Ponseti Casting

 

 

 

 

DEFINITION

Clubfoot, also known as congenital talipes equinovarus, occurs in approximately 1 in 1000 live births.

The clubfoot contains four identifiable components that are easily remembered using the acronym CAVE (cavus, adductus, varus, and equinus). Idiopathic clubfoot contains each of the four components to varying degrees.

The so-called postural clubfoot is held by the infant in an equinovarus position, but all components are nearly completely correctable with gentle manipulation and resolve over time without intervention.

A small proportion of clubfeet are teratologic, occurring as part of other neuromuscular diseases, such as Larsen syndrome, any of the arthrogryposis syndromes, and spina bifida.

The complex clubfoot, a severe type of idiopathic clubfoot, has a tighter hindfoot and plantar structures.

In 1948, Dr. Ignacio Ponseti began manipulating clubfeet through serial casting, completely correcting the clubfoot deformity. The principles of Ponseti casting lay in gently stretching the soft tissue structures and gradually inducing remolding of the primarily cartilaginous bones of the hindfoot during immobilization.

For the definitive publication on clubfoot and the Ponseti technique, the reader is referred to Dr. Ponseti's book.7

The success of the treatment protocol that bears his name has been borne out through over 30 years of follow-up, establishing it as the standard for initial treatment of clubfoot.1

In 2006, Dr. Ponseti published a modification to his original casting technique that addresses the specific deformities characteristic of the complex clubfoot.8

 

ANATOMY

 

The Achilles and posterior tibialis tendons, as well as the posterior and medial ligaments of the foot between the calcaneus, talus, and navicular, are thickened and fibrotic.7

 

The clubfoot contains a number of changes in bony alignment and shape (FIG 1).

 

 

Relative to normal foot anatomy, the first ray is plantarflexed, generating the cavus deformity. By comparison, all rays are plantarflexed in the complex clubfoot, resulting in full-foot cavus.

 

The navicular is medially displaced on the talus, and the cuboid is medially displaced on the calcaneus as part of the adductus deformity. The medial corners of the head of the talus and the anterior calcaneus are flattened.

 

The calcaneus is inverted under the talus, creating the hindfoot varus, while also being in equinus and elevated in the fat pad of the heel.

 

In children with unilateral clubfoot, the affected foot usually is smaller, as is the lower leg, relative to the unaffected side.

 

Up to 85% of clubfeet have an insufficient or absent anterior tibial artery.6

 

NATURAL HISTORY

 

The exact cause of the fibrotic changes in clubfoot is unknown. Recently, candidate genes have been identified in familial clubfoot, including Pitx1 and Tbx4.3

 

Left uncorrected the weight-bearing surface in a clubfoot becomes the dorsolateral surface.

 

 

Thick callosities develop, and the positioning of the foot creates significant functional disability.

 

PATIENT HISTORY AND PHYSICAL FINDINGS

 

Clubfoot may be identified on prenatal ultrasound as early as 12 to 13 weeks (FIG 2).

 

 

Half or more of fetuses with clubfeet identified on second trimester ultrasounds are found to have other anomalies (most commonly cardiac, neurologic, and/or urogenital) or are syndromic/teratologic.9

 

The exact sensitivity and specificity of prenatal ultrasound are unknown. False positives are rare on 20-week

ultrasounds but may be as high as 40% during the third trimester (when false negatives are rare).9 Cases not found on prenatal ultrasound are readily identifiable at birth.

 

 

 

FIG 1 • Anatomic alignment in neonatal clubfoot. Note the medial displacement of the navicular and cuboid, the inversion and internal rotation of the calcaneus under the talus, and equinus of the talus and calcaneus.

 

 

P.1068

 

 

 

FIG 2 • Ultrasound at 20 weeks of a child born with clubfoot.

 

 

All children with clubfeet should be examined for other findings that may suggest a syndromic or neuromuscular association, such as other contractures or joint dislocations (especially hip dislocation), cutaneous lesions, spinal abnormalities, and abnormal facial features.

 

The clubfoot is easily identified by the combined deformities of cavus, adductus, varus, and equinus.

 

 

Consider complex clubfoot if a deep midfoot crease and cavus extend transversely across the entire plantar aspect of the foot, and the foot appears short and broad.

 

The ability to abduct or dorsiflex the foot completely on examination suggests etiologies other than idiopathic clubfoot, such as isolated metatarsus adductus, neuromuscular disease, or focal anatomic abnormalities.

 

The fat pad of the heel will feel empty upon palpation due to equinus positioning of the calcaneus. This is especially dramatic in the complex clubfoot.

 

The lateral head of the talus is easily palpable over the dorsolateral surface of the foot. More laterally, the anterior calcaneal tuberosity is also palpable. Care must be taken in differentiating these two structures because Ponseti casting necessitates stabilizing the foot over the lateral head of the talus, allowing free motion of the calcaneus under the talus, whereas pressure at the calcaneal tuberosity blocks calcaneal rotation, allowing only forefoot abduction.

