Cavus Foot, from Neonates to Adolescents

Home , Pes cavus

Orthopaedics & Traumatology: Surgery & Research (2012) 98, 813—828

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REVIEW ARTICLE

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Cavus foot, from neonates to adolescents

P. Wicart

Paris Descartes University, Necker—Sick Children Hospital (AP—HP), 149, rue de Sèvres, Paris 75015, France

Accepted: 10 July 2012

KEYWORDS Summary Pes cavus, deﬁned as a high arch in the sagittal plane, occurs in various clinical situa-

Pes cavus; tions. A cavus foot may be a variant of normal, a simple morphological characteristic, seen in

Charcot-Marie-Tooth healthy individuals. Alternatively, cavus may occur as a component of a foot deformity. When it

disease; is the main abnormality, direct pes cavus should be distinguished from pes cavovarus. In direct

Neurology; pes cavus, the deformity occurs only in the sagittal plane (in the forefoot, hindfoot, or both).

Morphological types Direct pes cavus may be related to a variety of causes, although neurological diseases predom-

inate in posterior pes cavus. Pes cavovarus is a three-dimensional deformity characterized by

rotation of the calcaneopedal unit (the foot minus the talus). This deformity is caused by palsy

of the intrinsic foot muscles, usually related to Charcot-Marie-Tooth disease. The risk of pro-

gression during childhood can be eliminated by appropriate conservative treatment (orthosis to

realign the foot). Extra-articular surgery is indicated when the response to orthotic treatment is

inadequate. Muscle transfers have not been proven effective. Triple arthrodesis (talocalcanear,

talonavicular, and calcaneocuboid) accelerates the mid-term development of osteoarthritis in

the adjacent joints and should be avoided.

Introduction The cavus may be either one of the components or the

main component of the deformity (Tables 1 and 2).

All forms of pes cavus are characterised by a high arch in the

sagittal plane of the foot. The corollary is a bulge on the dor-

Background

sum of the foot. Weight is borne posteriorly on the calcaneal

tuberosity and anteriorly on the heads of the metatarsal

bones. Pes cavus is usually acquired, although a minority The foot can be divided in the sagittal plane into a lateral

of cases are congenital. column (calcaneus, cuboid, and 4th and 5th metatarsals) and

a medial column (talus, navicular, three cuneiform bones,

and ﬁrst three metatarsal bones). In the coronal plane, the

hindfoot is separated from the midfoot by the transverse

tarsal joint and the midfoot from the forefoot by the tarsal-

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metatarsal joints (Lisfranc joint).

This conference was presented at the 86th SoFCOT congress in

Paris, in November 2011. The calcaneopedal unit (CPU), which is the foot minus

E-mail address: [email protected] the talus, and its articulation with the talar-tibial-ﬁbular

814 P. Wicart

Table 1 Classiﬁcation of the 262 pes cavus deformities

treated surgically at the Saint-Vincent-de-Paul Teaching Hos-

pital, Paris, France, by R. Seringe (1978—2010). The cavus

deformity is listed ﬁrst when it was the predominant abnor-

mality and second otherwise.

Number of feet

Pes cavovarus

CMT 83

Figure 1 High calcaneal pitch angle: high-arch morphological

No CMT 36

variant.

Pes varus cavus

CMT 25

variant that imparts a completely different shape to the

No CMT 25 foot.

Idiopathic talipes equinovarus with 40 Reimers et al. reported that the proportion of children

cavus deformity with high-arched feet increased from 2% at 3 years of age to

7% at 16 years of age [2].

Pes calcaneocavus 15

Pes cavus equinus 8

Direct pes cavus

Pes cavus valgus 5

The deformity is entirely located in the sagittal plane. Com-

Non-idiopathic talipes equinovarus 6

parison to a compass (Pierre Queneau) is useful.

with cavus deformity

Flatfoot with cavus deformity 4

Clinical presentation

Miscellaneous forms of pes cavus 5

CMT: Charcot-Marie-Tooth. Anterior pes cavus is characterised by closure of the anterior

branch of the compass, i.e., direct descent of the fore-

foot and midfoot relative to the hindfoot. This deformity

Table 2 Causes of the 262 pes cavus deformities (Table 1).

was designated ‘‘total pes cavus’’ by Robert Méary [3], who

Neurological disorders: 173 described ‘‘irreducible plantar ﬂexion of the forefoot rela-

CMT 108 tive to the hindfoot’’, a step-off between the forefoot and

Other peripheral neuropathies 11 hindfoot, or true equinus of the midfoot and forefoot. An

Dysraphism 16 excessively horizontal orientation of the talus (‘‘inadequate

Central nervous disorder 20 dorsal slope’’ [4]) compensates for the equinus of the mid-

Myopathy 6 foot and forefoot and the step-off between the forefoot

Not identiﬁed 12 and hindfoot during weight bearing. A variant of anterior

pes cavus is congenital pes cavus, which is due to abnormal

Non-neurological disorders: 89

foetal position in utero.

