Children's Orthopaedics Flashcards
How many bones are found within a paediatric skeleton?
- 270 bones
Which regions of a paediatric skeleton is associated with growth post-natally?
- Epiphyseal growth plates
Which bones are formed from intramembranous bone development?
- Flat bones
What are the examples of flat bones (3)?
- Facial bones
- Mandible
- Medial part of the clavicle
Outline the steps of intramembranous ossification (4 steps).
- Condensation of mesenchymal cells which differentiate into osteoblasts → Ossification centre forms
- Secreted osteoid traps osteoblasts which become osteocytes
-
Trabecular matrix and periosteum form
- Angiogenesis occurs and blood vessels are incorporated between woven bone)
- Compact bone develops superficial to cancellous. Crowded blood vessels condense into red bone marrow.
Which bones are associated with endochondral ossification?
- Long bones
Where does long bone formation occur?
- At primary & secondary ossification centres
What is the primary ossification centre?
- Sites of pre-natal bone growth through endochondral ossification from the central part of the bone
What are the secondary ossification centre?
- Occurs post-natally after the primary ossification centre (long bones often have several)
Outline the steps of endochondral primary ossification (5 steps).
- Mesenchymal differentiation at the primary centre
- The cartilage model of the future bony skeleton forms
- Capillaries penetrate cartilage → calcification at the primary ossification centre → spongy bone forms → perichondrium transforms into periosteum
- Cartilage and chondrocytes continue to grow at ends of the bone
- Secondary ossification centres develop with its own blood vessel and calcification at the proximal and distal end
What happens at endochondral secondary ossification?
-
Post bone growth occurs, at the physis
- Long bone lengthening occurs at the physeal plate, containing cartilage (proliferation of chondrocytes and subsequent calcification of the extracellular matrix into immature bone that is subsequently remodelled)
What happens at the epiphyseal side during long bone lengthening?
- Hyaline cartilage active and dividing to form hyaline cartilage matrix
What happens at the diaphysial side of bone during long bone lengthening?
- Cartilage calcifies and necroses - replacement by bone
What is the main difference between adult and paediatric skeleton (3)?
- Elasticity
- Physis
- Speed of Healing & remodelling
Where does continuous endochondral ossification happen?
- At secondary ossification centre
Compare the speed of healing in an paediatric skeleton compared to that of the adult.
- The speed of healing is faster in a child
Why is paediatric bone more elastic than adult bone?
- Has an increased density of Haversian canals
Why does plastic deformities occur within paediatric bone?
- The energy is dissipated in altering the structure of the bone - (bending prior to fracture)
What is a buckle fracture?
- The bone buckles forming a torus-column prior to fracturing (2nd bone in picture)
What is a stable fracture?
- Bone fragments have not separated
What is a greenstick fracture?
- One cortex fracture, however the other side remains intact (is bent) (3rd bone in picture)
When does gradual physeal closure occur in females?
- Menarche
When does physeal closure occur in girls?
- 15-16
When does physeal closure occur in boys?
- 18-19
What classification is used to assess physeal injuries?
- Salter-Harris Classification
What can physeal injuries lead to?
significant trauma can elicit growth arrest
What happens in patients with a partial arrest of bone growth?
- Can manifest as deformities due to inconsistencies in bone growth between affected and non-affected areas
What factors does the speed of healing and remodelling potential are dependant on (2)?
- Location
- Age of patient
Which bones within the skeleton exhibits faster growth rates?
- Distal femur & proximal tibia (knee) exhibits faster growth rates as opposed to the proximal femur (hip) or ankle
- upper limb extremes (shoulder and wrist) grow faster than elbow
Why does the humerus tolerate angulation and deformity?
- Due to spontaneous rate of repair & remodelling potential or paediatric bone
What are the 4 common congenital conditions of bone growth?
- Developmental dysplasia of the hip
- Club foot
- Achondroplasia
- Osteogeneis imperfecta
What is developmental dysplasia of the hip?
- Group of disorders of the neonatal hip where the head of the femur is unstable or incongruous in relation to the acetabulum
- ‘Packaging disorder’
What does the normal development of the hip rely on?
