Shared article

Congenital Upper Limb Conditions

    

Introduction

 

Upper extremity malformations usually result in more distress to parents than to the child, at least until the child begins schooling, at which point he may notice a difference between himself and his peers. The role of the surgeon is to ensure a hand that functions and appears as normal as possible. However the surgeon must also be realistic about the results that could be achieved and make it clear to the parents that the child may never have a totally “normal” hand following surgical intervention. In the early stages it will usually be the parents who are consulted with, however as the child grows older he should also be given the necessary space to express his views.

 

Apart from the obvious congenital deformities of the hand it is also important that the surgeon excludes any less apparent but more serious congenital anomalies which may require more urgent surgical attention.

 

In terms of timing, surgery to correct the congenitally malformed hand is considered “early” if it is performed within the first 2 years of life. Early surgery is technically more challenging, yet is associated with the advantages of early incorporation of the limb in physical activity, less scarring and reduced psychological effect.

 

Classification

 

The American Society for Surgery of the Hand (ASSH) and the International Federation of Societies for Surgery of the Hand (IFSSH) have adopted the following classification which was proposed by Swanson. It is likely that this classification system may be altered as there is an increase in the understanding of the genetic and developmental basis of limb anomalies.

 

1. Failure of Formation

*** Transverse arrest 

               * Complete deficiencies

               * Intercalated deficiencies (phocomelia)

*** Longitudinal arrest

               * Preaxial - radial club hand

               * Central - central ray deficiency

               * Post-axial - ulnar club hand

 

2. Failure of differentiation

*** Soft tissue 

               * Syndactyly

               * Camptodactyly 

               * Trigger thumb 

               * Clasped thumb 

*** Skeletal 

               * Clinodactyly

               * Symphalangism 

               * Synostosis 

               * Arthrogryposis 

               * Windblown hand

 

 

3. Duplication

               * Ulnar polydactyly

               * Central polydactyly

               * Radial polydactyly

               * Ulnar dimelia

 

 

4. Overgrowth

               * Macrodactyly

 

 

5. Undergrowth

               * Brachydactyly

               * Thumb hypoplasia

 

 

6. Constriction ring syndromes

 

 

7. Generalized skeletal abnormalities

 

 

1. Failure of formation

 

TRANSVERSE

 

Complete

Complete arrest may occur at any level, although it most commonly occurs at the junction between the proximal third and middle third of the forearm. Complete failures of formation are usually treated non-surgically via the use of a prosthetic device. Recently developed myoelectric prostheses enable muscle action to trigger the prosthesis.

 

Intercalated deficiencies (phocomelia)

Absence of the entire upper limb is termed amelia. Phocomelia on the other hand is used when a functional terminal unit is present. The widespread use of the anti-emetic thalidomide in the 1960’s resulted in a high incidence of this condition. Phocomelia can be subdivided into three categories:

 

* Type 1 – the hand is directly attached to the shoulder (absence of forearm and arm)

* Type 2 – the forearm (with the hand attached to it) attaches to the shoulder (absence of arm)

 * Type 3 – the hand is attached to the arm at the elbow (absence of the forearm)

 

LONGITUDINAL

 

Longitudinal deficiencies are divided into prexial, postaxial and central types. What is meant by these terms is listed below.

 

* Preaxial – refers to the lateral/radial aspect of the  forearm

* Postaxial – refers to the medial/ulnar aspect of the forearm

* Central – where there is an absence of digits or metacarpals in the central region of the hand

 

A number of classification systems exist describing the variety of preaxial, postaxial and central deficiencies. In this article we will consider the most common types of preaxial, postaxial and central deficiencies.

 

Preaxial deficiency – radial club hand

 

Preaxial deficiencies include a variety of conditions varying from minor abnormalities of the thenar muscles to a complete absence of prexial (radial/lateral) structures. The most common presentation of prexial deficiency is radial club hand.

