A surgical instrument, comprising: a guide arm having a first portion configured to define an angle at which a bore is to be drilled into bone and a second portion configured to define a location of a distal end of the bore to be drilled into bone, wherein the first portion of the guide arm includes opposed first and second flat surfaces (222f, 222g) and first and second sidewalls (222s. 222r) extending between the first and second flat surfaces, the surface areas of the flat surfaces being substantially larger than the surface areas of the sidewalls, and wherein an angle extending between the first portion and the second portion is approximately 110 degrees or less and wherein the second portion includes a distal tip disposed at a terminal end thereof, the tip being configured to engage bone at an intended location of the distal end of the bore to be drilled into bone; and a carriage disposed on the first portion of the guide arm, the carriage having a length that is greater than a width or a thickness thereof, and the length of the carriage extending substantially transverse to a length of the first portion of the guide arm, the carriage being configured to translate along a length of the first portion and to be selectively locked at different locations along the length to set the angle at which a bore is to be drilled into bone, and wherein the carriage includes a bullet-receiving opening formed therein that is configured to receive a bullet; wherein the carriage is configured such that a bullet received by the carriage is held at an angle with respect to the first portion such that a distal tip of a drill pin extending through the bullet is configured to engage the distal tip of the second portion wherein the carriage includes first and second opposed facial surfaces (250f, 250g) and first and second side surfaces (250r, 250s) extending between the first and second facial surfaces, the first and second flat surfaces of the first portion of the guide arm and the first and second facial surfaces of the carriage extending substantially parallel to each other, with the first facial surface of the carriage facing away from the first flat surface of the first portion of the guide arm; and the bullet-receiving opening is formed in the first facial surface of the carriage; characterized in that the bullet-receiving opening is configured to allow insertion of the bullet through the first facial surface and into the bullet receiving opening. a guide arm having a first portion configured to define an angle at which a bore is to be drilled into bone and a second portion configured to define a location of a distal end of the bore to be drilled into bone, wherein the first portion of the guide arm includes opposed first and second flat surfaces (222f, 222g) and first and second sidewalls (222s. 222r) extending between the first and second flat surfaces, the surface areas of the flat surfaces being substantially larger than the surface areas of the sidewalls, and wherein an angle extending between the first portion and the second portion is approximately 110 degrees or less and wherein the second portion includes a distal tip disposed at a terminal end thereof, the tip being configured to engage bone at an intended location of the distal end of the bore to be drilled into bone; and a carriage disposed on the first portion of the guide arm, the carriage having a length that is greater than a width or a thickness thereof, and the length of the carriage extending substantially transverse to a length of the first portion of the guide arm, the carriage being configured to translate along a length of the first portion and to be selectively locked at different locations along the length to set the angle at which a bore is to be drilled into bone, and wherein the carriage includes a bullet-receiving opening formed therein that is configured to receive a bullet; wherein the carriage is configured such that a bullet received by the carriage is held at an angle with respect to the first portion such that a distal tip of a drill pin extending through the bullet is configured to engage the distal tip of the second portion wherein the carriage includes first and second opposed facial surfaces (250f, 250g) and first and second side surfaces (250r, 250s) extending between the first and second facial surfaces, the first and second flat surfaces of the first portion of the guide arm and the first and second facial surfaces of the carriage extending substantially parallel to each other, with the first facial surface of the carriage facing away from the first flat surface of the first portion of the guide arm; and the bullet-receiving opening is formed in the first facial surface of the carriage; characterized in that the bullet-receiving opening is configured to allow insertion of the bullet through the first facial surface and into the bullet receiving opening.