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U.S. Department of Health and Human Services

Medical Devices

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Information for Orthopaedic Surgeons


General Recommendations for Orthopaedic Surgeons BEFORE Metal-on-Metal Hip Replacement Surgery

  • Consider your patient’s individual characteristics. Each implant has a unique set of benefits and risks which will result in different outcomes in different patient populations.
  • Select a metal-on-metal (MoM) hip implant for your patient only after determining that the benefits of using a MoM hip implant outweigh the risks, in comparison to using alternative hip systems (metal-on-polyethylene, ceramic-on-polyethylene, ceramic-on-ceramic or ceramic-on-metal).
    • Use careful consideration in identifying best candidates for MoM total hip replacement.
    • Members of the FDA’s Orthopedic and Rehabilitation Devices Advisory Panel identified young males with larger femoral heads as the best candidates for MoM hip resurfacing systems.
  • Get adequate training in the technical aspects of each individual implant and the surgical instruments needed.
    • The success of MoM hip systems is highly dependent on correct placement and implantation.
    • Contact the manufacturer for device specific information on proper placement.
  • Do not implant MoM hip systems in:
    • Patients with known moderate to severe renal insufficiency
    • Patients with known metal sensitivity (e.g. cobalt, chromium, nickel)
    • Patients with suppressed immune systems
    • Patients currently receiving high doses of corticosteroids
    • Females of childbearing age
  • When discussing the implant and procedure with the patient, make sure the patient understands:
    • There are hip implants available with different bearing surfaces and each hip implant has unique benefits and risks.
    • All hip implants will need to be replaced eventually, and implant longevity is influenced by a patient’s age, sex, weight, diagnosis, activity level, condition of the surgery, and the type of implant.
    • The potential risks associated with MoM hip implants include, but are not limited to:
      • Infection
      • Loosening
      • Dislocation
      • Osteolysis
      • Bone or device fracture
      • Elevated metal ion levels in the joint and blood
      • Transplacental transport of metal ions
      • Development of local inflammatory reactions and lesions including soft tissue masses and tissue necrosis
      • Development of potential systemic events related to elevated metal ion levels
      • Revision surgery
      • Femoral neck fracture (for hip resurfacing)
    • Certain patients have an increased risk for greater wear of the device or for an adverse local tissue reaction (ALTR) and require closer follow-up. These patients may include:
      • Patients with implants in bilateral implants
      • Patients with resurfacing systems with small femoral heads (less than or equal to 44 mm)
      • Female patients
      • Patients receiving high doses of corticosteroids
      • Patients with evidence renal insufficiency
      • Patients with suppressed immune systems
      • Patients with suboptimal alignment of device components
      • Patients with suspected metal sensitivity (e.g. cobalt, chromium, nickel)
      • Patients who are severely overweight
      • Patients with high levels of physical activity
    • Previously implanted hardware at or near the hip joint may increase wear of the device or the amount of metal exposure to the patient who receives a MoM implant or revision.
    • There is currently no evidence to support the use of pre-operative skin patch testing or other tests to predict implant sensitivity prior to surgery.

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General Recommendations for Orthopaedic Surgeons DURING Metal-on-Metal Hip Replacement Surgery

  • Be aware that suboptimal placement may cause excess wear and early failure.
    • Pay particular attention to the angles of inclination and anteversion of the acetabular cup.
    • For resurfacing systems, make sure of appropriate orientation of the femoral stem-shaft angle before cementing into place (all resurfacing femoral heads are intended for cemented use only).
  • Do not mix components from different hip implant systems. Each hip implant system has different metallurgy and design specifications and it is imperative that all implanted components and their associated instruments be from the SAME manufacturer’s marketed hip implant system.

