Abstract: 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 mechanism 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 mechanism includes at least one motor for incrementally adjusting the adjustment mechanism of at least one of the rods and a controller mechanism for providing pulses to the motor and for storing information regarding the number of stepwise adjustments of the rod length by the motor. An internal orthopaedic system is also disclosed in which a telescoping rod driven by an internal drive screw is placed internal to the bone of a patient and driven by means of either a flexible drive shaft connected to a motor and controller assembly or an internal motor and controller assembly.