congenital talipes equinovarus (clubfoot)

OrthOpaEdic iV: dEgEnEratiVE/paEdiatric disOrdErs

Congenital talipes equinovarus (clubfoot)anne Foster

naomi davis

Abstractcongenital talipes equinovarus (‘clubfoot’) refers to foot deformity char-

acterized by equinus of the hindfoot, adductus and varus of the mid-

foot and a high arch (cavus). the annual incidence in the UK is about

1 per 1000 live births; the condition is bilateral in 50% of cases and

there is a male preponderance (3:1). there is a polygenic inheritance for

sensitivity to unknown environmental factors. Most ‘fixed’ clubfeet are

idiopathic, but clubfoot can be associated with a number of syndromes

(e.g. arthrogryposis, Larson’s, downs). Underlying neurological causes

must be excluded, particularly in stiff bilateral clubfeet.

the aim of management is to correct the deformity early and fully, and

maintain correction with growth until skeletal maturity; this should

result in a flexible, pain-free plantigrade foot. the trend towards surgi-

cal management has reversed during the past decade, with the ponseti

method of serial casting followed by bracing the first-line management

in the newly diagnosed clubfoot. Most feet treated by this method (95%)

achieve an excellent result. surgery tends to be reserved for recurrent

deformity (posteromedial release, ilizarov method, reconstructive surgery)

or as a salvage procedure (hindfoot fusion).

Keywords congenital talipes equinovarus; clubfoot; ponseti method;

soft tissue release; residual deformity

Congenital talipes equinovarus (‘clubfoot’) refers to foot defor-mity characterized by equinus of the hindfoot, adductus and varus of the midfoot and a high arch (cavus; Figure 1). Untreated or ‘neglected’ clubfoot can cause major physical disability and marginalization from society (with consequent extreme poverty) in the ‘developing’ world; various treatments are available in the ‘developed’ world.

Incidence

More than 100,000 babies are born with clubfoot every year worldwide; >80% occur in the developing world. The annual

Anne Foster FRCS(Tr&Orth) is a Research Fellow in Paediatric Orthopedic

Surgery at Booth Hall Children’s Hospital, Central Manchester and

Manchester Children’s Hospitals NHS Trust, Manchester, UK. Conflicts

of interest: none declared.

Naomi Davis FRCS(Ed)(Tr&Orth) is a Consultant Paediatric Orthopaedic

Surgeon at Booth Hall Children’s Hospital, Central Manchester and

Manchester Children’s Hospitals NHS Trust, Manchester, UK. Conflicts

of interest: none declared.

sUrgErY 25:4 17

incidence is about 1 per 1000 live births in the UK; it is lower in Japan but higher in black South Africans and Polynesians. There is a male preponderance (3:1). Bilateral involvement occurs in about 50% of cases. There is conflicting evidence regarding seasonal variation of clubfoot.

Aetiology

There is a polygenic inheritance for sensitivity to unknown envi-ronmental factors. The inheritance pattern has not been estab-lished nor a single gene identified. Wynne-Davis found that the incidence was 17 times higher than in the normal population for first-degree relatives and 6 times higher in second-degree rela-tives.1 She found that the risk of a second child having clubfoot was 1:35 (to unaffected parents).

It has been suggested that these genes activate an arrest in the normal development of the limb bud at five weeks’ gestation. Certain modulating environmental factors (e.g. maternal smok-ing, alcohol consumption) have been suggested as a contribut-ing factor, as has intravenous drug use by the mother during pregnancy.2

Most ‘fixed’ clubfeet are idiopathic, but clubfoot can be associ-ated with a number of syndromes (e.g. arthrogryposis, Larson’s, Down, Freeman–Sheldon) and spinal disease. The primary diag-nosis is often not made until some months or even years after birth. A patient with a severe stiff bilateral clubfoot should be referred to a paediatric neurologist.

Pathology

Gross anatomy: the deformity occurs with the anterior portion of the os calcis lying beneath the head of the talus, causing varus and equinus of the heel. The talus is wedge-shaped with the neck facing medially and plantar flexed. The navicular is displaced medially and articulates with the medial surface of the head of the talus (Figure 2). As well as bony abnormalities, there are posterior and medial soft tissue contractures of the capsule and ligaments of the ankle and subtalar joints. The tendons of tibialis posterior, flexor hallucis longus and flexor digitorum longus are medially displaced.

Histopathology: the muscles are abnormal in intrinsic struc-ture and anatomical insertion. The wasting of the calf muscles is related to the severity of the deformity. Electron microscopic

Figure 1 Bilateral clubfoot deformity.

1 © 2007 Elsevier Ltd. all rights reserved.


Figure 2 anatomy of clubfoot

deformity.

studies have shown an increase in collagen fibres that are wavy and densely packed. This wavy appearance or ‘crimp’ is impor-tant in the gradual stretching that is key to the Ponseti method of treatment (see below). There is an overall increase in cellularity though a decrease in myofibrils. Abnormal vasculature has been described with deficient dorsalis pedis flow.

