Understanding Femoral Neck Fractures (Part 1)

Femoral neck fracture is a common type of fracture. It is estimated that there are about 125,000 femoral neck fractures per year in the US. 80% of femoral neck fractures occur in women, with the rate doubling every 5 to 6 years in women starting from age 30.

There are 2 fracture patterns:

• The first type occurs in young people following a high-energy fracture.
• The second type occurs in the elderly following a low-energy trauma.

Risk factors for femoral neck fractures include female gender, Caucasian race, advanced age, poor health status, tobacco and alcohol use, previous fractures, history of falls, and low estrogen levels.

1. Anatomy

Femoral neck fracture is a type of fracture that is very difficult to heal due to poor blood supply to the femoral neck. The blood supply to the femoral neck is very sparse: the artery of the ligamentum teres supplies only 1/4 of the femoral head, and the circumflex arteries from the capsular ligaments..., while in trauma, the circumflex vessels are almost completely ruptured (Figure 1)

Complications at the hip joint leaving sequelae: avascular necrosis of the femoral head, nonunion... causing disability. Systemic complications are very severe, due to prolonged immobilization: pneumonia, urinary tract infections, or pressure ulcers.

Figure 1. Blood supply to the femoral neck

2. Diagnosis

For obvious cases with significant displacement, patients present with symptoms such as loss of hip mobility, limb shortening, thigh adduction, and lower leg external rotation.

For occult, non-displaced fractures, the most common sign is pain with active and passive motion; imaging diagnosis is required, which besides X-rays can include computed tomography (CT) or magnetic resonance imaging (MRI).

Figure 2. Pauwels type I femoral neck fracture on CT scan

a. Femoral neck fracture line on coronal slice

b. 3D reconstruction of the femoral neck fracture line viewed from posterior

3. Classification

3.1. Anatomical classification (subcapital fracture, transcervical fracture, basi-cervical fracture)

3.2. Pauwels classification (neck-shaft angle)

3.3. Garden classification (degree of displacement)

3.4. Classification of fracture stability into stable and unstable fractures. Stable fractures are typically compression fractures. Unstable fractures include displaced and comminuted fractures.

Source: Undergraduate Medical Training Materials - Vietnam National University

Author: Dr. Do Vu Anh

References

1. Human Anatomy, Trinh Van Minh, Hanoi Medical University.

2. Handbook of Fractures, 4th Edition, Kenneth A. Egol, Kenneth J. Koval, Joseph D. Zuckerman, Lippincott Williams and Wilkins.

3. Trauma Manual, 2nd Edition. 2002 Lippincott Williams & Wilkins.

4. Rockwood & Green's Fractures in Adults, 6th Edition. 2006 Lippincott Williams & Wilkins.

5. Campbell’s Operative Orthopaedics (Eleventh Edition) - Edited by S. Terry Canale & James H. Beaty 2007