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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;

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