Slipped Capital Femoral Epiphysis

Aka: Slipped Capital Femoral Epiphysis, SCFE

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II. Definitions

  1. Slipped Capital Femoral Epiphysis (SCFE)
    1. Hip Joint, posterior and inferior slippage of proximal femoral epiphysis on the femoral neck metaphysis

III. Epidemiology

  1. Age of onset: 8 to 16 years old
  2. Boys account for two thirds of cases
  3. Peak age of onset occurs during maximal pubertal growth spurt
    1. Males: age 14 to 16 years (mean 13.5 years)
    2. Females: age 11 to 13 years (mean 12 years)
  4. Most common adolescent hip disorder
    1. Prevalence: 10-24 per 100,000

IV. Pathophysiology

  1. Failure of the Epiphyseal Plate (Growth Plate) before it closes
  2. Femoral head displaces relative to the femoral neck at the Hip Joint
    1. Posterior and inferior slippage of proximal femoral epiphysis on the femoral neck metaphysis

V. Classification

  1. Stability
    1. Unstable SCFE (10% of cases) is defined as unable to ambulate without Crutches
  2. Chronicity
    1. Chronic SCFE is defined as being present for more than 3 weeks
    2. May present acutely after Trauma exacerbates the already existing SCFE

VI. Risk Factors

  1. Standard risks
    1. Black, pacific islander, or hispanic children affected more often than white children
    2. Overweight or obese (50 to 63% of cases)
  2. Younger onset or atypical cases (e.g. underweight, Short Stature)
    1. Arthritis
    2. Endocrinopathy
      1. Hypothyroidism
      2. Growth Hormone supplementation
      3. Hypogonadism
      4. Panhypopituitarism
    3. Renal Failure
    4. Radiation Therapy
    5. Chemotherapy

VII. Precautions

  1. SCFE is frequently misdiagnosed as benign diagnosis
    1. Examples: Adductor Strain (uncommon in this age group), Osgood-Schlatter Disease
    2. Correct diagnosis is often delayed as much as 3-4 months
  2. Best prognosis with early diagnosis before significant displacement occurs
    1. Have a high index of suspicion in a preadolescent or adolescent with Hip Pain
    2. Delayed diagnosis risks avsacular necrosis and severe Osteoarthritis

VIII. Symptoms

  1. Pediatric Limp
  2. Bilateral involvement in 35-60% of cases
  3. Poorly localized hip and Leg Pain
    1. Dull, aching pain in hip, groin, thigh or knee
    2. Worse with activity and better with rest
  4. Hip Pain with indolent course
    1. Unilateral in up to 90% of cases
  5. Pain may be referrred to knee
    1. May present primarily as knee or distal thigh pain in 15-40% of cases
  6. Provocative
    1. Hip flexion activities (e.g. squatting, prolonged sitting, biking)

IX. Signs

  1. Antalgic Gait
    1. Trendelenburg Gait (inferior Pelvis shift, torso tilt to affected side)
    2. May be unable to bear weight in severe cases
    3. Gait may be normal in early SCFE
  2. Compare exam to opposite side (except in bilateral SCFE)
    1. Gluteal and upper lateral thigh Muscle atrophy on affected side
    2. Thigh Muscles may be tender to palpation
  3. Hip held in abduction and external rotation
    1. Loss of internal hip rotation
  4. Obligatory external rotation (Drehmann Sign) or Out-toeing of the effective leg
    1. Patient externally rotates and abducts the hip when the hip is actively flexed to 90 degrees
    2. FADIR Test (Flexion ADDuction Internal Rotation Test) may also be positive in 59% of patients
  5. Markedly limited internal rotation (most predictive finding)
    1. Hip abduction and hip flexion are also limited

X. Labs

  1. Endocrine testing in SCFE onset age <10 years or age >16 years
    1. Thyroid Stimulating Hormone
    2. Parathyroid Hormone
    3. Complete metabolic panel
    4. Serum Vitamin D Level
    5. Growth Hormone Level

XI. Imaging

  1. Hip XRay AP with Frog-Leg Lateral View (Compare sides)
    1. Widened Epiphyseal Plate (Growth Plate) compared with uninvolved side
    2. Decreased epiphyseal height compared with uninvolved side
    3. Severity graded on frog leg view
      1. Measurements
        1. Displacement Percent by Wilson Method
        2. Southwick Slip Angle (SSA) between femoral shaft and line perpendicular to epiphysis
      2. Mild
        1. Hip epiphysis displaced <33% of metaphysis width
        2. Southwick Slip Angle (SSA) <30 degrees
      3. Moderate
        1. Hip epiphysis displaced 33-50% of metaphysis width
        2. Southwick Slip Angle (SSA) 30 to 50 degrees
      4. Severe
        1. Hip epiphysis displaced >50% of metaphysis width
        2. Southwick Slip Angle (SSA) >50 degrees
    4. Draw line down the femoral neck on AP View (Klein's Line)
      1. Line does not transect lateral 25% of femoral head and neck in SCFE (Trethowan Sign)
      2. Frog-leg view is important, as AP Hip will miss SCFE in up to 60% of cases
    5. Steel Sign (on AP View)
      1. Double density (double line) or blurring at the hip proximal metaphysis
      2. Occurs due to an overlap of the metaphysis and epiphysis
    6. S Sign (on Frog-leg View)
      1. Sharp turn or break along the inferior femur at the Physis
    7. Lesser trochanter prominent
      1. Due to external rotation of hip
  2. MRI Hip
    1. Consider in high suspicion cases where XRay is non-diagnostic
    2. May be indicated in early slippage and occult Fracture
    3. Demonstrates physeal widening and edema
    4. May identify physeal defects that increase risk of slippage (pre-SCFE)
  3. Hip Ultrasound
    1. May consider as an alternative to MRI when XRay is non-diagnostic
    2. May demonstrate metaphyseal step-off (similar to S Sign on XRay)