Idiopathic CTEV 40

Posterior pes cavus consists in isolated verticalisation of

Other congenital deformities 9

the calcaneus, with compensatory plantar ﬂexion of the

Syndromic deformity 17

ankle.

Post-traumatic deformity 4

In mixed pes cavus, both branches of the compass are

Miscellaneous 19

closed.

CTEV: congenital talipes equinovarus; CMT: Charcot-Marie- Regardless of whether the cavus deformity is anterior,

Tooth.

mixed, or posterior, the apex of the lateral and medial

arches is not in contact with the ground and the pencil sign

is positive (a pencil can be slipped transversally under the

unit (TTFU) via the subtalar joint complex are crucial to the sole). The reduction in the weight-bearing area of the foot

understanding of pes cavovarus [1]. results in increased pressure with metatarsalgia in patients

with direct pes cavus. Excessive pressure on the calcaneal

tuberosity may result in plantar ulcers in patients with sen-

Morphological variants of normal

sory impairments (e.g., due to spina biﬁda).

The foot may have a cavus in the absence of any disease.

This shape is simply a variant of the normal foot. The pitch Radiological analysis

angle of the calcaneus relative to the ground may affect the

◦

shape of the foot: it is usually less than 10 in the normal The various forms of direct pes cavus can be distinguished by

◦

ﬂatfoot variant and greater than 25 in the high-arch variant radiological analysis (Fig. 2). The Djian-Annonier and Hibbs

(Fig. 1). angles between the calcaneus and the sesamoid bones and

Familiarity with these variants is important, as an abnor- ﬁrst metatarsal, respectively, reﬂect the overall degree of

mal acquired deformity may develop on a pre-existing opening of the compass but fail to show the location of the

Cavus foot, from neonates to adolescents 815

◦

Figure 2 Direct pes cavus. 1: Méary’s angle: longitudinal axes of the talus and ﬁrst metatarsal bone (normal: 0 ). 2: Tibiotalar

◦

angle: longitudinal axes of the talus and tibia (normal: 110 ). 3: Calcaneal pitch angle: plantar aspect of the calcaneo-cavus

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(posterior pes cavus) (and ground (normal: 15—20 ). a: direct anterior pes cavus: increased Méary’s angle, increased calcaneal

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pitch angle, and decreased tibiotalar angle; b: direct posterior pes cavus: Méary’s angle = 0 , increased calcaneal pitch angle, and

increased tibiotalar angle; c: mixed direct pes cavus: increased Méary’s angle and increased calcaneal pitch angle with no change

in the tibiotalar angle.

cavus deformity. Their use is criticisable, since the posterior should be given to surgery during growth to correct the

measurement point is located on the lateral column and the muscle imbalances. Osteotomies may or may not be per-

anterior measurement point on the medial column. formed.Treatment options are as follows:

Causes • posterior pes cavus: surgery before growth completion

can stop the progression of the deformity. The ﬁrst step

consists in transferring one or more dorsal ﬂexors (tib-

The combination of neurological impairments and growth-

ialis anterior, extensor digitorum longus, peroneus tertius,

related changes results in the early development (before

peroneus brevis) to the calcaneal tuberosity to compen-

10 years of age) of rapidly progressive deformities (Table 3).

sate for the triceps surae weakness. Then, an osteotomy is

performed to displace the calcaneal tuberosity upwards

Treatment

and posteriorly, thereby increasing the moments of the

transferred muscles (Fig. 3);

The management depends on the radiological charac- •

anterior pes cavus: plantar fascia release with or without

teristics. Any motor impairments due to a neurological

dorsal tarsectomy is indicated;

disease must be corrected before the induced osteoarti- •

mixed pes cavus: a combination of the above-described

cular deformities are treated. To avoid having to perform

techniques is used.

triple arthrodesis at growth completion [5], preference

Pes cavovarus

Table 3 Causes of direct pes cavus deformity.

Pes cavovarus is also known as pes cavus varus or medial pes

Direct pes cavus Cause

cavus (Fig. 4).

Anterior Paralysis of the toe extensors

Congenital pes cavus

Aetiology

Posterior Paralysis of the triceps surae

(pes calcaneocavus)

