A Biomechanical Comparison of Scaphoid Fixation With Bone Grafting Using Iliac Bone or Distal Radius Bone Paul Jarrett, ChB, Vera Kinzel, MD, Karl Stoffel, MD, PhD From the Fremantle Orthopaedic Unit, The University of Western Australia, Fremantle Hospital, Fremantle, Western Australia, Australia. Purpose: Although many scaphoid fractures may be treated by immobilization, complex scaphoid fractures generally require bone grafting with internal fixation. A preferred source of bone graft for scaphoid grafting is the iliac crest. Donor site morbidity from iliac crest harvest, however, is a known complication, and the comparable strength and osteogenic properties of bone harvested from other sites are unclear. To this end, we have conducted a cadaveric comparative investigation of the strength of scaphoid nonunions with bone graft and internal fixation using either iliac crest bone or distal radius bone. Methods: Ten paired, human, fresh-frozen cadaveric wrists were used to create a standard midwaist wedge osteotomy into which identically shaped distal radius or iliac crest bone wedges were internally fixed using headless compression screws. After bone density and computed tomography assessment of the bones, benchtop biomechanical testing was con- ducted to compare the strength of the scaphoids after iliac and distal radius grafting, at 2-mm displacement, and at failure. Results: Analysis of scaphoid length, width, height, weight, density, and screw placement revealed no statistical differences between both bone graft groups. Although not significant, scaphoid nonunions grafted with distal radius bone evidenced a reduced load (3.23  0.26 Nm) to 2-mm displacement compared with iliac crest bone (5.97  0.68 Nm). Similarly, though not significant, scaphoids grafted with distal radius bone showed a reduced load (4.18  0.30 Nm) to failure compared with iliac crest bone grafting (6.42  0.66 Nm). Although no significance was found between the 2 grafting methods, a trend toward greater strength in the iliac crest graft group was observed. Conclusions: Given the comparable biomechanical strength shown between iliac and distal radius bone in this study and the simplified surgical technique of distal radius harvesting, the data justify use of distal radius bone as a viable alternative donor source in scaphoid fracture treatment. (J Hand Surg 2007;32A:1367–1373. Copyright © 2007 by the American Society for Surgery of the Hand.) Key words: Bone grating, distal radius, iliac crest, internal fixation, scaphoid nonunion. Fracture of the scaphoid is the most common (greater than 70%) fracture of the carpus and represents about 2% of all fractures. 1–3 Although more than 90% of these fractures can be treated by cast immobilization, more difficult cases require surgery. 4 Displaced or chronic scaphoid fractures are generally treated by reduction and internal fixation but succumb to non- union in approximately 10% of cases. 5–7 Further- more, when these fractures are accompanied by com- minution or bone loss, bone grafting with internal fixation is generally required. The 2 most common sites of bone graft harvest for scaphoid grafting are the iliac crest and the distal radius. Although many authors have advocated use of cancellous and corti- cocancellous bone from both the iliac crest and the distal radius, the most efficacious technique remains unclear. 8 –16 Iliac crest grafts allow more marrow retrieval, therefore more osteogenic mesenchymal stem cells, and hence are considered to provide bone of superior osteogenic properties compared with those from the distal radius. 12 Donor site morbidity from iliac crest harvest, however, is known to be The Journal of Hand Surgery 1367