A one-year-old female Eastern black-and-white Colobus (Colobus guereza) was evaluated after tangling its right forelimb in exhibit netting. Radiographs of the right forelimb revealed craniolateral luxation of the radial head and a complete transverse fracture of the proximal ulna, otherwise known as a type III Monteggia fracture. Open reduction was performed and a locking cuttable bone plate was placed to address the ulnar fracture. The reduced radial head was maintained by the placement of a Mini Tightrope Fixation System. Rapid return to normal activity was observed. Radiographs taken four weeks post-operatively showed healing of the fracture as well as appropriate articulation of the radial head. At three years post-operatively, the Colobus continued to demonstrate normal ambulation without evidence of growth disruption. This is the first documented report of this specific surgical technique and implant in an exotic species.