 

The complex clubfoot has a crease that extends transversely across almost the entire plantar aspect of the foot accompanied by full-foot cavus with plantarflexion of all metatarsals. Also, the heel crease is deeper than that of most other clubfeet. During the initial one or two casts, as the adductus is corrected, the first ray in the complex

clubfoot becomes retracted, if not noticeably retracted at presentation. The cavus also persists, with all metatarsals remaining plantarflexed.

 

It is important to examine the clubfoot before each casting to evaluate for the adjustments that must be made during casting to correct residual deformities or to identify and modify casting for a complex clubfoot.

 

 

A number of classification systems have been introduced as an attempt to predict outcome, but the ability of these systems to evaluate correction, predict recurrence and final function is still unclear.5

 

The degree of dorsiflexion and abduction, and the distance of the navicular anterior to the medial malleolus, provide other objective measurements of deformity and correction.

 

Some children are born with one or both feet held in an equinovarus deformity at birth that is nearly completely correctable on examination. Nearly complete dorsiflexion (more than 20 degrees) is present, although abduction may be slightly limited. The calcaneus is also readily palpable in the fat pad of the heel. These feet may be thought of as “postural” in nature, and most will resolve spontaneously or with parental stretching over 1 to 2 months.

 

 

If persistent, one or two casts usually correct the deformity, and Achilles tenotomy is rarely required. Feet corrected with casting may require maintenance in a foot abduction orthosis.

 

IMAGING AND OTHER DIAGNOSTIC STUDIES

 

Clinical examination is sufficient to diagnose the congenital clubfoot.

 

Plain radiographs at birth are not helpful in diagnosing clubfoot because the ossific nuclei of the talus and calcaneus are spherical, so orientation and relationship are not discernible, and the other tarsal bones are unossified.

 

Once full abduction is obtained by casting, if dorsiflexion of more than 10 degrees is present, forced dorsiflexion lateral films are helpful in differentiating midfoot breach, producing apparent dorsiflexion, from true dorsiflexion occurring at the ankle, obviating the need for a percutaneous Achilles tenotomy (FIG 3).

 

DIFFERENTIAL DIAGNOSIS

Metatarsus adductus

Neurologic equinovarus or cavovarus deformity

Both deformities may be differentiated from clubfoot by absence of the other components of clubfoot.

Teratologic or syndromic clubfeet (including neuromuscular disorders) Clubfoot deformity may be more difficult to correct and tends to recur.

Postural clubfoot Complex clubfoot

 

 

NONOPERATIVE MANAGEMENT

 

Ponseti casting of the idiopathic clubfoot involves a specific sequence of corrective maneuvers that correct the deformities of the clubfoot in combination.

 

 

Each manipulation is maintained with a plaster cast.

 

Ponseti casting ideally begins during infancy, although good results are achievable through toddlerhood.

Casting in older children can also produce good results or at least reduce the amount of surgery required for complete correction.

 

 

An open tendo Achilles lengthening may be more appropriate than a percutaneous tenotomy in children older than 2 years old.

 

 

P.1069

 

 

 

FIG 3 • A. Dorsiflexion of right clubfoot after five corrective casts, before tenotomy. Dorsiflexion of 10 degrees would appear to be sufficient to avoid Achilles tenotomy. B. Forced dorsiflexion lateral radiograph of same foot. Dorsiflexion of the metatarsals relative to the axis of the talus reveals midfoot breach as the source of clinical dorsiflexion. The calcaneus is still in equinus (relative to the tibial axis) and a percutaneous Achilles tenotomy is required to complete the correction. C. Forced dorsiflexion lateral radiograph of the left (uninvolved) foot. The calcaneus is dorsiflexed and the axis of the first metatarsal is almost parallel to the axis of the talus. D. Forced dorsiflexion lateral radiograph of the right foot 3 weeks after the percutaneous Achilles tenotomy. Now, the calcaneus is dorsiflexed relative to the tibial axis and in comparison to the pretenotomy radiograph (B).

 

 

Long-leg casts should always be used to prevent cast slippage and maintain rotational control of the lower leg.

 

 

Initially, applying a short-leg cast allows focused attention on maintaining foot position and molding before extending the cast above the knee.

 

Padding should be minimal, and plaster is preferable for its ability to be molded precisely to the contours of the foot and ankle.

 

Four to six casts should correct the cavus, adductus, and varus deformities. If correction is not achieved in eight casts or the child pulls back in the casts (FIG 4A), the possibility of an unrecognized complex clubfoot or improper casting technique should be considered.

 

Casting is facilitated by the child being relaxed and calm. Feeding the infant during casting assists in this.

 

 

For breast-fed infants, it is helpful if the family introduces, and uses once daily, a bottle so the child may feed during casting. If a bottle is not tolerated, other calming measures may be necessary.

 

For older children, music, television, or playing with toys often proves helpful, as does casting with the child sitting upright or on the parent's lap.

 

Before leaving the clinic, the toes should be checked to make sure they are pink and well perfused.

 

 

Some toes will become reddish-purple as the casts cool (appearing much like the acrocyanosis present at birth) but will become pink if the child is bundled and monitored over 1 hour or so (FIG 4B,C).

 

Toes that become more purple and dusky indicate that the cast is too tight and should be reapplied.

