Foot




(1)
Groningen, The Netherlands

 




Foot Deformities



Foot Deformities Present at Birth






  • A312070_1_En_13_Figa_HTML.gif Complaint: the parents find that their child’s foot has an abnormal appearance.


  • A312070_1_En_13_Figb_HTML.gif Assessment: the foot has an abnormal appearance.


  • A312070_1_En_13_Figc_HTML.gif Differential diagnosis:





  • metatarsus primus varus



    • flexible type rigid type


  • metatarsus adductus



    • flexible type


    • rigid type


  • metatarsus varus (one third of a clubfoot)


  • pes varus (two thirds clubfoot)


  • talipes equinovarus (clubfoot)



    • postural talipes equinovarus


    • idiopathic talipes equinovarus


    • Teratogenic talipes equinovarus


    • neurological talipes equinovarus


  • calcaneovalgus deformity


  • convex pes valgus (congenital talus verticalis)



    • isolated convex pes valgus


    • teratogenic convex pes valgus


    • neurological convex pes valgus


    • skew foot (Z-foot, serpentine foot)


  • A312070_1_En_13_Figd_HTML.gif Explanatory note: the incidence of most congenital foot deformities is 1–2 in 1000 live births, with exception in the case of convex pes valgus and the skew foot, which are rare anomalies occurring respectively 1 in 10,000 and 1 in 50,000 live births.


Metatarsus primus varus

The outer four metatarsals are parallel with normal spaces in between. The first metatarsal is extremely adducted with respect to the rest of the foot. There is a strikingly great space between the big toe and the second toe (Fig. 13.1). Normally on an anteroposterior X-ray of the foot there is an angle of 7° between the first and second metatarsals. An angle greater than 10° is abnormal. The deformity is an inborn error, often familial, usually bilateral and appears more often in girls than in boys. There is a distinction between a flexible and a rigid metatarsus primus varus.

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Fig. 13.1
(a) A right sided rigid metatarsus primus varus. The first metatarsal together with the big toe is adducted with regard to the rest of the foot. The space between the big toe and the second toe is conspicuous. (b) Anteroposterior X-ray of the feet. In a metatarsus primus varus the intra-metatarsal angle between the first and second metatarsal is greater than 10°. (c) Bilateral flexible metatarsus primus varus. On weight bearing the big toes are medially displaced. The big toes join the rest of the toes when the feet are non weight bearing. These are often called “searching toes”




  • Flexible type. A flexible metatarsus primus varus is only present when the child stands and not in a non weight bearing foot. This is often called a searching toe and is caused by an overactive abductor hallucis muscle (Fig. 13.1). This corrects itself spontaneously.


  • Rigid type. In this case the deformity remains in a non weight bearing foot. A hallux valgus will develop during puberty if this deformity remains untreated.


Metatarsus adductus

In this case the forefoot is adducted with respect to the midfoot. We see no deep creases on footsole inspection (Fig. 13.2). The metatarsus adductus can usually be passively corrected by the examiner.

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Fig. 13.2
(a) Bilateral metatarsus adductus. The forefoot is in adduction. (b) On inspection of the footsole we do not see a deep crease. The footsole is smooth. If the forefoot can be brought into abduction relative to the hindfoot (beyond the dotted line) then correction of the metatarsus adductus will be spontaneous




  • Flexible type. The forefoot can be brought into abduction with respect to the posterior part of the foot in 90 % of cases. In this case the metatarsus adductus will be corrected spontaneously.


  • Rigid type. In the other cases the forefoot can just or just not be brought into a neutral position. Spontaneous correction does not occur in these cases


Metatarsus varus

This deformity is often incorrectly called a rigid type of metatarsus adductus. The difference is not only that the mid- and forefoot is in adduction with respect to the hindfoot but also because the foot is in supination (Fig. 13.3). There is a deep crease at the level of the transition between the mid- and hindfoot (Fig. 13.3). This deformity will not spontaneously correct itself. The child walks on the lateral side of the foot.

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Fig. 13.3
(a) Right metatarsus varus (one third clubfoot). The mid- and forefoot are in adduction and supination. (b) Bilateral metatarsus varus (one third clubfoot) seen from the plantar side. A deep crease can be seen in the transition between the midfoot and hindfoot (see arrows) (see also the difference with Fig. 13.2b)


Pes varus

The mid- and forefoot is in adduction and supination and the hindfoot has a heel varus (Fig. 13.4). Dorsal extension is complete. The child walks completely on the lateral side of the foot if the problem is untreated.