Pes cavovarus is a rare deformity usually caused by a

Mixed Foot muscle paralysis

neurological disorder (Charcot-Marie-Tooth [CMT] disease

Morphological variants

in two-thirds of cases) [6,7]. Among patients with CMT

816 P. Wicart

Pathophysiology and pathology

Pes cavovarus was classically ascribed to weakness of the

tibialis anterior muscle responsible for plantar ﬂexion of the

ﬁrst ray, whereas the claw-toe deformity was ascribed to

compensatory activity of the toe extensor muscles [3]. In

CMT disease [8], denervation may affect the intrinsic foot

muscles ﬁrst [9] then the toe ﬂexors and extensors, fol-

lowed by the peroneal muscles and tibialis posterior and,

ﬁnally, by the tibialis anterior. Therefore, weakness of the

tibialis anterior muscle cannot explain the development of

pes cavovarus, since this abnormality occurs late in the

course of the deformity [10]. The ﬁbularis longus muscle may

be less severely affected than the ﬁbularis brevis and tib-

ialis anterior muscles [11]. The ﬂexor hallucis longus muscle

Figure 3 Bilateral pes calcaneo-cavus (posterior pes cavus) may be spared, and the posterior leg compartment mus-

(9-year-old boy with S1 spina biﬁda). cles are usually normal, except in advanced stages of CMT

disease.

The pathophysiology of pes cavovarus has been eluci-

dated in published studies and via observation of patients

with CMT disease, whose initial valgus ﬂatfoot deformity

progresses to pes cavovarus at about 3 to 6 years of age

(Fig. 5). Weakness of the intrinsic foot muscles (interosseous

muscles and lumbricals) or disorders of muscle synergy

are crucial to the pathophysiology of pes cavovarus [9,12].

The intrinsic foot muscles stabilise the metatarsophalangeal

joints during dorsal ankle ﬂexion and toe extension. Their

paralysis results in extension of the metatarsophalangeal

joints. This deformity is perpetuated by the new dorsal tra-

jectory of the interosseous muscle tendons, which become

dorsal ﬂexors of the metatarsophalangeal joints.

Fig. 6 summarises the pathophysiology of pes cavovarus.

The plantar fascia attaches to the proximal end of the

ﬁrst phalanges. Consequently, extension of the metatar-

sophalangeal joints puts the fascia under tension, causing

cavus deformity; there is no contracture of the fascia. The

Figure 4 Refractory pes cavovarus at the end of the growth

period. anatomical characteristics of the plantar fascia and the

medial to lateral decrease in the diameter of the metatarsal

heads acting as pulleys explain the development of pes cavo-

disease, 80% have pes cavovarus deformity [7]. A number of varus deformity, whose apex is at the cuneiform bones,

other central and peripheral neurological diseases can cause and of irreducible forefoot pronation. Pes cavovarus is not

pes cavovarus. Non-neurological causes are less common; related to isolated plantar ﬂexion of the ﬁrst ray [10,13,14]:

they include skeletal dysplasia syndromes, birth defects, to maintain tripod weight-bearing on the calcaneal tuberos-

progression of congenital idiopathic clubfoot, and trauma. ity and heads of the ﬁrst and ﬁfth metatarsals, the CPU

Idiopathic pes cavovarus is exceedingly rare. topples into supination [3]. This displacement combines a

Figure 5 Flatfoot deformity at 3.6 years of age (a) in a patient with Charcot-Marie-Tooth disease with progression to pes cavus

by 10 years of age (b).

Cavus foot, from neonates to adolescents 817

Paresis of the intrinsic foot muscles

™

Anter ior pes cavus (disruption of Méary’s line)

Hyperextension of the metatarso-phalangeal joints + excessively vertical orientation of the

metatarsals

Clinical test: heel walking

Exag gerated forefoot pronation

Cavus that increases from lateral to medial (plantar fascia)

™

- Growth = osteoarticu lar deformities with the apex at the cuneiform bones

- irreducibl e forefoot pronation with a dorsal bulge = intermediate and lateral cuneiform bones

™

Compens ation by overall supination of the calcaneopedal unit

- heel in neutral position then development of calcaneal varus

- lateral rotation of the talar-tibial-fibular unit

- twisting of the calcaneopedal unit

™

Grow th and an imbalance between the peroneus brevis and tibialis posterior muscles result in

- mid-tarsal adduction

- irreducibilit y of the subtalar and mid-tarsal deformities

™

Structural pes cavovarus + compensatory lateral torsion of the two bones of the legs

Figure 6 Pathophysiology of pes cavovarus.

three-dimensional helical twisting movement [3] of the CPU in chronic ankle instability, which has a severe impact

(forefoot pronation and hindfoot supination and, therefore, on functional outcomes and progression of the deformity

varus of the heel) and lateral rotation of the TTFU on the [10].

CPU (adduction of the CPU under the TTFU and/or transverse

tarsal joint). These displacements are reducible initially.

