Children's Orthopaedics Flashcards
What are physis?
growth plates - areas from which long bone growth occurs post-natally
What are the 2 different types of bone development?
- intramembranous
- endochondral
What is formed by intramembranous bone development?
flat bones
What is formed by endochondral bone development?
long bones
What is intramembranous ossification?
- condesation of mesenchymal cells that differentiate into osteoblasts, forming the ossification centre
- secreted osteoid traps osteoblasts which become 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?
primary and secondary ossification centres
What is primary ossification centres?
sites of pre-natal bone growth through endochondral ossification from the central part of the bone
What is secondary ossification centres?
occurs post-natal after the primary ossification centre and long bones often have several (the physis)
What happens in primary endochondral ossification?
- mesenchymal differentation at the primary centre
- the cartilage model of the future bony skeleton
- capillaries penetrate cartilage
- calcification at the POC forms spongy bone
- perichondrium transforms into periosteum
- cartilage and chondrocytes continue to grow at the ends of the bone
- secondary ossification centres develop
What is the difference between intramembranous and endochondral ossification?
in endochondral, the tissue that becomes bone is cartilage first
What happens in secondary endochondral ossification?
- at physis
- zone of elongation in long bone
- containsn cartilage
- epiphyseal side: hyaline cartilage active and dividing to form hyaline catrilage matrix
- diphyseal side: cartilage calcifies and dies and is then replaces by bone
How do children skeletons differ from adults?
- bone is elastic
- presence of physis
- increased speed of healing
- remodelling potential
Why are children’s bones more elastic than an adult?
increased density of haversian canals
What is the impact of the increased elasticity of bones?
- plastic deformity (bends before it breaks)
- buckle fracture (tarus like the column)
- greenstick (one cortex fractures but other side does not break)
When does growth stop?
when physis close
What impacts when physis close?
- gradual physeal closure
- puberty
- menarche
- parental height
When do physis typically close?
girls: 15-16
boys: 18-19
What is used to characterise physeal injuries?
the Salter-Harris
What is the possible impact of physeal injury?
- growth arrest
- eventual deformity
What is the speed of healing and remodelling dependent on?
location of injury
age of patient
What are common congenital conditions?
- dysplasia of the hip
- club foot
- achondroplasia
- osteogenesis imperfecta
What is developmental dysplasia of the hip?
a group of disorders of the neonatal hip where the head of the femur is unstable or incongruous in relation to the acetabulum
What is the spectrum of developmental dysplasia of the hip?
- dysphasia (2/100)
- subluxation
- dislocation (2/1000)
What are the risk factors of developmental dysplasia of the hip?
- female
- first born
- breech
- family Hx
- oligohyraminos
- native american/laplanders (hip swaddling)
- rare in african american/asian
What examinations are done for developmental dysplasia of the hip?
usually seen on baby check
- RoM of hip (limited hip abduction)
What investigations are done for developmental dysplasia of the hip?
- US (birth-4months)
- after 4 months - XR
- measures the acetabular dysplasia and the position of the hip
What treatments are there for developmental dysplasia of the hip?
if: reducible hip and <6 months
- Palvik harness (92%)
if failed Plavik harness or 6-18 months:
- secondary changes: capsule + soft tissue
- MUA + closed reduction and spica
What is clubfoot?
CAVE deformity due to muscle
Cavus - high arch, tight intrinsic RHL, FDL
Adductus of foot - tight tib posterior and anterior
Varus: tight tendoachillies, tib post, tib ant
Equinous: tight tendoachilles
What is the risk factors associated with clubfoot?
- males
- hawaiians
- genetic (PITX1 gene)
What is the gold standard treatment of clubfoot?
Ponseti menthod
- series of casts to correct deformity
- many require operative treatment (soft tissue releases)
- foot orthosis brace
- some with require a further operative intervention
What is Achondroplasia?
- G380 mutation of FGFR3 (autosomal dominant)
- inhibition of chondrocyte proliferation in the proliferative zone of the physis
- results in defect in endochondral bone formation
What is the resulting impact of Achondroplasia?
Rhizomelic dwarfism
- humerus shorter than forearm
- femur shorter than tibia
- normal trunk
- adult height: 125cm
- normal cognitive development
- significant spinal issues
What is osteogenesis imperfecta?
- hereditary (autosomal dominant or recessive)
- decreased Type 1 collagen due to: decreased secretion, abnormal collagen production
- insufficient osteoid production
What is the impact of osteogenesis imperfecta?
bones: - fragility fractures - short stature - scoliosis non-bones: - heart - blue sclera - dentinogenesis imperfeccta (soft, brown teeth) - wormian skull - hypermetabolism
How do you describe a pediatric fracture?
