Congenital hand surgery in children

Congenital hand malformations affect approximately one to three children per thousand births. They occur during the first weeks of embryonic development, between the fourth and eighth weeks of pregnancy, when the limbs are formed. Their origin is most often unknown, and it is important to remind families that no parental behaviour during pregnancy is responsible for them.

These malformations are extremely diverse. Some are purely cosmetic, while others affect hand function. Some occur in isolation, whereas others form part of a multiple-malformation syndrome requiring further assessment. The international classification currently recommended by the International Federation of Societies for Surgery of the Hand (IFSSH) is the Oberg, Manske and Tonkin classification, which distinguishes anomalies of formation, anomalies of differentiation, duplications, growth anomalies and amniotic band syndromes. The fact sheets below follow this logic, but present each condition separately to facilitate reading.

Syndactyly

In brief

Syndactyly refers to the fusion, to varying degrees, of two or more fingers. It is one of the most common congenital malformations of the hand, with an estimated incidence of approximately one case per two thousand births. It most commonly affects the third web space, between the middle and ring fingers, and may be unilateral or bilateral. A family history is frequently found.

Simple syndactyly, in which only the skin joins the fingers, is distinguished from complex syndactyly, in which the phalanges themselves are fused. Syndactyly is described as complete when it extends to the fingertips, and incomplete otherwise. Some forms occur as part of a syndrome, notably Apert syndrome or Poland syndrome, which justifies a comprehensive clinical assessment at birth.

Management

Treatment of syndactyly is surgical. It consists of separating the fingers by reconstructing an interdigital web space of physiological shape and depth, then covering the lateral surfaces of the fingers with local skin flaps and, sometimes, with a full-thickness skin graft harvested from the groin crease. The timing of surgery depends on the location and complexity of the malformation. Syndactyly involving the thumb or little finger, where the difference in length between adjacent fingers creates a risk of deviation, is treated early, generally between six and twelve months of age. Syndactyly of the central web spaces is treated later, usually between twelve and eighteen months. In bilateral or multiple forms, several surgical stages are necessary to avoid operating on both sides of the same finger during the same procedure, which would compromise its blood supply.

The procedure is performed under general anaesthesia, mainly as day surgery. A dressing immobilising the entire hand is applied for two weeks. Physiotherapy rehabilitation is often necessary, particularly in complex cases. Long-term postoperative follow-up makes it possible to detect a scar contracture or a growth-related secondary deviation of the axis, which may warrant revision surgery.

Thumb duplication (preaxial polydactyly)

In brief

Thumb duplication, or preaxial polydactyly, is the presence of an extra thumb. Its frequency varies between populations, with an overall incidence of approximately one case per three thousand births, and is higher in Asia. An isolated unilateral form is the most common. The reference classification is the Wassel classification, which distinguishes seven types according to the anatomical level of the duplication, ranging from simple duplication of the distal phalanx to complete duplication including the first metacarpal.

Management

Treatment is surgical. It aims to reconstruct a single, stable and well-aligned thumb, with a harmonious nail and an effective thumb–index pinch. Depending on the anatomical type, surgery combines removal of one of the two thumbs with transfer of elements from the removed thumb to the preserved thumb, such as a collateral ligament, part of a tendon, an epiphyseal fragment or a nail flap. In some duplications close to the midline, a technique involving fusion of the two thumbs (a modernised Bilhaut-Cloquet procedure) may be proposed.

Surgery generally takes place between twelve and eighteen months of age, before the development of a fine pinch and before the child becomes aware of their difference. It is performed under general anaesthesia, with a short hospital stay. Immobilisation in a splint is maintained for four to six weeks. Long-term follow-up is essential: growth may reveal axial deviations, joint instability or nail abnormalities that may warrant revision surgery at school age or during adolescence.

Supernumerary finger (postaxial polydactyly)

In brief

Postaxial polydactyly is the presence of an extra finger on the little-finger side. Two main forms are distinguished. Type A is characterised by a fully formed extra finger articulated with the fifth metacarpal, whereas type B consists of a simple, pedunculated skin appendage, usually without a skeleton. Type B is considerably more common and often bilateral. A family history is common. Postaxial polydactyly may occur in isolation or as part of a syndrome, which warrants a comprehensive clinical examination.