Diagnosis

History: a thorough perinatal and family history must be taken (e.g. oligohydramnios in pregnancy may be related to arthrogry-posis). The diagnosis of clubfoot is increasingly made prenatally at the 20-week anomaly scan, permitting counselling and an informed discussion with regards treatment and outcome. This allows parents to prepare emotionally and practically, though there is a false-positive value (≈30%) with ultrasound diagnosis. Prenatal diagnosis using ultrasound is not prognostic in terms of severity and does not dictate treatment. Advice may be sought from a geneticist if the clubfoot is bilateral because amniocentesis and karyotyping may be appropriate.

Clinical examination: the hindfoot is in equinovarus with the forefoot in adductus and cavus. Deep posterior and medial creases may be noted depending on the severity of the defor-mity (Figure 3). Calf atrophy on the ipsilateral side, together with shortening and internal rotation of the tibia, may not be seen at birth but may become apparent with growth. Examination should include the spine and a full neurological assessment. Other joints should be examined for stiffness and deformity, including the hips, which should also be assessed by ultrasound for dysplasia,

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particularly in postural clubfoot as part of the ‘moulded baby syndrome’.

Classification: a fully correctable positional clubfoot should be differentiated from fixed deformity. A valid classification sys-tem used at the onset of treatment helps to compare outcomes. The ideal system should be simple, reliable and reproducible,

Figure 3 deep posterior and medial skin creases.

2 © 2007 Elsevier Ltd. all rights reserved.


directing treatment and prognosis. There are a number of clas-sification systems, but no single classification is ideal. The three commonest are: • Harold–Walker • Dimeglio • Pirani (authors’ preference).3

Imaging: the initial diagnosis of clubfoot in the newborn is made clinically. Radiographs are of limited value because there is very little ossification in the bones of the foot at this age, making interpretation difficult.

Radiographs – a simulated weightbearing anteroposterior and a maximum dorsiflexion lateral radiograph (‘Turco’s view’) can be useful in determining the timing of surgery in the older child. On the anteroposterior view, the talocalcaneal angle (‘Kite’s angle’) usually measures 20–40° in the normal foot, but is <20° in the clubfoot (Figure 4). On the lateral view, the talocalcaneal angle is normally 25–50°, but is <25° in the clubfoot i.e. the talus and calcaneum show increased ‘parallelism’ in the clubfoot.

Management

The overall aim of treatment is to correct the deformity early and fully, and maintain correction with growth until skeletal maturity. This should result in a flexible, pain-free and plantigrade foot.

Management trendsHistorically, treatment was conservative with varying forms of strap-ping or serial casting applied soon after birth to correct deformity;

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this usually failed to correct the deformity due to an incomplete understanding of the functional anatomy of the foot. Conservative treatment was the mainstay of treatment for more than 40 years but, with improved anaesthetic and surgical techniques, a signifi-cant proportion of children then progressed to surgical manage-ment, usually with a posteromedial release at the age of one year.

The trend towards surgical management has reversed over the past decade. With increased understanding of the functional anatomy of the clubfoot and deformity parameters, non-surgical techniques have developed to give, in most cases, a result superior to that achieved by surgery.

Conservative managementPonseti method: Ignacio Ponseti (Iowa, USA) developed a method of serial manipulation and casting in the 1950s. The principal fea-tures of his technique are based on correct understanding of the functional anatomy of the foot. The Ponseti method is in two parts.

First part – the treatment is started as soon as possible after birth (but can be later) with a sequence of correction and weekly serial casts (average of six weeks). The initial manoeuvre is to elevate the first ray, thereby supinating the forefoot to align it with the hindfoot. This is followed by abducting the foot around the head of the talus. The talus is secured against rotation in the ankle mortise by counterpressure applied by the thumb against the lateral head of the talus. Abduction of the forefoot allows, by the nature of the subtalar joint, the hindfoot to swing into valgus from its varus position. The casts are applied in a very specific manner, avoiding ‘overpadding’ and areas of high pres-sure. With each manipulation, the viscoelastic property of the

Talocalcaneal (Kite’s) angle

a Anteroposterior view

b Lateral view

Medial

MedialLateralLateral

Normal Clubfoot

50°

45°

10°

10°

Figure 4

© 2007 Elsevier Ltd. all rights reserved.


soft tissues (‘creep’) is utilized as the ‘crimp’ in the in the liga-ments is stretched out (Figure 5).

After these manipulations, there is usually residual equinus requiring (in about 90% of feet) a percutaneous complete Achil-les tenotomy, which may be done under local anaesthesia in the clinic. This is followed by the final cast for three weeks.

The second part (‘bracing protocol’) involves a period of three months in ‘boots and bars’ (to maintain foot abduction) to maintain correction. The boots and bars should be worn for ‘nights and naps’ until at least the age of four years (Figure 6).

