children's orthopaedics Flashcards
how does the children’s skeleton differ from that of an adult?
The paediatric skeleton and musculoskeletal system is NOT a miniaturised version of an adult
A child’s skeleton has 270 bones (206 in adults) and is a system that is in continuous change
The physis (growth plates) are the areas from which long bone growth occurs post-natally
what are the different types of bone development?
intramembranous:
mesenchymal cells
->
bone
used for flat bones
endochondral: mesencymal cells -> cartilage -> bone
used for long bones
what Is the process of intramembranous ossification?
eg. in clavicle and skull
condensation of mesenchymal cells which differentiate into osteoblasts - ossification centre forms
->
secreted osteoid traps osteoblasts which become osteocytes
->
trabecular matrix and periosteum forms
->
compact bone forms superficial to cancellous bone. crowded blood vessels condense into red bone marrow
->
immature woven bone is remodelled and replaced by lemellar bone
what is the process of endochondral ossification?
All other long bone formation
- 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)
what happens in the pre-natal part of endochondral ossification (in primary ossification centres)?
During endochondral ossification, the tissue that will become bone is firstly formed from cartilage
The first site of ossification occurs in the primary center of ossification, which is in the middle ofdiaphysis of the bone - prenatal
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.
these become the secondary ossification sites
what happens In the secondary ossification centre part of endochondral ossification?
Post bone growth through Secondary ossification centres
“The Physis’
This is again by the proliferation of chondrocytes and the subsequent calcification of the extracellular matrix into immature bone that is then subsequently remodelled.
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
what are the main ways in that the Childs skeleton differs from that of an adults?
elasticity:
children’s bones are more elastic
physis:
growth happens at the physes, adult bones don’t grow
speed of healing:
much faster
remodelling:
the amount of deformity that can be corrected is greater in children
how is bone elasticity different in children to adults?
Children’s bone can bend – more elastic than adult
children have an Increased density of haversian canals (more of them)
Therefore you can get:
Plastic deformity
– bends before breaks
Buckle fracture
– Torus like the column
Greenstick
– like the tree
One cortex fractures but does not break the other side
how is physis different in children than adults?
Growth occurs at varying rates at varying sites
Growth stops as the physis closes
Gradual Physeal closure, depends on, Puberty, Menarche, Parental height
Complete a:
Girls 15-16
Boys 18-19
Physeal injuries are catgorised by Salter-Harris
Physeal injuries can lead to growth arrest
Growth arrest can lead to deformity
how does the speed of healing and remodelling differ from children to adults?
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
the faster a bit grows (knee, shoulder, wrist) the faster healing, and the more remodelling potential
what are some common children’s congenital bone conditions?
developmental dysplasia of the hip
club foot
achondroplasia
osteogenesis imperfecta
what is 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 - hips is on socket but not quite right, so socket doesn’t form a nice cup
subluxation - hip in socket, but socket is shallow so hip pops in and out
dislocation - hip isn’t in socket at all, so acetabulum is very shallow
Dysplasia 2: 100
Dislocation 2:1000
risk factors: Female 6:1 First born Breech FH Oligohydramnios Native American/Laplanders – swaddling of hip Rare in AfricanAmerican/Asian
what examination and investigations are done for developmental dysplasia of the hip?
examination:
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
investigations:
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 club foot?
Congenital Talipes Equinovarus
Congenital deformity of the foot occurs 1:1000 people Highest in Hawaiians M2:1F 50% are bilateral
Genetic:
Approx. 5% likely of siblings
Familial in 25%
PITX1 gene
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 club foot?
Treatment:
Ponseti Method
Gold standard
- First a series of casts to correct deformity
- Many require operative treatment
Soft tissue releases - Foot orthosis brace (looks like snowboard)
- 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
Rhizomelic dwarfism: Humerus shorter than forearm Femur shorter than tibia Normal trunk size Adult height of approx. 125cm
Normal cognitive development
Significant spinal issues
what is osteogenesis imperfecta?
Osteogenesis Imperfecta
Brittle bone disease
Hereditary – autosomal dominant or recessive
Decreased Type I Collagen due to:
Decreased secretion
Production of abnormal collagen
-> Insufficient osteoid production
Effects: Bones - Fragility fractures in some Short stature Scoliosis
Non-orthopaedic manifestations- Heart Blue Sclera Dentinogenesis imperfecta – brown soft teeth Wormian skull Hypermetabolism
how do we describe paediatric fractures?
same as adults
PAID Pattern Anatomy Intra/extra-articular Displacement
salter-harris - whether it effects the physis or not
what are possible patters on fractures in children?
same as adults?
transverse oblique spiral comminuted avulsion (chunk of bone pulled off by its ligamentous attachment)
but unlike adults you can also get greenstick fractures or torus fractures
due to the increased elacticity
what are the possible anatomical points for a fracture?
name the bone
then it is split into the proximal 1/3
middle 1/3
distal 1/3
proximal and distal contain the phases
what does intra and extra articular mean?
primary bone healing:
heals by direct union
no callus formation
is the the preferred healing pathway in intra-articular fractures it minimises the risk of post traumatic arthritis
secondary bone healing:
bone healing by callus
what are the possible displacements of fractures?
displaced
angulated
shortened
rotated
the improved remodelling potential in children means that there is more leeway with the extent of displacement
but remodelling can’t really happen with rotation
what is the salter-harris classification?
Salter-Harris
Classification of physeal injuries (SALT)
- physeal Separation
- Fracture traverses physis and exits metaphysis (Above)
- Fracture traverses physis and exits epiphysis (Lower) (end of bone)
- Fracture passes Through epiphysis, physis, metaphysis
- Crush injury to physis (uncommon)
Risk of growth arrest increases from 1 -5
Type 2 injuries most common