 

Casts are changed every 5 to 7 days. The final cast, following percutaneous Achilles tenotomy, is left in place for 3 weeks.

 

Almost all clubfeet will require a percutaneous Achilles tenotomy to correct the residual equinus deformity once the other components are corrected.

 

Once complete correction is obtained, correction must be maintained by placing the feet in a foot abduction orthosis (FIG 5A-D).

 

 

Constructs include straight last shoes, soft ankle-foot orthoses (AFO), or rigid AFOs mounted on rigid or articulating bars (see Postoperative Care).

 

SURGICAL MANAGEMENT

 

Percutaneous Achilles tenotomy is required in almost all idiopathic clubfeet to correct the residual equinus.

 

About 20% of patients require anterior tibialis tendon transfer at 3 to 4 years old to correct recurrent or persistent dynamic varus deformity (see Chap. 116).

 

Preoperative Planning

 

Degree of dorsiflexion

 

 

If dorsiflexion is less than 10 degrees, a percutaneous Achilles tenotomy is required to correct the residual equinus.

 

 

P.1070

 

 

 

FIG 4 • A. A complex clubfoot that has pulled back in the cast. The cast was originally trimmed to the base of the toes. The heel is elevated in the cast and the toes are no longer visible. B. Purple discoloration of toes after application of the first cast, as the cast begins to cool. C. One hour later, the cast temperature has stabilized and the toes are pink.

 

If dorsiflexion is more than 10 degrees, forced dorsiflexion lateral foot radiographs help to differentiate midfoot dorsiflexion, with residual calcaneal equinus, from true dorsiflexion occurring at the hindfoot (see FIG 3).

 

Location

 

 

The risk of anesthesia must be balanced against the perceived pain and duration of the procedure as well as the degree of sedation necessary for safe performance of the procedure and optimizing posttenotomy casting. Approximately half of pediatric orthopedists report performing the percutaneous tenotomy under general

anesthesia or conscious sedation.10

 

 

 

FIG 5 • The foot abduction orthosis. A. Straight last shoes attached to a solid bar. B. Heels of the orthoses should be placed at shoulder width with the buckles along the medial aspect of the shoe to ease application. Feet should be positioned in 60 to 70 degrees of abduction in cases of bilateral clubfoot. C. A soft AFO on a solid bar. D. A hinged bar to which straight last shoes or AFOs may be attached.

 

 

Local analgesia, with 1% lidocaine, affords the opportunity to perform the tenotomy in the clinic setting and avoids any potential risk of general anesthesia.

 

Positioning

 

The child should be supine on the table with the contralateral leg held out of the way by the parent or an assistant during tenotomy and casting.

 

Approach

 

A medial approach is used to remain posterior to medial neurovascular bundle.

 

 

P.1071

 

TECHNIQUES

• Casting

Stretching

Before casting, the foot should be stretched in the same manner as used for immobilization during casting (TECH FIG 1A,B).

 

 

The thumb of the examiner's contralateral hand (eg, the left hand when manipulating the right foot) should be placed over the head of the talus, and the index finger of the other hand should lie along the medial aspect of the first ray with the second through fourth fingers under the plantar aspects of the forefoot.

 

The calcaneocuboid joint should be avoided, so as not to block subtalar motion.

 

The first casting should focus on elevation of the first ray to correct the cavus deformity (TECH FIG 1C).

 

This places the forefoot in supination, locking the midfoot and aligning the forefoot with the hindfoot, allowing for correction of the hindfoot deformities during later abduction maneuvers.

 

Some of the adductus may also be corrected during the first casting.

 

 

 

TECH FIG 1 • A. The thumb should be placed over the lateral head of the talus, just anterior to the lateral malleolus, during all corrective maneuvers, including during stretching and casting. B. The fingers of the opposite hand are placed under the metatarsals of the foot to keep all rays aligned. The index finger is placed slightly more medially on the first ray to provide an abduction force to the forefoot. C. The first casting corrects the cavus deformity by elevation of the first ray, bringing it into alignment with the other rays. The metatarsus adductus also improves as a result of the first cast.

 

 

 

TECH FIG 2 • A. The foot should be held in the position of correction. Casting of the lower leg begins with two layers of cotton padding. B. A thin amount of plaster is applied and the foot is held in position while the plaster sets. The thumb provides counter-pressure over the lateral head of the talus as the foot is abducted. The cast is molded above the calcaneus and around the malleoli; the fingers should remain in constant motion to prevent pressure spots.

 

Lower Leg Cast Application

 

A thin layer of cotton padding should be applied.

 

The padding is wrapped three times around the toes distally, then extended proximally over the foot and lower leg to pad with no more than two layers of padding.

 

The foot should be held in the position to be casted throughout (TECH FIG 2A). The popliteal fossa should be avoided proximally.

 

A thin layer of plaster is applied over the foot and lower leg.

 

The plaster may be applied more loosely over the toes but should be snug over the hindfoot and ankle to immobilize the foot properly and allow for precise molding (TECH FIG 2B).

 

Avoid making the cast too snug so as to impair venous return or apply unnecessary pressure on the fat pad of the heel.

 

The lower leg cast should be precisely molded around the malleoli and above the calcaneus posteriorly.