- The normal development relies on the concentric reduction and balanced forces through the hip
- The hip needs to reside within the acetabulum (normal forces through the join)
How common is hip dysplasia?
- 2:100
How common is hip dislocation?
- 2:1000
Why does hip dysplasia occur?
- Abnormal pressure through the acetabulum and hip dysplasia (not centrally placed within the socket)
What are the risk factors of developmental dysplasia (6)?
- Female
- First born
- Breech
- Family history
- Oligohydraminos
- Native American / Laplanders
What is oligohydraminos?
- Insufficient fluid within the amniotic sac reducing the hydrodynamics and pressure exerted onto the developing foetus in utero
Which ethnicities are associated with developmental dysplasia of the hip?
- Native American / Laplanders
How is developmental dysplasia of the hip diagnosed?
- Usually picked up on baby check - screening in the UK
- USS birth to 4/12
What are the movements of the developmental dysplasia?
- Range of motion of hip
- Usually limitation in hip abduction
- Leg length (Galeazzi)
What investigations are conducted in patients with developmental dysplasia (2)?
- Ultrasound - birth to 4 months
- After 4 months - X-ray
Why is an X-ray non-beneficial in patients with development dysplasia within the first 4 months?
- The secondary ossification centres of hip have no yet ossified
What is the treatment for neonates with developmental dysplasia of the hip?
-
Reducible hip and < 6 months
- Pavlik harness
What is an abduction strap?
- Maintains the abduction position of the hip joint such that the head of femur is held in the acetabulum, therefore, during development the concentric pressures through the joint an support normal growth
What are the alternative treatments to dysplasia of the hip?
- MUA + Closed reduction + Spica
What is congenital talipes equinovarus (clubfoot)?
- There is congenital deformity of the foot
Congenital deformities of the foot are common in what demographic?
- Hawaiian
- M 2:1 F
Which gene is implicated in congenital talipes equinovarus?
- PITX1 gene
What does CAVE deformity due to muscular contracture stand for?
- Cavus – High arch: Tight intrinsic, flexor hallucis longus, flexor digitorum longus
- Adductus of foot: Tight posterior and anterior tibialis
- Varus: Tight Tendoachilles, tib post, tip ant
- Equinous: Tight Tendoachilles
What is cavus?
-
High arch
- Tight intrinsic, flexor hallucis longus, flexor digitorum longus
What is the treatment for club deformity?
- Ponseti method (Gold standard)
What is the Ponseti method (4 steps)?
- First a series of casts to correct deformity
- Many require operative treatment – soft tissue release
- Foot orthosis brace (Sufficient to treat the deformity)
- Some will require further operative intervention to correct final deformity
What is achondroplasia?
- Skeletal dysplasia that is characterised by an autosomal dominant condition
Which gene is implicated in achodnroplasia?
- G380 mutation of FGFR3
Why does achondroplasia occur?
-
Inhibition of chondrocyte proliferation in the proliferative zone of the physis
- Results in defect in endochondral bone formation
What is rhizomelic dwarfism (4 charactersitics)?
- Humerus shorter than the forearm
- Femur shorter than tibia
- Normal trunk
- Normal cognitive development + significant spinal issues
What is osteogenesis imperfecta?
- Brittle bone disease
What is the inheritance pattern of osteogenesis imperfecta?
- Autosomal dominant or recessive
Which type of collagen is decreased in osteogenesis imperfecta?
-
Decreased type I collagen due to decreased secretion and production of abnormal collagen
- There is insufficient osteoid production
What are the bone effects of osteogenesis imperfecta (3)?
- Fragility fracture
- Short stature
- Scoliosis
What are the non-orthopaedic manifestations of osteogenesis imperfecta (5)?
- Heart
- Blue sclera
- Dentiogenesis imperfecta - brown soft tissue
- Wormian skull
- Hypermetabolism - affecting the parathyroid pathway
What classification is used for paediatric fractures (4 + 1)?
- Pattern
- Anatomy
- Intra/extra-articular
- Displacement
- Salter-Harris Classification for those affecting the physis
What is an avulsion type fracture?
- When a bone is being pulled by a ligament
What is secondary bone healing characterised by?
