Abstract: A distraction system can include a distraction implant comprising a magnetic element and a distraction mechanism configured to expand the distraction implant in response to rotation of the magnetic element. The distraction system can include an external device comprising a motor configured to rotate a driver magnet while in a powered state, the driver magnet configured to rotate the magnetic element, a computing device configured. The computing device can be configured to measure an electrical current drawn by the motor during rotation of the driver magnet. The computing device can be configured to maintain the motor in the powered state in response to a mean value of the electrical current being greater than or equal to a mean value threshold, and a standard deviation value of the electrical current being less than or equal to a standard deviation threshold.