 

Do not apply pressure over the fat pad of the heel.

 

Throughout, the foot should be held in the position of correction, but the fingers should be in fairly constant motion to prevent pressure spots within the minimally padded cast.

 

 

P.1072

Completing the Cast

 

Once the lower leg cast has set, padding should be applied over the rest of the leg up to the groin, again in no more than two or three layers.

 

The knee should be held at 90 degrees, and the lower leg should be in slight external rotation.

 

Padding should be minimized in the popliteal fossa to prevent impingement of the neurovascular structures. The padding should be wrapped three to five times over the proximal thigh to pad adequately.

 

Plaster should then be wrapped over the short-leg cast above the ankle and extended proximally over the padded knee and thigh to the groin. A plaster splint of three or four layers of plaster roll should be placed over the knee from the proximal thigh to the middle of the shin to strengthen the cast against knee extension while minimizing bulk in the popliteal fossa. The plaster is then wrapped distally to incorporate the splint, ending once the lower leg cast has been adequately incorporated.

 

The knee should be molded while held at 90 degrees with the lower leg in slight external rotation until set (TECH FIG 3A). Rolling the plaster at the proximal edge of the cast before the plaster sets up completely helps minimize chafing of the thigh.

 

 

 

TECH FIG 3 • A. Padding and plaster are applied up to the proximal thigh, incorporating the short-leg cast into a long-leg cast. The knee is flexed to 90 degrees. The proximal margin of the cast is rolled to decrease skin irritation. B. The distal end of the cast is trimmed to the web space of the toes dorsally, revealing pink, well-perfused digits.

 

 

The cast should be trimmed distally to expose the toes. The practitioner should confirm that they are pink and well perfused (TECH FIG 3B) before the child is sent home.

 

Trimming the plaster over the dorsal aspect too far proximally, beyond the web space, may create a tourniquet effect over the forefoot.

 

Parents should be instructed on signs and symptoms of cast problems before discharge.

Cast Changes and Follow-Up

 

Casts are typically changed every 7 days, although they may be changed as frequently as every 5 days; up to 2 weeks may be tolerated if necessary to accommodate conflicts preventing weekly cast changes.

 

Casts should not be removed until just before recasting.

 

Casts can be soaked by the family before coming to the office, then removed with a plaster knife in the clinic.

 

Alternatively, dry casts may be removed with a cast saw, using extreme caution.

 

Having the parents remove the casts the night before results in varied degrees of recurrence overnight and prolongs casting.

 

After the first casting, the cavus deformity should be nearly, or completely, corrected. If not, adopt complex casting modifications.

 

Abduction may be increased.

 

Stretching is performed with the forefoot in supination, maintaining alignment of all rays, abducting the foot under the talus, again stabilizing the talus laterally.

 

The foot is then casted in the newly maintained position, just to where the foot may be comfortably corrected without significant resistance.

 

Trying to overabduct the foot during a single casting results in intolerance as the foot tries to return to its position of comfort and in the worst cases results in pressure sores or vascular compromise of the soft tissues along the medial foot. A keen sense of touch and patience are essential.

 

Each subsequent manipulation results in increased abduction of the forefoot and correction of the hindfoot varus (TECH FIG 4A-D).

 

Throughout, the forefoot should remain in neutral (appearing supinated due to the hindfoot varus) and the hindfoot in equinus (TECH FIG 4E).

 

Dorsiflexion of the calcaneus remains blocked under the neck of the talus until approximately 25 degrees of abduction has been obtained. Dorsiflexion before that point results in midfoot breach (see FIG 3).

 

Subsequent eversion of the calcaneus will bring the forefoot and hindfoot into more neutral positions, and dorsiflexion may be obtained by percutaneous Achilles tenotomy.

 

Once abduction of 70 degrees is obtained (TECH FIG 4F), correction of the remaining equinus deformity may occur.

 

Overabduction to 70 degrees is necessary to accommodate some of the inevitable recurrence, without allowing progression beyond a normal position that would require recorrection.

 

P.1073

 

 

 

TECH FIG 4 • A. Hindfoot varus and equinus are decreased following the second cast. B. By the third cast, the foot is in line with the leg. C. By the fourth casting, the foot is abducted 20 degrees and held in this position with the cast. D. With the fifth cast, the foot is now held at 45 degrees of abduction. E. Prior to the tenotomy, the foot remains in plantarflexion throughout abduction. F. After removal of the fifth cast, the foot can be abducted 70 degrees and is ready for percutaneous Achilles tenotomy. The amount of dorsiflexion in this foot is seen in FIG 3.

 

• Complex Clubfoot

   

  The complex clubfoot may not be immediately recognizable at presentation.

   

  Correction usually begins using the standard maneuvers, elevating the first ray with the first cast and continuing abduction with the second cast.

   

  Within one or two casts, the foot begins to clearly demonstrate a deviation from the expected correction as the cavus persists and evolves, involving plantarflexion of all metatarsals, and the first ray becomes retracted.

   

  At this point, the technique must be modified.

