Monday, September 19, 2011

Other Hip Recalls: In 2001-St. Gobain Desmarquest Case (3 of x)

2001 Recall.

The U.S. Food and Drug Administration had announced the second major recall of hip implants within the past year. On August 14,  2001, French manufacturer St. Gobain Desmarquest voluntarily recalled nine batches of zirconia ceramic femoral heads, the "ball" portion of the hip prosthesis. The potentially defective components were manufactured since early 1998 when St. Gobain Desmarquest changed part of its manufacturing process. One report suggests that the ceramic was left more fragile following a change in the heating process during manufacturing.

The recall of the zirconia ceramic femoral heads occurred following a higher than expected fracture rate in some patients, 13 to 27 months post-op. The FDA reported 14 cases of Americans who experienced fracture of the recalled hip implant.

Companies Affected

The zirconia ceramic components were distributed by more than 51 companies worldwide. Eight U.S. companies used St. Gobain Desmarquest zirconia ceramic femoral heads and participated  in the recall:

  • Apex Surgical, LLC (Lakeville, Massachusetts)
  • Biomet, Inc., (Warsaw, Indiana)
  • DePuy Orthopaedics, Inc. (Warsaw, Indiana)
  • Encore Orthopaedics, Inc. (Austin, Texas)
  • Osteoimplant Technology Inc. (Hunt Valley, Maryland)
  • Smith & Nephew, Inc. (Memphis, Tennessee)
  • Stryker Howmedica Osteonics (Allendale, NJ)
  • Zimmer, Inc. (Warsaw, Indiana)

Key Points

It was estimated that between 150,000 and 200,000 hip implants were performed each year in the United States int he early 2000's. Hip implants with zirconia ceramic femoral heads were used in less than 6 percent of hip replacement surgeries performed in the United States.

·  Not all zirconia ceramic femoral heads were expected to fail. The recall only applies to unimplanted zirconia ceramic femoral heads.

·  The FDA did not recommending surgery to replace hip implants that have not fractured or are not causing problems.

·  Sudden pain in the implanted hip joint often preceded by an audible "pop" often signal fracture of the defective component. Surgical correction is necessary if fracture does occur.

·  No test could  be performed to predict which patients will experience fracture of their zirconia ceramic femoral head component.

·  Patients with the potentially defective implant should be monitored more closely by their physician. Patients were being advised to contact their surgeons with any questions or concerns.

The issue raised in the manufacturing  Process
Change in manufacturing procedure Up until 1997, sintering was performed by SGCA-Desmarquest in a batch furnace, where an array of materials are placed at room temperature, then gradually heated, held at a higher temperature, and finally cooled back to room temperature. In early 1998, the company installed and began using a tunnel furnace, which operates by using a conveyor belt to move the items through multiple heating chambers. As it turned out, the first batches produced were the ones exhibiting the high rates of cracking. In a study of the failure mechanisms, Masonis et al found that the tunnel furnace and batch furnace exhibited the same temperature profiles upon heating to a maximum temperature of 1450 C, but differed in their cooling stage. Masonis found that the time for the materials to reach room temperature was three times shorter for the tunnel furnace than for the batch furnace. Upon examination of explanted, failed heads in the recalled batches, significantly elevated levels of monoclinic phases were found. In fact, a 100% transformation from the tetragonal phase to the monoclinic phase was found near the bore surface in a failed head from the tunnel furnace.
Saint-Gobain Desmarquest reported that using its batch furnace from 1990-1997, of 280,000 heads used, there were only 6 reported fractures equivalent ot about 1 fracture in every 46,000. [11] But once the tunnel furnace was employed, Masonis et al reported a 2.2% overall fracture rate in the 13 batches involved in the recall. This amounts to a 1 in 50 failure rate. Reported failure rates varied from batch to batch. Within the group of 13 recalled batches, the highest failure rate exhibited was 24% or 154 fractures in 655 hips (Batch TH 93038). In America, 39 zirconia heads from this batch were implanted, and by May 2002, 44% had fractured, while another batch, TH 9205 had 68 fractures in 611 patients worldwide.
It seeem that there were a number of suits filed but they seemed to have been filed against each company that used the materials and distributed the ceramic hip which are listed above.  I can't find any evidence of class action or a multi disctrict litigation effort.  This was 10 years ago so perhaps those proceedures weren't employed then?

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