Patterns of bone defect in scaphoid nonunion: a 3-dimensional and quantitative analysis.

PURPOSE: To clarify patterns and size of bone defect in scaphoid nonunion in order to facilitate accurate correction of scaphoid deformity.

METHODS

Three-dimensional computed tomography was used to examine 24 patients with scaphoid nonunion. Configuration and size of bone defect were quantified and computed on the basis of fracture location. Cases were categorized as distal or proximal based on location of the fracture line relative to the dorsal apex of the scaphoid ridge.

RESULTS

Distal scaphoid fractures displayed wedge-shaped bone defects with the base facing volarly. Proximal scaphoid fractures exhibited flat, crescent-shaped defects that presented only around the fracture site. The size of bone defects was significantly greater for distal fractures than for proximal fractures.

CONCLUSIONS

Whether the fracture line passes distal or proximal to the dorsal apex of the scaphoid ridge is a crucial factor in the generation of bone defect. A large wedge-shaped bone graft from the volar side is necessary for distal nonunion whereas a small cancellous bone graft from the dorsal side may be preferable for proximal nonunion.