Abstract: A fluid actuated orthopedic tool for cutting away degenerated or torn cartilage which includes a housing having a piston chamber in which a piston is reciprocally mounted and an associated head portion. The head portion includes an elongated tubular guide having a fixed cutter member connected thereto, and through which there extends a rotatable shaft having a movable cutter member connected thereto. The rotary shaft is driving connected by a pinion to a piston rack so that the displacement of the piston by fluid pressure and spring return effects the actuation of the movable cutter member to effect a cutting action. A lock is provided to lock the cutter members, and an internal adjustment is provided to adjust the stroke of the piston. Also, a valve means and associated actuator is provided to control the flow of actuating fluid to the piston chamber.