childrens orthopaedics Flashcards
how many bones does a child skeleton have
270
is a system that is a continuous change
how are flat bones e.g cranial/clavicle bones formed
intramembranous
mesenchymal cells -> bones
how are long bones formed
endochondral
mesenchymal -> cartilage -> bone
what happens in intramembranous ossification
condensation of mesenchymal cells which differentiate to osteoblasts
these secrete osteoids which trap osteoblasts becoming osteocytes
trabecular matrix and periosteum form
compact bone develops superficial to cancellous bone
crowded blood vessels condense into red bone marrow
where does endochondral ossification occur
1.primary ossification centres- sites of pre natal bone growth through endochondral ossification from central part of bone
2.secondary - occurs post natal after primary ossification centre
long bones often have several. (physis)
what are some primary ossification centres
middle of diaphysis
or shaft of bone
occurs in prenatal period
describe primary ossification
mesenchymal differentiation of primary centre
cartilage model of bony skeleton forms
capillaries penetrate cartilage
calcification - spongy bone forms
cartilage and chondrocytes continue to form end of bone
secondary ossification centres form
describe secondary ossification
happens at physis
proliferation of chondrocytes and calcification of cartilage which dies and is replaced by bone
why can childrens bone bend more
increased elasticity
increased density of haversian canals
what can an increased elasticity in childrens bones cause
- plastic deformity - bends before breaks
- buckle fracture -
- greenstick - like tree, one cortex fractures but does not break other side
when does growth stop in children
when physis closes
depends on gradual physeal closure, puberty, menarche, parental height
what can physeal injuries lead to
growth arrest
which can form deformities
what is the speed and remodelling potential dependent on
location
and age of patient
younger child heals more quickly
what is developmental dysplasia of hip
group of disorders of neonatal hip where head of femur is unstable/incongruous in relation to acetabulum
e.g. subluxation, dislocation, dysplasia
what are some risk factors for developmental dysplasia of hip
female 6:1
first born
fh
oligohydramnios
how to examine for developmental dysplasia of hip
usually picked up on baby check - screening in uk
range of motion of hip
what would you see in the examination of baby with ddh
usually limitation in hip abduction
leg length - galeazzi
in those 3mnths+ barlow and ortalani are non-sensitive
what are the investigations for developmental dysplasia of hip
ultrasound - effective and sensitive from 0-4mnths
measures acetabular dysplasia and position of hip
what is the treatment of ddh
reducible hip for <6mnths
pavlik harness is 92% effective
if failed pavlik harness/6-18mnths
mua and closed reduction and spica
what is congenital talipes equinovarus
congenital deformity of foot
highest in hawaiians
50% are bilateral
genetic - pitx1 gene
what are the features of congenital talipes equinovarus
cave deformity due to muscle contracture cavus - high arch, tight intrinsic muscles adductus of foot varus - tight tendoachillies, equinous - tight tendoachilles clubfoot
treatment for clubfoot
ponseti method - gold standard
- series of casts to correct deformity
- many require operative treatment usually in form of soft tissue release
- foot orthosis brace
- some require further operative intervention
what is achondroplasia
most common skeletal dysplasia
autosomal dominant - g380 mutation of fgfr3
inhibition of chondrocyte proliferation in proliferative zone of physis
- results in defect in endochondral bone formation
what is rhizomelic dwarfism
humerus shorter than forearm
femur shorter than tibia
normal trunk
