Slipped Capital Femoral Epiphysis

Topic updated on 09/27/16 10:49am
  • Disorder of the proximal femoral physis that leads to slippage of the epiphysis relative to the femoral neck
  • Epidemiology
    • incidence
      • most common disorder affecting adolescent hips, found in 10 per 100,000
    • demographics
      • more common in
        • obese children (single greatest risk factor)
        • males (male to female ratio is 3:2)
        • African Americans
        • Pacific islanders
        • during period of rapid growth
      • average age is
        • 13.4 for boys
        • 12.2 for girls
        • associated with puberty
    • location
      • left hip is more common
      • bilateral in 17 to 50%
    • risk factors
      • femoral retroversion
      • obesity (single greatest risk factor for SCFE)
      • history of previous radiation therapy to the femoral head region
  • Pathophysiology
    • mechanism
      • due mechanical forces acting on a susceptible physis
    • pathoanatomy
      • slippage occurs though the hypertrophic zone of the physis 
        • caused by weakness of the perichondral ring
        • cartilage in the hypertrophic zone acts as a weak spot 
      • epiphysis stays in the acetabulum while the neck displaces anteriorly and externally rotates (epiphysis is posterior)
  • Associated conditions
    • endocrine disorders
      • conditions to look for  
        • hypothyroidism (labs show elevated TSH)
        • osteodystrophy of chronic renal failure (abnormal BUN and creatinine)
        • growth hormone treatment
      • indications for endocrine workup
        • child is < 10 years old
        • weight is < 50th percentile
Stable vs. Unstable Classification (Loder Classification)
Stable Able to bear weight with or without crutches
Minimal risk of osteonecrosis (<10%)
Unstable Unable to ambulate (not even with crutches)
Associated with high risk of osteonecrosis (~47%)
  • Provides prognostic information
Temporal Classification (rarely used)
Acute Symptoms that persist for less than 3 weeks
Chronic Symptoms that persist for more than 3 weeks
Acute on Chronic Acute exacerbation of long-standing symptoms
Southwick Angle Classification
Mild <30°
Moderate 30-50°
Severe >50°
  • Measurement of the difference between both hips in the femoral head-shaft angle on the frog lateral radiograph  
  • Difference between these two angles obtained on the affected and unaffected sides determines the degree of slip and resulting abnormal alignment
 Grading System for SCFE
Grade I 0-33% of slippage
Grade II 34-50% of slippage
Grade III >50% of slippage
  • Symptoms
    • groin and thigh pain
      • most common presentation
    • knee pain
      • can frequently present as knee pain (15-23%)   
    • motion
      • patients prefer to sit in a chair with affected leg crossed over the other
    • duration
      • symptoms are usually present for weeks to several months before diagnosis is made
  • Physical exam
    • abnormal gait
      • coxalgic, externally rotated gait or Trendelenburg gait
    • decreased hip motion
      • obligatory external rotation during passive flexion of hip
      • loss of hip internal rotation, abduction, and flexion
    • abnormal leg alignment
      • externally rotated foot progression angle
    • weakness
      • thigh atrophy
  • Radiographs
    • recommended views
      • AP & frog-leg lateral of right and left hip 
        • lateral radiograph is best way to identify a subtle slip
    • findings on AP of pelvis
      • Klein's line 
        • line drawn along superior border femoral neck will not intersect femoral head in a child with SCFE (does in a normal hip) 
      • epiphysiolysis (growth plate widening or lucency) 
        • an early radiographic findings
      • blurring of proximal femoral metaphysis (metaphyseal blanch sign of Steel)
        • seen on AP due to overlapping of the metaphysis and posteriorly displaced epiphysis
  • MRI 
    • indications
      • can help diagnose a preslip condition when radiographs are negative
    • findings
      • shows growth plate widening and increased signal of the metaphysis
  • Operative
    • percutaneous in situ fixation   
      • indications
        • both stable and unstable slips
      • technique
        • one vs. two cannulated screws is controversial
          • 2 screw constructs have greater biomechanically stable than the single screw constructs 
          • benefit of 2 screws needs to be considered in the face of greater violation of the physis +/- articular surface
    • contralateral in situ prophylactic pinning (bilateral in situ fixation)
      • indications   
        • remains controversial
        • current indications are high risk patients (contralateral slip ~ 40-80%)
          • obese males
          • endocrine disorders (e.g. hypothyroidism)
          • initial slip at younger age (<10 years old or have open triradiate cartilage)
    • epiphyseal reduction and pinning
      • indications
        • reduction remains controversial
        • unstable, high grade SCFEs
    • proximal femoral osteotomy
      • indications
        • correction of painful or function-limiting proximal femoral deformities associated with severe, chronic slip
  • Percutaneous in situ fixation
    • goal
      • stabilize the epiphysis from further slippage and promote closure of the proximal femoral physis 
    • technique
      • reductions
        • forceful reduction is not indicated and increases risk of osteonecrosis
        • "serendipitous reduction" is often obtained with positioning
      • screw fixation
        • single cannulated screw sufficient and decreases risk of osteonecrosis (compared to multiple pins) in unstable SCFE   
        • screw must start on the anterior surface of the neck in order to cross perpendicular to the physis enter into the central portion of the femoral head  (which has slipped posteriorly) on both the AP and lateral views 
        • minimum of 3 threads crossing the physis
        • screws should be at least 5mm from subchondral bone in all views
      • imaging
        • use fracture table to obtain good radiographic visualization
        • rotate under live fluoroscopy to confirm that pin is not penetrating the hip joint
    • postoperative
      • stable slips are able to bear weight after in situ pinning
      • unstable slips are made non-weight bearing
  • Open reduction with capital realignment
    • techniques
      • surgical dislocation with epiphyseal reorientation
      • modified Dunn procedure with formation of a epiphyseal vascular flap
  • Proximal femoral osteotomy
    • techniques
      • can be performed at the subcapital, femoral neck, intertrochanteric and subtrochanteric regions
      • subcapital and femoral neck osteotomies provide the most correction but are associated with the highest risks of osteonecrosis and should be avoided
    • typical correction consists of flexion, valgus and derotation
  • Osteonecrosis of femoral head (4-6%)    
    • may occur as the result of
      • initial trauma
        • increased risk with high grade slips (~45-50%)
      • operative complication (4-6%)
        • hardware placement in posteriosuperior femoral neck has the greatest risk of disrupting the vascular supply 
  • Contralateral hip SCFE
    • most common complication after unilateral surgical fixation (20-80%) 
      • risk factors for contralateral slip include
        • male, obesity, young age of initial slip, endocrine disorders
  • Chondrolysis (0-2%)
    • associated with
      • unrecognized implant penetration of the articular surface (0-2%)
      • spica cast immobilization
      • decreased prevalence with modern fluoroscopy
  • Residual proximal femoral deformity & limb length discrepancy
    • increased α-angle associated with symptomatic impingement
    • caused by failure of proximal femur to remodel
    • treatment
      • intertrochanteric osteotomy (Imhauser) 
        • produces flexion, internal rotation and valgus
      • subtrochanteric osteotomy (Southwick's)
      • cuneiform osteotomy (controversial due to high rate of osteonecrosis and arthritis)
  • Slip progression
    • occurs in 1-2% of cases following single screw fixation
  • Infection (0-2%)
  • Chronic pain (5-10%)
  • Degenerative arthritis 
  • Pin associated proximal femur fracture
  • Labral tearing and degeneration
    • seen with high anterior and medial 2nd screw in-situ fixation 


