congenital hand anomalies 2011

8/9/2019 Congenital Hand Anomalies 2011

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Congenital hand anomaliesGr ainne Bourke

Abstract

Congenital upper limb anomalies affect 0.1e

0.2% of all newborns. Theyare often isolated phenomena but can be associated with other congen-

ital anomalies and may be the only external manifestation of a syndrome.

Knowledge of the treatment options is imperative to ensure appropriate

referral and counselling.

The aim of surgery for a congenital hand anomaly is to improve both

function and appearance. Apart from the face, the hand is the only other

part of the body on regular display.

Independent living is largely dependent on good bimanual hand func-

tion. For example a large proportion of activities of daily living such as

washing, dressing, and feeding consist of bimanual tasks. It is only

when we temporarily lose the function of one hand that the significance

of this becomes apparent. However, children with congenital hand anom-

alies adapt very well to limitations of hand function and can often find“trick” manoeuvres to achieve essential tasks.

As there is a wide variation in the types and severities of hand anom-

alies these cases are largely managed in specialized clinics. It is in this

setting that the child and family will have access to long-term multidisci-

plinary care which includes input from geneticists, psychologists, thera-

pists and children’s hand surgeons. For some children with more

complex anomalies, psychological support can be as valuable as surgery

to aid integration with and acceptance by their peers.

Keywords birth defect; congenital hand anomalies; duplication; finger

abnormalities; forearm abnormalities; hand deformity; newborn;

syndactyly; thumb abnormalities; toe transfer

Treatment principles

Functionality and cosmesis

The aim of surgery or therapy is to provide the child with the best

functional and cosmetic outcome possible. As some of these

children have other anomalies it is critical to look at the global

function of the child, rather than at specific elements of their

hand function.

The best functional outcome will provide the child with

normal grasp patterns for both single and bimanual tasks. In

simple anomalies this can be achieved with relative ease.

However in more complex and bilateral anomalies achieving an

acceptable level of function for activities of daily living can be

extremely challenging.

The limits of function are largely dependent on the number of

competent digits in the hand and their location. The presence of

a stable, sensate and mobile thumb is essential for competent

hand function. The thumb plays a key role in achieving the

varied grips possible e including key, pinch, large and small

object grasp.

If the thumb is competent, then the focus can turn to the other

digits.

In assessing and planning the reconstruction of a child’s hand

the surgeon must always plan for the future. A young child can

function well with basic hand grasp patterns. However, as they

grow and become more independent they will need more refined,precise hand movements.

Timing

There are very few congenital anomalies that require urgent

surgical intervention although ring constriction syndrome with

severe distal oedema and neonatal Volkmann’s ischaemic

contracture may be the exceptions.

However, referral to a specialized hand clinic where psycho-

logical, genetic and hand therapy input is available should be

arranged as soon as possible after diagnosis.

Certain conditions merit very early surgery not necessarily

because of the severity of the hand anomaly but more for the

benefit of performing surgery under local anaesthesia inneonates. This is possible for some with extra digits and for the

release of minor acrosyndactyly (the distal joining of finger tips

in ring constriction syndrome).

Early surgery before the age of 1 year is recommended for the

separation of syndactylized (joined) border digits including

involvement of the first web space. This will prevent the prob-

lems related to differential growth of the digits and optimize

hand function.

In general if surgery is performed before school age the child

will tend to forget any negative psychological experience and

make a speedy postoperative recovery.

However, if co-operation and compliance are essential for

good postoperative outcome, as in tendon transfers, then it isbest to wait unit the child is 6/7 years old.

Apart from these examples, surgery for the correction of most

congenital anomalies takes place once the following criteria are

satisfied: (i) each subsequent figure should be increased, the risk

of general anaesthesia is minimal or as low as possible given any

other organ anomalies; (ii) a knowledge of the severity of other

anomalies is apparent and they have been treated where

possible; (iii) the size of the hand structures is such that surgery

is possible; (iv) sufficient time has elapsed so that the benefit of

splinting has had time to be effective. i.e. clasp thumb, trigger

thumb, camptodactyly.

In the majority of children this is between the ages of 1 and

2 years.

Psychology

The attitude of the child’s parents affects their long-term

outcome. Their approach and method of coping with their child’s

hand anomaly will significantly affect how the child adapts

psychologically. This in turn will influence how the child inte-

grates into society.

