An instrument for preparing bone to receive an implant device is provided. The instrument includes a handle configured to be gripped by a user, a drive shaft and a support. The drive shaft extends axially from the handle. The support is configured to hold a spacer. The spacer is dimensioned in the same shape as the desired implant device. A piercing member is disposed on a distal end of the drive shaft. The drive shaft may be translated axially with respect to the spacer so as to slide the piercing member along the ramp-shaped member. The ramp-shaped member drives the piercing member beyond an outer surface of the spacer and into the bone. A stop may be mounted to the support. The stop is configured to limit the depth at which the spacer is inserted into the body.