- pattern
- anatomy
- intra-extra articular
- displacement
- salter-harris
What are the possible fracture patterns?
- transverse
- oblique
- comminuted
- spiral
- avulsion (pulled off by a ligament)
- greenstick
- buckle
- plastic deformity
What is the possible anatomy of paediatric fractures?
- distal 1/3
- middle 1/3 diaphysis
- proximal 1/3
What is primary bone healing?
- heals by direct union
- no callus formation
When is primary bone healing preferred?
in intra-articular fractures to minimise the risk of post traumatic arthritis
What is secondary bone healing?
- hematoma formation
- fibrocartilaginous callus formation
- bony callus formation
- bone remodelling
What are the different possible displacements of a fracture?
- displaced
- angulated
- shortened
- rotated
What form of displacement is not handled well for remodelling?
rotation
What is the Salter-Harris classification?
classification of physeal injury
What is a Slater-Harris Type 1 injury?
physeal seperation
What is a Slater-Harris Type 2 injury?
fracture transverses physis and exits metaphysis (above, towards middle of bone)
What is a Slater-Harris Type 3 injury?
fracture transverses physis and exits epiphysis (below, towards end of bone)
What is a Slater-Harris Type 4 injury?
fracture passes through the epiphysis, physis and metaphysis
What is a Slater-Harris Type 5 injury?
crush injury to physis
How does Salter-Harris classification relate to the risk of growth arrest?
the risk of growth arrest increases from 1-5
What type of Salter-Harris injury is most common?
Type 2
What can injury to the whole physis cause?
limb length discrepency
What can injury to the partial physis cause?
angulation as the non-affected side continues to grow
What is the impact of physis injury dependent on?
- location
- time of injury (how much growth left?)
What is the aim when treating growth arrest?
correct the deformity
- minimise angular deformity
- minimise limb length difference
How is limb length correction done?
- shorten the long side
- lengthen the short side
How is angular deformity correction done?
- stop the growth of the unaffected side
- reform the bone (osteotomy)
What are the principles of fracture management?
- resuscitate
- reduce
- restrict
- rehabilitate
What is the aim of reducing a fracture?
- correct the deformity
and displacement - reduce secondary injury to soft tissue/neurovascular structures
What is the aim of restricting a fracture?
- maintain the fracture reduction
- provides the stability for the fracture to heal
What is the implication of the remodelling and huge healing potential?
that operative internal fixation often can be avoided
What form of rehabilitation is recommended for children?
- play
- stiffness not as big of a concern
- children rehabilitate much quicker
- move, use and strengthen
What are the differentials of a limping child?
- septic arthritis
- transient synovitis
- Perthes
- SUFE
What is septic arthritis?
an infection in the inter-articular space
What is result of septic arthritis?
can cause irreversible LT problems
What is used to assess the probability of a child having septic arthritis?
Kocher’s classification:
- non-weight bearing
- ESR>40
- WBC>12,000
- temperature >38
What is needed to clear the infection causing septic arthritis?
a surgical washout of the joint
What Hx needs to be taken when septic arthritis is suspected?
- duration
- other recent illness
- associated joint pain
What is transient synovitis?
- a diagnosis after septic arthritis has been excluded
- an inflamed joint in response to systemic illness
What is the treatment of transient synovitis?
supportive treatment with ABx
How can septic arthritis cause long term joint problems?
- necrotic effect of proteases in the joint itself
- pressure effect on the chondrocytes and the cartilages that comes from the oedema in a closed space
What symptoms are associated with septic arthritis?
- joint pain
- rashes
- diarrhoea
- vomiting
What is Perthes disease?
Idiopathic necrosis of the proximal femoral epiphysis
What is the risk factors of Perthes disease?
- 4-8 years old
- more so in males
How can you differentiate septic arthritis and Perthes disease?
- no temperature and inflammatory markers in Perthes
- Perthes tends to have a longer onset
What must be done in order to diagnose Perthes disease?
- exclude septic arthritis
- plain film radiograph
What is the treatment of Perthes disease?
supportive
What is SUFE?
- slipped upper femoral epiphysis
- the proximal epiphysis slips in relation to the metaphysis
When is SUFE commonly seen?
- obese, adolescent male
- 12-13 years old
- hypothyroidism/hypopituitrism
What needs to be done before a diagnosing SUFE?
exclude septic arthritis
What is the treatment for SUFE?
operative fixation with a screw to prevent further slip and minimise LT growth problems
