Investigation: a review of the device history record confirmed that the device was manufactured and tested according to relevant procedures,and shipped according to manufacturer's specifications.Surgeon, information analysis: patient (b)(6) index procedure on (b)(6) 2021.On (b)(6) 2023 apifix was notified that patient (b)(6) (pas #086-a027) underwent revision surgery that day for reasons unspecified.Additional information received on 02-aug-2023 confirmed that the revision was due to ratchet malfunction.According to the reporter, the mid-c was able to compress while in distraction mode, so the device would not fully extend.No report of patient harm/complications was received.Corrective action: ratchet malfunction (resulting in a backup of the distraction) can result from physical trauma, practicing high-demand sports, and tissue growth inside the ratchet mechanism.Ratchet malfunction may be a coincidental finding and may also be reported together with pain/curve progression/noise.The company took several actions to mitigate ratchet malfunction: eco-13, the ratchet flat spring component was changed to a thicker spring (from 0.15 to 0.25mm).Eco-59, addition of a stopper pin to prevent the pole from dislocating from the base and inherit from the design to prevent the collapse of the ratchet.In march 2020, a highlight of the risk associated with practicing high-demand sports was added to the mid-c training presentation.The company continues to monitor the effectiveness of the mitigations.Risk assessment: reoperation events are a known risk that was assessed and recorded by the product risk assessment dms-777 rev r this complaint does not change the occurrences rate.The risk of the ratchet malfunction has been assessed and found to be acceptable (dms#777 rev q1 hazard id 1.6).The risks have been quantified, characterized, and documented as acceptable within full risk assessment.The device was returned to manufacturer and is awaiting failure analysis.When further relevant information is identified with which to determine a cause, a supplemental report will be filed.
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Return analysis: the explanted device was returned and was subjected to cleaning, steam sterilizing, and engineering evaluation.During the inspection, the device's ratcheting mechanism did not appear to be functioning properly.When in ratchet mode (arrow of control pin aligned with arrow on device body) the device should "click" upon lengthening and allow no shortening.However, upon applying an axial load the device could be forced to shorten.This excise was repeated in lock mode and the device was able to be shortened when applying an axial load.The exact cause of this malfunction could not be investigated because the internal mechanism is sealed by permanent closure (weld).The wear analysis portion of retrieval and analysis protocol (b)(4) was not conducted because the time of implantation was less than 12 months and the cause of failure was ratchet malfunction.No significant wear was visually observed.
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