   

  In the complex clubfoot, the tight plantar intrinsics and toe flexors induce full-foot cavus. This is exacerbated by the tight hindfoot structures, which also limit correction of the varus to just beyond neutral.

   

  As a result, the casting technique must be modified not only to correct these features but also to decrease the propensity for pulling out of even long-leg casts.

   

  Lateral counterpressure still occurs at the lateral head and neck of the talus, but stabilization of the fibula should also occur.

   

  The index finger of the contralateral hand (eg, the examiner's left hand when manipulating a patient's right clubfoot) should be flexed at the proximal interphalangeal joint and placed posterior to the distal fibula.

   

  The thumb of the same hand is placed just anterior to the lateral malleolus along the neck of the talus.

   

  As the foot begins to approach neutral, the full-foot cavus, along with the dramatic equinus, can pose significant casting difficulties and make the foot prone to pulling back in, or out of, the cast.

   

  After applying cotton padding, a posterior splint of three or four layers of plaster should be applied under the plantar surface of the foot, extending from beyond the tips of the toes proximally over the posterior lower leg.

   

  As in the upper leg portion of the traditional cast, the posterior splint about the foot strengthens the plantar portion of the cast against the forceful plantarflexion of the

   

  P.1074

  complex clubfoot without increasing bulk over the anterior ankle, which may impede molding and immobilization.

   

  Then, a thin layer of plaster may be wrapped in the usual manner to encompass the foot and lower leg. A minimal amount of plaster should be used because precise molding is even more important for the complex clubfoot.

   

  The pads of the thumbs of both hands are placed under the forefoot, with the pads of the index fingers placed over the dorsal surface of the talar neck, anterior to the medial and lateral malleoli, with the middle fingers posterior to the malleoli. The forefoot is then forcefully dorsiflexed against the counterpressure over the dorsal talar neck, enough to produce blanching of the digits (TECH FIG 5A).

   

  Further counterpressure to dorsiflexion is applied over the anterior thigh above the flexed knee.

   

   

   

  TECH FIG 5 • A. When casting the complex clubfoot, to correct the full-foot cavus, a dorsiflexion force is

  applied to dorsiflex the forefoot and stretch the midfoot. The fat pads of both thumbs are placed under the heads of the metatarsals, with the index fingers over the dorsal aspect of the talar neck; the middle fingers are placed behind the malleoli to help mold the cast. B. When dorsiflexing the complex clubfoot during initial castings (before tenotomy), the toes should blanch. When dorsiflexion pressure is released, the slight relaxation of the cast results in reperfusion of the digits. In this case, blood flow returned initially to the first, fourth, and fifth digits; the second and third became pink a few moments later.

   

   

  Upon release of dorsiflexion pressure after setting of the cast, the slight relaxation of the cast should result in revascularization of the digits and pink coloration (TECH FIG 5B). If not, the cast should be removed and reapplied.

   

  On extending the cast up over the lower leg, the knee should be flexed to 110 degrees to minimize the ability to pull out of the cast. An anterior plaster splint over the thigh and knee should be used just as in the traditional technique.

   

  Tenotomy occurs once the cavus and adductus deformities are corrected and about 40 degrees of abduction is obtained.

   

  Attempting to abduct the complex clubfoot beyond 40 degrees results in no further hindfoot correction and only overabducts the forefoot, creating deformity and making immobilization of the foot in the cast more difficult.

• Percutaneous Achilles Tenotomy

 

The tenotomy should occur 1 to 1.5 cm above the insertion of the Achilles on the posterior tuberosity of the calcaneus.

 

In many feet, this is 1 to 1.5 cm above the posterior heel crease.

 

Performing the tenotomy too low results in damage to the posterior calcaneal tuberosity.

 

For procedures in the clinic, local anesthesia must be used.

 

A small amount of 1% lidocaine may be injected locally adjacent to the tendon at the site of blade insertion before the procedure, taking care not to inject so much as to obscure the Achilles tendon to identification by palpation necessary for the procedure (TECH FIG 6A).

 

Whether performed in the operating room or clinic, sterile technique should be observed using skin preparation, sterile gloves, and draping and sterile equipment.

 

An assistant should hold the foot in maximal dorsiflexion to increase tension on the Achilles tendon, making it more easily palpable and able to be transected (TECH FIG 6B).

 

A second assistant should hold the contralateral leg and foot out of the field.

 

A thin, sharp scalpel should be used to perform the tenotomy. Cataract surgical blades (5100 or 5400 Beaver blades) are well suited for this procedure, although a no. 11 blade is also acceptable. One of two techniques may be used to insert the blade:

 

The blade of the scalpel may be inserted perpendicular to the skin, anterior to the Achilles tendon, from the medial side, with the blade itself oriented parallel to the longitudinal axis of the tendon. The blade must be advanced far enough to pass beyond the lateral side of the tendon so that complete transection occurs. Once advanced far enough, the blade may be rotated in place, orienting the blade perpendicular to the tendon (TECH FIG 6C).

