The "floating ankle": a pattern of violent injury. Treatment with thin-pin external fixation.

The "floating ankle" is an underappreciated pattern of injury that results from violent trauma and/or blast injuries in military personnel. It is characterized by an intact ankle mortise with a distal tibia fracture and an ipsilateral foot fracture, creating instability around the ankle. This pattern of injury may be the result of the military boot, which both protects the foot from immediate amputation or further injury and renders the distal tibia susceptible to fracture at the boot top. Four patients with open floating ankle injuries were treated with thin-pin circular fixation with good results. Two patients required bone transport for segmental loss. All patients are ambulatory without assistance or bracing. Thin-pin external fixation is a reasonable approach to this complex injury pattern, especially in the presence of marked soft tissue compromise with or without segmental bone loss.