A Guide to Treating Pediatric Clubfoot

Congenital clubfoot (talipes equinovarus) is a complex multiplanar deformity involving cavus, adductus, varus, and equinus components. Clubfoot is a heterogeneous disorder that, despite what its name implies, is not an isolated foot problem. Instead, it is a developmental limb disorder and the amount of involvement of the soft tissue structures of the lower limb can be highly variable between patients.

While a variety of deformities can present in infancy, clubfoot is truly defined by its hindfoot varus deformity in association with equinus (Figure 1). The condition affects 1 out of every 1000 live births with a male-to-female ratio of 2:1.¹ It remains one of the most common birth defects. While many are isolated birth defects, approximately 20% are linked to neuromuscular and/or genetic conditions. Specifically, mutations in the PITX1-TBX4-HOXC transcriptional pathway have been noted to cause familial clubfoot and vertical talus in a small number of families.² In children, 50% present with clubfoot bilaterally. Hawaiians and Maoris have been reported to have the greatest prevalence at 7 per 1000 live births.^1,3

Anatomically, this complex deformity involves the ankle, subtalar, and midfoot joints. The anatomy of these joints is distorted and remains the focus during correction. Both osseous and soft tissue components contribute to the deformity. The talus and calcaneus are both positioned in equinus. The hindfoot is positioned in varus due to subtalar joint inversion as well as internal rotation and adduction. The talus is smaller than normal, and the body is laterally rotated within the mortise while the talar head is laterally prominent and the navicular is medially subluxed. Adding to the hindfoot complexity, the calcaneus is internally rotated below the head and neck of the talus and in an equinus position. Along the transverse tarsal joint, the navicular is rotated medially around the talar head so much that it may contact the medial malleolus. The cuboid is translated medially in relation to the calcaneus. Instead of these joints being parallel to each other, they lay on top of one another. The midfoot and forefoot are adducted and plantarflexed on the hindfoot, creating a cavus deformity. The forefoot is not as inverted as the hindfoot. Occasionally, internal tibial torsion or bowing of the tibia is present.

Clubfoot may be associated with multiple other congenital disorders such as myelomeningocele, myelodysplasia, and arthrogryposis, most of which are neurologic.⁴ Since most cases are idiopathic and not associated with an additional congenital condition, it has been suggested that clubfoot is associated with a more complex trait, rather than a single gene (Figure 2). Current literature has examined the presence of mutations and deletions of transcription factor PITX.^2,5–6 The incidence among different races ranges from 0.39–7 per 1000.⁷ Chinese populations have been reported to have the lowest incidence. The male to female ratio is as high as 2.5:1.⁸ Twenty-four percent of cases have a positive family history and siblings have a 30-fold increased risk of congenital clubfoot. More recently, transcription factors have been tied to the etiology.²

Conducting a Physical Exam for Clubfoot

It is critical to perform a thorough physical exam on all clubfoot patients, which includes an examination of the hips, all 4 extremities, the neck, and the spine to rule out other associated anomalies. Assessing for a sacral dimple is important to rule out spinal cord issues such as a tethered cord, sacral agenesis, or spina bifida.

In terms of the feet, the treating physician must ensure an accurate diagnosis of clubfoot as well as rule out associated nerve or muscle problems indicative of atypical clubfoot. While all clubfeet share the same general characteristics, they are quite heterogeneous in etiology. Isolated clubfoot, those clubfeet that occur without other associated diagnoses, are the most common type, but this number is getting smaller. This is due to more careful physical examinations uncovering nerve and muscle abnormalities in many children with clubfoot, which were not diagnosed in infants in the past.

To diagnose these nerve and muscle problems, a few simple exam techniques are required. Simply stimulating the bottom of the child’s foot should elicit strong dorsiflexion and plantarflexion of the toes. If the infant cannot do this or does it weakly in any of the toes this should raise the suspicion of underlying congenital nerve problem or muscle weakness. Similarly, stimulation of the plantar lateral aspect of the foot should elicit firing of the peroneus brevis. This exam tactic should be done at each cast change to get a clear picture of motor ability in the foot. This is important as those children with weak/absent dorsiflexion and/or eversion have a more difficult treatment course with higher relapse risk. This needs to be explained to parents and caregivers.

The ability to perform a more careful physical examination will lead the treating physician and patient into the era of personalized medicine in which the risk of relapse will be more predictable based on specific physical exam findings.

