A saw blade assembly for use with a driver having an oscillatory drive member comprises an elongate sheath and an elongate monolithic blade. The sheaths proximal end is removably mountable on the driver. The sheath has an open interior which receives the blade. The blades proximal end is pivotably mounted to the sheaths proximal end. The blades distal cutting end extends out of the sheaths distal end and is transverse to the blades central longitudinal axis. When cutting bone, the drive member pivots the blades cutting end back and forth in an arc about a pivot point at the blades proximal end while the driver holds the sheath stationary to protect surrounding tissues from the motions of the remainder of the blade. The long pivot radius between the proximal pivot point and the distal cutting end contributes to minimizing the angle of engagement of the cutting end to the bone.