 

P.1075

 

 

 

TECH FIG 6 • A. Local anesthesia for percutaneous Achilles tenotomy of the left foot. Lidocaine is injected 1 to 1.5 cm above the insertion of the Achilles tendon on the calcaneus, which in this case occurs at the level of the hindfoot crease. B. An assistant dorsiflexes the left foot, applying tension to the Achilles tendon, making it easier to palpate and transect with the scalpel. C. One of the two techniques used to insert the scalpel blade and transect the tendon. (The illustration is of the left foot.) The handle of the scalpel is perpendicular to the skin over the medial heel cord, with the blade parallel to the axis of the tendon. Once the tip of the blade has been advanced beyond the lateral edge of the tendon, the blade is turned perpendicular to the tendon (arrow). D. The second of the two techniques for blade insertion. (The illustration is of the left foot.) The handle and the blade are advanced at a 45-degree angle to the skin, with the sharp edge of the blade oriented perpendicular to the tendon. Once advanced deeply enough for the tip to be beyond the lateral edge of the tendon, the handle is swung anteriorly to bring the blade into contact with the tendon (arrow). The handle is now perpendicular to the skin. E. Transection of the Achilles tendon of the left foot. Pressure is applied with the contralateral thumb, pressing the tendon onto the blade, resulting in tendon transection. The level of the tenotomy is 1 cm above the posterior heel crease. F. The foot is in plantarflexion before the tenotomy. (continued)

 

 

P.1076

 

 

 

TECH FIG 6 • (continued) G. After the tenotomy, 30 degrees of dorsiflexion is obtained. In extreme dorsiflexion, the digits blanch, presumably due to impingement of the posterior tibial artery. Decreasing dorsiflexion just a few degrees resulted in reperfusion. H. During application and molding of the short-leg cast, the foot should be held in maximum dorsiflexion and abduction. An assistant provides counterpressure above the knee. Dorsiflexion pressure is applied only over the plantar aspect of the midfoot and forefoot, and the heel remains untouched while the cast is molded around the ankle with the fingers of the other hand.

 

 

Alternatively, the blade may be advanced anterior to the tendon at a 45-degree angle to the skin, again advancing the tip of the blade deep enough to pass the lateral side of the tendon but with the blade oriented perpendicular to the tendon from the outset. The handle of the scalpel may then be lifted ventrally, bringing the blade perpendicular to the skin, resting against the tendon (TECH FIG 6D).

 

Once the blade is oriented perpendicular to the fibers of the Achilles tendon, the safest maneuver involves pressing the tendon onto the blade using the contralateral thumb (TECH FIG 6E).

 

Complete transection often results in a palpable “pop,” release of the Achilles tendon, and an immediate increase of 15 to 20 degrees of dorsiflexion (TECH FIG 6F). A palpable defect in the tendon confirms complete transection.

 

If incomplete transection occurs, the tendon should be revisited, adjusting blade position as necessary, to complete the release.

 

Care should be taken not to pull the blade through the tendon lest laceration of the overlying skin occur once the resistance of the tendon disappears following transection.

 

The skin prep (Betadine or chlorhexidine) should be cleansed from the skin to prevent burns to the neonatal skin, and pressure should be applied to the incision site to stop all bleeding before cast application.

 

The foot should now be held in the new position of maximum dorsiflexion and abduction.

 

In some cases, the increased dorsiflexion will cause spasm of the solitary posterior tibial artery, constricting it and resulting in blanching of the digits (TECH FIG 6G). Slight relaxation of dorsiflexion should result in reperfusion. The foot should be casted at the position of maximum dorsiflexion that still allows perfusion of the digits.

Casting

 

The lower leg is wrapped with sterile cotton in the usual manner, accommodating the increased dorsiflexion.

 

The plaster is applied in the usual manner, and the cast must be molded well at the anterior ankle to

 

accommodate the increased dorsiflexion and prevent pulling back in the cast (TECH FIG 6H). For the complex clubfoot, the posterior plaster splint should be used in the short-leg cast.

 

On release of dorsiflexion pressure after setting of the cast, the slight relaxation of the cast should result in revascularization.

 

If revascularization does not occur, the cast may need to be removed and reapplied. Although maximum dorsiflexion is prevented because of vascular compromise, what is gained is usually sufficient for adequate correction without the need for a second tenotomy or later recorrection.

 

Extension of the cast above the thigh as a long-leg cast should occur with the knee in the usual 90 degrees of flexion, first with padding (TECH FIG 7A) and then with plaster, holding the lower leg in slight external rotation (TECH FIG 7B).

 

 

The complex clubfoot should have the knee flexed at 110 degrees. An anterior knee splint should be used in both cases.

 

 

The posttenotomy cast should be left on for 3 weeks before removal to allow tendon healing. Frequently, blood seeps through the cast and becomes visible, and parents should be alerted to this.

 

Persistent bleeding, resulting in a spot above the heel larger than a quarter in size, may signify injury to vascular structures on the lateral aspect of the foot, rarely requiring any intervention other than further

assessment.2

 

When the cast is removed, complete correction should have been obtained (TECH FIG 7C,D).

 

 

P.1077

 

 

 

TECH FIG 7 • A. Cotton padding is applied from the proximal edge of the short-leg cast up to the groin. B. With extension to the long-leg cast, the lower leg is held in slight external rotation, and the knee is held at 90 degrees of flexion. The foot is now in maximum dorsiflexion and abduction. C,D. Three weeks after tenotomy, after the final cast is removed, complete correction is obtained. C. The foot abducts 70 degrees.