Practical Pearls for Clubfoot Treatment

The Ponseti method has proven to be successful in the treatment of both isolated and non-isolated clubfoot (Figure 3). The method should be executed prior to any pediatric invasive procedures and likewise should be attempted with any pediatric recurrence.⁹ Quite often, the method provides a stretch and can improve overall foot position, minimizing the procedures needed to obtain a plantigrade foot. Still, it is important to recognize that without proper bracing following serial casting recurrence is likely.^9–10 Despite the method’s effectiveness, 40% of children will require some form of surgical intervention in their lifetime.⁹ Proper use of the Ponseti method can minimize the extent of procedures required or eliminate the need for surgery.

The first stage involves a dorsiflexory force being applied beneath the first metatarsal head with counterpressure applied to the lateral talar head. This maneuver reduces the cavus and medial crease. This is performed, as the forefoot is not as inverted as compared to the hindfoot. One is cautious to not touch the calcaneus or cuboid during the manipulation as this will block movement of the calcaneus beneath the talus. Upon resolution of the medial crease, the forefoot is abducted with counterpressure applied to the lateral talar head. Upon reduction of the adduction, inversion, and cavus, one can proceed with correction of the equinus. The goal is to hyperabduct the foot about 50–70 degrees with respect to the leg. A complete Achilles tenotomy is performed to reduce equinus if less than 10 degrees of dorsiflexion is noted at the level of the ankle joint. A final cast is applied and left intact for 2–3 weeks (Figure 4).¹¹

Abduction bar bracing is utilized until at least 4 years of age. Many children are undergoing bracing for longer time periods. Other bracing strategies at a time of growth are now being utilized in older children. The affected foot is externally rotated at 50–70 degrees to the lower leg and an unaffected foot is positioned to 30–40 degrees to the lower limb.

Treating Complex Clubfoot

Complex clubfeet are neurologically normal (Figure 5). Historically, this term was utilized interchangeably for the atypical subset. We now recognize that while the treatment is the same, the etiology is quite different. Complex clubfeet appear short and fat with a retracted first ray. Cast slippage is a common issue with these feet and if it continues to occur a deep plantar crease is evident, indicating entire midfoot cavus.

Fortunately, Ponseti recognized this variation and developed a modified casting technique. The emphasis is on dorsiflexing the first and fifth ray to stretch the plantar crease. Serial casts can achieve 30 to 40 degrees of external rotation. At that time a tenotomy is done and the foot is casted in 50 degrees of external rotation and 10 degrees of dorsiflexion. Trying to externally rotate the foot further results in a midfoot breach laterally. Hyperflexion of the knee up to 110 degrees is helpful to prevent cast slippage. Care should be taken to use a posterior plaster slab for the lower leg and dorsal slab for the knee to minimize the amount of plaster rolls. This technique leads to better molding. Foot abduction bracing is used after the casting, but care should be taken to set the feet at no more than 50 degrees of external rotation.

When Children Present With Atypical Clubfoot

Atypical clubfoot, which is mistakenly used synonymously with complex clubfoot, is a different entity though the casting treatment is the same as it is for complex clubfoot. Atypical clubfeet share many of the same clinical features as complex clubfoot, but these are identifiable at birth and are associated with a neurologic condition.

Patients with atypical clubfeet often have weak or absent active dorsiflexion of the toes and ankle as well as weak or absent active eversion of the foot. This subset is associated with neurological and or motor deficits. Casting is done as for complex clubfoot, but these patients are at higher risk of relapse due to lack of motor strength.

Insights on Navigating the Bracing Period

In many ways the bracing period can be much more challenging for parents and families than the casting period. There is always a feeling of accomplishment and relief among parents with completion of casting. The adjustment period for braces can come as a surprise to the family. It is important to educate all caregivers on the importance of bracing and the high risks for recurrence of clubfoot without proper brace adherence. Immediately following the casting period, the child transitions to boots attached to an abduction bar (Figure 6).

Parents should attempt to soothe their child rather than removing the braces while the child is crying. Demonstrating how the child can use their legs attached to the bar is often helpful as well. Boots should be snug while not too tight. Sores can develop if straps are too tight. If sores do arise various products such as Moleskin, Molefoam, Mepilex (Mölnlycke), lambswool, athletic tape, etc., may be utilized to protect the skin. If ulcerations or tissue necrosis occur, a bracing vacation may be needed with expectation of a return to casting. The feet and ankles are stretched daily, and ankle dorsiflexion is performed prior to brace application. It is important to remember that the braces do not correct any deformities. The braces simply maintain the correction obtained from casting or surgery. Ongoing research is needed for the use of the ADM unilateral brace in the younger population.

