Subtrochanteric Femur Fractures

Subtrochanteric femur fractures account for 10–30% of all hip fractures and can occur across all age groups. The injury demonstrates a bimodal distribution, affecting younger adults aged 20–40 years (often from high-energy trauma) and older adults over 60 years (typically due to low-energy falls through osteoporotic bone).

Anatomy

The subtrochanteric region is defined as the femoral segment between the lesser trochanter and a point 5 cm distal. This area experiences high biomechanical stress:

• Medial and posteromedial cortices: high compressive forces
• Lateral cortex: high tensile forces

The subtrochanteric region is composed mainly of cortical bone, resulting in reduced vascularity and a slower healing potential compared with intertrochanteric fractures.

Deforming Muscle Forces

• Proximal fragment: abducted by gluteus, externally rotated by short rotators, flexed by psoas
• Distal fragment: pulled proximally and into varus by adductors

These forces often result in malalignment if untreated.

See Also: Hip Joint Anatomy

Mechanism of Injury

Subtrochanteric fractures may result from:

1. Low-energy trauma – Minor falls in elderly patients with osteoporotic bones
2. High-energy trauma – Motor vehicle accidents, falls from height, gunshot wounds (10% of cases)
3. Pathologic fractures – Tumors or metabolic bone disease (17–35% of cases)
4. Atypical fractures – Minimal trauma fractures, often associated with bisphosphonates, glucocorticoids, or PPIs

Clinical Evaluation

Patients typically present with:

• Inability to bear weight
• Gross deformity of the lower extremity
• Painful hip motion, swelling, and tenderness of the proximal thigh

Important considerations:

• Evaluate for associated injuries in high-energy trauma
• Neurovascular compromise is rare but should be assessed
• Monitor for hemorrhagic shock, as the thigh can conceal significant blood loss

See Also: Hip Intertrochanteric Fractures

Radiographic Evaluation

• AP pelvis and AP/lateral hip and femur
• Assess the entire femur including the knee
• Contralateral femur radiograph may help determine length in comminuted fractures

See Also: Hip Joint X-Ray Imaging

Subtrochanteric Femur Fractures Classification

Russell-Taylor Classification (historical)

• Type I: Fractures with intact piriformis fossa
  • A: Lesser trochanter attached
  • B: Lesser trochanter detached
• Type II: Fractures extending into piriformis fossa
  • A: Stable medial construct
  • B: Comminuted piriformis fossa and lesser trochanter

Subtrochanteric Fracture Treatment

Nonoperative (Historical)

• Skeletal traction followed by spica casting or cast bracing
• Reserved for nonoperative candidates (elderly or children)
• Increased risk of nonunion, malunion, varus angulation, and rotational deformity

Operative (Preferred)

• Interlocking Nails (Intramedullary nails)
  • First-generation: trochanteric entry, both trochanters intact
  • Second-generation cephalomedullary nails: for fractures with posteromedial cortex loss
• 95-degree Fixed Angle Plate
  • Suitable for fractures involving both trochanters
  • Accessory screw may increase proximal fixation
• Proximal femur precontoured locking plates: newer alternative

Important Notes:

• Sliding hip screws are not recommended for subtrochanteric fractures
• Bone grafting is used only if indirect reduction fails
• Open fractures require immediate debridement and stabilization

Complications

1. Loss of Fixation
   • Implant failure due to screw cutout, plate breakage, or nail fatigue
2. Nonunion
   • Inability to bear weight after 4–6 months
   • Associated with inadequate reduction
3. Malunion
   • Coxa vara, leg length discrepancy, malrotation
   • Corrected with valgus osteotomy and revision fixation

Key Takeaways

• Subtrochanteric fractures are biomechanically challenging due to high cortical stress
• Operative fixation with intramedullary nails or fixed-angle plates is standard
• Complications like nonunion and malunion are common if alignment and reduction are not optimal
• Careful clinical and radiographic evaluation is critical, especially in high-energy trauma

References & More

1. Medda S, Reeves RA, Pilson H. Subtrochanteric Femur Fractures. [Updated 2023 Jul 17]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2026 Jan-. Available from: Pubmed
2. Gösling T. Subtrochantäre Frakturen [Subtrochanteric fractures]. Unfallchirurg. 2022 May;125(5):389-403. German. doi: 10.1007/s00113-022-01175-y. Epub 2022 Apr 8. PMID: 35394157. Pubmed
3. Egol KA. Handbook of fractures. 6th ed. Philadelphia: Lippincott Williams & Wilkins; 2019.