Coxa vara

Question 1

Pathophysiology

Answer 1

Pathophysiology

• proximal femoral physis or ossification center defects at the inferior medial aspect lead to
  
  • decreased proximal femoral neck-shaft angle
  • vertical position of the proximal femoral physis and varus
• pathomechanics
  
  • coxa vara and vertical physis increases
    
    • physeal sheering forces
    • inferior medial neck compressive forces

Question 2

Classification

Answer 2

• developmental
• congenital (e.g. congenital short femur, PFFD)
• acquired (e.g. SCFE, infection, Perthes)
• dysplasia (e.g OI, Jansen, Schmid, SED)
• cretinism

Question 3

Radiographs measures

Answer 3

• recommended views:
  
  • AP hip with limb internally rotated + lateral hip
• findings
  
  • varus neck shaft angle <120 degrees
  • short femoral neck, vertical physis
  • increased Hilgenreiner’s epiphyseal angle (normal <25 degrees)
    
    • determined on AP as angle between Hilgenreiner’s line and a line through the proximal femoral physis
  • triangular metaphyseal fragment in inferior femoral neck (looks like inverted-Y radiolucency)
  • decreased femoral anteversion

Question 4

Nonoperative treatment

Answer 4

observation alone

• indications
  
  • Hilgenreiner-ephyseal angle (normal <25 degrees)
    
    • <45 degrees – unlikely to progress
    • 45-60 – may progress
      
      • will require close follow-up if non-symptomatic

Question 5

Operative

Answer 5

corrective valgus derotation osteotomy (VDRO)

• indications< >Hilgenreiner’s physeal angle > 60°Hilgenreiner’s physeal angle between 45-60° if symptomatic (e.g. limp & progression of varus)progressive decrease in neck shaft angle < 110 °
• aftercare
  • hip-spica or abduction pillow x 4-6 weeks depending on fixation and healing

Question 6

Complications

Answer 6

• Loss of correction
• Premature closure of the proximal femoral physis
• Overgrowth of proximal femur
• Dysplasia of acetabulum