Peds

Genu Valgum

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Genu Valgum, Knock-Knee

  • See Also
  1. Genu Varum
  2. Pediatric Leg Disorder
  3. Pediatric Limp
  4. Gait Evaluation in Children
  • Physiology
  • Normal Course
  1. Birth: Maximal varus
  2. Age 2 years: Neutral position
  3. Ages 3-4 years: Maximal valgus (>10 degrees)
  4. Age >10 years: Anatomic valgus at 6 degrees
  5. Valgus deformity persists more in girls than boys
  • Risk Factors
  1. Obesity
  2. Osteogenesis Imperfecta
  3. Rickets
  4. Renal Osteodystrophy
  5. Skeletal Dysplasia
  6. Klinefelter Syndrome
  • Signs
  1. Knock-Kneed appearance
  2. Evaluate standing knee alignment
    1. Intermalleolar distance
      1. Normally 0 cm at birth, 0-5 cm at age 3 years, 0-3 cm at age >=8 years
      2. Abnormal if >2 SD outside normal values
    2. Other measurements
      1. Intercondylar distance
      2. Tibiofemoral angle
  • Precautions
  1. Onset as teen is unusual and warrants referral
  2. Atypical acquired cases may result from Trauma, prior Osteomyelitis or Fracture
  • Differential Diagnosis (Pathologic Genu Valgum)
  1. Rickets
  2. Growth Plate Injury
  3. Prior proximal tibial metaphysis Fracture (Cozen Deformity)
  4. Diastrophic dysplasia
  5. Morquio's Syndrome
  6. Ellis-van Creveld or Chondroectodermal Dysplasia
  7. Spondyloepiphyseal Dysplasia
  8. Pseudoachondroplasia
  9. Rheumatologic Disorders (Genu Valgum-like deformity)
  • Management
  • Orthopedic Referral Indications
  1. Intermalleolar distance outside of normal range for age
  2. Associated syndrome suspected
  • Complications
  1. Premature Osteoarthritis
  • References
  1. Baird (2025) Am Fam Physician 111(2): 125-39 [PubMed]
  2. Rerucha (2017) Am Fam Physician 96(4): 226-33 [PubMed]