As the severity of the congenital abnormality may vary, so too

can the reaction of the child’s parents and does not necessarily

parallel theseverityof thechild’s handanomaly.1Parentsoften have

difficulty making decisions about surgery on behalf of their new

baby. This can lead to parental disharmony and feelings of guilt.

Gr ainne Bourke MB Bch BAO FRCSI FRCS(PLAST) Consultant Plastic,

Reconstructive and Hand Surgeon, Leeds Teaching Hospitals Trust,

United Kingdom. Conflicts of interest: none.

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ORTHOPAEDICS AND TRAUMA 25:2 143 2010 Published by Elsevier Ltd.

http://dx.doi.org/10.1016/j.mporth.2010.10.006




Early input from a psychologist with experience dealing with

parents and children with hand anomalies can be very valuable in

helping to allay fears and to encourage acceptance and support.2,3

Associated anomalies

Congenital hand anomalies can be part of a recognized genetic

syndrome or they may occur as a consequence of arrest or

disruption in gestational development. The limb bud develops

between the 4th and 8th week of gestation. At this time other

organs and systems are also developing so there can be disrup-

tion of both limb and other organs simultaneously. This explains

why radial ray deficiencies can be associated with other anom-

alies of cardiac, skeletal and gastrointestinal systems as occurs in

the VACTERL sequence (Vertebral, Anal, Cardiac, Tracheo-

oesophageal, Renal and Limb).

Simultaneous proximal and distal disruptions of limb devel-

opment may also occur as in Poland’s syndrome where there can

be associated anomalies of the hand with symbrachydactyly and

complete or partial absence of the pectoral muscles.

Knowledge of the common syndromes and typically associated

anomalies is very useful when assessing a child with a congenitalhandanomaly. Itcan help inplanning timingof surgery andensuring

appropriate specialist referral if other anomalies are diagnosed.

In some syndromes the limb anomaly may be the only

external manifestation of the syndrome. This is the case in

Thrombocytopenia Absent Radius syndrome and Fanconi ’s

Anaemia. The latter is a potentially fatal condition where the

radial ray deficiency or duplication may be the only external

feature of the syndrome. Children with Fanconi’s Anaemia

usually develop bone marrow failure within the first decade of

life and are at high risk of solid organ malignancy. Early diag-

nosis of Fanconi’s anaemia at the time of presentation of the limb

anomaly is essential to ensure appropriate referral to haematol-

ogy and genetic clinics for assessment and counselling.

Classification

In 1968 Swanson first classified congenital anomalies by their

morphology assuming these were related to defects in embryo-

genesis.4 This system has remained as the most commonly used

classification system to date. It has been amended and updated

with the progress of time and knowledge by Swanson, the Inter-

national Federation of Societies for Surgery of the Hand (IFSSH)

and the Japanese Society for Surgery of the Hand (JSSH).5,6

However there are still controversies about the classification

of certain anomalies such as symbrachydactyly which was orig-

inally classified in group V as undergrowth while atypical cleft

hand was classified in group I failure of formation. As thespectrum of congenital anomalies is so great there is, as one

would expect, a group of unclassifiable anomalies which was

added at the time of the JSSH modification to include all those

anomalies which do not fit into another category.

As further knowledge about the embryological aetiology of

various congenital hand anomalies unfolds a new classification

system based on embrynogenesis may supersede this current

system.

The Swanson classification system divides the anomalies

into the following categories: Failure of formation, Failure of

differentiation, Duplication, Overgrowth, Undergrowth, Constric-

tion band syndrome and Generalized Skeletal Abnormalities.

Each category is then divided into subcategories for example

group I failure of formation is divided into the subcategories: (Ia)

longitudinal, (Ib) transverse or (Ic) failure of finger ray induction

including cleft hand.

Each subcategory is then further catalogued by the anatomical

level of the deformity i.e. shoulder, arm, elbow, wrist etc.

Following this the anomalies are then listed by common diag-

nosis for example, cleft hand, cutaneous syndactyly (Table 1).

