Femur Fractures - Complete Overview

Classification by Location

1. Femoral Neck Fractures

Classification

• Garden classification (based on trabecular orientation and displacement):
  • Garden I & II = stable (nondisplaced/impacted)
  • Garden III & IV = unstable (displaced)
• Pauwels classification (young adults) based on fracture line angle:
  • Type III (vertical) = highest shear, most unstable, highest risk of nonunion and AVN

Clinical Features

• Displaced fracture: leg lies externally rotated, shortened, and abducted
• Avoid range-of-motion testing to prevent further disruption of blood supply

Imaging

• AP and lateral hip X-rays confirm diagnosis
• MRI if X-ray negative but clinical suspicion high (detects occult fractures within 24 hours better than bone scan)

Management

• Nondisplaced (Garden I/II): Internal fixation with 3 parallel cannulated screws; touch-down weight bearing 6-8 weeks
• Displaced in young patients (Garden III/IV): Anatomic reduction + internal fixation (ORIF); reduction quality is more critical than timing
• Displaced in elderly (Garden III/IV):
  • Hemiarthroplasty - for low functional demand patients; cemented femoral component preferred; lower dislocation risk than THA in patients with dementia or Parkinson's
  • Total hip arthroplasty (THA) - for higher-functioning, physiologically younger elderly patients
• Surgery within 48 hours reduces mortality risk
• Mortality during first year after femoral neck fracture: 14% (vs. 9% in age-matched controls)

Complications

• Avascular necrosis (AVN): 10-40% - caused by disruption of medial femoral circumflex artery terminal branch; higher risk with initial displacement
• Nonunion: 10-30% of displaced fractures; higher risk with varus malreduction
• Pulmonary embolism: Leading cause of death at 7 days post-fracture
• Deep infection (osteomyelitis/septic arthritis): more common because fracture line extends into joint

2. Intertrochanteric Fractures

• Extracapsular - therefore blood supply to femoral head is preserved
• Unlike intracapsular fractures, vessels in the retinacula are NOT damaged, so AVN is not a concern
• Treated with sliding hip screw (SHS) or intramedullary nail in the vast majority of cases
• If an intertrochanteric fracture were present instead of a neck fracture, hemiarthroplasty would NOT be necessary (as the blood supply is intact)

3. Subtrochanteric Fractures

Key Features

• Composed almost entirely of cortical bone - poor vascularity, harder to heal
• Deforming forces: iliopsoas (flexion), gluteals (abduction), external rotators - produce flexion, abduction, external rotation of the proximal fragment
• Account for ~10% of all proximal femur fractures
• High-energy mechanism in young patients: 30-50% have associated pelvic, spinal, or long bone fractures
• Consider pathologic fracture in elderly (metastases, Paget disease, osteomalacia)
• Hemodynamic instability can occur from blood loss at fracture site

Treatment

• Intramedullary nailing is the gold standard
• Provisional external fixation (damage control) if hemodynamically unstable

4. Femoral Shaft Fractures

Treatment Options

• Complications: Infection (<5% closed fractures), ARDS, leg-length discrepancy, malunion

5. Distal Femur Fractures

• Imaging: AP + lateral views; CT or MRI for nondisplaced fractures; angiography if vascular compromise suspected
• Management:
  • Femoral nerve blocks (ultrasound-guided) to reduce opiate need
  • Splint immediately to prevent motion and pain
  • Intra-articular fractures: ORIF
  • Stable uncomplicated fractures: skeletal traction + immobilization
  • Virtually all require admission
• Classification: AO/OTA (Müller) system used for treatment planning and prognosis

Blood Supply to the Femoral Head (Critical for Neck Fractures)

1. Retinacular vessels (deep to synovium, along fibrous capsule) - most important, damaged in neck fractures
2. Medullary vessels - attenuated in elderly due to fatty marrow replacement
3. Artery in ligamentum teres - attenuated with age/atherosclerosis

Periprosthetic Femur Fractures (Vancouver Classification)