Physical ﬁndings

Lateral torsion of the leg bones to compensate for the

adduction develops during the last few years of the growth

The patients may be seen before 5 years of age for evalu-

period. This concept differs from the classical pathophy-

ation of valgus ﬂatfoot deformity. The neuro-orthopaedic

siological descriptions, even those reported recently [14].

assessment is crucial as it can detect the presence of a

Although the ﬁrst metatarsal creates a considerably more

neurological disease. The heel-walking test is used. Normal

prominent bulge at the sole of the forefoot compared to

children have no difﬁculty walking on their heels. The ankles

the other metatarsals, the apex of the cavus deformity is

are ﬂexed dorsally and the toes harmoniously extended. The

not located on the ﬁrst ray but is found instead on the

sagittal alignment of the torso, hips, and knees is main-

second and third rays (intermediate and lateral cuneiform

bones). tained. Impairment of the intrinsic foot muscles results in

hyperextension of the toes and prominence of the extensor

Compensatory ﬂexion of the interphalangeal joints

tendons at the anterior aspect of the ankle, including the

causes claw-toe deformities that predominate on the medial

tibialis anterior tendon, but without dorsal ﬂexion of the

toes and progress independently from the other deformi-

ankle. Retroposition of the tibia and excessive knee exten-

ties. The claw-toe deformities may be lacking [15] and their

sion and/or anterior projection of the torso occur (Fig. 7).

severity does not correlate with that of the cavus deformity

[3]. The child is unable to walk on the heels. During this manoeu-

vre, dynamic pes cavovarus deformity develops, strongly

suggesting a neurological disorder.

Symptoms With the child in the standing position, the pes cavovarus

deformity, overall adduction, convexity of the lateral edge

During growth, pes cavovarus deformity may become more of the foot, and varus of the heel can be assessed (Fig. 4).

severe, particularly during puberty, causing symptoms that The reducible nature of the deformities, described in the

may develop early (before 10 years of age). Excessive pres- literature, deserves comment. The term ‘‘reducibility’’ is

sure on the head of the ﬁrst metatarsal or base of the ﬁfth not appropriate to describe the primary structural and

metatarsal during weight bearing may cause pain. Ankle irreducible abnormality of the forefoot (pes cavovarus

instability may manifest as recurrent tibiotarsal or subtalar deformity and pronation), which, at best, can be decreased

sprains (hindfoot varus and weakness of the peroneus bre- via speciﬁc manoeuvres. The secondary deformities (adduc-

vis muscle). Persistence of these abnormalities may result tion of the CPU and varus of the heel) are completely or

818 P. Wicart

Figure 7 Heel-walk test.

partly reducible early on but become permanent structural interpretation of the image, because the longitudinal axes

deformities as growth progresses. Reducibility of this com- of the talar bone and ﬁrst metatarsal bone are not located

ponent is assessed during weight bearing. If the deformity in the same sagittal plane. This difﬁculty can be overcome

is reducible, medial leg rotation diminishes the depth of by using the oblique block test to correct the transversal

the medial arch and corrects the heel varus (lateral rota- abnormalities [17], thereby allowing interpretation of the

tion of the CPU under the TTFU and untwisting of the CPU). lateral radiograph (Fig. 8).

The Coleman block test [16] corrects the forefoot pronation

because the forefoot drops off the side of the block while the

Dorsoplantar weight-bearing radiograph

heel is lifted. This test corrects the heel varus to a variable

This view shows the secondary abnormalities in the trans-

extent. The oblique block test [17] uses the same princi-

verse plane. Lateral rotation of the TTFU above the

ple but maintains weight bearing on the forefoot (Fig. 8).

CPU manifests as a decrease in the angle of talocal-

Reducibility of the heel varus has also been assessed by hav-

caneal divergence. This abnormality is readily corrected

ing the child kneel at the edge of the table or lie down in

by the oblique block test (Fig. 8). Adduction in the trans-

the prone position [13,18].

verse plane of the residual tarsus (angle between the

The excessive forefoot pronation is combined with

calcaneus and ﬁfth metatarsal) indicates progression to

restriction of dorsal ankle ﬂexion, although true equinus

a structural deformity with calcaneocuboid subluxation

deformity is rare. Examination of the sole of the foot

and deformities of the navicular and medial cuneiform

may show hyperkeratosis indicating excessive pressure on bones.

the head of the ﬁrst metatarsal and base of the ﬁfth

metatarsal. Increased lateral laxity of the ankle, sometimes

Anterior-posterior radiograph of the ankles with anklets

with perceptible cracking sounds, may be found in adoles- (Méary)

cents.

This view is useful for quantifying heel varus.

Dynamic varus/valgus radiographs of the ankle

Imaging studies

These views may show varus instability in adolescents.

