Congenital Hand Anomalies
Early Management
1. to prevent rapid progress of certain deformities in the early stage . (e .g . radial
club hand)
2. to detect any limb threatening condition when there is neurovascular impairment.
(e .g . constriction rings)
3. to design a overall treatment strategy .
4. to give early psychological support to the child and the parents
Team approach to caring for the needs of child and family. -Hand therapist, OT,
psychologist, pediatrician and hand surgeon.
The deformity is not a source of concern to the child until the age of 4-6
Goals of treatment of congenital hand
1. Improve functional ability
a. functional position of the components of the hand.
b. To provide good skin cover with adequate sensibility.
c. To achieve satisfactory power grip and precision pinch.
2. Allow unrestricted growth
3. Allow a socially acceptable appearance
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If above not met, no indication for surgery
Orthotics, prosthetic, and surgery may be required to achieve goal.
Careful observation of hand at play permits accurate assessment of deformity and
planning of surgical correction
If surgery planned,
a. Need to protect epiphyseal plates
b. Need to preserve normal sensation
Functional priorities
1. prehensability(grasp) with an opposable thumb
a. aim for thumb to single finger pulp pinch
b. key pinch if thumb has only limited ability to abduct and oppose and
where the fingers lack much movement.
2. Individual digit function – ie syndactyly release
3. Finger grip with some power
4. Palm as sensate paddle with wrist movement
a. May be improved with double toe transfer
5. small piece of proximal palm with wrist movement
6. Transverse deficiencies of the forearm with elbow movement
a. act as a hook to hold objects with straps or to fit a prosthesis
7. Thoraco-humeral pinch
Timing of surgery
The maximal functional gain after treatment should be acquired before the child
conforms to a fixed pattern of activities .
Developmental milestones
At the end of the first year, the child has well co-ordinated control of the grasp
and pinch between the thumb and the fingers
Between the age of 1 to 3, the child has progressively acquired the skill of
accurate comprehensive refinement of co-ordination with bimanual
dexterity and increase in the strength of grasp and pinch.
Before 12-18months of life persistently abnormal prehensile function influence
cortical mapping of the affected area
Surgery best undertaken during the period of cortical plasticity, 6-18 months
(subject to other medical problems)
Complex procedures best delayed until hand is large for technical ease, usually 1st
stage is undertaken after 6 months of age.
Most of the reconstructive plan should be completed by the time the child is of school
age .
Early surgery is indicated where ongoing growth will cause deformity or ischaemia
(complex syndactyly, constriction band)
Prevalence
1:463 to 1: 626 live births
Syndactyly > polydactyly > campylodactyly
Significant racial variation
Genetics
Most deformities random occurrence
5% cases show familial tendency
o Holt Oram
1. cardiac ASD/VSD and radial/carpal and thenar anomalies
2. autosomal dominant, TBX5 gene
3. left often worse than right
4. aplasia, hypoplasia, fusion or anomalous carpal, radial and thumb
bones
o Fanconi syndrome
1. pancytopenia, preaxial limb defects
o TAR syndrome
1. thrombocytopenia and absent radius (thumbs present)
o VATER
1. Vertebral, imperforate Anus, TracheoEosophageal fistula,
Radial/Renal dysplasia
o Aase syndrome
1. triphalangeal thumb and aplastic anemia
o Nager syndrome
1. preaxial aplasia associated with mandibulofacial dysostosis
(Treacher Collins)
o Roberts syndrome
1. four deficient limbs plus cleft lip and palate
Cleft hand, symphalangism, brachydactyly, campylodactyly show AD inheritance
pattern
Development of the hand
4 Processes:
Morphogenesis - Process by which part assumes a particular shape
Cell differentiation - Process by which individual cells, under genetic control
become specialized by carrying out specific functions
Pattern formation- is the process by which cellular differentiation is spatially
organized
Growth - is the enlargement of the structure reflecting both cell proliferation and
matrix elaboration
23 stages of embryonic development.
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Hand development occurs between week 4-8 or Streeter stages 12-20
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Upper limb precedes lower limb development
Outgrowth from the ventrolateral body wall located opposite the 5th -7th cervical
somites
Week 4 (Day 28) - Arm bud appears (Wolff crest) – condensations of
mesenchyme covered with thick ectoderm (apical ectodermal ridge)
Week 4 (Day 30) – Flipper
Week 4 (Day 32) – Paddle
Week 5 (Day 35) – Hand Plate
Week 6 (Day 42) – Fingers Appear
Week 7 (Day 49) – Fingers Separate and lengthens, limb undergoes pronation
90°
Week 8 (Day 56) – All regions of arms and legs are well defined
Thalidomide results in formation of abnormal cells in the progress zone
Lateral plate mesoderm gives rise to bones, ligaments and blood vessels of the
limbs
Musculature derived from somatic mesoderm that migrates into the limb
Axial condensations of cartilage form the precursor of bones
Areas of flattened cartilage form dense plates, called interzones – precursor of
articular cartilage
Tendons develop independent of muscles, linking later in development – if the
adjacent bone is no developed, the tendon attaches to the nearest adjacent
structure
Critical condensations help to guide limb formation
1) Upper and Lower limb
a. Guided by TBX genes (TBX5 upper limb, TBX4 lower limb)
2) Proximal-Distal interaction
a. between the underlying mesenchyme of the limb bud (Progress zone)
and the apical ectodermal ridge
b. under the influence of a continuous signal, now believed to be fibroblast
growth factor (FGF) produced by the AER.
c. Regulated by Hox genes
d. Theory of positional information - Time that cell spends in the progress
zone determined whether it becomes proximal structure (long duration)
or distal (short duration)
3) Dorsal – Ventral differentiation
a. Dorsal ectoderm – modulated by Wnt-7a
b. Ventral ectoderm – modulated by Engrail
4) Radial-Ulnar differentiation
a. Zone of polarizing activity – located ulnarly
b. Gradient of morphogen induces differentiation
c. Modulated by Shh protein (Sonic hedgehog)
Apoptosis plays important role in embryogenesis of limb
 The resorption of tissue between the digital mesenchymal condensations result
from release of lysosomal enzymes from cells
 Interdigital apoptosis occurs distal to proximal
 Bone morphogenic proteins responsible for the signaling in the interdigital
necrotic zone
Classification
 Many different classifications have been proposed
 Current classification was proposed by Swanson and revised and modified by the
International Federation of Societies for Surgery of the Hand (IFSSH)
 Defects can be categorized as follows:
1) Failure of formation of parts (arrest of development)
2) Failure of differentiation (Separation) of parts.
3) Duplication.
4) Overgrowth (gigantism).
5) Undergrowth (hypoplasia).
6) Congenital constriction band syndrome
7) Generalized skeletal abnormalities.