congenital clubfoot

Etiology

  • Genetic (incidence by race, familial concordance, male:female = 2.5:1, FH in 1/4)
  • Histologic (muscle ultrastructure, increased type I:II fiber ratio, cartilage defects, increased collagen synthesis, plantar flexion and varus deformity of talus, calcaneus, and cuboid.)
    • theory of retraction fibrosis
    • myofibroblast theory
  • Vascular anomalies – hypoplasia or absence of anterior tibial artery
  • Anomalous Muscles – 15%
  • Intrauterine factors
    • Left=Right, develops during third trimester, therefore external compression not likely to be a factor (despite popularity of theory)
    • ? interruption of normal development
    •  Associated with early amniocentesis (<week 11) = 10X (150X higher if leak occurs)
    • anterior horn cell death (due to maternal enterovirus infection)

Physical Examination

  • Associated with UE, back, leg anomalies, ABN reflexes.
  • reference with knee 90deg flexed.
  • torsional alignment, varus, valgus, overall size and shape of leg, ankle, foot.
    • usually shorter and wider than normal foot.
  • check equinus in flexion and extension (account for gastroc & soleus)
  • check resting varus / valgus as well as maximum correction
  • check lateral border of foot (calcaneocuboid)
    • n.b. check with foot dorsiflexed as well (avoid overcorrection = iatrogenic rocker bottom foot)
  • check dorsolateral foot (talar head — should line up with patella)
    • line up forefoot onto talar head
  • all deformites should be assessed in relation to next proximal segment.

Radiographs

  • tough to read, tough to reproduce – try to get in maximal correction with (simulated) weight bearing.
  • On AP:
    • AP talocalcaneal angle (usually < 20 deg in clubfoot)
    • tarsal – first metatarsal angle (up to 30 degrees of valgus in norma foot, mild to severe varus in clubfoot)
    • medial displacement of cuboid on calcaneus 
  • on lateral ( taken in max dorsiflexion & lat. rotation without pronation):
    • talocalcaneal angle (usu. < 25 deg in clubfoot)
    • talar – 1st MT angle (if plantar flexed, plantar soft tissues are contracted or midtarsal bony deformity is present

MORE TO COME (ON TREATMENT AND RECURRENCE)

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