Wrist function in malunion: Is the distal radius designed to retain function in the face of fracture?

INTRODUCTION Fractures of the distal radius are the most common fracture in humans and are the sempiternal hazard of 3.5 million years of bipedalism. Despite the antiquity of the injury, one of the most controversial topics in current orthopaedics is the management of distal radius fractures. It has been suggested that radiographic appearances rarely correlate with functional outcomes. As the success of the human species is predicated almost exclusively on its dexterity and intelligence, it is conceivable that the distal radius has evolved to preserve function even in the face of injury. We therefore hypothesise that the distal radius is designed to accommodate the possibility of fracture. METHODS We conducted a review of studies comparing fracture pattern and form with function. We also explore the paleoanthropological evidence and comparative studies with other primates. FINDINGS The evidence points to the human distal radius being highly tolerant of post-fracture deformity in terms of preservation of function. In addition, the distal radius appears to have apparently anatomically 'redundant' features that confer this capability. We believe these phenomena to be an evolved trait that developed with bipedalism, increasing the chances of survival for a species whose success depends upon its dexterity.