Failure of formation

Radial longitudinal deficiency: deficiencies on the radial border

of the hand and arm are not common. They are significant not

only because of the impairment of hand function but also

because there is a high risk of associated anomalies. The risk of

associated thumb hypoplasia is proportional to the severity of the

radial deformity.7 Radial border anomalies have a high incidence

Abbreviated IFFSH Swanson’s classification of congenital hand anomalies

Main category Subcategory Diagnosis

I. Failure of formation a. Transverse

b. Longitudinal Longitudinal radial

deficiency

Longitudinal ulnar

deficiency

c. Central Cleft hand

II. Failure of

differentiation

a. Soft tissue Cutaneous syndactyly

Camptodactyly

Congenital trigger digit

b. Skeletal Radioulnar synostosis

Synostosis of the

metacarpalsSynostosis of the

phalanges

Symphalangia

Clinodactyly

c. Tumorous Haemangioma

Malformation

Osteochondromatosis

Enchrondroma

Fibrous dysplasia

Epiphyseal abnormalities

III. Duplication Thumb duplication

Ulnar polydactyly

IV. Overgrowth Hemihypertrophy

Macrodactyly

V. Undergrowth Brachdactyly

Brachysyndactyly

VI. Constriction Band Syndrome Constriction band

with oedema

Constriction band

without oedema

VII. Generalized abnormalities

and syndromes

Marfan’s syndrome

Table 1

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of other associated congenital anomalies.8Up to 70% of children

with radial longitudinal deficiency will have other medical or

musculoskeletal anomalies while one third of those with thumb

hypoplasia will have associated anomalies.8

These include cardiac (HolteOram syndrome), haemato-

logical (Thrombocytopenia Absent Radii, Fanconi’s Anaemia),

osseous, renal and other anomalies. As the radial deformity may

be the only external feature of some of these syndromes it iscrucial that these children are all seen by a paediatrician and

geneticist.

A radiological classification of radial longitudinal deficiency

was first described by Bayne and Klug in 1987.9 Type 1 has

a small radius with both proximal and distal epiphyses present,

type 2 has a hypoplastic radius, in type 3 the distal radius is

absent and in type 4 the complete radius is absent. Later a type

0 was added where the radial carpal bones are hypoplastic and

the thumb is absent but the radius is of normal length.

Although the classification is based on the appearance of the

bone, the tendons, neurovascular structures joint capsule and

ligaments are also involved. In general the radial wrist extensors

and flexors are invariably involved. The radial nerve and arteryare often absent especially in the severe forms (Figure 1).

In general it is better both cosmetically and functionally to

correct the deviated wrist with a combination of distraction tech-

niques followed by centralization or radicalization of the carpus

over the distal ulna. This must be combined with soft tissue

procedures to allow skin cover and tendon rebalancing. Once the

wrist hasbeen corrected then associatedthumbhypoplasiacan then

be addressed with either augmentation procedures or pollicization.

However there are occasions when it is actually preferable not

to correct the deformity. These include those patients with absent

or limited elbow flexion. In these patients straightening the wrist

may leave the hand further from the mouth or perineum and so

disrupt function. In older patients who have already developed

patterns of use on the ulnar border of the hand changing the hand

pattern may decrease function. In those with severe soft tissue

contracture the neurovascular structures will limit completecorrection. In those patients with minor anomalies where there is

no limitation of function surgery does not add any advantage.9

Thumb hypoplasia: disorders of the thumb limit function more

than those of the other digits. The thumb plays a crucial role in

hand function and enables all forms of grip apart from palmer

grasp. The classification system routinely used for thumb hypo-

plasia is that described by Blauth in 196710 (Table 2).

Thumb hypoplasia can be an isolated unilateral deformity,

bilateral and may be associated with other anomalies of the

musculoskeletal system or of other organs8 (Figure 2).

It is thus important to ensure that other pathologies have been

sought and the child has been seen by a paediatrician. In some

children with Fanconi’s Anaemia or other rare disorders, the

thumb anomaly may be the only external feature of the condition

and so these children should be referred to a geneticist for

screening at an early age.

The aim of treatment of thumb hypoplasia is to improve

function. As the thumb functions well in type 1 hypoplasia

surgery is not indicated.

For type 2 deformities surgery must address the tight first web

space, the instability of the metacarpophalangeal joint with collat-

eral ligament reconstruction and the lack of thumb opposition. The

webspace tightening is usuallycorrected using a local flap.This can

be a transposition flap from the radial border of the index finger,

a rotationaladvancement flap from thebackof thehandor multiple

Z plasties. Multiple opponensplasty procedures have been

described but probably the most popular for congenital thumb

hypoplasia is the Huber transfer, using the abductor digiti minimi.11

Type 3 thumb hypoplasia is subdivided into two groups

depending on the competency of the basal joint. Where

a competent basal joint is present the treatment is similar to type

Figure 1 Longitudinal radial deficiency with thumb aplasia. The wrist is

flexed radially due to the lack of structures on the radial side of the

forearm and hand.

