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Flashcards in Congential Thumb Deck (20):
1

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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2

What is the epidemiology of thumb hypoplasia?

Incidence 1/100,000 live births

Males= Females

Location= Bilateral involvement in 60% pts

Right hand > left

3

What is the pathophysiology of thumb hyoplasia?

Eaxct cause during embrology development is yet to be ellucidated

4

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

5

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

 

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6

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

7

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

8

Can you describe an opponensplasty?

An Opposition transfer

Uses Flexor digitorium superficialis or abductor digiti minimi

 

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9

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

Z plasty

see picture below

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10

How would you stabilise the MCPJ in thumb hypoplasia?

3 options:

Fusion

Reconstruction of UCL with FDS

Reconstruction of UCL with Free tendon graft

 

11

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

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12

What is congenital trigger thumb?

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

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13

What is the epidemiology of trigger thumb?

Prevalence is 3 per 1,000 children at 1 year

 

14

What is the pathology of congenital trigger thumb?

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

15

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)

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16

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

Operative

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

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17

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

18

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
19

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

20

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