XII. Differential Diagnosis

  1. See Hip Pain Causes
  2. See Causes of Limp in Children

XIII. Management

  1. Orthopedic Urgency!
  2. Non-weight bearing status (Crutches or Wheel Chair)
  3. Do not attempt to forcefully relocate SCFE
    1. Risk of avascular necrosis
  4. Hospitalization and operative fixation
    1. Stable SCFE or Mild SCFE (displacement < 1/3 femoral neck width)
      1. In situ fixation with single screw is successful in 90% of mild cases (preferred method)
      2. Epiphysis is surgically pinned at current location at time of diagnosis
    2. Unstable SCFE (unable to bear weight without Crutches) or Severe SCFE (displacement > 1/2 femoral neck width)
      1. High risk for Hip Avascular Necrosis (50% of cases), Femoroacetabular Impingement (longterm Disability)
      2. Severe chronic SCFE may require osteotomies to realign and stabilize
      3. Repair timing and reduction method vary based on patient and surgeon preference
        1. Best outcomes for repair within 24 hours (higher AVN risk if delayed >72 hours)
  5. Postoperative Rehabilitation in Stable SCFE
    1. Unstable SCFE in contrast, is more slowly advanced
    2. Multi-phased return to activity managed by physical therapy
    3. Phase 1 (6 weeks): Reduce inflammation, protect repair, Crutches, gait analysis
    4. Phase 2 (2-4 weeks): Crutches discontinued if normal pain free gait and painless Straight Leg Raise abduction
    5. Phase 3/4 (4-6 weeks each): Improve strengthening, range of motion and aerobic fitness
    6. Phase 5 (4-6 weeks): Preparing for return to sport and other activity
  6. Older methods
    1. Spica hip Casting for 6 to 8 weeks
      1. Was used to reduce risk of Femoral Neck Fracture and protect epiphyses

XIV. Prevention

  1. Prophylactic pinning of unaffected hip
    1. Not typically recommended
    2. May be indicated in high risk for future SCFE (e.g. young patient, Obesity, endocrine cause)
  2. Longterm follow-up with orthopedics after diagnosis
    1. High risk of Hip Avascular Necrosis

XV. Complications

  1. Avascular Necrosis of the Femoral Head (20-50% of unstable SCFE patients)
    1. Premature degenerative Hip Arthritis (and need for hip reconstruction or total hip arthroplasty)
  2. Premature closure of the femoral head Growth Plate
  3. Chrondrolysis (articular cartilage acute loss)
    1. May result from pin penetration of femoral head during single screw placement
    2. Previously Incidence was as high as 7% following pinningm but now decreased to 1%
      1. Reduced risk attributed to improved pinning techniques
  4. Femoroacetabular Impingement
    1. Results from proximal femur anatomic changes with severe slip and malpositioning
    2. May be prevented with subtrochanteric osteotomy
    3. May be associated with labral tear
  5. Degenerative Arthritis
    1. Top cause of Hip Arthritis in age <60 years
    2. Hip replacement is common and is at least a decade earlier than with primary Osteoarthritis
  6. Limb Length Discrepancy
    1. Severity correlates with Southwick slip angle and progressive with age
  7. Hip Labral Tear
    1. Found in >80% of treated SCFE patients
  8. Chrionic Hip Pain
    1. Affects 33% of SCFE patients

XVI. Prognosis

  1. Stable SCFE
    1. In situ fixation has a good longterm outcome, with advancing of athletic activity after epiphysis closes
  2. Unstable SCFE
    1. High risk for Hip Osteonecrosis (20-50% risk) and Femoroacetabular Impingement
  3. Contralateral involvement may occur in up to 60% of cases (observe closely)
    1. Onset of contralateral involvement occurs within 18 months in 88% of those with bilateral involvement

XVII. References

  1. Broder (2022) Crit Dec Emerg Med 36(11): 18-9
  2. Gardiner (2018) Crit Dec Emerg Med 37(5): 3-14
  3. Jhun and Raam in Herbert (2016) EM:Rap 16(2):15-6
  4. Peck (2017) Am Fam Physician 95(12): 779-84 [PubMed]
  5. Webb (2025) Am Fam Physician 112(4): 414-23 [PubMed]

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