Lateral weight-bearing radiograph of the foot

The cavus deformity, located anteriorly, can be measured Global scores

by the lateral talar-ﬁrst metatarsal angle (Méary’s angle)

[3]. The lateral radiograph underestimates the depth of the The classiﬁcation scheme described by Paulos et al. [19]

arch: the abnormalities in the transverse plane hinder the rests on clinical criteria (correction of the forefoot and

Cavus foot, from neonates to adolescents 819

Figure 8 Oblique block test. a and b: the oblique block corrects the heel varus. Lateral radiograph without (c) and with (d) the

oblique block: the oblique block corrects the abnormalities in the transverse plane, allowing appropriate measurement of Méary’s

angle. Dorsoplantar radiograph without (e) and with (f) the oblique block: note the restoration of talocalcaneal divergence.

hindfoot deformities) and subjective criteria (patient sat- Orthotic treatment

isfaction). Wicart and Seringe developed a classiﬁcation

scheme [17] (Table 4) based on functional, morpho- Children

logical (orientation of the hindfoot), radiological, and Orthotic treatment is classically described as ineffective

outcome criteria (triple arthrodesis indicates treatment fail- [6,20,21]. This view is wrong. When a child with pes cavo-

ure). varus deformity is in the supine position, the cavus deformity

820 P. Wicart

Table 4 Score for pes cavovarus. The inﬂuence of hindfoot malalignment, when mild, is modulated by correction of the cavus

deformity and vice versa.

◦

Heel axis Méary’s angle (M) Symptoms

Very good VG 0 ≤ M < 15 None

N or slight VR 0 ≤ M < 5

Good VG 15 ≤ M < 20 None

—5 ≤ M < 0

N 5 ≤ M < 20

VR 5 ≤ M < 15

Fair VG or N M > 20 or M < —15 None or mild

VR 15 ≤ M < 20

Poor Recurrence or need for triple Plantar pain

arthrodesis Ankle sprains

VG: valgus; VR: varus; N: neutral.

Untwisting plaster boot cast. The objective is to correct

established pes cavovarus (Fig. 9).

Untwisting Perlstein-type orthosis for night wear. The

use of this orthotic device is rational in three situations

(Figs. 10—12):

•

at onset of the ﬁrst evidence of pes cavovarus (to prevent

or slow progression);

•

as follow-on therapy after the use of a derotating plaster

boot cast;

•

and after surgical treatment in a child to prevent recur-

rence due to growth and to the neurological disorder. The

rate of repeat surgical treatment ranges from 38% to 50%

[10,17,20].

The use of a derotating long leg cast extending from the

◦

Figure 9 Derotating plaster boot: casting technique. The thigh to the foot and keeping the knee in at least 20 of

lower limb is placed on a knee rod. A low plaster boot is fash- ﬂexion improves correction in the transverse plane.

ioned ﬁrst, without enclosing the proximal two-thirds of the A recent study conﬁrmed the effectiveness of this man-

leg, to which the aide applies various constraints. Role of the agement strategy [21]. Outcomes at growth completion

aide: one hand keeps the knee ﬂexed on a knee rod and applies were satisfactory for half the feet, obviating the need for

axial pressure to the leg (A3), thus serving as a counter-brace surgical treatment. Orthotic therapy delayed surgery by 5

to correct the cavus deformity and any equinus deformity; the years on average, thus allowing surgery at a more favourable

other hand rotates the leg (and therefore the TTFU) medially to age. No patients required triple arthrodesis.

facilitate correction of the adduction (A1) and applies lateral-

to-medial pressure (A2) to ensure correction of the varus or Adolescents

closure of the calcaneal osteotomy after surgical treatment.

Physical therapy prevents the development of contractures

Role of the surgeon: one hand displaces the heel in valgus (O1)

and preserves proprioception. Splints to be worn at night

in opposition to the lateral-to-medial pressure applied by the

are classically recommended to combat the development of

aide to the leg; the foot is placed in dorsal ﬂexion (correc-

equinus deformity.

tion of the cavus deformity and of any equinus deformity) (O2);

supination of the forefoot on the hindfoot (O3); global abduc-

Surgical treatment

tion (O4) to correct the adduction of the transverse tarsal and

subtalar joints, in opposition to the medial rotation of the leg

The challenges raised by the surgical treatment of pes cavo-

bones. When the short plaster boot is dry, the second step con-

varus [22] explain the large number of available techniques.

sists in releasing the pressure on the leg and extending the boot

circumferentially up the leg.

Surgery on the soft tissues

Soft tissue release procedures.

worsens and clawing of the toes appears. These ﬁndings indi-

Plantar fascia release. Simple selective fasciotomy can

cate a need for orthotic treatment at night. An orthotic

be performed through a small incision in the sole of the foot.

treatment protocol has been developed based on pathophy-

Steindler [23] described an extensive procedure consisting in

siological considerations.

incision via a medial approach of the plantar fascia, ﬂexor

Cavus foot, from neonates to adolescents 821

◦

Figure 10 Derotating Perlstein orthosis: keeping the ankle ﬂexed at 90 decreases the height of the arch (b); the forefoot is

placed in supination (correction of the pes cavovarus deformity) (a and c); the hindfoot is displaced in valgus (d); an oblique dorsal

strap placed under tension from lateral to medial corrects the pes cavus deformity (a and b).

hallucis brevis, abductor digiti minimi, abductor hallucis, hallucis muscle, and division of the medial plantar sep-

and plantar calcaneocuboid ligament. This procedure cor- tum. This procedure is indicated in patients with persistent

rects the cavus deformity by allowing plantar gaping of the adduction of the CPU and/or transverse tarsal joint after

foot joints but does not produce sustained results [3,24]. correction of pes cavovarus. Excision of the anterior extrem-

Anteromedial release. Medial release of the talonav- ity of the calcaneus [25] is in order when the lateral edge of

icular joint and, in some cases, of the subtalar and/or the foot remains convex after medial release of the medio-

calcaneocuboid joint is combined with lengthening of tarsal soft tissues (most notably in case of calcaneocuboid

the posterior tibial tendon, detachment of the abductor subluxation).

