Fractures and Dislocations Flashcards
What is a fracture?
Break in structural continuity of bone
May be a crack, break, split, crumpling or buckle
Give 3 broad reasons why bones fail
High energy transfer in normal bones:
-Takes a lot
Repetitive stress in normal bones:
-Stress fracture
Low energy transfer in abnormal bones:
- Osteoporosis
- Osteomalacia, metastatic tumour
- Other bone disorders
What is Wolff’s law in relation to bone shape?
Bone is laid down where it is needed and removed where it is not needed
(“form follows function”)
What 7 criteria should you cover when you are describing a fracture?
- Mechanism and energy of injury
- Skin and soft tissues
- Site
- Shape
- Comminution
- Deformity
- Associated injuries
What are the 3 aims in treating fractures?
Relieving Pain
Restoring Function
(Saving Life)
What is the key to understanding fractures?
SOFT TISSUE DAMAGE
fractures are a form of soft tissue damage with a broken bone
How will a severe soft-tissue injury effect fracture healing?
Delay healing
All severe soft tissue injuries require urgent treatment.
Give some examples
Open fractures Vascular injuries Nerve injuries Compartment syndromes Fracture/ dislocations
There are many different treatments for fractures
What does your choice depend on?
(6 possible)
Fracture Bone Soft tissue Patient Facilities (!) Abilities of surgeon (!)
What percentage of fractures have delayed or impaired healing?
5-10%
How does fracture healing differ from soft injury repair?
Think about how bone and soft tissue heal
Soft tissues heal by replacing injured tissue with a fibrous scar
Bone heals by regeneration of normal bony anatomy
Bone heals by the formation of callus
What is callus?
An intermediary stabilising structure fromed after a fracture, which has cartilaginous grwoth plate characteristics and results in eventual
Descrube the 3 phases of bone healing
Inflammatory:
- 24-72h
- Mesenchymal
- 10% of healing time
Reparative
- From 2 days
- Chondral and osseous
- 40% of healing time
Remodelling
- From middle of repair phase
- Osseous
- 70% of healing time
(NOTE: phases overlap so percentage healing time wont add up to 100)
Describe the 7 cellular events in fracture repair
Immediate response to injury
Haematoma formation
Release of vasoactive mediators (e.g. nitric oxide), cytokines
Proliferation of undifferentiated cells - migration, recruitment, proliferation, differentiation
Invasion by inflammatory cells (macrophages, PMNs)
Organisation of clot into fibrous tissue by fibroblasts
Formation of reparative granuloma
Vessel thrombosis and osteocyte death
Describe the 4 cellular events in intra-membranous ossification
Differentiation of osteo-progenitor precursor cells into osteoblasts
Angiogenesis
Collagen deposited along fibrin scaffold - new bone matrix synthesis (osteoid from osteoblasts - uncalcified mass = primary callus)
Bone formation in periosteum (woven bone) - converts primary external callus into hard secondary callus - clinical union)