Please note correction to d4 lot number.The reported event could be confirmed, since the device was returned for evaluation and matches the alleged failure mode.Device inspection revealed the following: the received nail is completely broken in the webs of the proximal lag screw hole.Significant drill marks were found at the lateral entrance of the hole along the anterior side; they progress through the bore towards medial.The drill marks were generated by a deviated lag screw step drill which most likely had created the starting point of the fracture (notching effect) somewhere at the lateral edge.Heavy metal chipping was also evident along the anterior wall.However, more significant thing to note apart from the drill marks was the sign of overloading.Bearing points of lag screw at the medial edge of the proximal hole showed significant deformation, indicating towards high compressive load.The fracture pattern resembles a fatigue fracture, evident by slight appearance of lines of rest.The breakage initiated in a fatigue manner but quickly broke instantaneously under high compressive loading.Mis-drilling was also evident in the distal oblong hole.A review of the device history for the reported lot did not indicate any abnormalities.No corrective actions are required at this time.No indications of material, manufacturing or design related problems were found during the investigation.A review of the labeling did not indicate any abnormalities.A clinical opinion regarding the event was sought from an independent medical professional based on the available patient information and the x-rays.Question was asked regarding the potential contributing factors for breakage, to which he opined that a high non union rate at an unfavorable location is evident.Additionally, the patient is pretty old and shows severe arteriosclerosis as an indirect indicator for a poor metabolism including the tendency to show slow bone repair.Therefore, even after 4 months there was no union which contributed to failure of the device.Based on the above investigation and available information, the root cause of the failure is both user and patient related but predominantly patient related.Appearance of mis-drilling marks indicates that the nail was damaged intra-operatively which created a starting point for fracture but due to non-union and consequent overloading the nail broke.If any further information is provided, the complaint report will be updated.
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