DEPARTMENT OF HEALTH & HUMAN SERVICES
Public Health Service
Food and Drug Administration
1350 Piccard Drive
Rockville, MD 20850

June 2, 1997

Steam Re-Sterilization Causes Deterioration of
Zirconia Ceramic Heads of Total Hip Prostheses

Dear Colleague:

This is to inform you that steam sterilization has been associated with surface roughening of zirconia ceramic femoral head components of total hip prostheses.¹ This occurs because exposure to steam and elevated temperatures may lead to a phase transformation in the crystal structure of the zirconia material. As a consequence of this roughening, increased wear on the ultra-high molecular weight polyethylene acetabular component may occur, which can cause premature failure and require early revision.

Because of the damage steam sterilization can cause, manufacturers of hip prostheses with zirconia femoral heads sterilize them using ethylene oxide. If these devices require re-sterilization because the package has been damaged or opened, we caution against using steam sterilization. The manufacturer should be contacted for further instructions.

If a clinician observes unusual damage or premature failure of a hip prosthesis with a zirconia ceramic femoral head, he or she should report this to FDA under the Safe Medical Devices Act of 1990 (SMDA), which requires hospitals and other user facilities to report deaths and serious illnesses and injuries associated with the use of medical devices. Practitioners should follow the procedures established by their facility for such mandatory reporting.

For problems and/or malfunctions, not required to be reported under SMDA, we encourage you to report directly to MedWatch, the FDA's voluntary reporting program by phone at 1-800- FDA-1088; by FAX 1-800- FDA-0178, or by mail to MedWatch, Food and Drug Administration, 5600 Fishers Lane (HF-2), Rockville, MD 20857.

Should you have questions about any of the matters discussed in this letter, please contact Gary Fischman, CDRH, Office of Science and Technology, HFZ-150, 12200 Wilkins Avenue, Rockville, MD 20852, or FAX 301-443-5259.

Sincerely yours,

D. Bruce Burlington, M.D.
Director,
Center for Devices and Radiological Health

1. U.K. Medical Devices Agency, Adverse Incidents Centre. Safety Notice MDA SN 9617, "Zirconia Ceramic Heads for Modular Total Hip Femoral Components: Advice to Users on Re-Sterilization".

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