Treatment

For type B forms, the appendage can be surgically removed during the first few weeks of life under local anaesthesia. Ligation at birth, which was used for many years, is no longer performed in our department because of the risk of a painful neuroma and an unsightly residual stump.

For type A forms, in which the supernumerary finger is complete, surgery is more complex. Its aim is to reconstruct a functional and aesthetically pleasing fifth finger, using the best-formed elements of both fingers. The procedure is performed under general anaesthesia, usually between twelve and eighteen months of age, followed by immobilisation for several weeks.

Central polydactyly

In brief

Central polydactyly, which is much rarer, is the presence of a supernumerary finger at the level of the index, middle or ring finger. It is frequently associated with syndactyly, which may conceal the extra finger. This combination systematically warrants radiographic assessment and careful clinical evaluation to look for a syndromic context.

Treatment

Treatment is surgical and tailored to the individual case, based on the precise anatomy of the malformation. It combines excision of the supernumerary finger with separation of the fused fingers and reconstruction of the web spaces. Several surgical procedures may be required. Surgery begins at around twelve to eighteen months of age, with prolonged follow-up so that the strategy can be adapted to the effects of growth.

Congenital trigger thumb

In brief

Congenital trigger thumb, or flexed thumb, is characterised by the thumb being locked in a flexed position at the level of its interphalangeal joint. It is caused by thickening of the A1 pulley, which prevents the normal gliding of the flexor pollicis longus tendon. The malformation is present at birth, but the diagnosis is generally made between one and three years of age when the thumb remains permanently bent, sometimes with a small palpable nodule at its base. Contrary to what its name suggests, true triggering is rare in children; the deformity is most often a fixed flexion.

Treatment

Spontaneous resolution is possible during the first few months of life, which justifies initial observation, possibly combined with passive stretching and a night splint. If the condition has not resolved by the age of two to three years, surgical treatment is offered. This involves releasing the A1 pulley through a short incision at the base of the thumb, under general anaesthesia as a day-case procedure. The thumb regains extension immediately after the operation. Prolonged immobilisation is not necessary, and the functional outcome is excellent.

Camptodactyly

In brief

Camptodactyly is a progressive, non-reducible flexion deformity of the proximal interphalangeal joint of a finger, most commonly affecting the little finger. It may be present at birth or develop during adolescence, a period of rapid growth during which it may worsen. It is usually isolated but may occur as part of certain syndromes. 

Management

Initial management is conservative. It consists of prolonged use of a night-time extension splint, combined with physiotherapy, often continued for several months. In most cases, this management leads to significant improvement, and sometimes complete correction.

Surgery is considered only if well-conducted conservative treatment fails and there is a genuine functional impact. It aims to release the contracted structures and, depending on the case, rebalance the tendon forces. Families should be informed that the correction achieved through surgery is rarely complete.

Clinodactyly

In brief

Clinodactyly refers to deviation of a finger in the plane of the palm, most commonly radial deviation of the distal phalanx of the little finger. It is caused by asymmetrical growth of a phalanx, often a delta phalanx. It is common, often familial, and generally isolated. 

Management

In the vast majority of cases, clinodactyly is purely cosmetic and requires no treatment. Surgery is offered only in severe cases, with a functional impact or significant cosmetic concern experienced by the child. It consists of an osteotomy of the affected phalanx to correct its alignment. Surgery is postponed until school age, as early surgery carries a risk of recurrence due to the persistence of an imbalanced growth plate.

Cleft hand (central longitudinal deficiency)

In brief

Cleft hand, or lobster-claw hand, is a failure of formation of the central rays of the hand, resulting in a median cleft of varying depth. The malformation is highly heterogeneous, ranging from a simple skin cleft to complete absence of the central rays. It is frequently bilateral and may sometimes be associated with foot involvement. Familial transmission is common. Genetic assessment is offered, as several syndromes may present with this malformation, including EEC syndrome (ectrodactyly, ectodermal dysplasia and cleft lip).

Management

Management is decided on an individual basis. Indeed, the paradox of cleft hand is that its function is often remarkable, with an effective pinch between the fingers. Surgery should therefore be proposed cautiously, taking care not to impair preserved function in pursuit of cosmetic improvement. It may involve closure of the central cleft, reconstruction of a broad first web space when syndactyly of the thumb and index finger is present, or correction of alignment deviations of the remaining fingers. These procedures are staged and generally begin at one to two years of age.