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General Recommendations for Orthopaedic Surgeons AFTER Metal-on-Metal Hip Replacement Surgery (Follow-up)

  • At the time of hospital discharge, schedule the patient for routine office follow-up and review with the patient or caregiver the signs/symptoms of adverse events.
  • The FDA recommends routine long-term follow-up of patients with metal-on-metal (MoM) hip implants, typically to occur every 1 to 2 years.
  • If the patient experiences any pain or decreased hip function approximately 3 or more months after surgery, instruct the patient to contact you for a follow-up exam.
  • Patient follow-up visits should include:
    • Physical exam with functional assessment;
    • Check for asymptomatic local swelling or masses; and
    • Assessment of organs and systems for changes including systemic adverse events in cardiovascular, nervous, endocrine (especially thyroid) and renal systems.
  • Schedule certain patients with increased risk of device wear or adverse local tissue reaction (ALTR) for closer follow-up. These may include:
    • Patients with bilateral implants
    • Patients with resurfacing systems with small femoral heads (less than or equal to 44 mm)
    • Female patients
    • Patients receiving high doses of corticosteroids
    • Patients with evidence of renal insufficiency
    • Patients with suppressed immune systems
    • Patients with suboptimal alignment of device components
    • Patients with suspected metal sensitivity (e.g. cobalt, chromium, nickel)
    • Patients who are severely overweight
    • Patients with high levels of physical activity
  • Pay close attention to signs of the following local and systemic symptoms or complications associated with metal-on-metal (MoM) hip implants:
    • Local symptoms or complications:
      • Hypersensitivity (allergic type reaction)
      • Loosening
      • Infection
      • Osteolysis (bone loss)
      • Aseptic lymphocytic vasculitis-associated lesions (ALVAL) (histologic reaction in surrounding tissue)
      • Soft tissue mass (fluid-filled or solid soft tissue mass around the replaced joint that is diagnosed radiologically)
      • Femoral neck fracture (for resurfacing systems)
    • Systemic symptoms or complications:
      • 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

Follow-Up for Asymptomatic Patients

Clinical Evaluation
  • If a patient with a metal-on-metal (MoM) hip implant is asymptomatic and has a well functioning hip, follow-up should occur periodically (typically 1 to 2 years).
  • Be aware the following patients may experience increased wear of the implant and/or adverse reaction to metal debris and require closer monitoring. They include:
    • Patients with bilateral implants
    • Patients with resurfacing systems with small femoral heads (44mm or smaller)
    • Female patients
    • Patients receiving high doses of corticosteroids
    • Patients with evidence of renal insufficiency
    • Patients with suppressed immune systems
    • Patients with suboptimal alignment of device components
    • Patients with suspected metal sensitivity (e.g. cobalt, chromium, nickel)
    • Patients who are severely overweight
    • Patients with high levels of physical activity
  • Patient follow-up visits should include:
    • Physical exam with functional assessment;
    • Checking for asymptomatic local swelling or masses; and
    • Assessment for possible systemic adverse events in cardiovascular, nervous, endocrine (especially thyroid) and renal systems.
Additional Testing for Asymptomatic Patients
  • If the orthopaedic surgeon feels the hip is functioning properly and the patient is asymptomatic, the FDA does not believe there is a clear need to routinely check metal ion levels in the blood or perform soft tissue imaging.
    • Findings of lesions on soft tissue imaging, or of elevated blood metal ion levels in the absence of symptoms have been reported in a limited number of research studies for some MoM hip implant patients. These studies are difficult to interpret because:
      • The exact incidence or prevalence of asymptomatic lesions and their natural history is not known.
      • The correlation between elevated blood metal ion levels and development of future local or systemic system adverse reactions is not well established.
    • If the orthopaedic surgeon determines it is in the best interest of the patient to conduct soft tissue imaging, please review FDA’s recommendations.
    • If the orthopaedic surgeon determines it is in the best interest of the patient to measure metal ion levels, please review FDA’s recommendations.