Blauth’s classification of hypoplastic thumb

Subtype Clinical findings

Type 1 Small thumb but functions normally

Type 2 Small thumb

Adduction contracture of the first web space

Absence of thenar muscle

Ulnar collateral ligament laxity at the

metacarpophalangeal joint

Type 3 Small thumb

Lack of intrinsics muscles

Lack of extrinsics muscles

Abnormal CMC joint.

Type 4 Pouce flottant

Type 5 Absent thumb

Table 2

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2 deformities. Where the basal joint is not competent then pol-

licization of the index finger is the current treatment of choice.

This is also the choice for reconstruction of type 4 and 5 thumb

hypoplasia where the thumb is absent or floating.

Ulnar longitudinal deficiency: this is rare. Bayne classified the

radiological appearance of the ulna, radius and associated radi-

ohumeral synostosis into four sub-types.12

These range froma short ulna to severe absence with bowing of the radius and

dislocation of the radial head. Radiohumeral synostosis is asso-

ciated with the more severe deficiencies. This classification

system was modified by Goldfarb and colleagues to include more

proximal anomalies.13 Associated hand anomalies are common

and have been classified by Ogino.14

When children with ulnar longitudinal deficiency first present

the affected short arm is often internally rotated and thus posi-

tioned behind the child’s back. This always improves over time

and eventually the arm lies in a normal plane to enable limb

function. Some children have radiohumeral synostosis while

others have radial head dislocation and a bowed radius. Thus

each child is different and should be examined for functionallimitations rather than cosmetic appearance.

Treatment involves the early application of splints to correct

the ulnar deviation of the wrist combined with stretching exer-

cises. It is not usually necessary to excise the fibrous anlage of

the distal ulna.

In the hand, any digit may be involved and the ulnar digits

may be absent. The thumb may lie in the same plane as the

fingers and there may be syndactyly between any of the digits

which must be corrected to improve function.

Overall, children with ulnar deficiency function well. Apart

from surgery to correct the associated hand anomalies they often

escape surgical intervention.15

Central longitudinal deficiency (typical cleft hand): cleft hand

or central longitudinal deficiency is a rare autosomal dominant

condition. It typically involves all four limbs in a V-shaped

central deformity (Figures 3 and 4). It may be associated with

other anomalies of the musculoskeletal system or other organs.

When associated with abnormalities such as cleft palate and

ectodermal dysplasia it is called as Ectodermal, Ectrodactyly Cleft

syndrome (EEC).Barsky differentiated between typical and atypical cleft hand

or symbrachydactyly. The latter being a U-shaped deformity

confined to one limb.16

The hand anomaly may vary from a simple soft tissue cleft to

suppression of all rays except the little finger. In general it

involves a combination of suppression of central rays, syndactyly

and central polydactyly with the presence of transverse bones in

the cleft increasing the deformity with growth.

The features which cause functional limitation are involve-

ment of the first web space which can be narrowed or even

syndactylized to the index ray and a number of remaining

digits.15

Despite the very unusual appearance of the hands, as long astwo or more digits are preserved on each upper limb, children

with typical cleft hands function well.

Surgery is aimed at improving the first web space, closing the

central cleft and reconstructing absent digits where possible, to

improve both function and cosmesis.

Several methods have been described for closure of the cleft.

The most common of these is the Snow Littler procedure and that

described by Miura and Komada.17 Both of these methods

involve a combination of local soft tissue flaps, transposition of

the index metacarpal and reconstruction of the transverse inter-

metacarpal ligament in order to provide an adequate first web

space and close the central cleft deformity.18

Associated foot abnormalities may also need to be addressedto allow the child to wear normal footwear.

Figure 3 A typical cleft hand illustrating a central cleft combined with

a narrow first web space.

Figure 2 A hypoplastic thumb with a tight first web space.

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Symbrachydactyly: in the original Swanson classification

system symbrachydactyly was classified in Undergrowth (V).