D. The foot actively dorsiflexes 20 degrees.

 

 

PEARLS AND PITFALLS

 

 

 

Failure to correct the cavus deformity with initial casting

• Failure to elevate the first ray will result in worsening cavus during abduction, and only the forefoot will abduct. The hindfoot varus will fail to correct. The foot will then pull back in the cast. The same deformities will occur in the complex clubfoot if the full-foot cavus is not corrected before or during early abduction.

   

  Toes turn purple after cast application (see FIG 4).

• Some neonatal feet have poor vascular control and will turn purple as the cast cools. Do not be too hasty to remove the cast. Bundle the child, elevate the feet, and recheck every 15 minutes for four times. As the cast dries, the toes should become pink (see FIG 4). Increasing purplish discoloration indicates a cast that is too tight and should be removed and reapplied.

   

  An older child who resists casting

  • A child who fights casting prevents good molding, and too much motion may prevent the cast from setting up in the desired position. A quiet room with music may relax the child. Likewise, entertaining the child with a toy may distract him or her. Feeding may also be helpful. Older children often do better if sitting slightly upright, propped against a pillow, or even in a parent's lap.

 

Child pulling out of foot abduction orthosis

• Add padding in the heel, above the posterior calcaneal tuberosity, use a shoe with a heel cutout, or both (see FIG 5C). If the child has a strong propensity for toe curling, try a Plastazote plate under the toes to keep them extended. For persistent intolerance, try using only the strap without the tongue. Switching to a different brace may be beneficial (see FIG 5D).

   

  Child cries while in casts or in bar and shoes

• Make sure the toes are well perfused. Discomfort for 24 hours after the first casting or tenotomy is common and easily relieved with acetaminophen. The child should be seen and the cast might need to be removed if discomfort persists for greater than 48 hours.

• If the child is in an orthosis, examine the feet for sores. If the orthosis is removed whenever crying occurs, the child may associate crying with subsequent bar removal. Feet may be hyperesthetic after casting: massage during diaper changes and other times out of the orthosis accelerates desensitization.

   

  Recurrence ▪ Monitor for decreases in abduction and dorsiflexion.

  • Treating an early identified, minimal recurrence with stretching by the parents with every diaper change may prevent progression. Later or more marked recurrence should be treated with recasting and possibly a second percutaneous tenotomy. For recurrence in older children, an open Achilles tendon lengthening may be more appropriate for feet with minimal dorsiflexion. For residual dynamic varus, a transfer of the anterior tibialis tendon may be necessary (see Chap. 116).

 

 

 

POSTOPERATIVE CARE

P.1078

 

After removal of the posttenotomy cast, the child should immediately be placed in a foot abduction orthosis. Acceptable constructs include straight last shoes or AFOs connected to a solid or articulated bar (see FIG 5A-D).

 

In the case of bilateral corrected clubfeet, both shoes should be placed in abduction/external rotation on the bar to the degree of comfortable correction, typically 60 to 70 degrees (see FIG 5A,B).

 

For unilateral clubfoot, only the shoe of the affected foot is placed near the extreme of abduction. The shoe of the uninvolved, normal foot is placed at 30 degrees of abduction/external rotation. The shoes should be placed at shoulder width on the bar.

 

Mounting the shoes on the bar such that the buckle of the anterior ankle strap is on the medial aspect of the foot eases application of the orthosis (see FIG 5A and C).

 

In cases of unilateral clubfoot, application of the orthosis is easier if the affected foot is placed into its shoe first, followed by the normal foot. In bilateral cases, one foot is usually “tighter” (more resistant to correction or had less correction from the tenotomy) and this is the one that should be placed in the orthosis first.

 

The anterior ankle strap secures the foot in the shoe and should be tightened sufficiently to prevent pulling the foot out of the shoe. Additional straps or laces should be tightened just enough to keep the shoe or orthosis in place on the foot.

 

Only a single, thin pair of socks should be worn with the shoes. For the first 1 or 2 days, two socks may be used to prevent blisters (much like the double sock method used by runners), but thereafter only one pair should be used.

 

 

Thick, well-padded socks prevent adequate securing of the foot and make it easier to pull the foot out of the shoe.

 

For the first week, the orthosis and socks should be removed with every diaper change to inspect the feet for evidence of developing pressure sores.

 

 

Red spots that do not disappear within 5 minutes signal a potential problem spot and require refitting of the shoes with Plastazote or repositioning on the bar.

 

Care should be taken to remove the orthosis when the child is calm to prevent the child from associating crying with subsequent removal, resulting in persistent resistance to orthosis wear with unrelenting crying.

 

After casting, the leg and foot are hyperesthetic.

 

 

Massaging the leg, initially deeply and progressing to light touch, with each diaper change during the first week helps with desensitization.

 

The lower leg may also develop intermittent purple discoloration when dependent to gravity after casting. This usually resolves over the first month out of casts.

 

After the first week, the orthosis should be worn full time, but it may be removed once daily for bathing and a short period of play (1 to 2 hours).

