The femur is the longest, strongest, and heaviest tubular bone in the human body and one of the principal load bearing bones in the lower extremity [1-4]. Fractures of the femoral shaft often result from high energy forces such as motor vehicle collisions . Complications and injuries associated with midshaft femur fractures in the adult can be life-threatening and may include hemorrhage, internal organ injury, wound infection, fat embolism, and adult respiratory distress syndrome [2,6].
Femoral shaft fractures can also result in major physical impairment due to potential fracture shortening, malalignment, or prolonged immobilization of the extremity with casting or traction . The art of femoral fracture care involves a balancing act between anatomic alignment and early functional rehabilitation of the limb.
The diagnosis and management of midshaft femur fractures in adults will be reviewed here. Pediatric femur fractures, major pelvic trauma, general trauma management, and the management of potential complications of femur fractures are discussed separately. (See "Femoral shaft fractures in children" and "Pelvic trauma: Initial evaluation and management" and 'Complications' below.)
EPIDEMIOLOGY AND RISK FACTORS
The annual incidence of midshaft femur fractures is approximately 10 per 100,000 person-years . The incidence peaks among the young, decreasing after age 20, and then again in the elderly . A marked increase occurs in those over age 75 years. The majority of femur fractures occur in the proximal third (ie, hip fractures), which are discussed separately . (See "Hip fractures in adults".)
The incidence of femoral, particularly diaphyseal, fractures due to severe trauma is greatest in young men. Patients younger than 40 are more likely to sustain high energy trauma (eg, motor vehicle crash) and fracture the midshaft of the femur, while those over 40 are more likely to sustain low energy trauma (eg, fall) and fracture the proximal third of the femur . Eighty percent of patients 35 years of age or older with femur fractures due to moderate energy trauma had prior evidence of generalized osteopenia or a condition likely to cause localized osteopenia . In older adults, low energy falls are the most common cause, accounting for sixty-five percent of fractures . These typically occur in the home. Long term use of bisphosphonates may increase the risk of femur fracture. The association between bisphosphonates and femur fracture is discussed separately. (See "The use of bisphosphonates in postmenopausal women with osteoporosis", section on 'Atypical femur fractures'.) Industrial accidents and gunshot wounds account for most other femur fractures.