The reported event could be confirmed since the device was returned for evaluation and matches the alleged failure.The device inspection revealed the following: the received screw was found to be having damaged threads around the middle moving towards proximal, covering approximately 6-8 threads.A metal splinter/wire was also formed which is most likely to have emerged from one of the middle threads and continued to form as the screw was pushed inside.The wire and the thread surface were found to be flat and plastically deformed.These damages and wire formation indicates towards excessive force that was applied to screw in the screw with some misalignment/angulation with the plate, leading to strip-off.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 manufacturing or design related problems were found during the investigation.A review of the labeling did not indicate any abnormalities.Based on the above investigation, the root cause of the failure is determined to be user related.There was a definite overtightening and misalignment of the screw involved as observed through the manner of deformation and stripping in the returned screw.The operative technique clearly provides a caution in inserting bone screws: ¿note: during bone screw insertion in an oblong hole, the surgeon should rely on tactile feedback to prevent excessive torque which may result in thread / bone stripping, screw damage / pull through, or screwdriver damage.Proper observation of bone quality, screw size, and instrumentation can help determine the appropriate insertion torque during insertion and final tightening of the screw in the plate.When the screw is fully seated during final tightening, an increase of resistance indicates sufficient screw fixation.¿ if any additional information is provided, the investigation will be reassessed.
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