Surgical Management of Clubfoot

Up to 40% of patients with clubfoot treated successfully by the Ponseti method do experience a recurrence of deformity.^2,9 Hence, it has become important not only to adhere to the strict details of the Ponseti method during the casting period but also to promote bracing adherence until 4–6 years of age. Some children, especially in the presence of neurologic influence, require not only nighttime bracing but also daytime ankle foot orthoses in conjunction with nighttime abduction bar bracing. Still, despite successful execution of the method and bracing compliance, the deformity can recur. The author has studied symptomatic recurrence. Possible causes for recurrence include the intrinsic contractile nature of the soft tissues in clubfoot deformity, genetic and neuromuscular factors, casting techniques,¹² different designs of braces,¹² and variable brace wear time due to parental nonadherence.¹⁰

While the syndromic foot or non-isolated clubfoot has an increased risk for symptomatic recurrence, along with an earlier age in which recurrence is noted, the isolated clubfoot can still reoccur. In a study by van Praag and colleagues, recurrence was seen in 19% of 382 children who were eligible for the study who were typically discharged after the age of 5 years from their clinic.⁹ This alludes to the importance of continued follow-up even after age 5.⁹ Treatment with casting for the recurrence was successful in many patients and may be a reasonable choice for recurrent idiopathic clubfeet.⁹

What You Should Know About Achilles Tenotomy

Most children with clubfoot will require an Achilles tenotomy to reduce the equinus deformity (Figure 7). A topical anesthetic is utilized on the skin in the posterior ankle region. EMLA or lidocaine plain are the most utilized anesthetics under occlusion. The author does not inject any further local anesthesia prior to the procedure as this can obscure the margins of the Achilles tendon. With the foot held in dorsiflexion, a small blade is introduced by the surgeon through the skin onto the medial edge of the tendo-Achilles about 1.5 cm proximal to its calcaneal insertion. The tendon is felt with the tip of the blade much like a probe. The blade is introduced in front of the tendon and then rotated 45 degrees. The angle of dorsiflexion of the ankle will increase about 10–15 degrees.¹³

Advancing the blade too far laterally can place the peroneal artery or lesser saphenous vein at risk of being severed. After the tenotomy is performed a temporary dressing is applied and the child is monitored for good skin perfusion and digital refill over several minutes. The temporary dressing is removed, and gauze is applied. Local anesthesia may be utilized at this time. A well-molded long-leg cast is then applied, maintaining the foot in maximum dorsiflexion and in about 70 degrees of external rotation to the lower leg. The final cast is left intact for 2–3 weeks to allow for tendon healing.

Using a more rounded Beaver blade may reduce the risk of vascular injury. This makes palpation of the tendon edge easier. If the Achilles is easily palpable, the procedure may be performed in clinic without anesthesia. If serial Achilles tenotomies are performed for recurrence the author may be more likely to perform a small open procedure in the operating room. Likewise, if a patient’s comorbidities or disposition make an Achilles tenotomy unsafe to perform in clinic, the author will perform the procedure in the operating room with the patient under general anesthesia. Most children under 12 months of age can undergo Achilles tenotomies in the office provided the borders of the Achilles are easily palpable.

A thorough lower extremity vascular exam is recommended prior to performing a percutaneous Achilles tenotomy. This should include palpation of the dorsalis pedis and posterior tibial pulses. Doppler ultrasound may be considered in those patients with an absent dorsalis pedis or posterior tibial pulse.¹³ If both are absent or diminished on Doppler, then consideration should be given to performing an arteriogram to assess whether the peroneal artery is the dominant supply to the foot.¹³ If the peroneal artery is dominant then consideration should be given to performing an open Achilles tenotomy.

In Conclusion

There has been an incredible paradigm shift in the treatment of clubfoot. We have moved from large, grandiose incisions to less invasive approaches. We apply the Ponseti method to both idiopathic clubfoot and clubfoot in the setting of a secondary neuromuscular diagnosis. We also apply the method in the older child in the management of recurrences. The author has written several children’s books to assist children understanding various conditions such as clubfoot and vertical talus.

Mitzi Williams, DPM, FACFAS is a pediatric foot and lower extremity surgeon who specializes in congenital deformities. Dr. Williams is the Co-Director of the Pediatric and Infant Foot Deformity Clinic at Kaiser Permanente in Oakland, CA. She is an attending surgeon at the SF Bay Area Foot and Ankle Residency Program. With great interest in congenital deformities, Dr. Williams directs clinics for clubfoot, vertical talus, and angular deformities often associated with neuromuscular conditions. 

References
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