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: 8-15 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: 10.8 per 100,000

IV. 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

V. 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

VI. Pathophysiology

  1. Posterior and inferior slippage of proximal femoral epiphysis on the femoral neck metaphysis, at the Hip Joint
  2. Occurs before the Epiphyseal Plate closes

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

VIII. Symptoms

  1. Pediatric Limp
  2. Bilateral involvement in 35% 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

IX. Signs

  1. Antalgic Gait
  2. Compare exam to opposite side (except in bilateral SCFE)
  3. Hip held in abduction and external rotation
  4. Obligatory external rotation (Drehmann Sign) or Out-toeing of the effective leg
    1. Patient externally rotates hip when the hip is actively flexed to 90 degrees
  5. Markedly limited internal rotation (most predictive finding)
    1. Hip abduction and hip flexion are also limited

X. 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. Displacement of femoral head (Wlison method of grading)
      1. Hip epiphysis displaced <33% of metaphysis width (mild)
      2. Hip epiphysis displaced 33-50% of metaphysis width (moderate)
      3. Hip epiphysis displaced >50% of metaphysis width (severe)
    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
      2. Frog-leg view is important, as AP Hip will miss SCFE in up to 60% of cases
    5. Steel Sign
      1. Double density (double line) at the hip metaphysis
    6. 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

XI. 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 or Severe SCFE (displacement > 1/2 femoral neck width)
      1. High risk for longterm Disability from Hip Osteonecrosis or avascular necrosis (50% of cases), Femoroacetabular Impingement
      2. Repair timing and reduction method vary based on patient and surgeon preference
      3. Severe chronic SCFE may require osteotomies to realign and stabilize
  5. Postoperative Rehabilitation
    1. Multi-phased return to activity managed by physical therapy
    2. Phase 1: Reduce inflammation, protect repair, Crutches, gait analysis
    3. Phase 2: Crutches discontinued if normal pain free gait and painless Straight Leg Raise abduction
    4. Phase 3/4: Improve strengthening, range of motion and aerobic fitness
    5. Phase 5: 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

XII. 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

XIII. 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

XIV. 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

XV. 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]

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