Genu Valgum

Basics

Description

  • Angling of the knee(s) toward the midline, giving the appearance of the knees touching while the ankles are apart
  • Classified as physiologic and/or pathologic
  • Physiologic genu valgum is a normal stage in the growth and development of healthy children between the ages of 2 and 7 years.
  • Pathologic genu valgum if
    • The extent of angulation is greater than the mean for that particular age.
    • The deformity persists beyond the age-appropriate progression of valgus.
    • There is an underlying etiology.

Epidemiology

Prevalence
Physiologic genu valgum is a normal variant in children 2 to 7 years of age. It is more common in females.

Etiology and Pathophysiology

  • Physiologic genu valgum
    • Lower extremity alignment in childhood progresses from varus to valgus in the first 2 years of life.
    • Around 2 years of age, lower extremity alignment progresses to valgus until it reaches a maximum (peak valgus angulation of 10 to 15 degrees) at approximately 4 years of age.
    • Most children reach neutral adult alignment (~5 degrees) by 7 years of age.
  • Etiologies of pathologic genu valgum include:
    • Physeal/bone damage
      • Trauma (e.g., proximal tibia metaphyseal)
      • Infection
      • Inflammatory disease (e.g., rheumatoid arthritis)
    • Metabolic disease
      • Rickets
      • Renal osteodystrophy
    • Skeletal dysplasias
      • Pseudoachondroplasia
      • Metaphyseal dysplasia
      • Multiple epiphyseal dysplasia
    • Neoplasms
      • Multiple hereditary exostoses
      • Osteochondromas
      • Other benign tumors
    • Other
      • Iliotibial band tightness
      • Vascular compromise
      • Neuromuscular disease
      • Obesity
      • Idiopathic

Genetics
Idiopathic genu valgum is heritable.

Risk Factors

  • Family history of genu valgum
  • Proximal tibia metaphyseal fracture (Cozen fracture)
  • Obesity

Commonly Associated Conditions

Flat feet and external tibial torsion frequently accompany physiologic genu valgum. When present, this often accentuates the appearance of valgus.

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