Follow-Up for Symptomatic Patients

Clinical Evaluation
  • If a patient experiences local symptoms (i.e. pain or swelling at or near the hip, a change in walking ability, or a noise from the hip joint) more than three months after metal-on-metal (MoM) hip implant surgery, conduct a thorough evaluation.
  • Follow-up of symptomatic patients with MoM hip implants should occur at least every six months.
  • Guide your clinical evaluation by the symptoms and physical findings, including an assessment for well-known emergent complications including joint infection, implant loosening, peri-prosthetic facture and dislocation.
  • Recognize that localized lesions associated with reactions to metal debris may also present with pain or a variety signs and symptoms including:
    • Local nerve palsy
    • Palpable mass
    • Local swelling
    • Joint dislocation or subluxation
Additional Testing for Symptomatic Patients
  • In some patients with symptoms, plain radiograph findings (e.g. osteolysis, femoral neck narrowing, component suboptimal positioning, fracture), in conjunction with other non-imaging information, are sufficient to indicate a need for revision surgery.
  • In other symptomatic patients, cross-sectional imaging should be considered to diagnose and assess soft tissue findings surrounding an implant.
  • Patients with MoM hip implants who develop any symptoms or physical findings that indicate their device may not be functioning properly, should be considered for metal ion testing. It is important to note that at the current time, the FDA believes there is not enough evidence in the U.S. to demonstrate a correlation between a metal ion level and the presence of localized lesions, clinical outcomes and/or the need for revision surgery.
Assessment for Systemic Effects
  • Evaluate patients with new systemic symptoms in collaboration with their primary medical physicians or specialists to determine the cause of their symptoms or findings.
  • Patients with evidence of excessive device wear or a localized adverse local tissue reaction (ALTR) should be assessed for potential systemic effects of exposure to metal ions.
    • A thorough physical examination should be performed by the patient’s health care team, which include primary medical physicians and/or specialists, with particular focus on cardiovascular, neurological, endocrinological (especially thyroid), and renal systems.
    • Because metal ions are cleared through the kidneys, a patient who has renal insufficiency may be at higher risk for systemic adverse events. Blood urea nitrogen (BUN) and creatinine levels may be measured to evaluate a patient’s renal function.

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Device Revisions

  • At this time, there is not enough evidence to provide a science-based recommendation for a threshold value of metal ion levels in the blood that would serve as a trigger for revision.
  • The decision to revise a patient’s metal-on-metal (MoM) hip implant should be made in response to the overall clinical scenario and results of diagnostic testing.
    • In extreme cases, adverse local tissue reactions (ALTR) may significantly damage periprosthetic bone, muscle, and nerves. Therefore patients with progressing ALTR, may be considered for earlier revision to prevent extensive damage.
  • If you recommend revision, advise patients of the surgical risks of revision as well as the expected outcomes, including:
    • Revision procedures are complicated and may not fully resolve a patient’s pain nor restore complete function;
    • In case of ALTR, revision of a MoM hip may have a worse prognosis than revision of other types of bearing surfaces;
    • Possible need for an additional revision procedure in the future; and
    • Metal ion levels should be expected to decrease after revision.
  • In selecting components for revision:
    • Check the specific device labeling for compatibility of device components.
      • Some failed hip resurfacing devices may be revised to a total MoM hip replacement system.
    • Consider the benefits and risks of all bearing surfaces for each patient.
    • If a patient is suspected to have developed metal sensitivity, carefully select the materials of the revision components (potentially avoiding materials with nickel or chromium).
  • In order to better understand the performance of these devices and causes of failure, a retrieval analysis is recommended, especially in cases where there is no obvious cause for implant failure such as suboptimal positioning.
    • Talk to the patient about returning the implant for retrieval analysis. A retrieval analysis is a vital part of a manufacturer’s quality system allowing them to assess manufacturing and quality processes through their Corrective and Preventative Action (CAPA) system.
    • If the patient agrees, contact the manufacturer prior to revision surgery for instructions on returning the implant for analysis.
    • Along with the implant, provide non-identifying information about the patient, the date of procedure, observations from the revision surgery and the histopathology report from any tissue sent to the hospital pathologist.
  • Report any adverse events believed to be related to the MoM system to FDA through MedWatch, the FDA Safety Information and Adverse Event Reporting Program.

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