 

The term radial club hand comprises a spectrum of disorders consisting of a dysplastic radial bone including a radially deviated flexed hand, absence of scaphoid and trapezium, and either a hypoplastic or absent thumb. The condition maybe unilateral or bilateral but rarely occurs symmetrically on both sides. It has an estimated incidence of between 1:30,000 and 1:100,000 live births.

 

Clinical feature of radial club hand include:

 

* A shortened forearm which is radially deviated

* The radius is either partially or completely absent, being replaced by a fibrous band (anlage)

* The thumb is either absent or hypoplastic

* Hypoplasia of other radial structures such as the scaphoid, trapezium, 1st metacarpal, radial artery, superficial branch of the radial nerve and radial-sided musculature

* Stiffness of the elbow due to synostosis (bony fusion)

* Stiffness of the fingers due to stretching of the tendons caused by radial deviation of the hand

     

    Radial club hand (and preaxial deficiencies in general) is associated with a variety of syndromes affecting the cardiovascular, gastrointestinal and haematological systems such as:

     

    * Holt-Oram syndrome – cardiac abnormalities, commonly septal defects and radial club hand

    * VATERR syndrome – Vertebral anomalies, anal atresia, tracheoesphageal fistula and renal and radial abnormalities (also referred to as VACTERL).

    * TAR syndrome – thrombocytopenia at birth which improves with time and radial club hand

    * Fanconi anaemia – aplastic anaemia which develops at around 6 years of age and radial club hand.

     

    O’Rahilly has classified radial club hand into four types:

     

    * Type 1 – short distal radius with no radial bowing or deviation; no treatment

    * Type 2 – hypoplastic radius (rare); no treatment

    * Type 3 – partial absence of radius with fibrous anlage which is the most common; centralization procedure required

    * Type 4 – radius totally absent which the second most common; requires soft tissue release and centralization

     

    Treatment of radial club hand (and prexial deficiencies in general) is dependent upon the patient’s age, severity of deformity and extent of functional deficit. It can be divided into conservative management which includes splints, casts and passive stretching techniques which help to reduce stiffness and maintain soft tissue length, and surgical management which includes soft tissue release, centralization or radialization procedures, thumb reconstruction via pollicization and tendon transfers.

     

    Central deficiency – cleft hand

    This involves an absence of digits or metacarpals of the central portion of the hand. The radius and ulna are typically normal. Cleft hands are divided into typical and atypical types. Typical cleft hand involves a partial or complete absence of the middle finger (central ray) in the hand. It is typically bilateral and inherited and maybe associated with absence of the third toe of the foot. Atypical cleft hand in contrast involves absence of the index, long and ring fingers giving rise to a U-shaped hand. Atypical cleft hand is now recognized to be a form of symbracydactyly. Treatment where possible, is via surgical intervention to improve cosmesis and function.

     

    Postaxial deficiency – ulnar club hand

    Compared with radial club hand, ulnar club hand has a much larger spectrum of abnormalities ranging from minimal hypoplasia of the ulnar digits to total absence of the ulna. In addition unlike preaxial deficiencies, postaxial deficiencies are only rarely associated with other syndromes. They tend to be more common in males, unilateral and left-sided and show an autosomal dominant pattern of inheritance.

     

    Ulnar club hand differs from radial club hand in a number of key ways:

    * The elbow join is unstable while the wrist join is stable, while in radial club hand it is the wrist that is unstable with the elbow being either stiff or stable

    * Syndromic associations are rare in ulnar club hand, but if they do occur they involve the musculoskeletal system unlike in radial club hand where they involve either the cardiac, gastro-intestinal or  haematological system

    * In ulnar club hand the ulnar is typically only partially absent while in radial club hand the radius is usually totally absent.

