What is SCFE (Slipped Capital Femoral Epiphysis)?
SCFE is a hip disorder where the femoral head (ball of the hip joint) slips backward and downward off the femoral neck through the growth plate, most commonly affecting adolescents during their growth spurt. 1, 2
Definition and Pathophysiology
SCFE represents a displacement of the femoral head from the femoral neck through the growth plate (physis). More accurately, while traditionally described as the epiphysis slipping posteriorly and medially, it's better understood as the femoral metaphysis (neck) rotating externally and migrating anteriorly and laterally while the femoral head remains stable in the acetabulum 3, 4.
Epidemiology and Risk Factors
SCFE is the most common hip disorder in adolescence, affecting approximately 10 per 100,000 children annually, typically between ages 9-16 years 5, 6. The condition shows a strong association with:
- Obesity - the single most important risk factor in typical SCFE 1, 7, 6
- Pubertal growth spurt timing - when growth plate is most vulnerable 6
- Male predominance - boys are more commonly affected
- Bilateral involvement - occurs in a significant percentage of cases 1
Atypical SCFE Risk Factors
Atypical presentations occur in patients who are:
- Short in stature and underweight (below 50th percentile for height/weight/BMI) 8
- Outside typical age range (younger than 10 or older than 16 years) 8
- Associated with endocrine disorders (hypothyroidism, growth hormone deficiency, hyperparathyroidism) 7, 8
- History of radiation therapy 8
- Chronic kidney disease patients on growth hormone therapy 2
- Renal osteodystrophy 8
Clinical Presentation
Hip or knee pain with limping is the hallmark presentation 9. Key clinical features include:
- Referred knee pain - a common pitfall causing diagnostic delay 9, 5
- Decreased internal rotation and flexion of the affected hip
- External rotation deformity - the leg appears externally rotated
- Antalgic gait or inability to bear weight (in unstable slips)
Common diagnostic pitfalls include: underestimation of symptoms by patients/families, initial evaluation by non-orthopedic providers, and failure to obtain appropriate imaging when knee pain is the presenting complaint 5.
Diagnostic Approach
Obtain AP pelvis and lateral femoral head-neck radiographs immediately when SCFE is suspected 10, 11. The lateral view (frog-leg or cross-table) is critical as subtle slips may only be visible on this projection 5, 12.
When to Screen for Atypical SCFE
Order endocrine laboratory screening if the patient has 8:
- Age <10 or >16 years
- Height, weight, or BMI <50th percentile
- Valgus slip pattern (rare, suggests endocrinopathy)
- Short stature with decreased growth velocity despite continued weight gain 7
Complications and Long-term Sequelae
Early diagnosis is critical because delayed diagnosis leads to:
- Avascular necrosis - develops within months in unstable slips, leads to rapid joint destruction 4
- Femoroacetabular impingement (FAI) - complicates almost all slips, causes progressive cartilage damage and early osteoarthritis (approximately 10 years earlier than general population) 4
- Chondrolysis - rapid cartilage degeneration with joint space narrowing 4
- Progression of slip severity - increases risk of all complications 5
Association with Other Conditions
SCFE is specifically mentioned as a complication to monitor in:
- Severely obese children - higher BMI correlates with increased SCFE risk, and bilateral involvement is more common 1
- Growth hormone therapy - recognized risk factor requiring monitoring 2, 13, 2
- Pediatric obesity evaluation - part of comprehensive comorbidity screening 7
Growth hormone therapy must be discontinued immediately if SCFE is diagnosed 2.
Key Clinical Pearls
- Never dismiss hip pathology in a child presenting with isolated knee pain - always examine the hip 9
- Bilateral disease is common - evaluate the contralateral hip even if asymptomatic 1
- Stability classification is treatment-relevant - unstable slips (inability to bear weight) have dramatically higher complication rates 4, 12
- Diagnostic delay remains common - maintain high index of suspicion in at-risk populations 5, 12