Subtrochanteric Femur — Fixation

Subtrochanteric femur fractures occur in the region extending from the lesser trochanter to approximately 5 cm distal to it. These fractures are biomechanically challenging due to the high stresses transmitted through the proximal femur and the strong muscle forces acting on fracture fragments. They represent about 10–15% of proximal femur fractures and are associated with significant morbidity, especially in elderly patients.

Subtrochanteric fractures may occur following high-energy trauma in younger patients or low-energy falls in elderly individuals with osteoporosis. The management of these fractures typically involves surgical fixation, most commonly with intramedullary devices such as proximal femoral nails.

Due to the high mechanical stresses in this region, achieving stable fixation and maintaining alignment are essential to prevent complications such as implant failure or nonunion.

The subtrochanteric region of the femur lies just distal to the lesser trochanter and is composed primarily of dense cortical bone. This region experiences high compressive and tensile forces during weight bearing.

• Extends from the lesser trochanter to approximately 5 cm distally
• Dominated by thick cortical bone
• Subjected to high bending stresses
• Important muscle attachments influence fracture displacement

Muscle forces significantly influence fracture alignment:

• Iliopsoas flexes and externally rotates the proximal fragment
• Gluteus medius abducts the proximal fragment
• Adductors pull the distal fragment medially

• Accounts for approximately 10–15% of proximal femur fractures
• Occurs in both young and elderly populations
• More common in elderly females with osteoporosis

• High-energy trauma such as road traffic accidents
• Fall from height
• Low-energy falls in elderly osteoporotic patients
• Pathological fractures due to metastatic disease

Subtrochanteric fractures are commonly classified using the Seinsheimer classification system.

• Severe pain in upper thigh
• Inability to bear weight
• Shortened and externally rotated limb
• Swelling around proximal thigh

• AP pelvis radiograph
• Lateral femur radiograph
• CT scan for complex fractures

Radiographs usually demonstrate the fracture pattern and degree of displacement.

The goals of surgical fixation are restoration of alignment, stable fixation, and early mobilization.

• Anatomical reduction of fracture fragments
• Restoration of femoral length and alignment
• Stable fixation capable of withstanding high stresses
• Early weight bearing when possible

• Nonunion
• Implant failure
• Malalignment
• Infection
• Deep vein thrombosis

• Subtrochanteric region experiences high mechanical stress
• Most fractures require surgical fixation
• Intramedullary nails provide biomechanical advantage
• Malreduction increases risk of implant failure