A literature article was received, entitled: "the cemented acetabular component of a total hip replacement - all polyethylene versus metal backing", by merrill a.Ritter, md, published in clinical orthopaedics and related research, number 311, pp 69-75.Following review by clinician, the author demonstrated that a cemented all-polyethylene acetabular cup component had better survivability versus a cemented metal-backed polyethylene acetabular component.Failure was defined as either cup loosening or revision surgery with a minimum follow-up period of one year.From 1969-1983, author performed 238 depuy charnley total hip replacements, 141 depuy mueller total hip replacements, and 659 competitor system total hip replacements.The charnley hips were cemented hips utilizing all-poly cups with 22 mm femoral heads and stainless steel stems.The mueller hips were cemented hips using all-poly cups with 32 mm cobalt-chrome heads and stems.It was noted that one hundred of the competitor products formed the group of metal backed acetabular components.No other product specific information, such as catalog or lot numbers was provided, nor were specific patient events identified.The author indicated that of the 238 charnley cups, 32 failed: 21 were noted as loose (interface unspecified), and an additional 11 were actually part of a revision surgery (reasons unspecified for the revision).Of the 141 mueller cups, 29 failed: 23 were noted as loose (interface unspecified), and an additional 6 were part of a revision surgery (reasons unspecified for the revision).
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Product complaint # (b)(4).Investigation summary: no device associated with this report was received for examination.A worldwide lot specific complaint database search, or device history record (dhr) review, was not possible because the required lot number was not provided.Based on previous investigations, this complication of joint replacement is unlikely to have been the result of a device failing to meet required specifications.The information received will be retained for potential series investigations if triggered by trend analysis, post market surveillance, or other events within the quality system.Device history lot: null.Device history batch: null.Device history review: null.If information is obtained that was not available for the initial medwatch, a follow-up medwatch, a follow-up medwatch will be filed as appropriate.
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