Congenital anomalies of hand (Classification)

Congenital anomalies of the hand have been classified under the following headings

International Federation of Societies for Surgery of Hand

1. Failure of formation of parts
2. Failure of differentiation of parts
3. Duplication
4. Over-growth
5. Under-growth
6. Constriction bands
7. Generalized skeletal abnormalities

Failure of formation of parts

a. Transverse arrest

Can be anywhere between shoulder and phalanx

Commonly :

• Proximal forearm
• The transverse arrest of fingers ( Vestigial fingers: Symbrachydactyly)

b. Longitudional arrest

Radial pre-axial (Radial club hand)

Ulnar post-axial

Central (Cleft hand)- V-shaped cleft in the center

Intersegmental (Intercalated)- Phocomelia

Phocomelia: Intercalated segment in upper limb fails to develop and forearm and hand may be attached directly to the trunk, or hand attached to humerus.

Failure of differentiation

a. Syndactyly

Syndactyly is more common in males, is present bilateral in 50% of affected patients, and often is associated with other musculoskeletal or systemic syndromes.

The goal of the release of syndactyly is to achieve a functional hand with the fewest surgical procedures while minimizing complications.

Release of syndactyly of unequal length digits should be performed as early as possible; between 3 and 6 months is a good time as the child is old enough to withstand the procedure without undue anesthetic risk, whilst the chance of damage to the joints is reduced, especially the PIP joint of the longer digit.

Special situations, such as complex syndactyly and involvement of border digits may warrant surgical intervention earlier than 6 months

Following surgery patient should be followed up until skeletal maturity because complications such as web creep can occur

Reconstruction of the web commissure is the most challenging part of the operation followed by the separation of the remaining digits.

Types:

• Simple: soft tissue only
• Complex: skin and bone
• Complete: affecting the entire web
• Incomplete: only part of the web

Achrosyndactyly: Multiple digits are involved

b. Synostosis

Fused/ Unseparated joints

Examples:

• Humeroulnar synostosis
• Proximal radioulnar synostosis
• Carpal coalitions

c. Camptodactyly

‘Bent finger’: flexion deformity of PIP joint usually of the little finger

Clinodactyly: digit bends sideways (radial and ulnar) due to abnormally shaped middle phalanx (Delta deformity)

Duplication

Polydactyly (extra digits)

• Preaxial (radial)
• Central
• Postaxial (Ulnar)

Overgrowth

Macrodactyly

• Static: Present at birth and grows proportionally to other digits
• Progressive: Enlargement of digits in early childhood, growing faster than other digits with a deviation of digits

Undergrowth

Brachydactyly

Eg. Hypoplastic thumb

Hypoplastic Thumb

Thumb Hypoplasia is the congenital underdevelopment of the thumb.

It consists of three elements:

1. Adduction contracture of the first web space is apparent because of
2. Lack of thenar muscle, and the hand compensates by exhibiting
3. Laxity in ulnar collateral ligaments that allows abduction of the MCP joint

Blauth classification of Hypoplasia

Type	Description	Treatment
Type I	Minor hypoplasia, All musculoskeletal and neurovascular components of the digit are present, just small in size	No treatment is necessary
Type II	Thenar hypoplasia, Osseous structure present (but small in size), MCP joint ulnar collateral ligament instability	Oppenenplasty and stabilization of MCP joint
Type IIIa	Musculotendinous structure and osseous structure deficit, CMC joint preserved	Oppenenplasty and stabilization of MCP joint
Type IIIb	Musculotendinous structure and osseous structure deficit, CMC joint deficit	Thumb amputation & pollicization
Type IV	Floating thumb, attachment to hand by the skin, and neurovascular structure	Thumb amputation & pollicization
Type V	Complete absence of thumb	Thumb amputation & pollicization

Always look for pollex abductus in thumb duplication

Constriction Ring Syndrome

Patterson has classified Constriction Ring Syndrome as

Types	Description
Type I	A simple band
Type II	A construction band with distal lymphoedema
Type III	A construction band with acrosyndactyly
Type IV	Congenital amputation

Miscellaneous Conditions of other Congenital anomalies

1. Madelung deformity
2. Congenital Clasped thumb
   • Clasp their thumb persistently under the fingers (due to weakness/ absence of extensor tendons)
   • Later: FLexor contracture of MCP, CMC joints
3. Congenital Trigger Thumb
   • Stenosing tenovaginitis of FPL
   • Thickening of tendon; Notta nodes palpable
4. Symphalangism
   • Congenital stiffness of PIP of finger
5. Arthrogryposis Multiplex Congenita (AMC)
   • The whole upper limb may get affected
6. Other generalized Syndrome
   1. Downs syndrome
   2. Marfans syndrome
   3. Neurofibromatosis
   4. Cerebral Palsy
7. Poland Syndrome: Whole upper limb hypoplasia, hand: brachydactyly, syndactyly and Symphalangism