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Casting for Club Foot

Discussion

pathoanatomy

  • whole foot is in extreme supination, however, the fore part of the foot is pronated with respect to the hindfoot, as a result of the cavus deformity (the first metatarsal is more plantar flexed than the fifth metatarsal);
  • navicular and the cuboid are rotated medially in relation to the talus, and are held in adduction and inversion by contracted ligaments and tendons;
  • tibial-navicular interval:
    • distance between the medial malleolus and the tuberosity of the navicular;
    • shorter intervals indicate worse deformity;
    • degree of resistance of navicular to be moved away from medial malleolus correlates with severity of deformity.
    • note that in severe clubfoot, complete reduction of the extreme medial displacement of the navicular may not be possible by manipulation;

timing

  • casting begins in the first week of life inorder to take advantage of the initial elasticity of contracted ligaments, joint capsules and tendons;
  • improvements from manipulation are maintained by immobilizing the foot in a plaster cast for five to seven days;
  • within the first 2-3 months, the surgeon attempts 5-6 manipulation and cast applications;
  • children who present for treatment after four or five months old may require operative correction because ligaments become stiffer;
  • total duration of treatment should be less than three months;
  • 6-8 toe-to-groin plaster casts, changed weekly after manipulation and worn for 7-10 weeks, should be sufficient to obtain maximum correction possible;

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Sequence of Correction: (Ponseti)

correction of cavus

  • cavus deformity must be corrected prior to correcting the other deformities;
  • forefoot is supinated and the first metatarsal is dorsiflexed;
    • this reverses the contracted forefoot pronation;
    • pronation of the foot will worsen the deformity and will increase the cavus;
    • an attempt to correct the inversion of the foot by forcible pronation of anterior part of the foot increases the cavus deformity as first metatarsal is plantar-flexed further;

correction of adduction and heel varus

  • goal is to abduct the supinated foot under the talus;
    • again, forceful pronation of the foot is avoided since it increases the cavus deformity, causes mid foot break down and does not address the varus heel deformity;
  • talus is rotated laterally so that the foot abducts underneath the talus which is fixed in the ankle mortice;
    • this causes lateral rotation of navicular, together w/ cuboid & anterior aspect of calcaneus, w/o pronation of foot;
  • to correct the varus and adduction, the foot in supination is abducted while counterpressure is applied with the thumb against the head of the talus;
    • foot is abducted in flexion and slight supination to stretch the medial tarsal ligaments, while counter pressure applied on the lateral aspect of the head of the talus;
      • this allows the calcaneus to abduct under the talus which correction of the heel varus;
    • heel must not be touched during this manipulation;
  • calcaneus abducts by rotating and sliding under the talus;
    • noted that the calcaneus can evert only when it is abducted (laterally rotated) under the talus.
    • as the calcaneus abducts it simultaneously extends and everts which corrects the heel varus;
    • note that the calcaneus cannot evert unless it is abducted;
  • casting involves a toe-to-groin plaster cast w/ knee flexed 90 degrees and the foot in maximum external rotation;
    • maintenance of correction of varus deformity of hind part of foot which requires external rotation of foot distal to talus;
  • radiographs may be taken at this point inorder to confirm that the talonavicular joint is reduced, prior to managing equinus;
  • cautions:
    • avoid forced external rotation of the foot to correct adduction while the calcaneus is in varus;
      • this causes a posterior displacement of the lateral malleolus by externally rotating the talus in the ankle mortice.
    • avoid abducting the foot against pressure at the calcaneocuboid joint the abduction of the calcaneus is blocked, thereby interfering with correction of the heel varus

correction of equinus:

  • equinus is corrected last, by dorsiflexion of foot w/ heel in valgus angulation;
  • if foot is dorsiflexed prior to correction of the hindfoot varus, rocker bottom foot may be created;
  • equinus is corrected by dorsiflexing the fully abducted foot;
  • correction entails stretching of the tight posterior capsules and ligaments of ankle and subtalar joints and the tendo achillis;
  • lateral x-ray are helpful in assessing quality of cast correction;
  • percutaneous tenotomy of the achillis tendon:
    • may be necessary inorder to avoid rocker bottom deformity;
    • dorsiflexion of ankle to > 10 to 15 degrees is rarely possible because of talar and calcaneal malformations and tight ligaments;
  • cautions:
    • care should be taken not to cause a rocker-bottom deformity, which can occur when dorsiflexion of foot is attempted w/ pressure under metatarsals rather than under the mid-part of foot, particularly when varus deformity of heel has not been corrected;
    • do not to exert excessive upward force on metatarsals, because this can result in midfoot break (rocker-bottom deformity);
  • ref: Radiographic Evaluation of Idiopathic Clubfeet Undergoing Ponseti Treatment

Complications

  • increased cavus deformity;
  • rocker-bottom deformity;
  • longitudinal breach
  • flattening of the proximal surface of the talus
  • lateral rotation of the ankle
  • increased stiffness of the ligaments and joints;
  • recurrence:
    • Ponseti advocates use of shoes attached to a bar in external rotation for three months full-time and at night for 2-4 years

 

Masters in Surgery

 



Motivation for Ponseti Method: Current Surgical Methods:


Example of Wound Breakdown following Surgery:



Casting Considerations for the Ponseti Technique: 1


Casting Considerations for the Ponseti Technique: 2

Achilles Tenotomy:

Use of x-rays to assist with achilles tentomy:


Dennis Brown Bar:


Outcomes:


Surgical Case Example: Ilizarov Method




Compliance:

References