822 P. Wicart

Figure 11 Orthotic treatment: untwisting cast then untwisting brace until growth completion (11-year-old patient with Charcot-

◦

Marie-Tooth disease). a: Méary’s angle with the block = 29 . Note the marked abnormalities in the transverse plane; b: outcome at

18 years of age: the cavus deformity and transverse abnormalities are fully corrected.

Figure 12 Bilateral pes cavovarus in a 10-year-old patient with Charcot-Marie-Tooth. The deformity is more marked on the left

than on the right (a). Outcome at 18 years of age (b) after surgery on the left foot (plantar opening-wedge osteotomy of the

cuneiform bones, selective plantar fascia release, and Dwyer’s osteotomy) and orthotic treatment on the right (untwisting cast and

untwisting brace worn at night).

Cavus foot, from neonates to adolescents 823

Figure 13 Plantar opening-wedge osteotomy of the cuneiform bones: surgical technique. a: radiograph to check proper position

of the pin guiding the osteotomy cut; b: plantar opening of the osteotomy of the cuneiform bones, with a dorsal hinge, ﬁlled with

the calcaneal graft removed during Dwyer’s osteotomy.

Surgery on the tendons and muscles. patients and provides good outcomes in half the cases of

Tendon lengthening procedures. Lengthening of the pes cavovarus.

•

Achilles tendon is best avoided, as this tendon serves as a Similarly, extensor digitorum longus tendon transfer to

counterbrace to correct the cavus deformity [26]. The tib- the necks of the metatarsal bones has been used.

ialis posterior tendon can be lengthened to diminish the

normal adducting effect of the muscle. Lengthening can

Few data are available on the outcomes of these soft-

be achieved either at the white/red junction behind the

tissue procedures in patients with CMT disease. Most of the

tibia or, preferably, via posterior displacement of the distal

case-series studies were heterogeneous in terms of both the

attachment site. This procedure should be considered with

patient population and the surgical techniques used [28].

discernment, as the tibialis posterior tendon can be used for

One study showed that triple arthrodesis was not necessary

tendon transfer surgery in adulthood.

in any of the patients after a mean follow-up of 14 years

Tendon transfers. Several tendon transfer procedures [29].

can be used at the hindfoot:

• transfer of the ﬁbularis longus tendon to the ﬁbularis bre- Osteotomies

vis [10,13] eliminates the pronation and plantar ﬂexion Several osteotomy procedures have been described.

induced by the ﬁbularis longus and increases the abduc- Dwyer calcaneal osteotomy [15]. A 10-mm wide lateral

tion due to the ﬁbularis brevis; wedge is removed from the body of the calcaneus to

•

transfer of the tibialis posterior tendon to the dorsum obtain non-anatomical valgus of the hindfoot. Studies have

of the foot is performed to restore active dorsal ﬂexion shown that the Dwyer procedure has little inﬂuence on

of the foot. This procedure decreases the varus-inducing the midfoot and forefoot abnormalities, most notably the

effect of the tibialis posterior muscle. high arch [24,30]. In contrast, this procedure is usually

required after correction of the primary midfoot and fore-

Transfers at the midfoot include transfer of half or all foot abnormalities, as secondary hindfoot supination is then

of the tibialis anterior tendon [10] to the cuboid or lat- insufﬁciently reducible. To obtain a greater degree of cor-

eral cuneiform bone, transfer of the extensor hallucis longus rection, curved osteotomies can be used [31]. Absence of

tendon to the cuboid or lateral cuneiform bone (Hibbs pro- calcaneal osteotomy after midfoot surgery is associated with

cedure), and transfer of the peroneus tertius tendon. The a high rate of residual hindfoot varus [10].

effect is often limited to tenodesis [10]. Metatarsal osteotomies. Dorsiﬂexion osteotomy of the

Finally, tendon transfers can be performed at the fore- ﬁrst metatarsal has been advocated [10,13]. This proce-

foot; dure cannot fully correct the high arch or forefoot pronation

and is illogical because it does not involve the apex of

• The extensor hallucis longus tendon can be transferred the deformity. When performed concomitantly with dorsal

to the neck of the ﬁrst metatarsal bone, as described closing wedge osteotomy of the medial cuneiform bone,

◦ ◦

by Jones. Interphalangeal arthrodesis must be performed overall correction ranged from 30 to 60 [13] and secondary

concomitantly to prevent distal claw-toe deformity [27]. osteotomies of the second and third metatarsals were there-

This isolated transfer procedure was ﬁrst described as a fore often required. Neither is there a sound rationale for

method for correcting great-toe claw deformity in polio performing osteotomies of all the metatarsal bones [32,35].

