SCFE

Question 1

What is SCFE?

Question 2

What is the incidence?

Answer 2

10 per 100,000

Question 3

Which groups is it more common in?

Answer 3

1. obese children
2. males (male to female ratio is 2:1.4)
3. specific ethnicities - African Americans, Pacific islanders, Latinos

during period of rapid growth (10-16 years of age)

Question 4

What is the average age?

Answer 4

13.4 for boys

Question 5

How many cases are bilateral?

Question 6

Risk factors?

Answer 6

1. Obesity
2. Acetabular & Femoral retroversion
   3.

Question 7

Associated conditions?

Answer 7

• Endocrine disorders
  
  • Hypothyroidism
    
    • most common etiology of nonidiopathic SCFE
  • Renal osteodystrophy
    
    • labs: elevated BUN and creatinine
  • growth hormone deficiency

panhypopituitarism

indications for endocrine workup

child is < 10 years old

weight is < 50th percentile

Down syndrome

Question 8

What is the pathoanatomy?

Answer 8

• Slippage occurs in the hypertrophic zone
• The metaphysis translates anterior and externally rotates
• The epiphysis lies in the acetabulum posterior to the metaphysis

Question 9

What are the indications for endocrine workup?

Answer 9

• child is < 10 years old
• weight is < 50th percentile

Question 10

What is the classification based on ability to bear weight?

Answer 10

The Loder classification

• Stable
  
  • able to bear weight without crutches
  • Minimal risk of osteonecrosis
• Unstable
  
  • Unable to ambulate
  • High risk of osteonecrosis (25%)

Question 11

What is the Southwick Slip Angle classification?

Answer 11

• Measures the femoral epiphyseal/diaphyseal angle difference
• Epiphyseal-diaphyseal angle can be measured on both AP and frog lateral pelvis radiographs
• Slip angle classification is based on the degree of difference between the affected and unaffected hip
• Mild <30 degrees
• Moderate 30-50
• Severe >50 degrees

Question 12

What is the grading system for SCFE?

Answer 12

• Mild is <33% slippage
• Moderate 33-50%
• Severe >50%

Question 13

What are the features on history and exam?

Answer 13

• History
  
  • Groin & thigh pain
  • Limp
  • Symptoms usually present for weeks/months before presentation
• Exam
  
  • Antalgic gait
  • Decreased hip motion
    
    • Drehmanns sign
    • Loss of internal rotation, abduction and flexion
  • Abnormal leg alignment
    
    • External foot progression angle

Question 14

What are the findings on x ray?

Answer 14

• Klein’s line
  
  • Should normally intersect lateral portion of epiphysis
• Epiphysiolysis
  
  • Growth plate widening or lucency
• Metaphyseal blanch sign of Steel
  
  • Blurring of prox femoral metaphysis

Question 15

What are the findings on MRI?

Answer 15

• Growth plate widening
• Oedema in the metaphysis

Question 16

What are the indications for contralateral prophylactic fixation?

Answer 16

*

Question 17

What is the technique for screw fixation?

Answer 17

• Usually one screw sufficient
• Should be perpendicular to physis
  
  • Start on anterior surface of the proximal femur in order to cross perpendicular to the physis and enter into the central portion of the femoral head on both the AP and lateral views (center-center)
  • Starting point should not be medial to intertrochanteric line - will result in impingement between the head of the screw and acetabulum with hip flexion
• Advance until 5 threads cross physis
• Screw should be at least 5mm from subchondral bone in all views

Question 18

What are the key points of the modified Dunn procedure?

Answer 18

• Ganz surgical hip dislocation
• Develop retinacular soft tissue flaps
  
  • incise periosteum along femoral neck