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Fig. 13.4
Left pes varus (two thirds clubfoot). The mid- and forefoot are in adduction and supination and the hindfoot has a varus angulation. Dorsiflexion is normal. (a) Anterior view. (b) Posterior view


Talipes equinovarus

The mid- and forefoot is in adduction and supination and the hindfoot has a heel equinus and varus deformity (Fig. 13.5). If the foot is turned inwards in newborns it is sometimes difficult to tell if we are dealing with normal feet or if one or both feet are abnormal. A child can for instance hold the foot or feet in a preferential clubfoot position. In order to check this one can tickle the lateral foot border and if this foot is actively everting we are dealing with a normal foot (Fig. 13.6).

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Fig. 13.5
(a) Bilateral idiopathic talipes equinovarus (clubfoot) seen dorsally. The mid- and forefoot are adducted and supinated and the hindfoot has a heel equinus and varus deformity. (b) The same clubfeet as in Fig. 13.5. A seen from the plantar side


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Fig. 13.6
There is a normal foot position if the foot actively achieves a normal position after the lateral foot border has been tickled. There is a positional deformity if this is not the case

The child will walk continuously on the outside of the foot if the clubfoot remains untreated.

An untreated clubfoot looks like a golfclub (Fig. 13.7). A clubfoot can be divided into 4 types:

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Fig. 13.7
An untreated talipes equinovarus (clubfoot) looks like a golfclub (From: Handbuch der Orthopädische Chirurgie, prof. dr. Joachimstahl, 1905)




  • Postural talipes equinovarus. This is a flexible deformity which can be brought into a neutral position directly after birth (Fig. 13.8).

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    Fig. 13.8
    (a) A postural talipes equinovarus. (b) This is a flexible deformity which can be brought into a neutral position directly after birth


  • Idiopathic talipes equinovarus. This is a clubfoot in which the cause is unknown. This is the most common type and varies in rigidity. The degree of rigidity can be classified with a scoring system such as that of Dimeglio and Pirani.


  • Teratogenic talipes equinovarus. This clubfoot is associated with a syndrome (Table 13.1). These feet are generally rigid (in Greek teras means monster and genan is production) (Fig. 13.9).


    Table 13.1
    Syndromes with a pes equinovarus















    Arthrogryposis multiplex congenita

    Cranio-carpo-tarsal syndrome

    Diastrophic dwarf growth

    Larsen syndrome

    Möbius syndrome


    See Appendix for details of these syndromes


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    Fig. 13.9
    Teratogenic clubfoot. These feet are generally shapeless and very stiff


  • Neurological talipes equinovarus. This is particularly associated with spina bifida. The clubfoot is usually rigid in these cases. An idiopathic clubfoot is seen in 1 or 2 per 1000 live births. Incidence between boys and girls is 3:1 and in 40 % of the cases bilateral. Parents without a clubfoot or feet who have a child with a clubfoot or feet have a 2.5–6.5 % chance that their next child will also have a clubfoot or feet.

    If one of the parents has idiopathic clubfeet, then the chances that their child will be born with clubfeet is 10–25 %. In monozygotic (identical) twins the chance that both children will have clubfeet is 32.5 % and in dizygotic twins 3 %.


Calcaneovalgus deformity

The forefoot has a neutral position. The hindfoot has extreme dorsiflexion, with a slight heel valgus (Fig. 13.10). If the foot can be manually manipulated into slight plantar flexion the deformity will spontaneously be corrected within 3 months. If this is not possible then the deformity will persist. In this case the deformity is part of a generalized problem such as in spina bifida.

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Fig. 13.10
Calcaneovalgus deformity. The hindfoot is in extreme dorsal extension with a light valgus angulation


Convex pes valgus

The mid- and forefoot is fixed in abduction and dorsiflexion and the hindfoot has a heel equinus and valgus deformity. The footsole is convex (Fig. 13.11). In some cases this deformity is difficult to differentiate from a calcaneovalgus deformity directly after birth. One must have a good look at the footsole. These are flat in the case of a calcaneovalgus deformity and in a convex pes valgus it will be convex. The heel sticks out posteriorly and it looks as if the lower leg is implanted into the middle of the foot. A convex pes valgus is also much stiffer than in calcaneovalgus deformity. There is a dorsolateral dislocation in the talonavicular joint in convex pes valgus. There are three types:

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Fig. 13.11
(a) A bilateral convex pes valgus in a newborn. (b) Bilateral convex pes valgus (untreated) when the child starts to walk. The mid- and forefoot is fixed in abduction and dorsalflexion and the hindfoot has a heel equinus and valgus deformity. The footsole is convex




  • Isolated convex pes valgus. This is unilateral and the least rigid.


