Chapter 40: Lower Extremity

INTRODUCTION

Lower extremity injuries represent the primary cause of more than half of all hospitalizations for trauma. Their frequency, severity, and costs emphasize the impact of those injuries on society.^1,2 Lower extremity fractures may be caused by either low- or high-energy forces and occur both in isolation and as multiple injuries. The mechanism of injury defines the specific individual fracture pattern. Typical trauma mechanisms include blunt versus penetrating trauma, low-energy versus high-energy forces, twisting, bending, or crushing forces. Significant lower extremity injuries compromise functional outcome and can lead to long-term pain, abnormal gait, degenerative joint disease, chronic infection, and limb loss.

Dislocations of the hip, knee, or more distal joints, as well as displaced fractures, may cause pressure on nerves, vessels, or skin that can result in permanent deficits if not dealt promptly. Many of these injuries are either surgical emergencies or, at the very least, require urgent treatment in the operating room. Failure to recognize the significance of these injuries can lead to sequela as significant as amputation or death. While not true emergencies, open fractures of the lower extremities require timely surgical treatment to minimize the risk of infection and limb loss.

The wide prevalence of safety belt usage and changes in vehicular design such as crumple zones and mandatory airbags has led to an increased number of survivors of high-energy crashes who consequently suffer from a higher severity of lower extremity injuries. For example, Shock Trauma in Baltimore noted a drop in the mortality associated with bilateral femur fractures from 26 to 7% over a 15-year period. There was an associated drop in Injury Severity Score (ISS) that suggested a contribution to this decrease in mortality from changes in motor vehicles.³ Any trauma victim involved in a high-energy trauma mechanism may have associated potentially life-threatening injuries to the head and torso. Thus, the initial evaluation of lower extremity fractures must focus on the patient as a whole, and not focus exclusively on the injured limb.^4,5,6

The concept of “damage control orthopedics” (DCO) was established based on the principle that prolonged early definitive treatment of long bone fractures can be detrimental for severely injured patients who are in unstable physiological conditions.^7,8 In these patients, the early mitigation of the “lethal triad” of persistent metabolic acidosis, hypothermia, and coagulopathy represents the prime goal for survival.⁴ More recently, however, our ability to resuscitate patients has improved, and multiple high-powered studies have shown improved outcomes while utilizing an “early total care” (ETC) model. In resuscitated patients, definitive intramedullary nailing of femur fractures and open fixation of pelvic and acetabular fractures has proceeded within 24–36 hours after injury with subsequently shorter ICU stays and fewer pulmonary complications, all at an overall lower cost.^9,10,11,12 The controversial concept of “limb for life” entails the early amputation of a ...