Objective To evaluate the results of treating unstable scaphoid waist fracture nonunion by anterior wedge bone graft and internal fixation with Kirschner wires.Methods Twelve adult male patients with unstable scaphoid waist fracture nonunion with a humpback deformity were treated by reduction of the collapse deformity,insertion of anterior wedge bone graft,and internal fixation with Kirschner wires.The mean patient age was 32.5 years,and the mean duration of the nonunion before surgery was 15.7 months.Results The follow-up time ranged from 9 to 23 months (mean,12.5 months).Radiographic bone union was seen in all cases.Union was achieved in a mean of 3.6 months.Most of the patients had satisfactory correction of scaphoid deformity and the associated dorsal intercalated segment instability.Postoperatively,improvements were seen in the range of wrist flexion and extension,grip strength,and degree of dorsal intercalated segment instability.Conclusion The results of this series suggest that anterior wedge bone graft and internal fixation with Kirschner wires is an effective method for the treatment of unstable scaphoid waist fractures nonunion. Key words: Scaphoid; Fractures, nonunion; Kirschner wire fixation