     

    The most commonly used classification system used for ulnar club hand is that which has been proposed by Bayne:

     

                   * Type 1 – hypoplasia of the ulna with minimal deformity

                   * Type 2 – partial absence of  the ulna

                   * Type 3 – total absence of ulna with anlage and a normal radiohumoral joint

                   * Type 4 – radius is fused to the humerus with no elbow joint (radiohumeral synostosis)

     

    Treatment of ulnar club hand involves hand therapy and splinting to improve the range of motion and where appropriate surgical intervention. Surgical intervention usually involves release of the fibrous anlage and realignment of the carpus and forearm.

    

    2. Failure of differentiation

     

    SOFT TISSUE

    Syndactyly

     

    The term “syn” is derived from Greek and means “together” while dactyly is also derived from the greek term “dactylos” which means “digit”, both of them used in this instance to describe a condition where the fingers of the hand are joined together. Syndactyly is thought to be caused by a failure of programmed cell death (apoptosis) in the interdigital tissue.

     

    Figure 1. Complete simple syndactyly involving the middle and ring fingers.

    When all the different varieties of syndactyly are counted together it becomes the most common congenital deformity of the hand. It has an incidence of approximately 1 in 1000-2000 live births. Males are affected more commonly than females with 30% being bilateral and 20% of cases having a positive family history. Syndactyly is thought to be associated with at least 28 other syndromes including Apert’s and Poland’s syndrome. The third web space (between the middle and ring finger) is the most commonly affected in the hand, whereas the foot may also be affected, with the commonest form being an incomplete second web space syndactyly.

     

    Syndactyly is classified as follows:

     

    •  Complete – the digits are fused together up to the level of the tips of the fingers.
    •  Incomplete – fusion of the digits does not reach up to the level of the fingers.
    •  Simple – the connection between the digits only involves soft tissue.
    •  Complex – in addition to soft tissue connections, there are also bony connections between the fingers.
    •  Acrosyndactyly – there is distal soft tissue and bony connections (i.e. complex syndactyly) but proximally the web space is present to a degree, resulting in small spaces referred to as fenestrations.

     

    Web spaces that are affected in order of decreasing commonality include:

     

    1)      58% of cases involve the middle-ring finger web space

    2)      27% of cases involve the ring-little finger web space

    3)      14% of cases involve the middle-index web space

    4)      1% of cases involve the thumb-index finger web.

     

    Treatment involves surgical correction of the deformity. Goals of surgery include separation of the digits, creation of a web space, skin coverage, immobilization and avoidance of scars. A number of surgical techniques exist but most share the following principles:

     

    •  If several digits are involved, the border digits are released first.
    •  If a digit is joined on both sides a single stage release procedure to separate that finger should be avoided as this may adversely impact finger vascularity.
    •  Zigzag incisions should be used and straight-line incisions avoided along the borders of digits to reduce the likelihood of scar contracture which may lead to digital deformity.
    •  A proximally based dorsal flap is usually used to reconstruct the webspace as skin grafts in this area may cause a partial recurrence of syndactyly.
    •  Defects along the borders of the digits are closed via volar and dorsal interdigitating flaps.
    •  Any other resultant defects are closed via full-thickness skin grafts.
    •  Skeletal abnormalities need to be corrected.
    •  Reconstruction of a normal nail fold.

     

    The timing of surgery depends upon the deformity. Surgery to release fingers of unequal length, such as the ring and little finger and the thumb and index finger, maybe carried out as early as 6 months. Complex and acrosyndactyly are also often released early as the bone to bone connections between the digits may adversely affect growth. Most other less-severe deformities can be deferred to age 12-36 months.

     

    Camptodactyly

     

    This condition is characterized by a congenital flexion deformity of the proximal interphalangeal joint (PIPJ). It most commonly involves the little finger although other fingers could be involved.

     

    The condition presents at two distinct time periods: one that presents at infancy (1 to 4 years) with an equal sex incidence and one that presents at adolescence (10-14 years) which occurs more commonly in girls.

