It was reported that the pt was implanted a unk alloclassic stem on an unk date.Thirteen years after implantation, the pt began to feel pain and noise around the hip joint.On the plain radiographs, a space was observed between the ceramic head and stem taper, as well as a micaceous shadow around the head and the ectopic bone completely surrounding the bearing couple.Revision surgery was performed on an unk date.
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The mfr did not receive devices, x-rays, or other source documents for review.As no log number were provided for the devices, the device history records could not be reviewed.The info was taken from a medical journal article.A cause for this specific event cannot be ascertained from the info provided.Should add'l info become available and an investigation result be available, that changes this assessment, an amended medical device report will be submitted.Zimmer's ref number of this file is (b)(4).
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Dhr review: the dhr check could not be performed as the lot number was not available.Trend analysis: trend analysis could not be performed as no reference number was available.Review of incoming information: it was reported that a patient was revised after more then 13 years implantation due to pain and noise.During revision has been noticed that the neck of the stem was highly abrated and metallosis was found.Only one picture was available visible on the publication attached showing the stem neck highly abraded.Two x-rays were available in the attached paper.One taken 10 years after implantation and showed the growing ectopic bone.On the follow-up x-ray performed 13 after implantation the ectopic bone was completely surrounding the bearing.Inclination and antiversion angle were impossible to measure with accuracy.No surgical notes or other documents were provided.Devices analysis: a device analysis could not be performed as the product was not available for investigation.Possible causes for the reported event: failure of connection between stem and ball head, metallosis due to fretting corrosion, wear.Possible as the picture of the stem neck shows clearly that a lot of wear occured between stem and head.This could lead to metallosis formation.Failure of connection between stem and ball head due to mechanical properties of the material.Not possible as the compatibility is certified.Failure of connection between stem and ball head due to insufficient connection strength between femoral head and stem or due to residuals (e.G.Bone, cement) on taper (uncleaned taper).Possible as neither x-rays, operative notes, nor devices were received; therefore the condition of the components was unknown.Therefore, could not be excluded.Failure of connection between stem and ball head.Possible as neither x-rays, operative notes, nor devices were received; therefore the condition of the components was unknown.Therefore, could not be excluded.Failure of connection between stem and ball head due to corrosion due to wrong material combination.Not possible as the material compatibility specification certify the suitability of the material.Metal ions in blood due to metal reaction with body fluid , chemical reduction of metals in body fluid.Not possible despite metallosis has been observed, no tissue reaction was reported.Failure of connection between stem and ball head due to fracture of ceramic head due to unclean cone surface.Not possible as no ceramic fracture reported.Excessive wear, disassembly of femoral head from stem, implant failure due to combination with competitor products (off label use).Or failure of connection between stem and ball head, fracture of stem due to wrong selection of ball heads due to unknown compatibility list.Not possible as the compatibility is certified.Based on the given information and the results of the investigation, we were not able to identify a specific root cause for this issue.The need for corrective measures is not indicated and zimmer (b)(4) considers this case as closed.Zimmer's reference number of this file is (b)(4).
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