824 P. Wicart

Figure 14 Treatment with plantar opening-wedge osteotomy of the cuneiform bones, Dwyer’s osteotomy, and selective plantar

◦

fascia release. a: preoperative appearance (12 years of age): Méary’s angle = 20; b: three months postoperatively: Méary’s angle = 0 ,

full correction of the abnormalities in the transverse plane; c: at growth completion: the correction is sustained, in part via the

use of an untwisting brace at night.

In contrast, adjunctive dorsiﬂexion osteotomy of the base Several variants or adjuncts can be suggested:

of the ﬁrst metatarsal is in order when the plantar bulge

produced by the ﬁrst metatarsal persists after correction of

• removing a bone fragment of maximal thickness from the

the high arch and mid/forefoot pronation [17].

intermediate and lateral cuneiform bones (apex of the

Tarsometatarsal osteotomies. Dwyer suggested a dorsal

deformity in the coronal and sagittal planes) avoids exac-

closing-wedge tarsometatarsal osteotomy to achieve the

erbation of the initial adduction, which would occur after

legitimate goal of preserving hindfoot mobility. However,

maximal resection of the medial cuneiform bone (Fig. 17);

the loss of tarsal-metatarsal joint mobility and the distal •

dividing the short plantar ligament is neither necessary

location of the osteotomy relative to the apex of the arch

nor desirable;

explain that this technique was not further developed. •

Dwyer’s osteotomy corrects residual hindfoot varus,

Plantar opening-wedge osteotomy of the cuneiform

which is common. This fact led Méary [32] to con-

bones [17]. This procedure has several advantages. The

clude that ‘‘combining anterior tarsectomy with Dwyer’s

cuneiform bones are at the apex of the deformity. The

osteotomy can constitute an elegant solution’’;

osteotomy involves all three cuneiform bones and therefore •

dorsiﬂexion osteotomy of the base of the ﬁrst metatarsal

corrects the overall pronation of the forefoot. The plantar

bone is indicated in the event of persistent prominence

opening with a dorsal osteoperiosteal hinge is maintained via

of the head of the ﬁrst metacarpal bone at the sole of the

the insertion of a bone graft, which corrects the cavovarus foot;

deformity (Figs. 13 and 14). The loss of mobility is conﬁned •

claw-toe deformity shows little or no response to tarsec-

to the two inter-cuneiform joints. Plantar opening-wedge

tomy, as it develops late during growth, and therefore

osteotomy conﬁned to the medial cuneiform bone [33] acts

requires an additional corrective procedure.

only on the ﬁrst ray and fails to correct the overall forefoot

pronation.

Wedge tarsectomy. The objective of wedge tarsectomy

(Méary) [32] was to correct ‘‘the verticalisation of the

Triple arthrodesis (subtalar, talonavicular, and

ﬁrst metatarsal bone and the pronation of the forefoot’’

calcaneocuboid arthrodesis)

( Figs. 15 and 16). These goals explain the use of a closing-

This procedure is not desirable. The bone resections are

wedge osteotomy removing a wedge of navicular, cuneiform,

located proximal to the apex of the deformity. Medium- and

and cuboid bone with a dorsal and medial base. Méary

long-term complications can develop as a result of exces-

suggested adding plantar fascia release to the procedure.

sive mechanical stress on the ankle and distal foot joints,

Because a plantar hinge is kept, correction of the high arch

which are particularly deleterious in patients with impair-

induces lengthening of the foot.

ments of deep sensation [34]. Varus instability of the ankle

Cavus foot, from neonates to adolescents 825

Figure 15 Clinical appearance before surgery (at 16 years of age) and after dorsal tarsectomy/Dwyer’s osteotomy/dorsiﬂexion

osteotomy of the ﬁrst metatarsal bone of the right foot (at 18 years of age). a: note the correction of the hindfoot varus; b: note

the relative increase in foot length and improved footprint distribution.

with rapidly progressive osteoarthritis may begin to appear The development of pes cavovarus deformity indi-

before 30 years of age (Fig. 18). cates a need for treatment with the derotating Perl-

stein orthosis, preceded in patients with marked defor-

mities by a derotating plaster cast. This orthotic

Selection of the therapeutic strategy

treatment may postpone or obviate the need for

surgery or allow the use of less invasive procedures.

The treatment aims to correct the deformity while preser-

It is extremely effective before 10 to 12 years of age

ving range of motion of the transverse tarsal and subtalar

(Fig. 12). joints.

