An 84-year-old woman with Alzheimer dementia is brought to the emergency department for evaluation after refusing to get out of bed. She has been known to wander the halls at her facility, and a nursing aide reported finding her on the floor next to her bed earlier that day. Vital signs are within normal limits. On examination, the patient is in pain. Her right leg appears shorter than her left. She is able to wiggle her toes but has significant external rotation of the right lower extremity compared with the left. There is no evidence of head trauma and the lower leg compartments are soft. Which of the following is the most likely diagnosis in this patient?
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This elderly woman has an acutely shortened, externally rotated leg following a fall. This presentation is most consistent with either a femoral neck or an intertrochanteric fracture, which are the most common hip fractures in older adults, typically occurring due to mechanical falls. The classic pattern of shortening and external rotation of the leg compared with the contralateral side is primarily due to contraction of the psoas and iliacus without the normal acetabular counterforce. This pattern is also seen in anterior hip dislocation, which is significantly less common than fracture and typically occurs following severe trauma (eg, industrial accident, motor vehicle collision). An x-ray generally confirms the diagnosis of fracture.
Hip fractures are classified as either intracapsular (femoral head and neck) or extracapsular (intertrochanteric or subtrochanteric). Intracapsular fractures typically present without significant ecchymoses and have a higher risk of avascular necrosis. Extracapsular fractures are at higher risk for displacement and usually have visible ecchymosis. Both types generally require surgical correction (eg, open reduction with internal fixation). In stable patients, surgery within 48 hours is associated with lower mortality and a lower risk of pressure ulcers and pneumonia.
(Choices B and D) Femoral shaft fracture in elderly patients can present with shortening of the leg, often with angulation. Pubic ramus fracture can occur from minor (or no) trauma in elderly patients and also can cause shortening of the ipsilateral leg. However, external rotation is more typical of femoral neck fracture.
(Choice C) Posterior hip dislocation typically presents with adduction and internal rotation at the hip. It usually occurs from an axial force on the femur (eg, dashboard injury), and some patients have neurologic manifestations due to involvement of the sciatic nerve.
(Choice E) Isolated fracture of the greater trochanter can occur due to a ground-level fall in older patients. Typical features include pain with abduction and tenderness at the trochanter. However, leg length is not affected.
Educational objective:
Femoral neck and intertrochanteric fractures are the most common hip fractures in older adults and most typically occur due to mechanical falls. Examination findings include shortening and external rotation of the leg compared with the contralateral side.