Camptodactyly

MEM camp = bent tent

 

Definition

 

Greek for bent finger in sagittal plane

 

Usually little finger

 

Typical deformity is FFD of PIPJ & extension of MCPJ

 

Epidemiology

 

<1% of population

 

Strong familial predisposition

- 60% bilateral

- bimodal pattern

- present in infancy or adolescence

- 1 in 1000 live births

 

Aetiology 

 

Unknown

- not related to trauma, infection, NMD

- ? due to incomplete extensor mechanism

 

Usually due to imbalance of pull between flexor & extensor mechanisms

- contracture of collaterals 

- secondary abnormality PIPJ common

- usually base of P2 is subluxed volar to head P1

 

Most commonly accepted theory 

- an anomalous insertion of the lumbrical muscle into the flexor sheath causes the abnormality

 

Multiple causes reported

- aberrant lumbrical insertion 

- flexor sheath contracture

- phalangeal head deformity

- FDS contracture

- abnormal extensor tendon mechanism

 

Classification

 

1. Infantile

2. Adolescent

3. Severe form affecting all triphalangeal digits

 

DDx

 

Traumatic boutonnière deformity

 

Juvenile aponeurotic fibromatosis 

- involves palmar fascia & skin

- increased flexion deformity

 

NHx 

 

80% progress

- progress during growth spurts

 

Doesn't progress after maturity

 

Clinical Features

 

85% present at birth

15% present in adolescence

 

Volar skin may bowstring

- can be mild to severe FFD

- functional compromise when FFD ->90o

 

Fixed v flexible

 

Xray

 

Head of P1 has bullet shape

PIPJ is subluxed

 

Management

 

Non-operative

 

Usual treatment

- watch to see if deformity progresses especially at growth spurts

- some studies show that splinting does work if 24 hours per day

- other studies without 24 hours splinting show not much difference

- passive stretching & static & dynamic splinting

 

No series has shown surgical release does better than well motivated and controlled regimen of flexion and extension splinting

 

Operative

 

Indications

 

Progressive deformity

Failure of non-operative management

> 60° & functional disability

 

Poor outcomes especially loss of flexion

- some series report only 35% success rate

 

Technique

 

Fixed

- release all tight volar structures

- skin / FDS / volar plate / capsule

- +/- FDS transfer to the extensor hood

 

Skeletally mature

- extension osteotomy / dorsal closing wedge

- must avoid excess straightening -> stretch nv bundle 

 

Do not perform release and simultaneous transfers as need to mobilise immediately post-operatively