FDA today announced that eight U.S. firms that make hip implants are, or will be, voluntarily recalling certain of their hip implants due to a potential problem with a component.

The component, a zirconia ceramic femoral head, was recalled by its French manufacturer St. Gobain Desmarquest August 14 because it was fracturing at a higher rate than expected in some patients 13 to 27 months after being implanted. The component is the ball portion of the hip prosthesis that connects the femoral stem to the pelvis. St. Gobain Desmarquest distributes zirconia and alumina ceramic femoral heads worldwide to most of the orthopedic industry.

The French recall applies to nine batches of zirconia ceramic femoral heads manufactured since early 1998. The affected batches have the prefix "TH" before the batch number. All these potentially defective batches were manufactured after the beginning of 1998 when St. Gobain Desmarquest changed part of its manufacturing process. No metal or alumina femoral heads are involved in the recall.

U.S. companies estimate that hip implants with zirconia ceramic femoral heads are used in less than six percent of hip implant procedures in the United States. An estimated 150,000 to 200,0000 hip implants are performed annually in the United States.

Surgeons should not continue to implant artificial hips with zirconia ceramic femoral heads manufactured by St. Gobain Desmarquest since early 1998.

Patients who already have these hip implants should contact their surgeons with any questions or concerns. Not all zirconia ceramic femoral heads are expected to fail, and not all patients will experience a problem; therefore, FDA is not recommending surgery to replace hip implants that have not fractured or are not causing problems. Physicians will likely choose to monitor the performance of the implant more closely as a result of the potential problem.

Fracture of implants with this component is usually signaled by a sudden pain in the implanted hip joint, sometimes preceded by an audible "pop" from the hip just before the onset of pain. If a hip implant fractures, surgery to replace it will be necessary.

No tests exist that can predict which patients will experience failure of their hip implants because of defective zirconia ceramic femoral heads.

The U.S. companies that use the St. Gobain Desmarquest zirconia femoral heads are:

Apex Surgical, LLC, Lakeville, Mass.; Biomet, Inc., Warsaw, Ind.; DePuy Orthopaedics, Inc., Warsaw, Ind.; Encore Orthopedics, Inc., Austin, Tex.; Osteoimplant Technology Inc. (OTI), Hunt Valley, Md.; Smith & Nephew, Inc., Memphis, Tenn.; Stryker Howmedica Osteonics, Allendale, N.J.; and Zimmer, Inc., Warsaw, Ind.

Further details on the recall are available on FDA's web site at www.fda/gov/cdrh/recalls/zirconiahip.html. The current recall of hip implants is the second major hip implant recall in the past year. Sulzer Medica announced a voluntary recall of certain of its hip implants last December due to a lubricant residue on the implant that prevented it from bonding with the hipbone. Like Desmarquest, Sulzer's problem was traced to a change in a manufacturing process.