However following the Japanese modification of the classifica-

tion system it is now placed in Failure of formation (I).5

Symbrachydactyly has previously been described as atypical

cleft hand. It is sporadic in nature and presents as a U-shapeddeformity. It classically involves one limb. It is a combination of

short, joined digits which may be of variable severity. In some

cases only rudimentary digits called as nubbins remain. It has

been classified into short finger, oligodactylic, monodactylic and

peromelic subgroups depending on the severity of the deformity

and the number of digits remaining (Figures 5 and 6).19

The treatment of symbrachydactyly is based on improving both

handfunction andcosmesis.In the short finger type where a normal

thumb is present simply separating the joined digits may suffice.

However, in the other more severely affected types digit

reconstruction is indicated to enable competent hand function.

This can be achieved with the use of microvascular toe transfers.

These transferred digits have excellent growth potential and areboth mobile and sensate.20e22

Symbrachydactyly is associated with Poland’s syndrome. This

syndrome presents with deficiency of skeletal and soft tissue

components around the shoulder girdle and can include sym-

brachydactyly. Classically there is an absence of all or part of the

pectoralis major muscles but this may be associated with defi-

cienciesof theskeletal componentsof thechestwall. Howeverother

shoulder girdle muscles can be involved in isolation or

combination.

The absent pectoralis major can be reconstructed at an early

age using an ipsilateral latissimus dorsi transfer. Staged breast

reconstruction is then undertaken during teenage years.

Failure of differentiation

Syndactyly: meaning joined digits, is one of the commonest

congenital hand anomalies (Figure 7). It occurs in 1 in every2000e2400 births and is often bilateral.23,24 It is more common in

males than females and is variable in presentation. Five different

types of autosomal dominant syndactyly have been described

which may or may not involve the foot.25

Syndactyly is a consequence of an absence of apoptosis in

mesodermal tissue between digits during embryonic develop-

ment. This has been associated with a decrease in BMP 4.23

It is classified by the length of the skin shared between the two

digits into complete where the join includes the finger tips and

incomplete where the join is partial only. It is also classified by

the type of tissue involved. If the join only involves skin it is

called simple syndactyly while if there is bony involvement it is

called as complex (Figure 8).Syndactyly is associated with several syndromes. These

include the multiple suture craniosynostosis syndromes such as

Apert’s and Saethre Chotzen as well as Greig’s Cepha-

lopolysyndactyly. In these syndromic cases the syndactyly tends

to be complex and often complicated.

Syndactylized border digits such as the thumb and the index

finger are usually separated between 6 and 12 months of age.

Figure 6 Symbrachydactyly-oligodactylic type with a single ulnar digit and

radial nubbins.

Figure 5 Symbrachydactyly-short finger type. The first web space is also

tight and requires release. This child also had deficiency of the shoulder

girdle muscles and thus had a diagnosis of Poland’s syndrome.

Figure 4 A typical cleft foot in the same child. The toes are splayed which

can lead to problems with footwear.

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This is to promote the normal development of hand grasp frompalmar to pincer grip and prevent deformity due to unequal digit

length and growth. The separation of central rays is less essential

to hand function but does improve the span of hand grasp and

cosmesis. This is usually performed between the age of 1 and 2

years.

Various techniques for syndactyly release have been described.

The essential components are creationof an adequateand aesthetic

web spacebetween thedigits using a flap, reconstruction of thenail

folds and separation of the digits while avoiding linear scars that

may cause contractures26,27 (Figures 8 and 9).

Camptodactyly: camptodactyly or “arched finger” was first

described in 1846 by Tamplin.28 It is a flexion contracture of the

proximal interphalangeal joint which can be progressive

(Figure 10). It is not associated with trauma and unless there isadditional joint laxity it is not associated with any abnormality of

the distal interphalangeal joint. Benson and colleagues classified it

into three main groups: infantile, adolescent and syndromic.29

Infantile and adolescent types are usually isolated to a single

digit. This is usually the little finger. Syndromic types have

multiple digit involvement and tend to have more severe

deformities.

The aetiology is due to an imbalance between the flexor and

extensor systems of the finger. There is often but not always an

anomaly of the lumbrical or flexor digitorum superficialis inser-

tion. There is a secondary soft tissue shortage particularly of skin

on the volar surface of the proximal phalanx which also needs to

be addressed. It can be associated with bony and joint abnor-malities such as loss of the normal curve of the head of the

proximal phalanx.

