MARY
Subtrochanteric femur fractures occur within the region extending from the lesser trochanter to approximately 5 cm distal. These fractures are characterized by high mechanical stress, strong deforming muscular forces, and a relatively high risk of fixation failure and nonunion.
Management is technically demanding and requires stable fixation and precise reduction.
EPIDEMIOLOGY
Accounts for ~5–10% of proximal femur fractures
Bimodal distribution:
Elderly: low-energy (osteoporotic)
Young: high-energy trauma
Associated with:
Pathologic fractures (metastasis)
Atypical fractures (bisphosphonate-related)
ETIOLOGY & MECHANISM
Low-energy fall (elderly)
High-energy trauma (young)
Repetitive stress → atypical fractures
PATHOANATOMY
Dense cortical bone → limited blood supply
High stress concentration (transition zone)
Healing slower than intertrochanteric fractures
DEFORMING FORCES (VERY HIGH-YIELD)
Proximal fragment:
Iliopsoas → flexion
Gluteus medius/minimus → abduction
Short external rotators → external rotation
Distal fragment:
Adductors → medial displacement + shortening
👉 Result:
Varus deformity
Flexion + external rotation of proximal fragment
ANATOMY
Thick cortical bone
High compressive + tensile forces
Reduced vascularity compared to intertrochanteric region
CLASSIFICATION
AO/OTA
32-A → simple
32-B → wedge
32-C → complex
Atypical fractures (important subgroup)
Lateral cortex origin
Transverse pattern
Minimal comminution
Associated with bisphosphonates
PRESENTATION
Severe thigh/hip pain
Inability to bear weight
Deformity (shortening, rotation)
IMAGING
Radiographs:
AP pelvis
Full-length femur (critical!)
Evaluate:
Fracture extension
Comminution
Lateral wall
Bowing (IM nail planning)
CT:
Selected cases (complex fractures)
TREATMENT
General Principles
Almost always operative
Goals:
Restore alignment
Achieve stable fixation
Allow early mobilization
SURGICAL TREATMENT
1. Intramedullary Nailing (Gold Standard)
Long cephalomedullary nail
Advantages:
Load-sharing device
Shorter lever arm
Better biomechanics
2. Plate Fixation (Selected cases)
Indications:
IM nail contraindicated
Severe deformity
Periprosthetic fractures
REDUCTION PRINCIPLES (CRITICAL)
Correct:
Varus deformity
Flexion deformity
Rotation
Techniques:
Traction table
Clamp-assisted reduction
Open reduction if necessary
KEY SURGICAL PEARLS
Avoid varus → most common failure nedeni
Nail entry point critical
Restore medial cortex continuity
Consider blocking screws
COMPLICATIONS
Mechanical
Nonunion
Malunion (varus)
Implant failure
Biological
Delayed union
Infection
Specific
Iatrogenic fracture
Hardware failure
PROGNOSIS
Worse than intertrochanteric fractures
Dependent on:
Reduction quality
Stability
Bone quality