  • Teratogenic convex pes valgus. This is always combined with other inborn deformities such as hip dislocation, hand deformities and a contralateral clubfoot. This type is often familial. The deformity is rigid and usually bilateral.


  • Neurological convex pes valgus. This type is associated with spinal canal abnormalities such as in spina bifida, sacral agenesis and diastematomyelia. The rigidity varies in this group.


Skew foot

This is also referred to as a Z-foot or serpentine foot. This is a complex deformity in which the forefoot is in adduction, the midfoot is in abduction and the hindfoot is in equinus and valgus (Fig. 13.12). Sometimes there will be a tarsal coalition (see pp. 279–285).

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Fig. 13.12
Skew foot. This is a complex positional deformity in which the forefoot is in adduction, the midfoot in abduction and the hindfoot in valgus and equinus





  • A312070_1_En_13_Fige_HTML.gif Supplementary assessment: in the first instance no further studies are necessary in the case of metatarsus primus varus, metatarsus adductus, metatarsus varus, pes varus and calcaneovalgus deformity. It is wise to carry out X-rays in two directions in case of other defomities. In a normal foot the angle between the talus and calcaneus (T.C.-angle = talocalcaneal angle) should be between 20° and 40° in both the anteroposterior and the lateral X-rays. In a clubfoot this angle is much smaller and the longitudinal axes of the talus and calcaneus are often more or less parallel to each other (Fig. 13.13). The angle between the talus and calcaneus in a convex pes valgus is much greater and the longitudinal axes of talus and calcaneus are more or less perpendicular to each other and that is why it is also called congenital talus verticalis (Fig. 13.14). In a skew foot the longitudinal axis of the hind-, mid- and forefoot on the anteroposterior X-ray show a Z-shape (Fig. 13.15). That’s why the deformity is also known as a Z-foot.

    It is wise to do an ultrasound or an anteroposterior X-ray of the pelvis because these foot deformities have a high incidence of developmental dysplasia of the hip except in the case of metatarsus primus varus.


  • A312070_1_En_13_Figf_HTML.gif Primary care treatment: a wait and see approach should be taken in the case of a flexible metatarsus primus varus or metatarsus adductus in which the forefoot can be manually brought into abduction with respect to the posterior part of the foot and in the case of a postural talipes equinovarus. These deformities will be spontaneously corrected before the fourth year of age. A pes calcaneovalgus corrects itself within 3–6 months of age.


  • A312070_1_En_13_Figg_HTML.gif When to refer: all other foot deformities must be referred.


  • A312070_1_En_13_Figh_HTML.gif Secondary care treatment: metatarsus primus varus. A rigid metatarsus primus varus is treated with manual reduction and lower leg plaster immobilization. If a normal position is achieved then the child will be treated with a ankle-foot orthosis during the night for 1 year (Fig. 13.16).


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Fig. 13.13
Lateral X-ray. (a) This is a normal foot with a normal angle between the talus and calcaneus. (b) Clubfoot, the longitudinal axis of the talus and calcaneus on the right side are almost parallel


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Fig. 13.14
Lateral X-ray of a convex pes valgus. The longitudinal axis of the talus is more or less perpendicular to the axis of the calcaneus and that is why it is also called a talus verticalis


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Fig. 13.15
Anteroposterior X-ray of a skew foot. The longitudinal axes of the hind-, mid- and forefoot have a Z-shape


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Fig. 13.16
Ankle-foot orthosis


Metatarsus adductus

In a rigid metatarsus adductus in which the forefoot can be brought into a neutral position, an ankle-foot orthosis should be worn at night for 1–2 years (with the foot in the corrected position). The foot will be manually corrected and immobilized with a long-leg plaster cast if the forefoot cannot be manipulated into a neutral position. Once the medial foot border is straight, an ankle-foot orthosis will be applied for 1–2 years at night (Fig. 13.17). A release of the abductor hallucis muscle and a capsulotomy of the first tarsometatarsal joint will be carried out if operative treatment is necessary.

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Fig. 13.17
Manual correction of a metatarsus adductus. (a) Sideways pressure on the cuboid with the thumb of one hand and sideways pressure on the head of the first metatarsal with the other. (b) The final position achieved

In children up to the age of 5 a capsule release of the tarsometatarsal and intermetatarsal joints should be considered if the above mentioned treatment is insufficient. (Heyman-Herndon procedure) (Fig. 13.18). A dorsal subluxation of the Lisfranc joint is a risk after this treatment. A crescentic shaped osteotomy at the level of the base of the metatarsal bones may be carried out in children older than 5 years who have a persistent rigid metatarsus adductus (Fig. 13.19).