Outcome – Ponseti published follow-up data at 35 years which showed that 95% of clubfeet had excellent pain-free function.4,5

Complications – the commonest cause of relapse is non- compliance with the post-tenotomy bracing protocol. Recurrence can occur due to continued muscle imbalance, particularly with growth in brace-compliant patients. Recurrence is initially treated with an identical recasting programme. Children may develop a dynamic supination deformity between the ages of 2–4 years that requires tibialis anterior tendon transfer to the lateral cuneiform (when the ossification centre is present at about 30 months).

Surgical managementDespite the success of treatment by the Ponseti method, there is a limited role for surgery, usually in recurrent deformity or as a salvage procedure.

Primary surgical release of a clubfoot is reserved for the foot that has failed to correct by conservative means (assuming good casting technique and patient compliance).

Considerations – a neurological cause or syndromic diagno-sis must be considered in resistant, bilateral stiff feet. One must consider the timing of surgery, the exact technique and post-operative regimen.

The timing of surgery is controversial; some surgeons operate between 4 months and 9 months, others wait until 12 months to allow for a good trial of conservative management and foot growth. It has been postulated that early surgery may stimulate a myofibro-blastic response that may lead to increased scarring and rigidity.

The general principles of surgery are to protect the neuro-vascular bundle at all times with meticulous handling of soft

Figure 5 initial ponseti cast.

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tissue and haemostasis. The two main incisions for posterome-dial release are the extended medial approach (Turco) or the posterior circumferential approach (Cincinnati). The Achilles tendon, flexor hallucis longus, tibialis posterior and flexor digi-torum longus are divided and lengthened. The capsule of the posterior aspect of the ankle joint and subtalar joint are released. The plantar ligament, abductor hallucis and flexor digitorum brevis are released while preserving the deep deltoid ligament. Kirschner wires hold the corrected foot. Wounds are closed with-out tension but can be left to heal by secondary intention if this is not possible at the index procedure.

Postoperative casting is recommended for 2–3 months fol-lowed by splinting and long-term follow-up.

Outcome – a number of series have reported 60–80% good or excellent early results with primary surgical release. Surgically corrected feet can show a variable degree of weakness of push off due to: • gastrocsoleus weakness • stiffness and pain • over- or undercorrection • recurrence with growth.6

Surgery for residual deformity or recurrence: undercorrection or residual deformity after conservative or surgical treatment can leave a deformity that is flexible or fixed.

Dynamic supination and adduction are relatively common and can be treated with a tibialis anterior transfer. If the defor-mity is fixed, a medial column release and lateral column shortening or calcaneocuboid fusion (Dilwyn–Evans) may be considered.

Residual hindfoot equinus can respond well to serial casting rather than further Achilles lengthening (which can lead to further weakness and calcaneus of the heel).

Fixed varus hindfoot deformity in the older child can be treated by wedge or lateral displacement of calcis osteotomy.

Residual internal rotation with a reasonably aligned foot can be treated with supramalleolar osteotomy.

Previous multiple surgery – options include correction of deformity by means of a circular frame (Ilizarov method); this method of gradual soft tissue distraction can be combined with osteotomy if appropriate. Further scarring of soft tissue is

Figure 6 ‘Boots and bars’ to maintain corrected feet.



avoided with this method, but it can lead to hindfoot stiffness. The Ilizarov method should be reserved for appropriately coun-selled patients and their relatives because it is labour-intensive and demanding for relatives.

Other – triple arthrodesis is the definitive salvage procedure for severe stiff residual deformity not amenable to treatment by the above methods, but should be reserved for children aged >10 years to avoid compromising foot growth. ◆

ReFeRenCeS

1 Wynne-davies r. genetic and environmental factors in the aetiology

of talipes equinovarus. Clin Orthop Rel Res 1972; 84: 9–13.

sUrgErY 25:4 175

2 Barker s, chesney d, Miedzybrodzka Z, Mafulli n. genetics and

epidemiology of idiopathic congenital talipes equinovarus. J Pediatr

Orthop 2003; 23: 265–72.

3 Wainwright aM, auld t, Benson MK, theologis tn. the classification

of congenital talipes equinovarus. J Bone Joint Surg (Br) 2002; 84: 1020–4.

4 ponseti iV, smoley En. congenital clubfoot: the results of treatment.

J Bone Joint Surg (Br) 1963; 45: 2261–70.

5 cooper dM, dietz Fr. treatment of idiopathic clubfoot: a thirty-year

follow-up note. J Bone Joint Surg (Am) 1995; 77: 1477–89.

6 dobbs M, nunley r, schoenecker pL. Long-term follow-up of

patients with clubfeet treated with extensive soft-tissue release.

J Bone Joint Surg (Am) 2006; 88: 986–96.


congenital talipes equinovarus (clubfoot)

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