MSK - Children's orthopaedics Flashcards
What are the 2 types of bone development and which bones do they effect?
1) Intramembranous - Flat bones
2) Endochondrial - Long bones
How does intramembranous bone development occur?
- Mesenchymal cells differentiate into osteoblasts
- Secreted osteoid traps osteoblasts which become osteocytes
- These then form the woven trabecular matrix and periosteum form
- Then angiogenesis occurs and forms bone marrow
- Compact bone develops superficial to cancellous bone
What are primary ossification centres?
Sites of pre-natal bone growth through endochondral ossification from the central part of the bone
What are secondary ossification centres?
Post-natal growth after the primary ossification, long bones often have several
What is the process of primary endochondral bone growth?
- Mesenchymal cells differentiate at the bones centre
- The cartilage model of the future bony model forms
- Through angiogeneis, capillaries penetrate into the cartilage and cause calcification at the primary ossification centres (spongy bone forms)
- Cartilage continues to grow at the ends and form secondary ossification centres
In what 4 ways does a child’s skeleton differ to an adutls?
- Elasticity
- Speed of healing
- Remodeling
- Physis (growth at these)
Why are children’s bones more elastic than adults?
- They have an increased density of haversian canals
Why can growth arrest lead to deformity?
If one end of the bone stops growing but the other does not, it can create an imbalance and therefore a deformity
What is developmental dysplasia of the hip?
When the growth of the hip and acetabulum is effected due to the hip not sitting in the acetablulum centrally or is dislocated completely
How is developmental dysplasia of the hip treated?
- The baby is put in a harness to keep the head of the femur in the acetabulum and promote normal development in the child
- If discovered too late then surgery may be needed
How does congenital talipes equinovarus/clubfoot arise?
CAVE muscles contracture:
- Cavus - high arch
- Adductus of foot
- Varus - tight tendoachilles, tib post & ant
- Equinous - tight tendoachilles
How is clubfoot treated?
The baby’s foot is placed in several harnesses to gradually change the shape of the babies foot back to normal shape
What is achondroplasia?
Skeletal dysplasia which inhibits chondrocyte proliferation in physis
Leads to defect in endochondral bone formation - Dwarfism
What is osteogensis imperfecta (brittle bone disease)?
Decreased type 1 collagen -> insufficient osteoid production
What acronym is used to describe fractures?
PAID:
- Pattern (type of fracture)
- Anatomy (where the fracture is located)
- Intra/Extra articular
- Displacement (what has happened to the position of the two parts of broken bone relative to each other)
