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Although it cannot be determined at this time which of the reported screws pulled through the plate, a list of the devices used is noted below: catalog: lot: qty: 661755.Ah6442.1.662330.Aj1041.1.662350.Unknown.1.662350.Aj7134.1.662375.Ak1914.3.662380.Aj2418.1.662385.Ak1002.1.Upon completion of the investigation, additional information will be provided in a supplemental report.
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The reported event could be confirmed, since the reported screw migration is visible on the received x-rays as described in the event description.The device inspection revealed the following: the evaluation of both 50mm locking screws has shown that the thread flanks at the locking thread are damaged.The damages indicate that there was a in-situ movement between the screw head and the plate.It is clear that the damage is only present on one side of the screw heads.This suggests that the screw head of both screws did not go through the plate, because otherwise the head would be damaged all around.Based on this finding it is very likely that the returned screws are the screws which did back out on the x-rays.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.The complaint and the received x-rays were reviewed by medical affairs and lifecyle management with following conclusion: there was no x-ray provided which shows the complete construct in one view.On one x-ray (pangea plate set 3) are four migrated locking screws in the shaft of the femur visible.The most distal and the most proximal screw are backed out while the two screws between the backed out screws were pulled through the plate.All the affected screws in the shaft area have about the same length of around 50mm.But only two screws in this length range were returned for evaluation, the other screws are either much shorter (30mm) or longer (75mm).This means two of the affected screws, including the initially reported catalog # 662346 and as well the affected plate is missing.During the evaluation of the x-rays, it appeared that two of the displaced screws were too small and therefore may not have been held in place in the universal holes of the plate.This impression is particularly evident in the ap view (pangea plate set 5), where it appears that the screws have different diameters, and also in the lateral view (pangea plate set 4), where it appears that the head diameters of the screws are too small in comparison to the plate holes.Ultimately, without images of the entire construct, information about the patient's activities, and having all affected devices back for evaluation, it is not possible to determine the final cause of the reported event.If more information is provided, the case will be reassessed.
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