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Fig. 13.18
Heyman-Herndon procedure for metatarsus adductus. (a) Release of the joint capsules of the tarsometatarsal and intermetatarsal joints (red). (b) Corrected position


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Fig. 13.19
(a) Crescentic osteotomies (red dotted lines) at the level of the base of the metatarsals for rigid metatarsus adductus. (b) Corrected position


Metatarsus varus and pes varus

The treatment is more or less the same as in talipes equinovarus. However, in a metatarsus varus, an equinus and varus deformity of the hindfoot need not be operatively corrected and the same applies to the equinus deformity of the hindfoot in a pes varus. Operative treatment is generally not necessary and one can treat these with serial manual corrections followed by a short-leg plaster cast.


Talipes equinovarus

The initial treatment of clubfeet is conservative (not operative) and consists of manual correction and long-leg plaster cast immobilization. There are two methods for treating clubfeet.


Kite method

In the Kite method the center of rotation in the midfoot is at the level of the joint between the calcaneus and cuboid. In the first instance the forefoot adduction and supination is treated with manipulations and long-leg plaster cast immobilization, followed by correction of the varus deformity of the hindfoot and finally correction of the equinus position of the hindfoot. When correcting the equinus deformity one must take care that correction is carried out in the hindfoot and not in the midfoot, otherwise the footsole will develop a convex shape, the so-called “rocker bottom foot” (Fig. 13.20). The chances of success using this technique varies from 15 to 50 %. Between the ages of 4 and 12 months evaluation will establish whether the conservative treatment has been sufficient. If this is not the case then a so-called “posteromedial release à la carte” will be carried out. This is an operation in five stages in which the following procedures will be carried out (Fig. 13.21):

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Fig. 13.20
(a) Bilateral rocker bottom foot. (b) Lateral X-ray of a rocker bottom foot


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Fig. 13.21
(a) In a posteromedial release the achilles tendon and tibialis posterior tendon are lengthened. (b) See the above text regarding the extensive operative procedures




  1. 1.


    The hindfoot equinus,

     

  2. 2.


    The hindfoot internal rotation,

     

  3. 3.


    The hindfoot varus,

     

  4. 4.


    The adduction deformity at the level of the Chopart joint,

     

  5. 5.


    The adduction position at the level of the tarsometarsal joint (Lisfranc joint).

     

In a posteromedial release the posterial tibial nerve and vessels must be localized and held on one side. After that the following structures can be lengthened or divided:




  1. 1.


    The equinus position of the posterior foot is corrected by Z-shaped achilles tendon lengthening and division of the posterior capsule of the talocrural and subtalar joints. This is also called a posterior release.

     

  2. 2.


    The internal rotation of the calcaneus can be corrected by division of the calcaneofibular ligament and the posterior talofibular ligament.

     

  3. 3.


    The varus position of the hindfoot can be corrected by dividing the superficial deltoid ligament on the medial side of the subtalar joint.

     

  4. 4.


    After that the adduction and supination at the level of the Chopart joint is corrected by lengthening the posterior tibial tendon, division of the talonavicular joint capsule on the medial and plantar side and if necessary the joint capsule between the calcaneus and the cuboid on the plantar side.

     

  5. 5.


    Finally the metatarsus adductus can be corrected by lengthening the abductor hallucis and releasing the first tarsometatarsal joint on the medial side.

     

After each of these five procedures one can assess the necessity for the following procedure or if a procedure can be omitted. Postoperative treatment of a posterior release is 6 weeks immobilization with a long-leg plaster cast and after a posteromedial or a medial release 12 weeks long-leg plaster immobilization. After this the child will wear an ankle-foot orthosis day and night until the child starts to walk, after which it will be worn only at night and depending on the tendency for recurrence from 2 to 5 years if necessary. One can stop the post-operative treatment with the ankle-foot orthosis if the child can actively dorsiflex and evert the foot and if there is no forefoot adduction. A312070_1_En_13_Figi_HTML.gif

Overcorrection is a risk after this operation as a result of a too extensive release. As a result a flatfoot may develop which can be difficult to treat, in which case a triple arthrodesis must be carried out (Fig. 13.22). Another complication is dorsiflexion of the first metatarsal bone as a result of overactivity of the anterior tibial muscle with respect to the peroneus longus muscle with plantar flexion of the first metatarsophalangeal joint as a result with hyperextension in the interphalangeal joint. A hallux flexus is the result. It looks as if there is a swelling on the dorsal side of the head of the first metatarsal (Fig. 13.23). Wearing shoes can be painful.