The treatment for infantile and adolescent types is quite

similar. Many of patients in these groups respond well to

a combination of dynamic and static splints. The aim of this

treatment is to try to address the imbalance between the flexor

and extensor tendons. In those who are symptomatic and do not

improve with splints, surgery is an option.

Figure 8 Complex syndactyly with sparing of the first web space. The

differential growth of the central rays is visible when compared to the

little finger.

Figure 9 The same patient postoperatively. All four fingers have been

separated using a combination of local flaps and full thickness skin grafts.

Figure 7 Simple, complete syndactyly.

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Shortage of skin is corrected with either a local transposition

flap from the border of the digit or a full thickness skin graft. Any

abnormal or tight fascial bands can be divided. The abnormal

anatomical insertions of the lumbrical or flexor digitorum

superficialis tendons can be corrected. Several techniques have

been described involving transfer of the flexor digitorum

superficialis to the extensor, transfer of extensor indicis to the

lumbrical insertion or lengthening or dividing the FDStendon.30e32

In cases where there is an abnormality of the head of the

proximal phalanx correction by soft tissue procedures is unlikely

to yield a satisfactory outcome. In these cases a closing wedge

osteotomy of the proximal phalanx or arthrodesis may be

indicated.

Clinodactyly: means “bent finger”. It describes a curvature of the

digit in the radioulnar plane (Figure 11).

Familial clinodactyly is an autosomal dominant condition. It is

usually bilateral and classically affects the little finger. The

middle phalanx has an abnormal ‘c’ shaped epiphysis and is

trapezoidal due to the deficiency in longitudinal growth. Thisresults in a radial curvature of the digit.33

Familial clinodactyly cannot be treated with splints and

surgery is usually for cosmetic rather then functional reasons.

Vickers described resection of the central portion of the ‘c’

shaped epiphysis and placement of a fat graft into the defect.

These cases were not splinted and showed gradual correction of

the deformity over time.34 Other methods of correction that have

been described are osteotomies- opening wedge, reverse wedge

and closing wedge. The latter should be avoided as it will further

shorten the middle phalanx.32

Clinodactyly is often associated with other congenital anoma-

lies and syndromes including Down syndrome, Apert’s syndrome,

Treacher Collins syndrome and Kleinfelter’s syndrome. It can

affect any digit but the little finger and thumb are the most

commonly involved.

In Apert’s syndrome the thumb and/or index finger are/isusually affected and require surgical correction to improve

function. An opening wedge osteotomy combined with a local

skin flap to correct the soft tissue deficiency works well.35

Clinodactyly also occurs in some triphalangeal thumbs. This

should be suspected in a thumb which is long and has an ulnar

curvature. The extra triangular phalanx may not be obvious on

early X-rays but will be seen once the bone ossifies. If these are

diagnosed early and the extra phalanx is small it can be removed

and the thumb realigned to give and excellent result.36

Duplication

Ulnar polydactyly: polydactyly is the most common congenital

anomaly of the hand. It can be preaxial (radial), postaxial (ulnar)or central.

Ulnar polydactyly is more common in those of African origin.

It is more common in males than in females and is an autoso-

mally dominant inherited condition. Ulnar polydactyly is usually

bilateral but may affect all four limbs. The extra digit may either

be a pedunculated digit (type 1b) or else a fully formed finger

that articulates with the 5th metacarpal (type 1a).37

Ulnar polydactyly does not usually cause any functional

problems but the extra digit is frequently removed for cosmetic

reasons. If the digit is pedunculated there is a risk of the pedicle

twisting and infarcting the digit causing pain.

Simple ulnar polydactyly with a pedunculated digit can be

excised under local anaesthetic in the neonatal period(Figure 12). If the metacarpophalangeal joint is involved, the

ulnar collateral ligament must be reconstructed, the metacarpal

Figure 11 Clinodactyly of the little finger.

Figure 10 Camptodactyly of the little finger with compensatory hyperex-

tension of the MCP joint.

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head narrowed and the tendons assessed and realigned at the

time of surgery.

Radial polydactyly: thumb duplication was categorized based

on the radiological appearance into six groups by Wassel in

196938(Table 3). In 1978 Wood extended the classification to

include triphalangeal thumb duplication39 (Table 3). It occurs

more frequently in Caucasians and is usually an isolated abnor-mality (Figures 13e15).

However, it can be associated with other congenital abnor-

malities and syndromes including Fanconi’s Anaemia, VACTERL

syndrome and Duane radial ray syndrome.

