reactions from wearing certain jewelry or from your skin contacting your belt buckle.

What are the risks of having a metal-on-metal hip resurfacing implant?

See the section above, called "Information for Patients who have Metal-on-Metal Hip Implants."

Is there a way to determine ahead of time if I might have a reaction to the metal in the metal-on-metal hip resurfacing implant?

Currently there is no widely accepted test to predict if you will develop a reaction to the metal from a hip system, and there is insufficient evidence to support using a skin patch test or any other type of test to determine your sensitivity to a metal-on-metal hip implant. If, however, you have a known sensitivity to metal, it is important to share that information with your surgeon.

Part of the difficulty in answering this question is that individuals vary in how they react to metal ions in their bodies. For example, one patient may develop a reaction in response to a very small amount of metal ions in their body, whereas a different patient may have a much larger amount of metal ions in their bodies and yet not develop a reaction.

Certain patients may have an increased risk of device wear or adverse local tissue reaction (ALTR) and should follow-up with their surgeon more frequently. They include:

  • Patients with bilateral implants (hip replacements on both the right and left sides)
  • Patients with resurfacing systems with small femoral heads (device sizes less than or equal to 44mm)
  • Female patients
  • Patients receiving high doses of corticosteroids
  • Patients with evidence of renal insufficiency (kidney problems)
  • Patients with suppressed immune systems
  • Patients with suboptimal alignment of device components (device components not placed in the ideal positions)
  • Patients with suspected metal sensitivity (e.g. cobalt, chromium, nickel)
  • Patients who are severely overweight
  • Patients with high levels of physical activity

Are there any ways to prevent the metal from reaching the joint and bloodstream if I get a metal-on-metal hip resurfacing implant?

No. All artificial hips require one component to slide against another component and it is inevitable that material at the surfaces will wear as they interact. In metal-on-metal hip implants, some tiny metal particles or metal ions are released into the joint space and the metal ions may enter the bloodstream. Certain characteristics outlined in the previous question may place patients at risk for increased wear and metal ion production and these patients will need closer follow-up after implantation. Patients will react differently to metal ion levels.

With the risk of adverse reactions to metal-on-metal hip resurfacing implant, why are these devices still being offered to patients?

Every hip implant has a distinct set of benefits and risks and should be considered on its own merit. The key design features of each implant including size, material, and dimensions make each system unique. In addition, the same hip system will have different outcomes in different patients.  

The FDA's assessment of medical devices, including metal-on-metal (MoM) hip implants is based on the, ratio of benefits to risk with the data available. MoM hip implants were designed to offer the following benefits:

  • Less device material wear is generated when the ball and socket rub against each other in comparison to other hip implants
  • Decreased chance of dislocation when the ball of the thighbone (femur) slips out of its socket in the hip bone (pelvis)
  • Decreased chance of device fracture

Although the exact prevalence of adverse local tissue or systemic reactions is not known, for some patients, currently available information supports a favorable benefit-risk ratio.

The orthopaedic surgeon should assess the patient's individual needs and should avoid using MoM hip implants in patients where the risks outweigh the benefits.