In a retrospective analysis of 500 neck of femur fractures in elderly Indian patients, researchers identified the most common cause of injury. Which of the following is the most common cause of neck of femur fracture in the elderly population?

Explanation

## Epidemiology of Neck of Femur Fractures ### Most Common Cause: Low-Energy Trauma **Key Point:** Low-energy falls from standing height or bed height account for >90% of neck of femur fractures in elderly patients, making it the most common cause by a large margin. ### Mechanism and Risk Factors | Factor | Role in Low-Energy Fractures | |--------|------------------------------| | **Osteoporosis** | Severely compromised bone mineral density; primary risk factor | | **Age > 65 years** | Exponential increase in fracture incidence | | **Female sex** | 2–3× higher risk due to post-menopausal bone loss | | **Fall from bed/standing** | Minimal kinetic energy required due to poor bone quality | | **Comorbidities** | Diabetes, chronic kidney disease, malabsorption | ### Why Low-Energy Trauma Dominates 1. **Osteoporosis prevalence**: In India, >1 in 3 women >50 years have osteoporosis; in men >60 years, prevalence is ~1 in 8. 2. **Minimal force needed**: A simple fall from standing or rolling out of bed is sufficient to fracture a femoral neck weakened by osteoporosis. 3. **Age demographics**: The elderly population is at highest risk, and low-energy falls are the most frequent injury mechanism in this group. **High-Yield:** In young patients, neck of femur fractures typically require high-energy trauma (motor vehicle accidents, falls from height). In elderly patients, the same fracture occurs from low-energy mechanisms—this distinction is crucial for clinical reasoning. **Clinical Pearl:** Always screen for osteoporosis and metabolic bone disease in elderly patients with neck of femur fractures, as prevention of recurrent fractures depends on identifying and treating the underlying bone pathology.