The principles of treatment for thumb polydactyly are to

fashion a thumb of adequate length, stability and motion so that it

works well and is similar in appearance to the contralateral

normal thumb. Where the duplicates are of unequal size and one

is superior in size and function then the smaller is removed

making sure to realign the shared joint and reconstruct the

collateral ligament. This may also necessitate osteotomies of the

metacarpal or phalanx. If both duplicates are equal then a sharing

procedure such as described by Bilhauth Cloquet may berequired.40,41 It is best to avoid a nail bed scar where possible as

this often causes a ridge or a split nail and can be difficult to treat.

Overgrowth

Macrodactyly: is probably one of the most difficult congenital

hand anomalies to treat. It was classified by Flatt into four groups

based on its aetiology. These are gigantism with lipofibromatosis,

gigantism with neurofibromatosis, gigantism with digital hyper-

ostosis and gigantism with hemihypertrophy.42

It can be associated with neurofibromatosis, Ollier’s disease

and Maffucci’s syndrome. The later two are syndromes involving

multiple encondromatosis.

Lipofibromatosis is usually unilateral and more common in

males than females. The overgrowth follows the distribution of

a nerve i.e. median nerve and can involve adjacent digits and

extend into the palm of the hand. The affected digits are oftendivergent. There are two growth patterns either static or

progressive. Static macrodactyly is present at birth and the digit

grows proportionally with the child. Progressive macrodactyly is

also present at birth but the digit grows disproportionally when

compared with the rest of the hand. This type of macrodactyly

will require more aggressive and earlier treatment.43

The psychological implications of macrodactyly are signifi-

cant. Both parents and child are usually more concerned about

the abnormal size and appearance of the macrodactylous digit

than any limitation of function.

Early surgical intervention is aimed at debulking soft tissues

but preserving vital structures such as nerves and arteries. It is

important to inform both parent and child that multiple stagedprocedures will be necessary to achieve an acceptable outcome.

Access incision should be placed in a midlateral plane where

possible to avoid obvious scars, prevent contractures and

promote motion.

Limitation of bone growth can be achieved with epiphyseal

arrest. This is performed when the digit is the same radiological

length as that of the same sex parent. Differential arrest of the

epiphysiscan be performed to correct the abnormal curvature that

occurs when adjacent involved digits are divergent. Osteotomies

Figure 13 In correcting thumb duplication, nail bed scars should be kept

to a minimum as there is a high risk of split or ridged nail deformities.

Wassell’s classification of thumb duplication

Type Radiological findings

1 Bifid distal phalanx

2 Duplication of distal phalanx

3 Bifid proximal phalanx

4 Duplication of proximal phalanx 5 Bifid metacarpal

6 Duplication of metacarpal

7 Duplication triphalangeal thumb

Table 3

Figure 12 Ulnar polydactyly type 1b.

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can be performed to correct abnormalities of width, length and

curvature.

If a single digit is involved it is worth considering ray ampu-tation and in the case of the thumb, reconstruction with

a microvascular toe transfer.43

Ring constriction syndrome: also called amniotic band

syndrome, it has an incidence of 1 in 1,200e1 in 15,000.44 It

occurs equally in males and females and usually involves more

than one limb. It involves a combination of distal ring constric-

tion, intrauterine digit amputation and acrosyndactyly. There is

distal syndactyly with proximal fenestrations.44There are two

theories describing its aetiology e intrinsic and extrinsic.

The intrinsic theory attributing the deformities to an abnor-

mality in the development of the subcutaneous tissues was first

described by Streeter in 1930 and subsequently modified byPatterson in 1961.26,45

The extrinsic theory describes a rupture of the amniotic

membrane with the limb or body part then lying between the

amniotic and chorionic membranes. This was described by

Torpin in 1965.46

It is associated with other anomalies such as club foot, cleft lip

and palate, craniofacial anomalies and limb length discrepancies.

The hand anomalies vary considerably, but if the constricting

band is tight it can result in abnormalities of nerve and vessels as

well as skin and subcutaneous fat. If there is severe oedema distal

to the ring constriction then urgent surgery is indicated to avoid

further compromise of lymphatic and venous flow in the limb.