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Qbank (23 Questions)

(OBQ12.240) A 12-year-old mildly overweight female presents with complaints of left hip pain. She is not dependent on crutches for ambulation. Physical examination reveals external rotation of the extremity with hip flexion. Her parents indicate that outside radiographs were interpreted to be normal. They present an MRI of the pelvis, as shown in Figures A and B. What is next best step in management? Topic Review Topic
FIGURES: A   B        

1. Observation
2. Arthroscopic labral repair
3. In situ screw fixation
4. Closed reduction and percutaneous pinning
5. Debridement of CAM impingement femoral lesion

(OBQ12.259) A 13-year-old male presents with left hip pain and an inability to ambulate. He does not have a history of kidney disease. The initial radiograph is shown in Figure A. Which of the following zones of the growth plate (Figures B-F, all the same magnification) is most commonly involved in this condition? Topic Review Topic
FIGURES: A   B   C   D   E   F

1. Figure B
2. Figure C
3. Figure D
4. Figure E
5. Figure F

(OBQ11.81) An 11-year-old obese male presents with a slipped capital femoral epiphysis. Which of the following figures accurately represents the method used to determine the radiographic severity of the epiphyseal slip and help guide treatment? Topic Review Topic
FIGURES: A   B   C   D   E  

1. Figure A
2. Figure B
3. Figure C
4. Figure D
5. Figure E

(OBQ11.127) A 12-year-old girl presents with groin pain six months after treatment of a slipped capital femoral epiphysis. Preoperative radiographs are seen in Figure A, radiographs six months after in situ fixation are seen in Figure B. Which of the following is associated with the radiographic abnormality seen in Figure B? Topic Review Topic
FIGURES: A   B        

1. Lack of reduction prior to fixation
2. Single screw fixation
3. Female sex
4. Inability to bear weight preoperatively
5. Obesity

(OBQ10.66) A 13-year-old boy complains of a 3-month history of left knee, thigh and groin pain. His pain has significantly worsened over the past week. He denies pain in the right leg. Radiographs are taken and shown in Figures A and B. The history and physical do not reveal any findings concerning for an endocrine disorder. What is the preferred method of treatment? Topic Review Topic
FIGURES: A   B        