     

    Figure 2. Camptodactyly involving the little finger in an adult

    Almost every structure in the region of the PIPJ has been implicated in the pathogenesis of camptodactyly although the most common causes seem to be either an abnormal lubrical insertion or an abnormal flexor digitorum superficialis (FDS) insertion.

     

    Initial treatment is conservative and involves splinting and stretching. On the other hand, if either the conservative management fails or there is rapidly progressing deformity of the finger, then surgical intervention is considered. Surgery can be deceptively complex and may involve: release of any anomalous lumbricals or lengthening a tight FDS, agulation osteotomy or athrodesis of the joint.

     

    Trigger thumb

     

    This condition presents in infants with similar clinical features to that in adults and includes a thumb that clicks, catches or locks as the interphalangeal joint moves from a flexed to an extended position. The interphalangeal joint is usually held in the flexed position by the child. Around 25% of tigger thumbs are present at birth and 25 % are bilateral. About 30% of trigger thumbs resolve spontaneously by 1 year of age. A nodule known at “Notta’s node” is usually palpable over the flexor aspect of the metacarpophalangeal joint.

     

    Initially stretching exercises with splintage are used. However if this fails to resolve the deformity surgical release of the A1 pulley is carried out. This provides excellent results with few complications.

     

    Clasped thumb

     

    Here the thumb is held adducted at the metacarpophalangeal joint of the thumb and the proximal phalanx of the thumb is also flexed. Treatment may involve splintage in extension for upto 6 months. If conservative treatment fails or there is significant adduction contracture, release of the first web space may be indicated. Tendon transfers, tendon grafts and arthrodesis maybe in indicated in more severe cases.

     

    SKELETAL

    Clinodactyly

     

    This is characterized by curvature of a digit in a radioulanr plane. The most common presentation is inward deviation of the little finger. The pathoanatomical basis of clinodactyly rests with an abnormally shaped middle phalanx known as a delta phalanx. Due to an abnormality of its epiphysis the delta phalanx assumes an abnormal trapezoidal shape which in turn gives rise to curving of the digit.

     

    Figure 3 Clinodactyly of the little finger in an infant

    Most patients with this condition do not have any functional deficits and hence surgery is not indicated purely for aeasthetic purposes. However if there is severe angulation and interference with function then a range of wedge osteotomy techniques can be employed to correct the deformity.

     

    Symphalangism

     

    Harvey Cushing used the term Symphalangism to describe congenital stiffness of the PIPJs. It has now been extended to include stiffness of the DIPJs as well. Symphalangism is caused by a failure of differentiation of the interphalangeal joint. There is an absence of the joint capsule. It most commonly involves the PIPJs, although the DIPJs could be involved aswell. Symphalangism occurs in association with a number of other conditions including, Apert’s syndrome, Polands syndrome and Radial club hand.

     

    Symphalangism is usually managed conservatively as the hand functions quite well. Thus the mainstay of treatment involves hand therapy and dynamic splintage. Surgical options including arthroplasty and arthrodesis may be considered following skeletal maturity to obtain a more functional position.

     

    Synostosis

     

    This involves the fusion of two bones, either in a partial manner permitting some degree of movement, or in a complete manner permitting absolutely no movement at the joint. It may occur at any site along the upper limb where there are two bones adjacent to one another. Synostosis may occur between phalanges (complex syndactyly), metacarpal bones, carpel bones and the radius and ulnar. The mainstay of treatment is surgery and involves rotational osteotomies to improve the position and hence function of the hand.

     

    Arthrogryposis

     

    This term refers to a collection of conditions where there are multiple joint contractures. An abnormality of the nerves in the motor unit it thought to be the cause of this condition. Patients with arthrogryposis have internally rotated and adducted shoulders, club-like hands and wrists and also fixed flexion or extention deformities of the knees and elbows. Treatment is usually confined to dynamic and static splinting with surgery being indicated to correct specific functional problems.

