congh

Congenital Deformities of the Hand & Upper Limb

Classification - Swanson

  1. Failure of formation - A part doesn’t form properly
  2. Failure of differentiation - Part forms but does not differentiate
  3. Duplication
  4. Overgrowth
  5. Undergrowth
  6. Other - e.g., Constriction ring syndrome

Failure of Formation

  1. Symbrachydactyly
  2. Radial, central, or Ulna club hand

Embryonic Development

  • Occurs along 3 axes:
    1. Proximal to Distal – longitudinal growth
      • Controlled by Apical Epidermal Ridge (AER)
    2. Radial to Ulna
      • Zone of Polarized Activity (ZPA)
      • Sonic Hedgehog gene
    3. Dorsal to Volar
      • Less important in anomaly development
  • Failure of formation may be:
    • Transverse Arrest
    • Longitudinal arrest (radial, central, or ulna)

Transverse Arrest

  • Can occur at any level – Proximal 1/3 forearm most common
  • Less common than longitudinal arrest syndromes
  • Symbrachydactyly
    • Absence of part or all fingers – does not affect metacarpals
    • When associated with ipsilateral chest wall deformity → Poland Syndrome

Longitudinal Arrest – Radial, Central, or Ulna Deficiency

Radial Deficiency (Radial Club Hand/Radial Hemimelia)
  • Right > Left arm
  • Male > Female
  • 50% bilateral
  • Typical Deformity:
    • Short upper limb with marked radial deviation of wrist
    • Bowed thickened ulna
    • Thumb always affected (except in TAR syndrome)
    • Thumb/Radius/radial carpal bones may be hypoplastic or absent
    • Humerus, glenoid, scapula may also be abnormal if severe
  • Associated Conditions:
    • VATER Syndrome (Vertebral anomaly, anus imperforate, tracheo-esophageal fistula, renal and radial dysplasia)
    • TAR Syndrome (Thrombocytopenia Absent Radius) – Thumbs normal!
  • Classification (Heikel):
    1. Short Radius
    2. Hypoplastic Radius
    3. Partial Absence of Radius
    4. Absent Radius
  • Management Principles:
    • Educate patients
    • Genetic screening
    • Screen for other systemic anomalies
    • Centralize carpus on ulna
    • Pollicize a digit – allows pincer grip
    • Maintain motion
Central Deficiency (Cleft Hand)
  • Never affects proximal to carpus
  • Metacarpals absent (distinguishes it from Symbrachydactyly)
  • Carpus may be affected
  • 50% bilateral
  • Autosomal dominant inheritance
  • Often other associated abnormalities
  • Two Components:
    1. Central Cleft (associated syndactyly or polydactyly)
    2. Hypoplastic Thumb
  • Management:
    • Dysfunction mainly due to thumb hypoplasia – treatment primarily aimed at thumb reconstruction
    • Closing the cleft is primarily aesthetic
Ulna Deficiency (Ulna Club Hand)
  • Less common than radial or central deficiency
  • Radius always present but never normal
  • Ulna digits or ulna itself is hypoplastic or absent
  • Polydactyly, syndactyly, absent digits on ulna side of hand
  • Elbow often unstable/stiff – deficient ulnohumeral articulation
  • Management:
    • Address elbow contracture/instability, release syndactyly

Failure of Differentiation

  • Bony or soft tissue contractures & deformities:
    1. Syndactyly
    2. Arthrogryposis
    3. Camptodactyly
    4. Clinodactyly

Syndactyly

  • Fusion of digits
  • Male > Female
  • 50% bilateral
  • Autosomal Dominant inheritance
  • Most common in 3rd web space (50%)
  • Classification:
    1. Simple – Soft tissue only (web space webbing)
    2. Complex – Bone and soft tissue involvement
    3. Complicated – Part of a syndrome
  • Associated Syndromes:
    • Apert’s Syndrome – Midface hypoplasia, complicated syndactyly, visceral abnormalities
  • Management Principles:
    • Generally treat after 1 year old
    • Often require skin grafts due to inadequate skin after separation
    • Avoid concurrent release of adjacent syndactylies – risk of devascularization

Arthrogryposis

  • A spectrum of presentations
  • May be part of a wider condition (Arthrogryposis multiplex congenital)
  • Due to lack of fetal movement (myogenic or neuromuscular cause?)
  • Intellectually normal or advanced
  • Typical Hand Appearance:
    • Thumb adducted (thumb-in-palm)
    • Ulna deviated wrist
    • Flexed fingers
  • Management Principles:
    • Improve ROM
    • Provide function
    • Hand therapy (passive stretching, splinting)
    • Surgery: Soft tissue release, fusion, corrective osteotomy, tendon transfer

Camptodactyly

  • Flexion deformity of PIPJ – resembles a boutonniere deformity
  • Aetiology:
    • Flexor-extensor imbalance
    • Abnormal lumbrical insertion
  • Usually affects little finger (can be multiple)
  • Management:
    • Reassure & encourage non-operative treatment
    • Surgery for severe symptomatic deformities (soft tissue release or fusion)

Clinodactyly

  • Angular deformity of the finger at PIPJ
  • Usually affects the little finger
  • Due to abnormal shaped middle phalanx (Delta phalanx)
  • Associated with Down’s Syndrome (25%)
  • Management:
    • Usually none required
    • Osteotomy +/- fusion if severe

