Ortho Splinting Flashcards
What are osteoblasts derived from?
Mesenchymal cells
What do osteoblasts produce?
- Osteocalcin (which needs Vit D)
- Type I collagen
Osteoblasts are affected by:
- ILs
- Platelet derived growth factor
- Insulin derived growth factor
Describe osteoclasts
- Multinucleated giant cells
- Attach to bone by integrins (decreases acidity, proteolytic digestion)
- Specific receptors for calcitonin (helps regulate resorption)
What do osteoclasts originate from?
Hematopoetic tissue (monocyte progenitors)
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)
What is inorganic bone matrix composed of?
- Calcium Hydroxyapatite (responsible for compressive strength)
- Osteocalcium Phosphate (brushite)
What type of bone makes up 80% of the skeleton?
Cortical bone
Describe cortical bone
- 80% of skeleton
- Haversian canals (nutrient supply)
- Stress oriented formation
Describe cancellous bone
- Trabecular (spongy)
- Higher rate of remodeling
What are the non-collagenous proteins in organic bone matrix?
- Osteocalcin
- Osteonectin
- Osteopontin
Describe immature bone
-Not stress oriented
-Elastic in nature
(embryonic skeleton, fracture healing)
Describe pathologic bone
-Random organization
-Weak
(tumors)
Stages of fracture healing
- Inflammatory (bleeding/hematoma)
- Repair (primary callous at 2 weeks, bridging)
- Remodeling (complete when repopulation of marrow space
When does primary callous occur in fracture healing?
2 weeks
Initial response of fracture healing is to:
Decrease blood flow
How does bone differ in kids?
- Thicker periosteum
- Cambium has increased ability for osteoblast formation
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
What is Wolff’s Law?
- Bone remodeling
- Decreased stress = decreased density
- Piezoelectric charges (compression which stimulates osteoblasts, tensile which stimulates osteoclasts)
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
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
Which piezoelectric charges stimulate osteoblasts?
Compression (electronegative)
Which piezoelectric charges stimulate osteoclasts?
Tensile (electropositive)
How are bone types classified?
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
