the proximal fixation member 112 and the flexible ligament member 116 may be separately harvested or manufactured components that are assembled to form the implant 100 in an embodiment the implant 100 is a btb allograft and each of the distal 108 and the proximal fixation member 112 is formed from a harvested bone block at an end of the allograft the distal fixation member 108 is substantially cylindrical in shape and includes external screw threads 118 centered about the longitudinal axis 106 and having a major thread diameter 120 a minor thread diameter 122 and a longitudinal thread spacing 124 by major thread diameter of an external screw thread we mean the outer diameter of an external screw thread measured at peaks of the threads a major thread diameter of a threaded fixation member corresponds to an outer diameter of the fixation member by minor thread diameter of an external screw thread we mean the diameter of an external screw thread measured from the bottom of valleys between the threads longitudinal thread spacing thread spacing is the longitudinal distance between adjacent threads and is inversely related to thread pitch that is thread pitch equals 1 thread spacing thread depth is the radial distance between the peaks and valleys of the thread equal to half of the difference between the major thread diameter and the minor thread diameter the proximal fixation member 112 is substantially cylindrical in shape has external screw threads 126 of substantially the same screw thread specifications with regard to major diameter 120 minor diameter 122 and thread spacing 124 as the distal fixation member 108 screw threads may be formed on the implant 100 by any thread forming method.