Blount’s disease

• Blount’s disease is a growth disorder of the tibia characterised by bowing of legs
• Also called pathologic tibia vara, non rachitic bowlegs, Blount Barber disease
• Clinical features
  • Presents with progressive bowing of legs in a child
  • There is varus angulation and internal rotation of tibia
  • Usually seen in children if African origin
  • Associated with obesity, early walking and short stature
• Clinical types
  • Infantile – early onset (<3 years of age)
  • Juvenile – 4-10 years
  • Adolescent – >11 years
• Pathology
  • There is disordered bone ossification in the medial part of proximal tibial epiphysis, physis and metaphysis
  • Presumed to be caused by excessive compressional forces on the proximal medial tibial epihysis and alteration in bone formation
  • Weight bearing is necessary for development of Blount’s disease as it is not seen in non ambulatory individuals
• Differential diagnosis
  • Physiological bowing – in contrast with blount’s disease which has a acute angulation in the proximal tibia, physiological bowing is characterised by smooth angulation of femur and tibia
  • Congenital bowing
  • Rickets – Other features of rickets will be present, responds to treatment with Vitamin D
  • Ollier’s disease – Radiographs will reveal presence of multiple enchondromas
  • Trauma, osteomyelitis – can damage the growth plate and defects similar to blount’s disease
• Treatment
  • Braces are worn to correct the deformity (usually Knee Ankle Foot Orthosis – KAFO)
  • If deformity is not corrected even after wearing braces for 12 months, corrective surgery can be done

Reference:
Obesity in childhood and adolescence By Wieland Kiess, Claude Marcus, Martin Wabitsch