Information was received that the nail was not opening and a revision procedure had to be performed.The patient used a wheelchair to ambulate and has no history of trauma or accidents.During the revision procedure, the surgeon attempted to increase the osteotomy with the nail still placed in the medullary canal, causing internal damage by the osteotome to the nail causing it to move freely.The nail was replaced and the procedure was completed.
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Device evaluation: the nail was returned for evaluation.A visual inspection revealed several deep scratches on the housing tube.Additionally, the device was found to exhibit pistoning, a free movement of the distraction rod, indicating an internal mechanical failure.The provided x-rays from the complaint were also reviewed.Although the image from the first x-ray dark, it does appear that the gap between the distraction rod and the coupler is significantly smaller than the gap shown in the second x-ray.This would indicate that it is possible that the nail was over-retracted.In-house device x-ray analysis confirmed the internal failure by identifying significant empty space within the device, attributed to the disconnection of the gear train and magnet.This internal separation was caused by the assembly pulling away from the grooves in the housing tube, leading to the internal components becoming disjointed.The device was then sectioned to review the internal components.Due to this separation, functional testing was unable to be performed.A visual inspection was conducted on the section of the housing tube where the grooves are featured.It was discovered that the grooves had been completely stripped as the inside of the housing tube was shiny from the removed anodization.Based on these findings, the failure to distract cannot be confirmed because the device was returned in a non-operational state.It is possible that the implant was over-retracted based on the x-rays provided and upon removal of the implant, excessive force was required to cause the distraction rod coupler to come off free from the housing grooves.However, it is not known what caused the excessive force required to disjoint the implant.
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