The reported event could be confirmed, since the provided details showed screw migration.The available images were forwarded to a health care professional, which confirmed the migration as well but cannot be further specified based on existing one plane view.No further additions.Furthermore, a bony ingrowth between lag screw and set screw was reported, which could be a hint that the positioning of set screw was not as intended from the beginning on.Therefore, it was forwarded for statement as well and from clinical point of view following was stated [excerpts]: ¿in the pictures you cannot judge that in my opinion.If they describe it this way, in my opinion the set screw cannot have set properly in the lag screw¿.The basics of the gamma-system are the interaction of nail set including a set screw and lag screw in the proximal area.The intention is to allow the fracture site to subside [if the fracture gap is too big] in order to support bone union.This requires motion in a relative rigid construction and is solved by lateralization of the lag screw.The set screw ¿ as part of the nail kit - is designed to fit into one of the four grooves of the shaft of the lag screw with ascending shapes at both medial and lateral.This prevents both rotation and complete migration of the lag screw but allows sliding in a limited and defined range.Known from previous cases it¿s rather related to a not properly seated set screw [set screw had not been reached the ground of the groove resp.Was unscrewed for more than ¼ of a turn resulting in exceeded motion of the lag screw towards medial].More detailed information about the complaint event as well as the affected device must be available in order to determine the root cause of the complaint event.Therefore, from technical point of view in this case a statement is impossible.A review of the device history for the reported lot did not indicate any abnormalities.No corrective actions are required at this time.With available information a deficiency of the devices in question was not verified.
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