Review Question - QID 101941

This 30-year-old woman has a femoral neck fracture secondary to a motor vehicle collision. The most common complication of femoral neck fractures in young people is avascular necrosis.

Femoral neck fractures are common in the elderly population, but can also occur in young patients who experience high energy trauma such as a motor vehicle collision. Diagnosis is based on a shortened, externally rotated leg on exam and hip radiographs. In adults, the primary blood supply to the femoral head is the medial femoral circumflex artery, which can be disrupted in the event of a hip dislocation or femoral neck fracture, leading to avascular necrosis.

Davidovitch et al. review the challenges in treatment of femoral neck fractures in non-elderly adults. The authors note that this is a rare event often accompanied by concomitant traumatic injuries. However, they stress prompt diagnosis and treatment of femoral neck fractures due to the increased risk of avascular necrosis and subsequent fracture non-union and poor functional outcome when the diagnosis is missed or treatment is delayed.

Dedrick et al. retrospectively reviewed a series of femoral neck fractures in patients between ages 15 and 50 years and found that avascular necrosis occurred in 36% of patients and nonunion of the fracture site was observed in 20%. In addition, they reported that 83% of patients with fractures occurring immediately inferolateral to the femoral head (subcapital fractures) developed nonunion or avascular necrosis, compared to 21% with a more distal femoral neck fracture.

Figure A is an A/P radiograph of the pelvis demonstrating a fracture of the left femoral neck.
Illustration A is an artist's depiction of the vascular anatomy of the femur, note the location of the medial femoral circumflex artery.
Illustration B is a hybrid radiograph and drawing demonstrating the potential for a femoral neck fracture to disrupt the medial femoral circumflex artery.

Incorrect Answers:
Answers 2,3,4, and 5: All of these answer choices are possible complications of hip trauma, but none of these would be considered the most common complication in a young patient with a femoral neck fracture.