Treatment for scaphoid nonunion with associated dorsal intercalated segmental instability (DISI) secondary to scaphoid humpback deformity aims to restore carpal alignment and achieve fracture union. To attain these goals, standard procedures of surgical treatment for scaphoid nonunion with deformity involves adequate reduction of the scaphoid deformity, internal fixation, and bone grafting [1], [2], [3]. Various bone grafting techniques have been described, using two types of bone graft: cortcicocancellous bone graft or pure cancellous bone graft [3,4]. For scaphoid nonunion with DISI secondary humpback deformity, the reduction is most commonly supported by a wedge-shaped corticocancellous bone graft placed volarly between the fragments [5], [6], [7], [8]. Although corticocancellous bone grafts can provide mechanical stability against scaphoid collapse, it can be technically challenging and time-consuming to carve the graft into the exact wedge-shape [2]. Pure cancellous bone grafts are another popular approach to treating scaphoid nonunion and is gaining popularity due to its technical ease and its potentially superior osteogenic characteristics [[1], [2], [3], [4],9,10]. However, pure cancellous bone grafts lack the structural integrity provided by corticocancellous grafts. Thus, internal implants, such as headless compression screws, should support the nonunion site during the graft incorporation period [11].

An anatomically pre-contoured volar locking-plate of the scaphoid is a newly developed type of implant that may be indicated in scaphoid nonunion with DISI secondary to scaphoid humpback deformity and in cases of significant bone loss that makes screw placement difficult [11]. Previous published case series have showed satisfactory outcomes of plate fixation with vascularized bone graft or corticocancellous bone graft, or pure cancellous bone graft in patients with scaphoid nonunion [11], [12], [13], [14]. Since the mechanical properties, including rotation stability, stiffness, and failure load, of the plate are superior to those of a single headless screw [15,16], it may be a suitable implant for pure cancellous bone grafting.

In this study, we compared the union rate and radiographic/clinical outcomes of patients with scaphoid nonunion with DISI secondary to scaphoid humpback deformity who were managed using an anatomically pre-contoured volar locking-plate for fixation along with either corticocancellous bone grafting or pure cancellous bone grafting. We hypothesized that pure cancellous bone grafting from iliac crest would provide equivalent postoperative outcomes in terms of the union rate, restoration of the scaphoid anatomy, and clinical outcomes to those obtained with corticocancellous bone grafting from iliac crest.