Slipped Capital Femoral Epiphysis(SCFE):

• a disorder of paediatric & adolescent
  
• the displacement of capital femoral epiphysis relative to the femoral neck
  
• an instability of proximal femoral growth plate
  
• an accurate diagnosis & immediate treatment needed to prevent complication
  
• Boys> girls (3:2); Obese Children; Age(average)- Boys:12.7 yrs & Girls: 11.2 yrs (with some variations in different text)
  
• Left hip> Right hip; B/L in 17-50%
  
• Risk factors: Obesity, Metabolic endocrine disorder, Femoral Retroversion, H/o- radiation to the hip area.
  

Pathophysiology:

• PathoAnatomy- Expansion of hypertrophic zone with widening of physeal plate; Weakness/instability of the perichondral ring & abnormal cartilage maturation in the hypertrophic zone- a weak point
  
• Mechanism– Changing of the orientation of proximal physis normally from horizontal to oblique during preadolescence & adolescence→ hip forces change from compression forces to shear forces
  -Slippage through the weakened area of hypertrophic zone by mechanical forces acting on susceptible physis.
  
• Proximal epiphysis remains in the acetabulum; the distal part(neck): anterior displacement & external rotation
  

Associated Medical Conditions:

• Endocrine disorders:
  

  -hypothyroidism(↑TSH)
  -panhypopituitarism
  -hypogonadism
  -osteodystrophy of chronic renal failure (deranged BUN & creatinine)
  -Growth hormone abnormalities (h/o-Growth hormone(GH) treatment)
  

• Bilateral SCFE- more common in the younger pts. with metabolic/endocrine disorders
  
• Indications for endocrine workup–
  -child age < 10 yrs old
  -Wt. < 50th percentile
  

Types & Classifications:

• Acute– symptoms< 3wks; Chronic– > 3wks; Acute on Chronic– acute exacerbation; Pre-slip– not obvious on x-ray
  
• LODER Classification: Stable– pt can bear wt. with/without support; risk of Osteonecrosis <10%
  Unstable– unable to bear wt.; greater risk of Osteonecrosis (40-50%)
  
  

• SOUTHWICK Angle Classification: Mild–30⁰; Moderate-30-50⁰; Severe–50⁰
  
• Grading (percentage of slip): Grade I– 0-33%; Grade II– 34-50%; Grade III– >50%.
  

Clinical Symptoms & Signs:

• Symptoms: Obese Child with Groin & Thigh Pain(MC); many children also have knee pain
  -presentation- may be acute or longer (for weeks to months)
  -H/O- trauma- ±
  
• Sign: -hip pain on movement & decreased/loss of hip motion
  -Wt. bearing- variable (Stable vs Unstable)
  -If pt ambulatory: abnormal gait- antalgic, externally rotated/out-toeing or Trendelenburg gait
  -if chronic: thigh muscle atrophy
  
• Examination of opposite hip- must
  

D/D:

• AVN femoral head
  
• Fracture neck of femur(NOF)
  
• Stress fracture NOF
  
• Proximal femur fracture
  
• Groin injury
  
• Osteitis pubis
  

Radiological Studies:

• X-ray: AP & Frog-leg lateral views of B/L hips
  AP view– Klein line– normally should intersect the epiphysis-if not→ SCFE (Trethowan’s sign);
  
  

  Trethowan Sign & the Line of Klein

  
  -Growth plate widening- epiphysiolysis;
  -Sickle shaped head
  -Metaphyseal blanch sign of Steel– due to overlapping metaphysis & epiphysis
  -Herndon’s hump-? in chronic casesFrog-leg Lateral View– best view for mild case;

  -Measurement of Southwick Angle to determine the degree of slip
  

  

  Fig: Measurement of Southwick angle- the difference between the affected & the normal side: 44 degree

  
  

• MRI: may diagnose preslip condition if x-ray is normal; ↑ed signal of metaphyseal area with widened growth plate.
  

Treatment: on emergency basis if acute

Pre-op management: Immediate bed rest & no wt bearing; preparation for surgery- Blood investigations & PAC

Surgery-

• In situ percutaneous cannulated screw fixation of affected hip:-both stable & unstable hips
  –Fixation of opposite hip in high risk pt. (obese, endocrine disorders, early age- <12 in male; <10 in female)
  
• Reduction of Epiphysis & fixation- controversial; only in unstable high grade cases- high risk of osteonecrosis
  
• Epiphysiodesis combined with early Imhauser intertrochanteric osteotomy
  
• Dunn procedure
  
• Proximal Femoral Osteotomy: for deformity correction in chronic severe slip with pain/limited function
  -Intertrochanteric Osteotomy (Imhauser),
  -Subtrochanteric osteotomy (Sothwick)
  –
  

Complications:

• Osteonecrosis– 40-50% in high grade unstable slip; 4-6% due to surgery- more risk if two screws used
  
• SCFE in Opposite hip: 20-80%; risk factors- male child, obesity, endocrine disorders, early age
  
• Chondrolysis:  destruction of articular cartilage→ joint space narrowing; by Intra-articular penetration of implant (0-2%)
  
• Proximal femur deformity: treated by Osteotomy: – Intertrochanteric Osteotomy (Imhauser); Subtrochanteric osteotomy (Sothwick)
  
• Progression of slip– in some cases with single screw fixation (1-2%)
  
• Others- Chronic pain, Infection, Degenerative changes of the joint, Implant related proximal femur facture.