Macrodactyly

In brief

Macrodactyly is excessive growth of one or more fingers, affecting all tissues (skin, fat, bone and nerves). It is rare. Two forms are classically distinguished: static macrodactyly, in which the growth of the finger remains proportional to that of the rest of the hand, and progressive macrodactyly, in which the finger continues to grow disproportionately. Macrodactyly is often part of a broader spectrum of overgrowth syndromes, including CLOVES syndrome and Klippel–Trenaunay syndrome, which are now associated with somatic mutations in the PIK3CA pathway. A multidisciplinary assessment is warranted.

Treatment

Treatment is difficult and never entirely satisfactory. It aims to limit the growth of the finger and reduce its volume while preserving its function and sensitivity. Depending on the case, techniques may include epiphysiodesis (early growth-plate arrest), resection of excess soft tissue, skeletal reduction or, in severe cases, partial amputation, which may restore an acceptable level of function. Follow-up is prolonged, and several procedures are often required during growth.

Amniotic band syndrome

In brief

Amniotic band syndrome results from the formation in utero of fibrous bands originating from the amnion, which constrict one or more fingers or even an entire limb. The consequences depend on the location and degree of constriction. Findings may include simple cutaneous constriction rings, deep grooves affecting the blood supply and growth of the finger beyond the constriction, distal acrosyndactyly (fusion of the fingertips across the band) or congenital amputations. The malformation is generally sporadic and not hereditary.

Treatment

Treatment is surgical and progressive, tailored to each situation. Constriction rings are excised and the circumference of the finger reconstructed using Z-plasties or multiple plasties, in one or more stages depending on the depth of the groove. Acrosyndactyly is separated according to the principles of syndactyly surgery. Amputated fingers may sometimes benefit from reconstruction using digital ray transfers or toe transfers in the most severe cases and in older children. Initial surgery usually begins during the first year of life, taking into account the functional impact of each anomaly.

At Brussels University Hospital, the management of congenital hand conditions in children is based on close collaboration between several teams, each involved at key stages of the care pathway.

The paediatric plastic surgeon, together with the paediatric orthopaedic surgeon, conducts the initial consultation, establishes the diagnosis, coordinates the assessment and performs the surgical procedures. They are the child’s and family’s main point of contact throughout follow-up.

The paediatrician and neonatologist become involved when the malformation is identified at birth, in order to look for any associated conditions and provide the child’s general follow-up. 

The paediatric radiologist performs the imaging examinations required for the lesion assessment, primarily X-rays and, less frequently, ultrasound or magnetic resonance imaging.

The geneticist is consulted whenever a syndromic context is suspected, in order to clarify the diagnosis, propose appropriate investigations and inform the family about the risk of recurrence. 

The physiotherapist provides most of the functional care, both before and after surgery. They make orthoses in collaboration with orthotists, oversee rehabilitation and support the acquisition of everyday skills. 

The psychologist may be offered to the family and child, particularly when the malformation is visible and as the child grows older and becomes sensitive to how others perceive them. 

The social worker is available to help families with administrative procedures, particularly with organisations providing disability support.

Follow-up is structured around appointments scheduled throughout the first years of life and continuing until the end of growth.

Initial consultation

The first consultation takes place shortly after birth, as soon as the family and child are available. It has several objectives: to confirm the diagnosis, explain the nature of the malformation and its expected progression to the parents, reassure them about aspects that are not threatening, and plan any investigations that may be necessary. This consultation is also an opportunity to listen, allowing parents to express their concerns and ask their questions.

Assessment at one year of age

A second consultation is scheduled before the child reaches one year of age, including an X-ray of the hand. At this age, the bone structures are sufficiently ossified to allow a precise analysis of the malformation and, if necessary, to plan the first surgical procedure. This consultation also makes it possible to assess the spontaneous function of the hand, as the child will by then have started handling objects and exploring their environment.

Surgical planning and postoperative follow-up

When surgery is indicated, it is scheduled at the most appropriate age for the condition concerned. The course of the hospital stay, the anaesthesia procedure, the duration of the stay and the expected postoperative course are explained in detail during a preoperative consultation. Postoperative follow-up includes appointments at short intervals during the first few weeks, followed by long-term follow-up until the end of growth, in order to detect any adverse changes secondary to growth.