     

    Windblown hand

     

    In this congenital condition the fingers are deviated in an ulnar direction. It is usually bilateral and becomes progressively worse as the child matures. Treatment is surgical and involves reconstruction of the deformed hand

     

    3. Duplications

     

    The entire limb or any part of it may be duplicated. Polydactyly refers to the presence of more than five fingers in the hand. It can occur on its own or as a condition associated with a syndrome. For simplification, duplications can be divided into ulnar (postaxial), central and radial (preaxial).

     

    Figure 4. An extra digit in the ulnar (postaxial) plane giving rise to ulnar polydactyly

    Ulnar polydactyly

     

    This is also known as postaxial polydactyly and is eight times as common as polydactyly of the other fingers. Stelling has divided ulnar polydactyly (duplication of the little finger) into three types:

     

    * Type 1 – a mass of soft tissue lacking a skeletal structure attached to the postaxial region.

    * Type 2 – an extra digit with all the normal components articulating with a normal or bifid metacarpal or phalanx.

    * Type 3 – an extra digit articulating with an extra metacarpal.

     

    Treatment involves surgical removal of the extra digit in types 2 and 3 and removal of the skin tag in type 1.

     

    Central polydactyly

     

    This includes duplications of the index, middle and ring fingers. It tends to be seen in association with varying degrees of syndactyly and in this case it is referred to as polysyndactyly. Surgical intervention usually involves release of the syndactyly, removal of the extra digit and augmentation of the retained digit via reconstruction. The operative procedures required to correct this deformity are complex and may require more than one operation.

     

    Radial Polydactyly

     

    Radial polydactyly (generally thumb duplication) is also known as preaxial polydactyly. Duplication of the thumb is usually unilateral. Wassell has classified radial polydactyly into 7 types:

     

    * Type 1 – bifid distal phalanx.

    * Type 2 – duplicated distal phalanx.

    * Type 3 – bifid proximal phalanx with duplicated distal phalanx.

    * Type 4 – duplicated proximal and distal phalanx.

    * Type 5 – bifid metacarpal with duplication of the proximal and distal phalanx.

    * Type 6 – duplicated metacarpal, proximal and distal phalanx.

    * Type 7 – triphalangeal thumb.

     

    Out of the 7 types, type 4 is the commonest, occurring in approximately 44% of cases of thumb duplication. A variety of surgical techniques are available to correct this deformity depending on which type it falls into. These techniques are beyond the scope of this article and a description of them can be found in any text dealing with surgery of the hand.

     

    Ulnar dimelia

     

    This is a rare condition where there is duplication of the ulna, absence of the radius and 7 or 8 fingers with no thumb. It is also sometimes referred to as mirror hand. In addition to the above mentioned pathoanatomy, there usually is stiffness of the elbow with reduced forearm rotation. Treatment involves excision of the olecranon (to improve elbow stiffness) and excess fingers.

     

    4. Overgrowth

     

    Macrodactyly

     

    Macrodactyly refers to enlargement of all structures within a digit. True macrodactyly needs to be differentiated from other causes of englarged digits such as vascular malformations, osteoid osteomas, fibrous dysplasia and lipomatoses. The most common presentation of macrodactyly is macrodactyly associated with nerve-orientated lipofibromatosis. In this condition there is adipose tissue and fibroblast deposition in the cutaneous nerve supplying the digit (leading to its enlargement) and hence it is alternatively described as nerve-territory orientated macrodactyly. It most commonly occurs in the median nerve distribution supplying the index finger and is usually unilateral. Other less common presentations of macrodactyly include; macrodactyly associated with neurofibromatosis, macrodactyly associated with hyperostosis and macrodactyly due to gigantism and hemihypertrophy.

     

    Macrodactyly is classified into two types:

     

    * Static macrodactyly – the englarged digit grows in proportion with the rest of the child’s body.