The treatment is surgical with excision of the constricting

band and z plasty closure, release of the acrosyndactyly and

where necessary digit reconstruction. It is important to realize

that anatomical structures proximal to the constricting band arenormal. Thus free microvascular toe transfer is an effective

means of digit reconstruction in cases of complete digit loss.

However, the involvement of multiple limbs often interferes with

available donor toes (Figure 16e18).

In general, despite the loss of distal digital parts children with

ring constriction syndrome have good hand function. Often

simply releasing conjoined digits and correcting deep constric-

tions will yield a very functional result.

Generalized skeletal abnormalities

Trigger thumb: is a common condition seen in young children.

Whether it is actually a congenital anomaly is often debated.

Several studies have illustrated its absence at birth.47,48

Notta first described the swelling of the flexor pollicis longus

at the level of the A1 pulley in 1850.49 This description has

remained and the swelling is now classically called Notta’s node.

This palpable swelling combined with a thickened A1 pulley

causes the triggering. However once the pulley has been released

the tendon reverts to normal and the node disappears.

The child usually presents with a thumb flexed at the inter-

phalangeal joint rather than with triggering as this is too painful.

Children presenting before the age of one can be treated conser-

vatively. One third of those presenting before the age of 6 months

resolve spontaneously and 12% of those presenting between the

agesof 6e12 months also resolve without intervention.50 Children

Figure 15 Proximal thumb duplication. Here as the ulnar digit was smaller

and less functional it was excised.Figure 14 Where there are two unequal components the smaller is sacri-

ficed. It is essential to reconstruct the collateral ligament during the

procedure.

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who present after the age of 3 years are at risk of developing

a flexion contracture at the interphalangeal joint and thus shouldbe managed with an A1 pulley release.

The surgery is performed through a transverse incision at the

level of the metacarpophalangeal joint with preservation of the

adjacent digital bundles. The A1 pulley is released in full and

the tendon motion should be checked before the skin is sutured.

Once the pulley has been fully released the symptoms resolve

and seldom recur.

Clasp thumb: congenital clasped thumb involves flexion of the

thumb at the metacarpo-phalangeal (MCP) joint with an adduc-

tion contracture of the first web space (Figure 19). The thumb is

flexed across the palm. The interphalangeal joint may be

involved also if the extensor pollicis longus is absent or hypo-plastic. It must be differentiated from congenital trigger thumb

where only the interphalangeal joint is involved.

It may be an isolated anomaly but more commonly is part of

a syndrome such as,windblownhand, FreemanSheldon syndrome,

arthrogryposis or other neuromuscular syndromes.49

The deformity is present at birth but children present after 3/4

months. They are classified into three main groups: types 1/supple

thumbs with aplasia of the extensor pollicis brevis and a tight web

space. These usually correct with the use of splints, Type 2 are

complex thumbs with associated abnormalities of the MCP joint,

collateral ligament instability, hypoplasia of the thenar musclesand collateral ligament instability. Type 3 clasped thumbs are

associated with syndromes such as arthrogryposis and windblown

hand anomalies.51

The treatment for all types is with splints initially. These help

to release the web space contracture and hold the thumb in an

abducted and extended position. A significant number of type 1

thumbs will correct with splint therapy alone. In those cases with

Figure 18 Foot involvement in ring constriction syndrome demonstrating

the band encircling the great and second toes.

Figure 16 Ring constriction syndrome illustrating the tight constricting

rings and distal oedema.

Figure 17 The same patient (as shown in Figure 16 with ring constriction

syndrome) 6 weeks after digit reconstruction with synchronous bilateral

second toe transfers.

Figure 19 A clasped thumb with a tight first web space, flexion of the

metacarpophalangeal joint and flexion of the interphalangeal joint. The

thumb is positioned across the palm.

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a supple deformity that has not corrected with splints as well as

types 2 and 3, surgery aims to release the web space contracture

with the use of local flaps, reconstruct the extensor mechanism

and correct any deformity of the metacarpophalangeal joint.

Summary

Congenital hand anomalies are common and can be associated

with other anomalies.52 It is important to have an awareness of treatment principles so that parents receive the appropriate

counselling and children are referred to specialist clinics if

warranted.

The Swanson classification system is widely accepted and

helps with both communication and documentation of

anomalies.

The types of anomalies are very diverse and it is not possible

to produce a comprehensive and complete algorithm of treatment

options in this article. However, the principles of management,

including the important role played by skilled therapists and

psychologists are demonstrated. A

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