 

 

Full-time wear continues for 3 to 4 months to maintain correction.

 

Tighter feet, or those more difficult to correct, may benefit from periodic stretching in dorsiflexion and abduction whenever the orthosis is removed.

 

If the foot is not secured in the shoe or sores develop, adjustments to the shoe may be necessary.

 

 

If necessary, pads or pressure saddles on the tongue distribute pressure and/or restrict pulling the foot out of

the shoe.

 

In some cases, the tongue provides an obstruction to secure the foot, and removing the tongue may actually improve the ability of the strap to secure the foot.

 

Other modifications that may help prevent pulling out include slightly decreasing the degree of external rotation of the shoes (no less than 45 degrees), widening or narrowing the bar or placement of Plastazote pads under the toes or above the calcaneus.

 

Use of an articulated bar allows the child to move each leg independently and decreases the ability to use one leg as a counterforce to pulling with the contralateral foot.

 

Children should be reexamined in and out of the orthosis after 1 month, then 2 months later.

 

After 3 months of full-time wear and maintenance of full correction, children wear the orthosis for 16 hours per day, primarily at nighttime and during naps.

 

 

Children should be examined every 3 to 6 months, depending on the level of concern regarding recurrence, until bar and shoe wear is complete.

 

Any episodes of recurrence warrant recasting as soon as identified.

 

 

Casting is performed in the usual manner to obtain complete correction again.

 

Casting is usually sufficient to correct the recurrence. Rarely, a repeat percutaneous tenotomy is necessary for more severe recurrence. Once complete correction is again obtained, orthosis wear occurs for 3 months full time before resuming part-time wear.

 

Straight last shoes may be worn until the child's toes curl over the edge of the shoe. Then the next appropriate size should be fitted and attached to the bar which may need to be widened to maintain shoulder width positioning of the heels.

 

Part-time wear continues until the child is 4 years old, when orthosis wear may be discontinued. Children should be monitored for recurrence, which occurs rarely after 4 years old.

 

Complex clubfeet almost always pull out of standard straight last shoes. A variety of newer bar-and-shoe constructs have been developed to address the limitations of traditional foot abduction bracing (see FIG 5C,D).

 

OUTCOMES

A corrected clubfoot tends to recur to its original position, requiring maintenance of correction in the orthosis. Noncompliance with bar-and-shoe wear increases the likelihood of recurrence to more than 80%.

Compliance is increased with close follow-up and explicit discussions with the family and all caregivers.4

Twenty percent to 50% of corrected clubfeet will require anterior tibialis tendon transfer to correct dynamic varus present during ambulation (see Chap. 116).

 

 

COMPLICATIONS

Cast sores, cast saw burns

Prolonged casting or pulling back in the cast due to improper technique, unrecognized clubfoot, or failure to modify casting for complex clubfoot

Overabduction from unrecognized complex clubfoot or overabduction in foot abduction orthosis (beyond

 

degree of correction)

P.1079

Posterior tibial artery impingement

Peroneal artery or lesser saphenous vein laceration during tenotomy2

Pulling back in cast from poor cast molding, unrecognized complex clubfoot, or not enough knee flexion in long-leg cast if complex clubfoot

Recurrence due to incomplete correction or lack of orthosis wear

 

 

REFERENCES

1. Cooper DM, Dietz FR. Treatment of idiopathic clubfoot. A thirty-year follow-up note. J Bone Joint Surg Am 1995;77(10):1477-1489.

    

    

2. Dobbs MB, Gordon JE, Walton T, et al. Bleeding complications following percutaneous tendo Achilles tenotomy in the treatment of clubfoot deformity. J Pediatr Orthop 2004;24:353-357.

    

    

3. Dobbs MB, Gurnett CA. Genetics of clubfoot. J Pediatr Orthop B 2012;21:7-9.

    

    

4. Dobbs MB, Rudzki JR, Purcell DB, et al. Factors predictive of outcome after use of the Ponseti method for the treatment of idiopathic clubfeet. J Bone Joint Surg Am 2004;86-A(1):22-27.

    

    

5. Flynn JM, Donohoe M, Mackenzie WG. An independent assessment of two clubfoot-classification systems. J Pediatr Orthop 1998;18: 323-327.

    

    

6. Greider TD, Siff SJ, Gerson P, et al. Arteriography in club foot. J Bone Joint Surg Am 1982;64(6):837-840.

    

    

7. Ponseti IV. Congenital Clubfoot: Fundamentals of Treatment. New York: Oxford University Press, 1996.

    

    

8. Ponseti IV, Zhivkov M, Davis N, et al. Treatment of the complex idiopathic clubfoot. Clin Orthop Relat Res 2006;451:171-176.

    

    

9. Treadwell MC, Stanitski CL, King M. Prenatal sonographic diagnosis of clubfoot: implications for patient counseling. J Pediatr Orthop 1999;19:8-10.

    

    

10. Zionts LE, Sangiorgio SN, Ebramzadeh E, et al. The current management of idiopathic clubfoot revisited: results of a survey of the POSNA membership. J Pediatr Orthop 2012;32:515-520.