    * Progressive macrodactyly – the enlarged digit grows progressively out of proportion with the rest of the child’s body.

     

    Treatment is surgical and includes:

     

    •  Soft tissue reduction (debulking)
    •  Amputation of the enlarged digit
    •  Resection of the nerve in cases involving nerve-territory orientated macrodactyly
    •  Epiphysiodesis ( procedure involving the growth plate employed to limit growth of the enlarged digit)

     

    5. Undergrowth

     

    Brachydactyly

     

    Brachydactyly is the term used for fingers which are shorter than normal. It tends to occur in association with symbrachydactyly where the fingers are replaced by small nubbins. It is treated either via distraction, free phalangeal transfers from the toes or free microvascular joint or bone transfer.

     

    Thumb hypoplasia

     

    The thumb is the digit that is most commonly hypoplastic. Blauth classified thumb hypoplasia into 5 types:

     

    * Type 1 – small thumb with normal components. This deformity does not affect function adversely and hence in the vast majority of cases does not require surgical correction.

    * Type 2 – the thenar muscles are hypoplastic, the first web space is narrowed due to adduction contracture and the MCP joint is unstable due to laxity of the ulnar collateral ligament. The skeletal structure of the thumb however is normal. It is treated via release of the first web space and an opponensplasty (an opearation where a muscle is transferred to restore thumb opposition)

    * Type 3 – there is hypoplasia of the skeletal structure and intrinsic muscles with abnormalities of the extrinsic tendons. It is treated via amputation and pollicization of the index finger (an operation where the index finger is removed and used to create a thumb) or by soft-tissue and skeletal reconstruction.

    * Type 4 – here a small thumb is attached to the hand via a skin bridge. This deformity is referred to as floating thumb.

    * Type 5 – absence of the thumb. Both types 4 and 5 are treated via pollicization of the index finger.

     

    6. Constriction ring syndromes

     

    This involves the presence of tight bands around any part of a limb or digit. It may encircle the entire circumference of the affected region or it might only encircle it partially.

     

    Congenital constriction band syndrome has an incidence of approximately 1 in 15,000 live births.

     

    Figure 5. Constriction bands around the index finger and thumb have lead to their partial deformity

    There are two hypotheses with regards to its etiology. The first one proposes that it is caused by extrinsic amniotic bands encircling the limb in utero, while the second one proposes that it is caused by an intrinsic defect in the germ cell layer.

     

    Constriction ring syndromes have been categorized by Paterson into 4 main groups:

     

    * Type 1 – simple constriction ring involving only a groove in the skin.

    * Type 2 – constriction ring with distal lymphoedema.

    * Type 3 – constriction ring associated with fusion of digits distally (known as acrosyndactyly).

    * Type 4 – intrauterine amputation.

     

    Treatment typically involves excision of the ring via multiple Z-plasty or W-plasty. If acrosyndactyly is present, it should be released within the first year of life to enable the digits to grow normally.

     

    References:

     

    Thorne CH, editor-in-chief. Grabb and Smith’s Plastic Surgery. 6th ed. Philadelphia: Lippincott Williams and Wilkins; 2007.

    Mary O’Brian. Plastic and hand surgery in clinical practice – classifications and definitions. London: Springer; 2009.

    Beasley RW. Beasley’s surgery of the hand. New York: Thieme; 2003.

    Richards AM. Key notes on plastic surgery. Oxford: Blackwell science; 2002

    Siemionow MZ, Eisenmann-klein M, editors. Plastic and reconstructive surgery. London: Springer; 2010.

    Weinzweig J, editor. Plastic surgery secrets plus. 2nd edition. Philadelphia: Mosby Elsevier; 2010.

    Laub Jr DR. Congenital hand deformities. eMedicine; 2010.[cited 2011 Feb 10]. Available from: URL: http://emedicine.medscape.com/article/1285233-overview.

    Advertisement

    Fastbleep © 2019.