- Callus formation
What is primary bone healing characterised by?
- By direct union, there is no associated callus formation
What is the preferred healing pathway for intra-articular fractures?
- Primary bone healing
What is a shortened fracture?
- The fracture gap is minimised due to overlap
When is displacement optimised in a paediatric fracture?
- In the best angle of function (remodelling does not occur in a rotated fracture)
What is the SALT classification of physeal injuries?
- Physeal separation
- Fracture transverse physis and exits metaphysis (Above)
- Fracture transverse physis and exits epiphysis (Lower)
- Fracture passes Through epiphysis, physis, metaphysis
- Crush injury to physis
Which type of SALT fracture is most common?
- Type 2
What happens to the risk of growth arrest between SALT type 1 and type V fractures?
- Risk increases with type
What happens in a whole physis growth arrest?
- Limb length discrepancy
What happens in a partial growth arrest?
- Angulation as the non-affected side keep growing
What happens during an injury at a period near to physeal closure?
- There is a small degree of potential growth left
- Therefore, the impact of growth arrest on the individual is less
What are the 2 aims of treating growth arrest?
- Limb length correction
- Minimise angular deformity
How is limb length correction performed?
- Shorten the long side
OR
- Lengthen the long side
What are the 2 methods to which angular deformity is corrected (to shorten the longer side)?
- Stop the growth of the unaffected side
- Reform the bone (osteotomy)
How can growth arrest fractures be treated using cross-screws?
- Prematurely fused the physis, the shorten the unaffected side
Which device can be used to lengthen the short side of a limb?
- Intramedullary device
What is the first step to fracture management after resuscitation?
- Reduce - correct the deformity and displacement
What is closed reduction?
- Reducing a fracture without making an incision (Traction and manipulation)
What is open reduction?
- Make an incision, and the realignment of the fracture under direct visualisation (Open reduction and internal fixation (ORIF))
What is Gallows Traction (Closed)?
- Holding the skin, the long bones of the lower limb can be reduced
- Manipulation Under Anesthesia (MUA)
What are the risks of healing in paediatric populations (2)?
- Overgrowth and excessing healing
What is a spica cast?
- Holds the lower limb in place
What is external restriction?
- Splints and plasters
Why can an ORIF be avoided in a paediatric fracture?
- Due to remodelling and healing potential
What is internal restriction?
- Using plates and screws
- Intra-medullary devices
Why may operative restriction be required?
- Operative intervention maybe required due to fracture affecting the physis (correct the deformity to avoid further trauma)
What is recommended during the rehabilitation phase of a patient paediatric fracture?
- Playing
What is classified as an orthopaedic emergency in a paediatric patient presenting with a fracture?
- Septic arthritis
What is septic arthritis in a paediatric patient?
- Presence of infection within the intra-articular space / synovium
- Necrotic effect is exhibited by proteases and generates pressure effect on chondrocyets and cartilage due to oedema within closed space
Why is there a risk of necrosis within septic arthritis?
- Proteases generate pressure effect on chondryocytes and cartilage due to oedema within a closed space
What classification criteria is used in a patient with septic arthritis?
- Kocher’s classification
What is Kocher’s classification?
- Non-weight bearing
- ESR > 40
- WBC > 12,000
- Temperature > 38 oC
What is the treatment of septic arthritis in a paediatric patient?
- Surgical lavage is required in order to clear the infection, in addition to antibiotic treatment
How can transient synovitis be diagnosed?
- Once septic arthritis has been excluded
- Inflamed joint response to a systemic illness
What is Perthe’s disease? What is its demographic (2)? What needs to be excluded first? What symptoms are absent (2)? What is the diagnostic test?
- Idiopathic necrosis of the proximal femoral epiphysis
- Demographic:
- Usually in 4-8 years olds
- Male 4:1 Female
- Septic arthritis needs to be excluded first
- No hyperpyrexia or raised inflammatory markers
- Radiograph is diagnostic test
What is the treatment for slipped under femoral epiphysis (SUFE) disease?
- The proximal epiphysis slips in relation to the metaphysis
- Treatment is operative fixation with screw to prevent further slippage
