A C-shaped or ring shaped implant formed of cortical bone has its C-shaped or inner channel filled with a bone promoting material which is preferably demineralized bone fibers formed as a flexible wet sheet or may be cancellous bone, pressed bone fibers formed from demineralized cortical bone chips soaked in acid, or a flex material formed of demineralized bone growth promoting bone fibers. The discrete bone filler element may be secured by a bonding agent, pins or screws, metal, polymer or bone material. The bone filler material is preferably bonded by filling a section of a long bone medullary cavity with wet bone fibers and then drying the fibers to bond them to the outer bone.