Automatic compression-distraction-torsion method and apparatus

An orthopaedic system is provided which includes a plurality of support members, a plurality of rods interconnecting the support members, a plurality of pins attached to the support members for passing through bone of a patient, and an automatic drive device to control an adjustment mechanism of the rods to adjust the rod length of the rods to alter the relative positions of the support members. The drive device includes at least one motor for incrementally adjusting the adjustment mechanism of at least one of the rods and a controller device for providing pulses to the motor and for storing information regarding the number of stepwise adjustments of the rod length by the motor.