Duplication - Polydactyly

  1. Pre Axial - radial
  2. Central
  3. Post Axial – ulna
  4. Mirror Hand & Multiple Hand

Pre-Axial Polydactyly – Thumb duplication

  • Most common type
  • More in Europeans
  • Refers to various forms of thumb duplication
  • Mostly spontaneous and isolated but can be associated with syndromes
    • Holt-Oram
    • Fanconi Anaemia
    • Blackfan-diamond anaemia

Classification - Wassel

  1. Bifid Distal Phalanx - Rarest
  2. Duplicated Distal Phalanx
  3. Bifid Proximal Phalanx
  4. Duplicated proximal phalanx - Most common (45%)
  5. Bifid Metacarpal
  6. Duplicated Metacarpal
  7. Triphalangia

Remember by:
- Odd numbers are bifid from distal to proximal (type 1 bifid P3)
- Even numbers are duplications of the previous phalanx (type 2 duplicated P3)

Management

  • Educate family
  • Genetic counseling
  • Screen for other anomalies
  • Preservation of the skeleton of one thumb, excising the other but using its soft tissues to augment preserved thumb
    • Remove the smaller thumb - usually radial
    • Maintains UCL
    • Rebalance soft tissues
  • Bilhaut-Cloquet
    • Remove central components of both thumbs
    • Combine the two to make a new thumb
    • Stiffness and deformities are problematic – rarely performed

Post Axial (Ulna) Polydactyly

  • 2nd most common
  • Much more common in Africans
    • Isolated usually
    • Autosomal dominant
  • In Caucasians
    • Likely to be part of a complex genetic abnormality
  • Refers to duplication of ulna digits
    • From skin tags to true duplication of digit

Management Principles

  • Same principles as pre-axial polydactyly
    • Remove the outer (ulna) digit; balance the soft tissues

Central Polydactyly

  • Very rare
  • Duplication of central digits
  • Often associated with a complicated syndactyly

Management

  • Amputation is better for single digit affliction
  • Reconstruction for multiple or thumb

Mirror Hand & Multiple Hand

  • Exceedingly rare form of duplication
  • Mirror hand and ulna digits are duplicated around a common central digit
    • Radius is absent.
  • Multiple hand is presence of a duplicate hand

Overgrowth - Macrodactyly

  • Enlargement of a digit or multiple digits
  • Very rare
  • Spontaneous or secondary to another condition
    • Maffuci syndrome; proteus syndrome; neurofibromatosis
  • Treatment is very difficult – a normal digit cannot be restored

Undergrowth

  1. Hypoplasia
  2. Brachydactly

Hypoplasia/Aplasia

  • Uncommon
  • Most common type is thumb Hypoplasia or Aplasia
  • Spontaneous or part of a syndrome
  • Often associated or cross over with failure of formation
    • Especially radial club hand
  • Classification (Blauth)
    • 5 Types from short to absent thumb

Goal of treatment

  • Maintain or create a thumb to act as a post
  • Key to decision making is stability of CMCJ
  • Pollicisation if CMCJ incompetent

Brachydactyly

  • Short fingers – normal structure but small bones

Other Conditions

Congenital amniotic band syndrome

  • In utero amniotic bands cause constriction or amputation of digits/limb
  • Proximal to constriction, the limb is normal
  • Not properly understood
  • Streeter’s dysplasia

Kirner’s Deformity

  • Bowed distal phalanx
  • Often mistaken for Clinodactyly
  • No functional deficit
  • Surgery is cosmetic

Madelung Deformity

  • More common in females
  • Usually presents as minimally symptomatic deformity as an adolescent

Aetiology

  • Premature fusion of the volar-ulnar part of the distal radial epiphysis
  • Results in:
    • Prominent Ulna head
    • Volar-ulnar subluxation of the carpus

Management

  • Restore distal radius anatomy, reduce DRUJ and improve ROM
  • Techniques
    • Distal radius osteotomy, ulna-shortening osteotomy etc.

Trigger Thumb

  • Not clear if congenital or acquired.
  • May be hereditary
  • Often bilateral
  • Presents with fixed flexed IPJ

Aetiology

  • Due to a nodule (Notta’s nodule) in FPL just beyond A1 pulley
  • Prevents tendon passage

Management

  • Splint before 1 year old
  • Surgery to release A1 pulley
    • After 2 years (may spontaneously resolve)
    • Before 4 years (contracture & stiffness will hinder results)

Trigger Finger

  • Rare
  • Different pathology to adult trigger finger or pediatric trigger thumb
  • Usually due to anatomical abnormality between FDP and FDS
  • A1 pulley release is unlikely to be curative alone

Congenital Clasped Thumb

  • Weakness of EPL and/or EPB causes decreased active extension
  • Flexors overpower thumb
  • Treated with tendon transfers
  • May need contracture release or osteotomy if stiff deformity

Congenital Dislocation of the Radial Head

  • Often bilateral
  • 60% have another skeletal abnormality

X Ray features

  • Hypoplastic capitellum
  • Rounded Radial head
  • Long radius and short ulna

Management

  • None if function good
  • Excision of radial head if painful – uncommon

Symphalangism

  • Congenital stiffness of the digits at PIPJ
  • Usually ulna digits
  • Manifests as the child starts using hands
  • Loss of skin creases
  • XR shows small irregular joints

Associations

  • Alperts
  • Radial club hand
  • Hearing loss

Management

  • Non-operative in children
  • In adults if functionally limiting, bony osteotomies can be performed
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