Hypoplastic Thumb

Associations

 

Radial club hand

VECTRAL

Holt Oram

 

Blauth Classification

 

Grade I 

 

Minor hypoplasia, all element presents

 

Management

- may need opposition tendon transfer if APB and opponens deficient

 

Grade II 

 

Thenar muscles hypoplasia / aplasia

MCPJ ligament instability

Normal skeleton

Wed space adduction contracture

 

Management

1.  Release web space

2.  Oppensplasty

- FDS RF

- stabilise MCPJ

- provide opposition 

 

Grade III

 

Skeletal hypoplasia

Variable absence MC

Aplasia of CMC

Variable absence of radial carpal bones

Thenar muscle hypoplasia

 

Management

- pollicisation

 

Grade IV

 

Absent metacarpal / rudimentary phalanges

Pouce flottant / floating thumb

 

Management

- LA & tie off at birth

- pollicisation

 

Grade V

 

Total absence

 

Management

- pollicisation

 

Pollicisation

 

Concept

 

Use index finger as thumb

 

Best Results / Aims

 

30% normal strength

Good opposition

- should get pulp to pulp pinch

 

Timing

 

Between one and two years

 

Technique

 

1.  Skin incision for new web space

 

2.  Isolating on radial and ulna NV bundles

- splitting common digital nerve

- division of radial digital artery to middle finger

 

3.  Shorten finger

- remove metacarpal

 

4.  Stabilise MCPJ

 

5.  Balance MT units

- dorsal interossei becomes thumb abductor

- palmar interossei becomes thumb adductor

 

6.  Reattach extensor tendons, leave flexors