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The reported event could be confirmed based on the inspection performed on the nail and on the x-rays received.The device inspection revealed the following: the identification of the returned nail was confirmed based on the catalog # and the lot # marked.The implant is broken in two parts, at the level of the lag screw hole.Both parts were returned.The evaluation revealed that the nail broke due to fatigue after 5 months of implantation.This can be stated based on the lines of rest clearly visible on the anterior side of the nail, which are a classic indication of a fatigue fracture.According to the observations made, the fatigue fracture had its origination on the lateral side of the anterior portion of the lag screw hole.Material damage, which was caused by misaligned drilling, may have weakened the device and contributed to the breakage.This statement is confirmed by the significant signs of wear (shiny area) on the lateral side of the hole.The removed material created a sharp-edged chamfer.The posterior side of the lag screw hole shows evidence of a sudden "catastrophic" brittle fracture, resulting from the fatigue fracture aforementioned.Material deformation (bearing points) be observed on the edge of the proximal hole, below the lag screw.This indicates that the nail was subjected to severe loads, leading to displacement of the lag screw, associated with the breakage of the nail.This statement is confirmed by the wear marks observed on the returned lag screw.Based on investigation, the root cause of the implant breakage was attributed to bone delayed union.The position and the extent of the fracture prevented a proper bone healing, which caused extensive load being applied to the implant and therefore, its breakage.The misdrilling most probably contributed to the fracture, by facilitating and/or accelerating its development.However, it is unlikely to have been the main cause.Its must be noted, that patient medical records where not provided, therefore, no statement could be made regarding a possible influence of any patient health condition or post-operative behavior on the delayed union.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.If more information is provided, the case will be reassessed.
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