Arthrogryposis Multiplex Congenita

Definition

 

AMC characterised by non progressive congenital rigidity of 2 or more joints

- Arthrogryposis means curved joint

- Arthrogryposis refers to 150 syndromes

 

Types

 

1.  Amyoplasia

- involves all 4 limbs

 

2.  Distal Arthrogryposis

- AD

- type 1 98% hand / 87% feet

- type 2 involve other systems

 

Epidemiology

 

1 in 3000 live births

-  hereditary pattern unknown

 

Aetiology

 

Fibrosis of periarticular soft tissues during joint development

- leads to development of incomplete fibrous ankylosis

- unknown cause

 

Numerous theories

- CNS abnormality / anterior horn cell 

- environmental factors - toxins / virus

- packaging defect

- oligohydramnios

- limitation of foetal movement

 

Pathology

 

Muscles replaced by fibrous tissue

Spinal cord decreases in size, especially at the limb enlargements

- decreased number of anterior horn cells

 

Clinical feature

 

Normal intelligence

 

Wooden doll facies

 

Usually involves all 4 limbs (AMC)

- joint contractures with webbing

 

Marked limitation of joint ROM

- no skin creases

- scant subcutaneous tissue & muscles

- skin tense & glossy

- ± dimpling at joints

 

Typical Deformities

 

UL

- shoulders adducted and IR

- elbows extended

- wrists flexed, pronated & UD

 

LL

- hips flexed, ER & abducted / dislocation

- knees flexed

 

Scoliosis

 

Also

- teratologic DDH

- teratologic CTEV

- congenital patella dislocation

 

Management

 

Goals

 

Achieve maximum function

Permit mobility / ability to transfer

Enable Feeding & hygiene

 

Principles

 

Lower limbs first

- plantigrade feet first

- extend knees

- reduced hips

 

Upper limbs

- ability to bring hand to mouth / elbow flexion

- ability to toilet & push off when rising with other hand

 

Timing

- correct all LL deformity by 2 years to allow walking

- address UL deformities later

- allows bimanual function to be established

- allows functional assessment

 

Algorithm

- full-time bracing until age 6

- night splints until skeletal maturity

- soft tissue procedures in young child

- bony procedures as approach skeletal maturity

 

Talipes Equinovarus

 

Infant

- rarely responds to bracing

- requires PMR before walking age

- AFO's required post-operatively until skeletal maturity

- failure be require talectomy

 

Older child

- triple arthrodesis is procedure of choice

 

Knee Flexion Contracture

 

Non-operative

- daily passive ROM

- serial casts

- night splints

- surgery for resistant cases

 

Operative

 

Surgical release 

- capsule

-  ± collaterals & cruciates

- hamstring lengthening

- serial casting post-op

 

Salvage

- supracondylar osteotomy near skeletal maturity

 

Hip Dislocation

 

Operative

 

Open reduction ± femoral shortening & derotation osteotomy

- age 1

- when knee FFD corrected

- accept situation if reduction not achieved by 2 years

- because of increased risk of unilateral failure with pelvic obliquity & scoliosis consider accepting if bilateral 

 

Hip Contractures

 

Issues

 

Hip FFD > 30°

- increases lumbar lordosis

- increases knee flexion contracture

- crouch gait

 

Non operative

- correction of knee contracture

- maintaining patient prone

 

Operative

- subtrochanteric osteotomy near skeletal maturity

 

Hand

 

Little to offer for severe deformity

 

Wrist flexion

 

1.  Hand stiff

 

Non operative

- pronated flexed wrist enables forearm radial borders to appose each other to produce pincer grip

 

2.  Hand functional

 

Treat FFD

- Gives same range of wrist movement, but in more functional position

 

A.  Dorsal closing wedge capitate / FCU transfer

B.  Carpectomy

C.  Wrist fusion

 

Shoulder Internal Rotation

 

Issue

 

Should be addressed before elbow corrected

 

Management

 

External rotation osteotomy in proximal shaft

 

Elbow Extension

 

Issue

 

Need one elbow bent & one straight

 

Operative

 

Options

- unilateral posterior capsulotomy & triceps transfer

- steindler flexorplasty

- pectoralis major bipolar transfer

 

Scoliosis

 

Brace may be successful

Often requires segmental fusion