A bone saw tool includes a bone saw (102) and a bone saw blade assembly. The bone saw blade assembly includes a bone saw blade (118) and a bone saw blade guard (120). The bone saw blade guard is movable to an extended position to reduce the cutting effectiveness of the bone saw blade and/or the maximum cutting depth of the bone saw blade. The bone saw may be configured to activate the bone saw blade guard in response to a signal received from a computer system when the bone saw is moved outside a predetermined cutting region.