826 P. Wicart

osteotomy is inserted into the plantar opening fashioned

in the cuneiform bones. Medial soft-tissue release is indi-

cated in patients with persistent CPU adduction and/or

adduction of the transverse tarsal joint. An osteotomy to

shorten the lateral column [25] is performed in the event

of persistent convexity of the lateral edge of the foot after

soft-tissue release. When the head of the ﬁrst metatarsal

bone is seen to bulge into the sole of the foot compared to

the head of the second metatarsal bone at the end of the

procedure, dorsiﬂexion osteotomy of the ﬁrst metatarsal

bone is in order. The osteotomies are adjusted via plaster

casting, and no internal ﬁxation is needed. Postopera-

tive immobilisation relies on a derotating plaster boot

(worn for 3 months) fashioned on the 7th postoperative

day under general anaesthesia. Then, the derotating Perl-

stein orthosis is used at night to prevent recurrence of

the deformity due to growth and to the persistence of

Figure 16 Radiographs taken before surgery (at the neurological impairments. Whether orthotic or surgi-

16 years of age) and after dorsal tarsectomy/Dwyer’s cal treatment is used, the claw-toe deformity resolves,

osteotomy/dorsiﬂexion osteotomy of the ﬁrst metatarsal further supporting the use of early treatment;

•

bone of the right foot (at 18 years of age). adolescents (11 to 14 years in girls and 13 to 16 years

in boys): the limited reducibility of the deformity and

the risk of recurrence after surgical treatment warrant

Progressive symptomatic pes cavovarus (despite appro-

postponement of surgery until growth is completed. A

priate orthotic therapy) requires surgery before the end of

derotating orthosis should be worn at night to prevent

the growth period, in keeping with the joint-sparing princi-

the exacerbation of the deformity seen at the end of the ple [10,13,17,35].

growth period;

Three age groups should be distinguished:

•

end of the growth period: dorsal tarsectomy [32] with

the above-described variants and adjuncts, to obviate the

• children (< 10 years in girls and < 12 years in boys): plantar

need for triple arthrodesis. In the absence of previous

opening-wedge osteotomy of the cuneiform bones after

treatment the claw-toe deformity will have progressed

selective plantar fascia release, combined with Dwyer’s

and may require surgical treatment.

osteotomy [17]. The wedge removed during Dwyer’s

Figure 17 Tarsectomy. a: correct (technical variant): remove a very small bone fragment from the medial cuneiform bone to avoid

inducing adduction / the wedge is thickest at the intermediate cuneiform bone, which is the apex of the arch / remove as much of

the cuboid bone as needed to correct the adduction; b: incorrect (original technique): removal of a wedge having a dorsomedial

base causes adduction, which is not desirable, as adduction is among the components of the initial deformity.

Cavus foot, from neonates to adolescents 827

Figure 18 Varus instability 15 years after triple arthrodesis. a: note the adequate alignment of the hindfoot; b: views in val-

gus/varus.

Conclusion magnetic resonance imaging features in leg and foot muscles.

Brain 2006;129:426—37.

[10] Ward CM, Dolan LA, Bennett L, Morcuende JA, Cooper RR.

Considerable advances in the knowledge of pes cavus defor-

Long-term results of reconstruction for treatment of a ﬂexible

mities have been achieved over the last 25 years [6]. Taking

cavovarus foot in Charcot-Marie-Tooth disease. J Bone Joint

normal morphological variants into account has reﬁned the

Surg 2008;90A:2631—42.

diagnosis. A clinical study and a critical review of the litera-

[11] Mann RA, Missirian J. Pathophysiology of Charcot-Marie-Tooth

ture have established that pes cavovarus is due to weakness disease. Clin Orthop Relat Res 1988;234:221—8.

of the intrinsic foot muscles, in contradiction to classical [12] Duchenne de Boulogne GB. Physiologie des mouvements. Paris:

theories. A modern treatment strategy for the orthotic and Baillière; 1867.

[13] Mubarak SJ, Van Valin SE. Osteotomies of the foot for cavus

surgical treatment of pes cavovarus in children is suggested.

deformities in children. J Pediatr Orthop 2009;29:294—9.

[14] Guyton GP. Current concepts review: orthopaedic aspects of

Charcot-Marie-Tooth disease. Foot Ankle Int 2006;27:1003—10.

Disclosure of interest

[15] Dwyer FC. Osteotomy of the calcaneus for pes cavus. J Bone

Joint Surg Br 1959;41:80—6.

The author declares that he has no conﬂicts of interest con-

[16] Coleman SS, Chesnut WJ. A simple test for hindfoot ﬂexibility

cerning this article.

in the cavovarus foot. Clin Orthop Relat Res 1977;123:60—2.

[17] Wicart P, Seringe R. Plantar opening wedge osteotomy of

cuneiform bones combined with selective plantar release and

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