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The associated trigen screw, intertan nail and subtroch lag screw were returned and evaluated.A lab analysis conducted during this investigation indicated that the nail showed burnishing, damage to distal slot and polished fracture surface on distal and proximal nail fragments.The trigen screw showed the tip is missing.Microscopic examination of the devices showed beach marks on the surface of the screw.Fatigue striations are observed on the fractured surface of the nail and the screw indicating a fatigue fracture.The nail and screw fractured by the initiation and subsequent propagation of fatigue cracking.For the nail, the fracture likely initiated on the lateral side of the part through the lag screw hole.The fatigue cracking eventually propagated to an extent that the remaining cross-sectional area of the nail could not bear the imposed patient loading, which led to an overload fracture of the nail.Fatigue cracking is caused by the nail bearing cyclic (i.E.Repeated) stresses in excess of the material endurance limit for an extended period of time.These excessive cyclic stresses may be caused by any number of conditions, including but not limited to excessive patient activity levels prior to full bone union, applications of loads in excess of the material¿s strength, and/or poor bone quality.No deviation was found during a review of the manufacturing records for the listed batches.A review of the complaint history for the listed parts revealed no prior complaints for the listed failure mode with the same batch number.Our clinical evaluation noted that the x-rays provided confirm the non-union of the previous femoral fracture.The future impact to the patient beyond the revision cannot be determined.No further investigation warranted for this complaint; however we will continue to monitor for future complaints and investigate as necessary.Should additional information be received, the complaint will be reopened.
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