Children's Orthopaedics Flashcards
How many bones does a Child’s skeleton have?
A child’s skeleton has 270 bones and is a system that is in continuous change
What are the physics?
The physis (growth plates) are the areas from which long bone growth occurs post-natally
How do flat bones develop?
Intramembranous
Mesenchymal cells»bone
How do long bones develop?
Endochondral
Mesenchymal»cartilage»bone
Describe Intramembraneous Ossification
4 key stages
In intramembranousossification, a group of mesenchymal cells in the central ossification centres differentiate first into preosteoblasts and then intoosteoblasts.
These cells synthesize and secreteosteoidand the osteoblasts further differentiate into osteoclasts
These cells then collectively create the immature woven trabecular matrix and immature periosteium.
Angiogenesis occurs and Blood vessels incorporated between the woven bonetrabeculaewill form the future bone marrow.
Later, the woven bone is remodeled and is progressively replaced by mature lamellar bone.
What happens during Endochondrial Ossification?
At both the primary and secondary ossification centres
Primary Ossification Centres
Sites of pre-natal bone growth through endochondral ossification from the central part of the bone
Secondary Ossification Centres:
Occurs post-natal after the primary ossification centre and long bones often have several (the physis)
TISSUE that will become bone is firstly formed from cartilage.
What happens during Primary endochondral ossification?
a) Mesenchymal Differentiation at the primary centre
b) The cartilage model of the future bony skeleton forms
c) Capillaries penetrate cartilage.
Calcification at the primary ossification centre – spongy bone forms
Perichondrium transforms into periosteum
d) Cartilage and chondrocytes continue to grow at ends of the bone
e) Secondary ossification centres develop with its own blood vessel and calcification at the proximal and distal end – calcification of the matrix
f) Cartilage remains at epiphyseal (growth) plate and at joint surface as articular cartilage.
Where does primary endochondral ossification take place?
The first site of ossification occurs in the primary center of ossification, which is in the middle ofdiaphysis of the bone - prenatal
What happens in secondary endochondral ossification?
Long bone lengthening
Happens at the physis (physeal plate)
Zone of elongation in long bone
Contains cartilage
Epiphyseal side – hyaline cartilage active and dividing to form hyaline cartilage matrix
Diaphyseal side – Cartilage calcifies and dies and then replaced by bone
How do children bones differ in elasticity?
Children’s bone can bend – more elastic than adult
Increased density of haversian canals
What does increased elasticity lead to
Plastic deformity
– bends before breaks
Buckle fracture
– Tarus like the column
Greenstick
– like the tree
One cortex fractures but does not break the other side
What happened at the Physis?
Growth occurs at varying rates at varying sites
Growth stops as the physis closes
Gradual Physeal closure, Puberty, Menarche, Parental height
Complete at
Girls 15-16
Boys 18-19
What do Physical injuries lead to?
Growth arrest
Can lead to deformity
What is speed and remodelling dependent on?
The speed of healing and remodeling potential is dependent on the location and the age of the patient
Younger child heals more quickly
Physis at the knee grows more
Physis at extreme of upper limb grows more
What are some common Children’s congenital conditions?
Developmental Dysplasia of the Hip
Club Foot
Achondroplasia
Osteogenesis Imperfecta
What happens in Developmental Dysplasia of the Hip?
Group of disorder of the neonatal hip where the head of the femur is unstable or incongruous in relation to the acetabulum.
A ‘Packaging Disorder’
The normal development relies on the concentric reduction and balanced forces through the hip
Spectrum with dysplasia – subluxation – dislocation
What are the risk factors for Developmental Dysplasia of the Hip?
Dysplasia 2: 100
Dislocation 2:1000
Risk Factors Female 6:1 First born Breech FH Oligohydramnios Native American/Laplanders – swaddling of hip Rare in African American/Asian
What are the examinations for Developmental Dysplasia of the Hip?
Usually picked up on baby check – screening in UK
RoM of hip
Usually limitation in hip abduction
Leg length (Galeazzi)
In those 3 months or older Barlow and Ortalani are non-sensitive
What are the investigations for Developmental Dysplasia of the Hip?
Ultrasound – birth to 4 months
After 4 months X-ray
If prior to 6 weeks needs to be age adjusted
Measures the acetabular dysplasia and the position of hip
What is the treatment for Developmental dysplasia of the hip?
Reducible hip and <6 months
Pavlik harness 92% effective
Failed Pavlik Harness or 6-18 months
Secondary changes- capsule + soft tissue
MUA + Closed reduction and Spica
What is Clubfoot?
Congenital Talipes Equinovirus Congenital deformity of the foot 1:1000 Highest in Hawaiians M2:1F 50% are bilateral
Genetic
Approx. 5% likely of siblings
Familial in 25%
PITX1 gene
What is CAVE in clubfoot?
CAVE deformity due to muscle contracture
Cavus –high arch: tight intrinsic, FHL, FDL
Adductus of foot: Tight tib post and ant
Varus: Tight tendoachillies, tib post, tib ant
Equinous: tight tendoachilles
What is the treatment for clubfoot?
Ponseti Method
Gold standard
- First a series of casts to correct deformity
- Many require operative treatment
Soft tissue releases - Foot orthosis brace
- Some will require further operative intervention to correct final deformity.
What is Achondroplasia?
The most common skeletal dysplasia
Autosomal Dominant
G380 mutation ofFGFR3
inhibition of chondrocyte proliferation in theproliferative zoneof thephysis
results in defect in endochondral bone formation
