A self-contained, implantable bone distraction device is provided. The device is controlled by a programmable microcontroller that communicates with the outside world wirelessly, for example, via radio frequency or infrared. The microcontroller can be instructed, for example, to initiate an immediate distraction, or to stop a distraction in progress. Nitinol wire is used in conjunction with a one-way clutch to cause a distraction increment. The length of the wire is maintained after deactivation mechanically. Optional sensors allow the monitoring of the amount of actual distraction or the distraction force experienced by the bone under distraction.