April 11, 2024

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

congenital anomalies

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
International Federation of Societies for Surgery of Hand

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.


  • 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


  • 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)


Polydactyly (extra digits)

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



  • 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



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 IMinor hypoplasia, All musculoskeletal and neurovascular components of the digit are present, just small in sizeNo treatment is necessary
Type IIThenar hypoplasia, Osseous structure present (but small in size), MCP joint ulnar collateral ligament instabilityOppenenplasty and stabilization of MCP joint
Type IIIaMusculotendinous structure and osseous structure deficit, CMC joint preservedOppenenplasty and stabilization of MCP joint
Type IIIbMusculotendinous structure and osseous structure deficit, CMC joint deficitThumb amputation & pollicization
Type IVFloating thumb, attachment to hand by the skin, and neurovascular structureThumb amputation & pollicization
Type VComplete absence of thumbThumb amputation & pollicization
Blauth classification of Hypoplasia

Always look for pollex abductus in thumb duplication

Constriction Ring Syndrome

Patterson has classified Constriction Ring Syndrome as

Type IA simple band
Type IIA construction band with distal lymphoedema
Type IIIA construction band with acrosyndactyly
Type IVCongenital amputation
Patterson Classification

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