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The reported event could not be confirmed, since the returned device is conforming to specifications and is fully functional.In addition was no other evidence, like x-rays that would confirm the loosening of all screws, provided.The device inspection revealed the following: the visual inspection has shown that both received bone screws are in a good condition.There are very slight wear marks at the bottom side of the head visible, the marks indicate that there was a contact with the plate.As the plate does not have comparable marks an over-tightening of the screws can be excluded.But similar to the locking screws it can also not be confirmed if the screws were sufficiently tightened during insertion.A functional test with the also received four locking screw was performed, all locking screws can be locked in the locking holes of the plate without any issue.Due the nature of the bone screws a locking of these devices is not possible, but the received screws do fit into the oblong hole of the plate without any issues.All in all no functional issue with the returned devices could be detected.A review of the device history for the reported lot did not indicate any abnormalities.No corrective actions are required at this time.A review of the labeling did not indicate any abnormalities.No indications of material, manufacturing or design related problems were found during the investigation.Based on investigation, the root cause was attributed to a patient related issue.The failure that the screws did get loose after they were for almost one year implanted was most likely caused by the reported activity level and behavior of patient, where the surgeon said that the patient was highly active and may have been working too hard.However, it can also not be excluded that insufficient tightening of the screw did contribute to the loosening of the screw as the received devices show in the screw interface regions less damage than expected after a screw was driven in.If more information is provided, the case will be reassessed.
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