General information: we received a complaint regarding univation implants from the (b)(4).In the meantime several explants are available for investigation in a decontaminated condition this is the second report.The first report can be found within cc 400473156.Consequences for the patient.Post-operative medical intervention was necessary: revision surgery.Investigation: the components were examined visually and microscopically with the digital microscope vhx-5000 keyence eq.-nr.2000024840 and the digital-camera "panasonic dmc tz8".In the delivered condition there are no bone cement residues on the tibial component.The plasma pore coating shows no abnormalities or damages.The femoral component shows bone cement residues nearly on the whole intended area.The gliding surface of the meniscal component shows little scratches and imprints probably resulting from third body wear (bone chips and/or bone cement residues.The provided picture/x-ray figures give no hints regarding the root cause of the implant loosening.Batch history review: the device quality and manufacturing history records have been checked for all available lot numbers and found to be according to our specification valid at the time of production.No similar incidents have been filed with products from these batches.Conclusion and root cause: based on the information available it is not possible to determine a definitive root cause for the failure.It could be possible that the failure is usage related.Rationale: on the basis of the current information, a clear conclusion can not be drawn.The device history records have been checked and no abnormalities could be observed.There are no hints for a material/device problem.Based on the information provided and the conclusion from our investigation we assume that only the tibial component has been loosened.It could be possible that there were problems with the cement technique.If cement was not on the implant, the failure was between implant and cement interface.Possible reason for loosening could be: a wrong handling with the cement.The plasmapore coated surface has been contaminated with fat or blood before the cement was applied.The gloves of the nurse were not changed/ were decontaminated when touching the cement.So fat and/ or blood was on the cement.Corrective action: product safety case was created.
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