1. Subtrochanteric valgus, extension, and external rotational osteotomy
2. Non weight bearing on the left side for 6 weeks.
3. Bilateral in situ single screw insertion across the proximal femoral physis
4. In situ single screw insertion across the left proximal femoral physis only
5. Varus derotational osteotomy of the proximal femur

(OBQ07.2) Southwick angle (epiphyseal-shaft angle) serves what purpose in the evaluation of a slipped capital femoral epiphysis (SCFE)? Topic Review Topic

1. Determine prognosis for AVN
2. Determine the severity of the slip
3. Determine the presence or absence of a slip
4. Determine the etiology of a slip
5. Determine the chronicity of the slip

(OBQ07.187) Which of the following treatment techniques decreases the risk of osteonecrosis in patients with unstable slipped femoral capital epiphysis (SCFE)? Topic Review Topic

1. Open reduction and pinning with multiple cannulated screws in an inverted triangle configuration
2. Closed reduction and pinning with multiple cannulated screws in an inverted triangle configuration
3. Closed reduction and pinning with a single cannulated screw
4. In situ percutaneous pinning with multiple cannulated screws in an inverted triangle configuration
5. In situ percutaneous pinning with a single cannulated screw

(OBQ06.183) Hypothyroidism is most commonly associated with which of the following pediatric conditions? Topic Review Topic

1. Legg Calve Perthes
2. Slipped capital femoral epiphysis
3. Toxic synovitis
4. Achondroplasia
5. Rickets

(OBQ05.60) An 11-year-old girl with hypothyroidism and obesity presents with groin pain and the inability to ambulate. Her radiograph is shown in Figure A. What is the most appropriate treatment? Topic Review Topic
FIGURES: A          

1. Toe-touch weightbearing for 3 weeks
2. Hip spica cast and non-weight bearing for 4 weeks
3. In situ pinning of the right hip
4. Open reduction and pinning of the right hip
5. In situ pinning of both hips

(OBQ05.125) A 13-year-old Polynesian boy presents with left groin pain and inability to place weight on the left leg. His radiographs are shown in Figures A and B. All of the following are true regarding this condition EXCEPT: Topic Review Topic
FIGURES: A   B        

1. The left hip is more commonly involved
2. Forceful manipulation is not indicated because it is associated with an increased risk of complications
3. Associated with decreased femoral anteversion and decreased femoral neck-shaft angle
4. Pain is localized to the knee more often than the hip on initial presentation
5. Males are more commonly affected than females

(OBQ05.162) A 14-year-old boy presents with left groin and knee pain for 3 weeks. He is now unable to place weight on the left lower extremity, even with the assistance of crutches. AP pelvis radiograph is shown in Figure A. He is treated with surgical intervention and post-operative radiographs are shown in Figures B and C. What is the most common limb length and rotational profile found as a sequelae of this condition? Topic Review Topic
FIGURES: A   B   C      

1. Limb shortening, decreased hip flexion and decreased hip internal rotation
2. Limb lengthening, increased hip flexion, and increased hip internal rotation
3. Limb lengthening, decreased hip flexion, and decreased hip external rotation
4. Limb shortening, decreased hip flexion, and increased hip internal rotation
5. Limb shortening, increased hip flexion, and decreased hip internal rotation

(OBQ04.67) A 14-year-old female presents with a history of an undiagnosed left slipped capital femoral epiphysis 3 years ago. She has 2 years of activity-related left hip pain and pain with prolonged sitting. On physical examination she has restricted hip flexion motion, an external rotation deformity, and obligatory external rotation upon hip flexion manuevering. Radiographs are shown in Figures A and B. Which of the following osteotomies is MOST appropriate? Topic Review Topic
FIGURES: A   B        

1. Medial displacement Chiari salvage osteotomy
2. Proximal femoral varus osteotomy
3. Flexion, internal rotation, and valgus-producing proximal femoral osteotomy (Imhauser osteotomy)
4. Bernese periacetabular osteotomy with extension, external rotation, and valgus-producing femoral osteotomy
5. Valgus-producing intertrochanteric proximal femoral osteotomy (Pauwel osteotomy)

(OBQ04.83) A right hip of an 8-year-old patient is modeled in Figure A. Which of the following vessels gives the greatest blood supply to the femoral head? Topic Review Topic
FIGURES: A          

1. 1
2. 2
3. 3
4. 4
5. 5

(OBQ04.165) A 14-year-old overweight boy complains of vague left knee pain which worsens with activity. He has an antalgic gait and increased external rotation of his foot progression angle compared to the contralateral side. Knee radiographs, including stress views, are negative. What is the next step in management? Topic Review Topic

1. Knee MRI
2. Knee CT
3. AP pelvis and frog-lateral views
4. Diagnostic knee arthroscopy
5. Hip MRI

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