What causes Clubfoot?
Clubfoot can occur in isolation (idiopathic clubfoot) or as part of other medical conditions (syndromic clubfooot). Approximately 20% of patients have clubfeet on both sides (bilateral clubfeet). Idiopathic clubfoot is associated with hereditary and environmental factors. Researchers into the genetics clubfoot have noted that “the susceptibility to develop TEV [talipes equinovarus] is determined by a number of environmental and genetic factors, although the nature and level of interplay between them remains unclear.”
Several genes have been found to be associated with clubfoot. Hordyjewska-Kowalczyk and colleagues wrote that the most prominent genetic association is with “PITX variants, which were linked to clubfoot phenotype in mice and humans.” Other genetic associations with clubfoot include “copy number variations encompassing TBX4 or single nucleotide variants in HOXC11, the molecular targets of the PITX1 transcription factor.” They noted that “in general, genes of cytoskeleton and muscle contractile apparatus, as well as components of the extracellular matrix and connective tissue, are frequently linked with clubfoot aetiology.” Bashit and Khoshhal noted genetic correlations including “variants in TBX4, PITX1, HOXA, HOXC and HOXD clusters genes, NAT2 and others.” Sun and colleagues reported have found diminished cross-sectional muscle area in clubfeet compared to the non-clubfoot side, with elevated myostatin (a protein which inhibits muscle growth) in atrophied calf muscles and diminished expression of TAZ (a gene which counteracts myostatin-induced atrophy).
Some researchers have reported findings that clubfeet may have less vascular perfusion (blood flow) than healthy feet, but this claim is controversial. Merrill and colleagues reported an increased rate of vascular anomalies in patients with recurrent idiopathic clubfeet. Shaheen and colleagues in Sudan reported decreased flow on Doppler ultrasound and/or Ankle Brachial Index in 39% of idiopathic clubfoot patients (and 76% of patients with severe clubfoot. In contrast, a larger study by Forrester and colleagues comparing 64 patients with clubfeet against control found that perfusion was not measurably decreased in idiopathic clubfeet.
How is Clubfoot treated?
The Ponseti method is widely considered the “gold standard” for clubfoot care. The Ponseti Method is a system that includes serial manipulation and casting according to a specific protocol, a percutaneous Achilles tendon lengthening for most patients, and bracing, first full-time and then at night until the age of 5 for many patients.
Ponseti manipulations are based on anatomic study of the child’s foot. Briefly summarized, the first casts involve supination of the forefoot and elevation of the first metatarsal base to unlock the transverse tarsal joint while the ankle is maintained in plantar flexion, allowing the “unlocking” of the talus from the calcaneus that allows more anatomic correction of the clubfoot deformity. Subsequent manipulations involve rotation about the lateral aspect of the talar head and progressively stretch and straighten the foot. A full description is found in Ponseti’s 1963 article.
The Ponseti method is less invasive and has been found to offer superior results compared to historical surgical approaches. A Computed Tomography (CT) research study found that “The Ponseti manipulative technique provided better anatomical results in comparison to…traditional technique.”
From the clinical and radiographic side, Ippolito and colleagues reported that “use of Ponseti’s manipulation technique and cast immobilization followed by an open heel-cord lengthening and a limited posterior ankle release gave much better long-term results than those obtained” with traditional extensive surgical release. A follow-up CT study by the same group reported that “three-dimensional CT reconstruction of the whole foot showed that cavus, supination and adduction deformities were corrected much better in the [Ponseti] group.”
In France, clubfoot has historically been treated by the French functional physical therapy method involving near-daily clinic visits to a trained therapist for manipulation and stretching, accompanied by intermittent casting and Achilles tendon lengthening. French authors have noted that both methods have strengths. However, French method’s multiple relapses have often required casting and limited available research has failed to demonstrate any compelling advantages. Advocacy of a “hybrid Ponseti” crossover technique by proponents of the French method acknowledge that the latter does not achieve adequate results for many patients. The French method’s intense schedule, greater costs, and lack of perceived benefits present barriers which have resulted in little adoption outside of France.