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Fig. 13.22
(a) Overcorrection in carrying out the posteromedial release may result in a flatfoot which is difficult to treat. (b) If really necessary a triple arthrodesis may be carried out in which the lateral foot border will be lengthened and the subtalar joint raised up and brought into a neutral position


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Fig. 13.23
(a) The hallux flexus (flexed big toe) as a result of domination of the anterior tibial muscle activity compared to that of the peroneus longus. As a result the distal part of the first metatarsal is pulled up dorsally with compensatory plantar flexion of the first metatarsophalangeal joint and hyperextension in the interphalangeal joint. It looks as if the distal part of the first metatarsal has a swelling (arrow). (b) Lateral X-ray of a hallux flexus. (c) Schematic representation of the operative correction of a hallux flexus. The treatment consists of a flexion osteotomy in the proximal part of the first metatarsal bone, division of the joint capsule of the metatarsophalangeal joint on the plantar side, lengthening of the tendon of the flexor hallucis longus and cleavage or dorsal transposition of the flexor hallucis brevis tendon. The dominant anterior tibial tendon will be lengthened or transposed to the second ray


Ponseti method

Correction of the midfoot using the Kite technique involves rotation around the joint between the calcaneus and cuboid. In the Ponseti technique the foot is rotated around the talus. In the first instance the first ray is brought into dorsiflexion so that the plantar aponeurosis will be stretched and the talonavicular joint will be more mobile making further correction possible.

Next, the foot is abducted in supination with one hand, whilst the talus is stabilized with the thumb using the other hand. The supination and adduction of the forefoot and the varus position of the hindfoot is corrected in this way. If these components have been corrected then an effort will be made to correct the equinus position of the hindfoot (Fig. 13.24). In 90 % of cases a percutanious achilles tendon tenotomy is necessary at 6 weeks of age (Fig. 13.25). After serial manual corrections and longleg plaster cast immobilization and a possible tenotomy of the achilles tendon a Dennis Brown bar or a similar bar will be applied that will be worn day and night until the child starts to walk after which it will be worn up to 3–4 years of age only at night (Fig. 13.26). In 30 % of cases an adduction/supination deformity persists in the forefoot in which case lateral reinsertion of the tendon of the anterior tibial muscle will be carried out between 3 and 4 years of age in order to correct the deformity (Fig. 13.27). In case of a idiopathic talipes equinovarus most surgeons prefer the Ponseti technique to the Kite method.

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Fig. 13.24
Ponseti clubfoot correction technique. Hereby we have a mnemonic namely CAVE in which the C stands for cavus, the A for adduction, the V for varus and the E for equinus. (a) In the first instance the cavus position must be corrected by bringing the first metatarsal bone into dorsiflexion. (b, c) The foot in supination will be abducted while the surgeon stabilizes the talus with the thumb of the other hand. As a result the foot rotates around the talus by which the adduction/supination in the mid- and forefoot and the varus deformity in the hindfoot will be corrected. (d) The equinus deformity of the hindfoot will be finally corrected


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Fig. 13.25
Percutaneous achilles tendon tenotomy


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Fig. 13.26
Modified Dennis Brown bar


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Fig. 13.27
(ac) The complete insertion of the anterior tibial muscle tendon will be transposed laterally in the case of a persistent adduction/supination deformity. (d) The arrow points to the transposed tibialis anterior tendon

A teratogenic and neurological talipes equinovarus are usually corrected operatively.

A correction can be carried out by repeating the lengthening of the achilles tendon and capsulotomies on the posterior side of the talocrural and subtalar joints if there are still elements of the equinus foot at a later age. The varus position in the hindfoot can be corrected between the 3rd and 10th year of life by carrying out a lateral closed wedge osteotomy of the calcaneus according to Dwyer (Fig. 13.28). An extra long lateral foot border in which the foot has the shape of a bean can be corrected between 4 and 8 years of age by shortening the lateral border according to the Evans technique (Fig. 13.29). If a medial release has not been carried out, then the above mentioned procedure must be combined with the Evans operation. A possible remaining metatarsus adductus can be treated from the age of 5 years by carrying out osteotomies at the level of the metatarsal bases (Fig. 13.19). If all of the components of the clubfoot are still present at an older age a corrective triple arthrodesis may be carried out after the age of 12. In this case an arthrodesis is carried out in the subtalar joint, the calcaneocuboid joint and in the talonavicular joint.

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Fig. 13.28
Lateral closed wedge osteotomy of the calcaneus according to Dwyer for a persistent varus position of the hindfoot. (a) Planned osteotomy for wedge excision (dotted line). (b) Closed wedge osteotomy fixed with a staple

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Jun 26, 2017 | Posted by in PEDIATRICS | Comments Off on Foot
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