- Multinucleated giant cells - Attach to bone by integrins (decreases acidity, proteolytic digestion) - Specific receptors for calcitonin (helps regulate resorption)

- Bone remodeling - Decreased stress = decreased density - Piezoelectric charges (compression which stimulates osteoblasts, tensile which stimulates osteoclasts)

Ortho Splinting Flashcards by Megan MacNabb

What are osteoblasts derived from?

Mesenchymal cells

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What do osteoblasts produce?

Osteocalcin (which needs Vit D)

- Type I collagen

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Osteoblasts are affected by:

ILs
Platelet derived growth factor
Insulin derived growth factor

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Describe osteoclasts

Multinucleated giant cells
Attach to bone by integrins (decreases acidity, proteolytic digestion)
Specific receptors for calcitonin (helps regulate resorption)

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What do osteoclasts originate from?

Hematopoetic tissue (monocyte progenitors)

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What is organic bone matrix composed of?

Collagen (90% of organic matrix, tensile strength)
Proteoglycans (inhibit mineralization, partially responsible for compressive strength)
Non-collagenous proteins (osteocalcin, osteonectin, osteopontin)

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What is inorganic bone matrix composed of?

Calcium Hydroxyapatite (responsible for compressive strength)
Osteocalcium Phosphate (brushite)

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What type of bone makes up 80% of the skeleton?

Cortical bone

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Describe cortical bone

80% of skeleton
Haversian canals (nutrient supply)
Stress oriented formation

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Describe cancellous bone

Trabecular (spongy)

- Higher rate of remodeling

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What are the non-collagenous proteins in organic bone matrix?

Osteocalcin
Osteonectin
Osteopontin

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Describe immature bone

-Not stress oriented
-Elastic in nature
(embryonic skeleton, fracture healing)

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Describe pathologic bone

-Random organization
-Weak
(tumors)

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Stages of fracture healing

Inflammatory (bleeding/hematoma)
Repair (primary callous at 2 weeks, bridging)
Remodeling (complete when repopulation of marrow space

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When does primary callous occur in fracture healing?

2 weeks

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Initial response of fracture healing is to:

Decrease blood flow

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How does bone differ in kids?

Thicker periosteum

- Cambium has increased ability for osteoblast formation

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Why shouldn’t a cast be put on the first few hours following a fracture?

Inflammatory response causes bleeding/hematoma and casting it could cause compartment syndrome

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What is Wolff’s Law?

Bone remodeling
Decreased stress = decreased density
Piezoelectric charges (compression which stimulates osteoblasts, tensile which stimulates osteoclasts)

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Salter Harris Classification

I: transverse through physis
II: through physis w/metaphysis fragment
III: physis w/epiphysis fragment
IV: epiphysis, physis and metaphysis
V: crush injury to physis

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When does blood flow begin to increase and when does it return to normal after a fracture?

Begins to increase hours-days after fracture

- Returns to normal 3-5 months

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Which piezoelectric charges stimulate osteoblasts?

Study These Flashcards

Compression (electronegative)

Which piezoelectric charges stimulate osteoclasts?

Study These Flashcards

Tensile (electropositive)

How are bone types classified?

Study These Flashcards

FAILSS

Flat
Accessory
Irregular
Long
Short
Sesamoid

How to describe fractures?

- Which bone - Open or closed - Location (rule of 1/3) - Direction of fx - Type of comminution

How to describe the direction of a fracture?

- Oblique - Transverse - Spiral - Comminuted

Types of comminution

- Butterfly | - Segmental

How is aposition of a fracture described?

Alignment and angulation

Describe alignment of a fracture

- Distal fragment in relation to proximal fragment | - 100%, 75%, 50%, 25%

Describe angulation of a fracture

- Reference distal fragment | - Reference apex

What should ALWAYS be evaluated with fractures and when?

Neurovascular status (before AND after treatment)

When are closed reductions difficult to manipulate?

After 10 days (esp kids)

How can most fractures be treated?

Closed reduction

When should angulations be corrected?

Adults | kids - angulations can be accepted

Describe fractures in kids

- Angulations can be accepted - Kids remodel - Kids ok for shortening - Kids rarely form non-unions - Kids rarely need PT

What part of the bone doesn't remodel as well?

Mid-shaft

What are layers of the physis?

Horizontal (physis) | Spherical (epiphysis)

What does the epiphyseal plate consist of?

- Articular cartilage - Ossification center - Physeal (reserve, proliferation, and hypertrophic zones) - Metaphysis

Types of growth plate fractures

- Traction (usually apophyseal) | - Compression (usually epiphyseal)

What can cause early closure of the growth plate?

Growth plate fracture

Types of open fractures

- I: less than 1 cm (low energy) - II: less than 10 cm (moderate energy) - IIIa: high energy, adequate soft tissue coverage - IIIb: high energy, massive soft tissue destruction, exposed bone - IIIc: high energy, vascular injury

Which fractures are considered emergent?

- Open - Intra-articular - Femur - Both bone extremity fractures

Which fractures have high complication rate in kids?

- Supracondylar humerus - Radial neck - Radial head - Lateral condylar humerus

Which fractures have high complication rate in adults?

- Both bone extremities - Pilon - Distal humerus

Describe splints

- Immobilize fracture (joint above and below) - Allows for swelling - Extra padding to bony prominence - Good as a cast acutely (if applied well)

When does most swelling occur after fracture?

6-12 hrs post injury

Benefits of plaster

- Easily molded - Inexpensive - Can be removed quickly

Cons of plaster

- Weaker - Heavier - More technical to apply

Benefits of fiberglass

- Light weight - Strong, durable - Waterproof

Cons of fiberglass

- Difficult to mold - Shorter shelf life - More expensive

Potential complications of splinting/casting

- Compartment syndrome - Skin necrosis - Foreign bodies

Surgical treatments of fractures

- Percutaneous pinning - CRIF - ORIF - Intramedullary fixation - External fixation

What indicates child abuse?

- History of prior injuries - Story doesn't match injury - Bone scan w/multiple areas of uptake

Ortho Splinting Flashcards

(53 cards)