Is the Distal Femur an Osteoporotic Fracture Site?
Yes, the distal femur is officially recognized as a major osteoporotic fracture site by the European Medicines Agency (EMA), though it is less commonly emphasized than the classic sites of hip, spine, wrist, and humerus. 1
Classification of Osteoporotic Fracture Sites
The 2024 International Working Group on DXA Best Practices provides clear definitions distinguishing major from minor osteoporotic fractures:
Major Osteoporotic Fractures
- Traditional sites: Clinical vertebral, hip, humerus, and forearm fractures 1
- EMA-designated additional sites: The European Medicines Agency specifically designates the distal femur, proximal tibia, pelvis, and multiple ribs as major osteoporotic fracture sites 1
Minor Osteoporotic Fractures
- All other fractures except face, hands, skull, feet, and ankles 1
Clinical Significance in Older Adults
Both major and minor osteoporotic fractures demonstrate relationships with low BMD and increased future fracture risk in older adults, and both should be considered when assessing fracture risk. 1
Key clinical implications:
- Any fragility fracture confirms skeletal fragility, regardless of BMD T-score, as 60% of osteoporotic fractures occur in patients with T-scores higher than -2.5 1
- The relative risk of subsequent fracture following any prior fracture increases approximately 2-fold 1
- Imminent fracture risk is highest in the 1-2 years following any major osteoporotic fracture 1
Practical Considerations
While the distal femur is recognized as an osteoporotic site, it is less common than the classic sites:
- The most frequent osteoporotic fractures remain vertebral, hip, wrist, and proximal humerus 1, 2, 3
- Lifetime osteoporotic fracture risk at age 50 is approximately 1 in 2 women and 1 in 5 men, predominantly at the traditional major sites 1, 2
Important Caveat
A distal femur fracture in an older adult with osteoporosis should trigger the same comprehensive evaluation and treatment as any major osteoporotic fracture, including:
- Immediate pharmacological intervention to reduce future fracture risk 1
- Assessment for additional undiagnosed fractures 1
- Recognition of the patient's very high fracture risk status 1
The distinction between "major" and "minor" sites matters primarily for regulatory purposes and clinical trial endpoints, but any fragility fracture in an older adult warrants full osteoporosis evaluation and treatment. 1, 4