A system comprises an adjustable implant configured for implantation internally within a patient, wherein the adjustable implant has a magnetically responsive element configured for rotation about an axis of rotation. The magnetically responsive element is operatively coupled to a drive transmission configured to change a dimension of the adjustable implant. Moreover, the system comprises an external adjustment device configured for placement on or adjacent the skin of the patient, comprising at least one magnet configured for rotation, wherein the external adjustment device is further configured to rotate the at least one magnet, whereby rotation of the at least one magnet of the external adjustment device effectuates rotational movement of the magnetically responsive element of the adjustable implant and changes the dimension of the adjustable implant. Finally, the system comprises a motor control circuit configured to control the rotation of the at least one magnet of the external adjustment device to achieve a change in dimension of the adjustable implant.
