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