What is the medical term for being bow-legged?

Medical Term for Bow-Legged Condition

The medical term for being bow-legged is genu varum, which describes a condition where the distal part of the leg is deviated inwards in relation to the femur, resulting in a bow-legged appearance. 1

Clinical Definition and Characteristics

Genu varum is characterized by:

• Outward bowing of the legs with increased distance between the knees when the ankles are together
• Medial deviation of the tibia in relation to the femur
• Can be physiologic (normal developmental variant) or pathologic (disease-related)

Types and Etiology

Physiologic Genu Varum

• Common in infants and toddlers
• Part of normal development
• Typically resolves spontaneously by 24-36 months of age 2
• Children with physiologic genu varum often walk earlier than average (around 10 months versus 12-15 months) 2

Pathologic Genu Varum

May be caused by:

• Metabolic disorders (rickets, renal osteodystrophy)
• Skeletal dysplasias (achondroplasia)
• Tibia vara (Blount disease)
• Focal fibrocartilaginous dysplasia
• Trauma affecting growth plates
• Neuromuscular disorders
• Osteogenesis imperfecta
• Neurofibromatosis 3

Diagnostic Evaluation

Clinical Assessment

• Measurement of intercondylar distance (distance between knees when ankles are together)
• Fingerbreadth measurements to document progression or resolution 2
• Assessment of gait pattern
• Evaluation for associated deformities or systemic conditions

Radiographic Assessment

• Standing radiographs of the entire lower limbs are necessary for proper evaluation 1
• Key measurements include:
  • Mechanical axis deviation
  • Tibiofemoral angle
  • Metaphyseal-diaphyseal angle (in Blount disease)
• Radiographic findings vary by etiology:
  • Developmental bowing: varus angulation centered at knee, metaphyseal beaking, thickened medial tibial cortices
  • Tibia vara: depression of the proximal tibia medially
  • Rickets: widening of the zone of provisional calcification
  • Achondroplasia: shortened, thickened long bones with metaphyseal flaring 3

Management Approach

Management depends on:

1. Age of the patient
2. Severity of the deformity
3. Underlying cause
4. Progression of the condition

For Physiologic Genu Varum

• Observation and monitoring during well-child visits
• Regular follow-up to track progression or resolution
• Typically resolves spontaneously by 30-36 months of age 2

For Pathologic Genu Varum

• Treatment of underlying condition
• Bracing in some cases
• Surgical intervention may be necessary for:
  • Persistent deformity after conservative management
  • Progressive deformity
  • Significant functional impairment
  • Pain or gait abnormalities 4

Surgical Options

• Medial opening wedge high tibial osteotomy
• Lateral closing wedge osteotomy
• Growth modulation techniques in skeletally immature patients
• Restoration of mechanical axis is the principal goal 5

Clinical Pearls and Pitfalls

Pearls:

• Differentiate between physiologic and pathologic bowing
• Most cases of physiologic bowing resolve spontaneously
• Standing radiographs of entire lower limbs are essential for surgical planning 5

Pitfalls:

• Unnecessary referrals to orthopedic specialists for physiologic bowing
• Failure to identify underlying systemic conditions
• Focusing only on the proximal tibia when the deformity may involve the distal femur 5
• Delaying treatment for pathologic cases that require intervention

When to Refer

• Children with bow legs persisting beyond 3 years of age
• Asymmetric deformity
• Progressive worsening of the deformity
• Associated pain or functional limitations
• Presence of other skeletal abnormalities suggesting systemic disease