Slipped Capital Femoral Epiphysis (SCFE)

SCFE is a common hip disorder in adolescents characterized by displacement of the proximal femoral epiphysis relative to the metaphysis through the physis (growth plate).

Key Points

• Most common hip disorder in adolescents
• Peak age: 10-16 years
• Bilateral in 20-40% of cases
• More common in males (male:female ratio 1.5:1)
• Associated with obesity and endocrine disorders

Associated Conditions

• Endocrine disorders:
  • Hypothyroidism
  • Growth hormone deficiency
  • Hypogonadism
  • Panhypopituitarism
• Metabolic conditions:
  • Obesity (most common)
  • Renal osteodystrophy

Demographics

• Incidence: 2-13/100,000 children
• Age range: 8-15 years
• Mean age:
  • Boys: 13.5 years
  • Girls: 12.0 years
• Racial predisposition:
  • Higher in Pacific Islanders
  • Higher in African Americans

Risk Factors

• Obesity (>95th percentile)
• Rapid growth during puberty
• Family history
• Endocrine disorders
• Male gender
• African American race

Temporal Classification

• Pre-slip: Early changes without displacement
• Acute: Symptoms <3 weeks
• Chronic: Symptoms >3 weeks
• Acute-on-chronic: Acute symptoms in chronic SCFE

Stability Classification (Loder)

• Stable SCFE:
  • Can bear weight with or without crutches
  • Better prognosis
  • 85% of cases
• Unstable SCFE:
  • Cannot bear weight even with crutches
  • Higher risk of avascular necrosis
  • 15% of cases

Southwick Angle Classification

• Mild: <30°
• Moderate: 30-50°
• Severe: >50°

Symptoms

• Pain:
  • Hip pain (most common)
  • Knee pain (33% cases)
  • Thigh pain
• Limping
• Decreased range of motion
• External rotation when hip is flexed

Physical Examination

• Obligatory external rotation with hip flexion
• Limited internal rotation
• Trendelenburg gait
• Drehmann sign: Passive hip flexion causes automatic external rotation
• Wilson test often positive

Imaging Studies

• X-rays (standard):
  • AP pelvis view
  • Frog-leg lateral view (stable SCFE only)
  • Cross-table lateral view
• Klein's line abnormality
• Metaphyseal blanch sign
• MRI: Pre-slip detection

Laboratory Studies

• Endocrine workup if indicated:
  • TSH, Free T4
  • Growth hormone levels
  • FSH, LH

Initial Management

• Non-weight bearing
• Urgent orthopedic consultation
• Pain management

Surgical Management

• Stable SCFE:
  • In-situ pinning
  • Single cannulated screw fixation
• Unstable SCFE:
  • Urgent stabilization
  • Modified Dunn procedure
  • Consideration for surgical hip dislocation

Prophylactic Pinning

• Consider in:
  • Contralateral hip in young patients
  • Endocrine disorders
  • Young age at presentation

Early Complications

• Avascular necrosis (most severe)
• Chondrolysis
• Hardware problems
• Infection

Late Complications

• Femoroacetabular impingement
• Early osteoarthritis
• Leg length discrepancy
• Contralateral SCFE (20-40%)

Prognostic Factors

• Better prognosis:
  • Stable slips
  • Mild displacement
  • Early diagnosis
• Poor prognosis:
  • Unstable slips
  • Severe displacement
  • Development of AVN

Long-term Outcomes

• Risk of early osteoarthritis
• Need for long-term follow-up
• Possible need for total hip arthroplasty in adulthood