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Flashcards in Congential Thumb Deck (20):

What is thumb hypoplasia?

Congenital underdevelopment of the thumb frequently associated with partial or complete absence of the radius

NB thumb on side of radius

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What is the epidemiology of thumb hypoplasia?

Incidence 1/100,000 live births

Males= Females

Location= Bilateral involvement in 60% pts

Right hand > left


What is the pathophysiology of thumb hyoplasia?

Eaxct cause during embrology development is yet to be ellucidated


Name the associated anomalies of thumb hypoplasia?

VACTERL- Vertebral anomalies, Anal atresia, Cardiac defects, Tracheoesophageal fistula and/or Esophageal atresia, Renal Radial anomalies and Limb defects

Holt- Oram

Thrombocytopenia- absent radius (TAR)

Faconi Anaemia


What is the classification system for thumb hypoplasia?

BLAUTH Classification ( see pic)

Tx depends on CMCJ stability


1 = Minor Hypoplasia- all muscleskeletal + neurovascular intact just small hand  = NO surgery

2= All bones present. MCPJ + Ulnar collat lig instability

Thenar hypoplasia = Stabilise MCPJ, Release 1st Web space, opponensplasty (opposition tendon transfer)

3A= muscle/bone def. CMCJ intact. Absent active motion MCPJ/ IPJ = Stabilise MCPJ, Release 1st Web space, opponensplasty (opposition tendon transfer)


3B= muscle/bone def. Basal MC aplasia w def CMCJ. Absent active motion at MCPJ/IPJ = Thumb amputation/ pollicization

4= Floating thumb, attach to hand by skin alone = Thumb amputation/ pollicization

5= Complete absence of thumb


A image thumb

What are the physical findings of thumb hypoplasia?

Pollex Abductus- FPL attaches to normal insertion and extensor tendon

Hypoplasia of thenar musculature

Absence of skin creases= muscle/tendon abnormalities

Range of motion and instability- Ulnar collat lig laxity

Web space tightness

Evaluate for other anomalies- vertebra, anal, cardiac, tracheoesphageal, radius, renal and limbs


What investigations are useful in thumb hypoplasia?

xrays- bilateral hands, wrists and forearm

Bloods- peripheral blood smear and FBC= rule out Fanconi anaemia

Chromosomal challenge test= detects Fanconi anaemia before bone marrow failure


Can you describe an opponensplasty?

An Opposition transfer

Uses Flexor digitorium superficialis or abductor digiti minimi


A image thumb

How do you deepen the first web space, can you draw this?

Z plasty

see picture below

A image thumb

How would you stabilise the MCPJ in thumb hypoplasia?

3 options:


Reconstruction of UCL with FDS

Reconstruction of UCL with Free tendon graft



Describe pollicization?

Process of creating a thumb from the exisiting index finger

Principles are:

Plan skin incision to avoid skin graft

isolate index finger NV bundles

Detach 1st dorsal and palmar interosseous muscles

shorten digit - removing index finger MC and epiphyseal plate

stabilise MCPJ

reattach and balance musculotendinous units

Reconstruct long extensor tendons

rebalance flexor tendons

A image thumb

What is congenital trigger thumb?

Stenosing tenosynovitis of  Flexor pollicis longus at Iat the Interphalangeal joint of the thumb

A image thumb

What is the epidemiology of trigger thumb?

Prevalence is 3 per 1,000 children at 1 year



What is the pathology of congenital trigger thumb?

Thought to be due to CONSTRICTION of Flexor Pollicis Longus (FPL) at A1 pulley


What do you find on examination of a congential trigger thumb?

Fixed flexion deformity cf 'triggering'

Flexor tendon nodule at MC Head- aka Notta's node ( see pic)

A image thumb

What is the Tx of congential trigger thumb? 

Non operative

clinical observation

outcomes- 30% resolve < 1 year old

 <10% resolve over 1 year

None resolve if in a 3 yr old


A1 pulley release: if no resolution by 12 months, perform at 12 months.

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Complications of congenital trigger thumb?

Digital nerve injury whilst doing the A1 pulley release- high proximity to flexor tendon and A1 pulley

Radial digital nerve especially at risk-both nerves hug flexor tendon


What is congenital clasped thumb?

Deficient Active Thumb extension

Slight limitations of passive extension

Flexion-adduction deformity of the thumb, [2] pollex varus, [3] thumb in the hand

A image thumb

What are the classification types of clasp hand?

Supple Type- due to weak /absent EPL/EPB

Rigid type- due to hypoplastic extensor tendons, MCPJ contractures, Ulna collateral ligament deficiency, thenar muscle hypoplasia and indequate 1st web space skin


What is the tx of congenital clasp thumb?

Non operative- first line SPLINTING 3-6 months

Operative- tendon transfer to EPL- for SUPPLE type with residual deficiency in active extension

Thumb reconstruction- rigid type with MCPJ contracture may include web space deeping, opposition transfer, extensor transfer, muscle releases, capsular release, FPL z lengthening