MSS20 Introduction To Soft Tissue Injury And Fractures Flashcards
1
Q
High energy vs Low energy injury
A
High energy injury:
- younger people
- higher mortality
- poly-trauma (road traffic accidents, industry incidents)
- energy ∝ (velocity)^2
Characteristics:
- blunt / penetrating injuries
- massive soft tissue injury
- nerve / blood vessels involved
- complex and comminuted fractures
- multiple injury sites
- severe bleeding, life threatening
Treatment:
- difficult to treat
- death / complications common
- prevention is best
Low energy injury:
- older people
- if poor health also high mortality
- isolated trauma (fall on level ground)
Characteristics:
- localized (can still be dangerous)
- isolated soft tissue / skeletal injury
- less common nerve injury and complications
Treatment:
- problems with delay in treatment
- extreme age / frail patients / weak bones (osteoporosis)
- prevention more difficult
2
Q
Problem of injury
A
- Higher mortality than HIV/AIDS, TB, malaria
- Leading killer of youth
- Poorer countries worst-affected
- Prevention is key
- speeding enforcements
- drinking regulations
- helmets / seatbelts
- child restraints
- infrastructure upgrades
- vehicle and equipment standards
- graduated drivers licence
3
Q
Soft tissue injury
A
- Contusion
- ruptured capillaries and bruising
- **Hematoma formation (localized bleeding outside of blood vessels): **SC/IM - Sprain injury
- stretching to joint / other soft tissue
- may have ***ligamentous tears –> bleeding to joint (Haemarthrosis)
- e.g. MCL / ACL tear - Abrasions
- damage to ***epidermis and dermis
- SC layer not exposed
- skin will regenerate from below / from surrounding - Lacerations
- sharp edge (by knives / glass)
- irregular edge (by blunt objects)
- ***down to SC / deeper layer
- Suturing recommended - Avulsions
- forceful detachment of body parts
- nerve and vessel damage at different level
- traction (stretch) injury often irreparable - Deglove injury
- extensive section of skin completely torn off the underlying tissue
- skin circulation severely compromised –> skin flap may die
- Internal (closed) deglove: sheering force separating SC fat from deep fascia –> fluid collection in potential space: blood, serous, lymphatics, liquefied fat, pus - Puncture wound
- may have retained foreign body –> may get infected / pain
- presence of exit site: penetrating
- e.g. bullet / missile injuries, dog bite, human bites: prone to infection
4
Q
Bones and fractures
A
Bone characteristics:
- strong in compression
- not so in bending / twisting
Fracture patterns depend on:
- Force direction
- Energy
- **Fracture patterns (from lower to higher energy) (SO WhaT):
1. Spiral (twist)
2. Oblique (bending)
3. Wedge (bending + compress)
4. Transverse (traction / pull)
5
Q
Low energy fractures
A
- Distal radius fractures (dinner fork deformity)
- Hip fracture
—> **Extracapsular / intertrochanteric / outside femur neck (very common; treatment: heal / internal fixation)
—> Displaced **intracapsular neck fracture (femur neck)
- Loss of blood supply hinders fracture healing
- if unable to heal: Prosthesis replacement (Hip-arthroplasty)
6
Q
Limb injury
A
Distal body parts more prone to open injuries
- Finger - Wrist
- lacerations, puncture, amputation (>50%)
- fractures (17%) - Elbow - Shoulder
- fractures dislocations (~60%)
- sprains, contusions (~30%)
7
Q
Open / Compound fractures
A
- High grade
- often contaminated
- difficult to cover
- -> prone to infection - Low grade
- inside out (break of skin from inside bone fracture)
8
Q
Fractures and Soft tissue injuries
A
Fractures: Bones (hard tissue)
Soft tissue injuries:
- muscle
- nerve
- skin
- tendon
- ligament
- vessels
9
Q
Healing
A
either by:
- Regeneration
- Repair
10
Q
***Skin / Epithelial wound healing
A
4 Phases:
- Exudative phase
- wound filled by fibrin / coagulated blood - Resorptive phase
- scavenger cells remove dead cells and germs - Proliferative phase
- new cells formed which fill wound - Repair phase
- cells formed around edge of wound
- new skin created
- wound finally closed
- **Timing:
1. Bleeding (hours) - -> Hematoma formation
- -> ***Haemostasis
- -> ***Exudative
- Inflammation (days)
- -> **Resorptive
- -> **Granulation
- onset after hours
- max 3 days
- **vasodilatation (↑ blood supply)
- exudates (leaky vessels)
- **inflammatory cells
- ***growth factors, cytokines
- chemically amplified cascade - Proliferation (weeks)
- -> **Contraction
- -> **Re-epithelization
- -> **Fibrous scar
- 2-3 weeks
- recruitment of **fibrocytes
- collagen deposition, fibrous scar formation
- poorly arranged
- non-functional other than a “patch”
- adaptation to mechanical stress - Remodeling (months) / Maturation
- **reabsorption and replacement of Type 1 collagen
- **rearranged collagen fibres
- functionally / mechanically sound tissue
11
Q
Important growth factors in healing
A
- IGF-1 (inflammation, proliferation) (growth factor: ↑ chondrocyte + osteoblasts proliferation)
- TGFβ (inflammation)
- VEGF (proliferation, remodeling)
- PDGF (proliferation, remodeling)
- bFGF (proliferation, remodeling)
12
Q
***Bone tissue healing
A
Primary bone healing:
- repair of physiological microfractures from stress
- usual business remodeling and homeostasis
- NOT true healing (Contact healing: NO gap in fracture)
- Osteoclast remove bone
- Osteoblast laydown bone
- **Secondary bone healing:
- True healing (presence of gap)
- driven by inflammatory response
1. **Haematoma formation
2. **Inflammation (widening of healing zone: more mechanical stability –> soft callus converted to hard callus)
3. ***Soft callus (fibrous) proliferation —> Fibrocartilage - external callus (bridging of fracture)
- internal callus (fibrous tissue + cartilage)
4. ***Hard callus (calcified) proliferation
5. Remodeling of bone
Requirement for bone healing:
- ***Blood supply: oxygen, nutrients, growth factors
- Mechanical ***stability
- Bone ***contact / scaffold
- Some mechanical ***stimulus beneficial
Unable to heal: Non-union
- poor biology, instability, gaps
- fracture fixation implant breakage
- however non-healing =/ loss of function
- example:
- -> Varus deformity of tibia malunion
- -> bone shortened / angulated
13
Q
Healing in different tissue
A
- Tendon –> fibrous scar –> tendon (by Tenocytes / Tenoblasts)
- Muscle –> fibrous scar –> muscle (by Myocytes / myoblasts)
- Cartilage –> fibrous scar –> fibrocartilage (by Chondrocytes / chondroblast)
- Bone –> fibrous soft callus –> hard callus (by Osteocytes / osteoblasts)
- Neurological injuries:
- more difficult to recover from e.g. cervical facet dislocation with spinal cord injury
14
Q
Neurological injuries
A
Seddon and Sunderland classifications:
- Type 1: ***Neurapraxia (local myelin damage secondary to compression)
- Type 2-4: ***Axonotmesis (loss of continuity of axons)
- Type 5: ***Neurotmesis (complete physiologic disruption of entire nerve trunk)
Recovery (regeneration rate ~1mm / day):
1. Injury
-
**Wallerian degeneration (2 weeks)
- degenerating fibre and myelin sheath of **distal axon
- macrophage - Proliferating **Schwann cells + **Axonal sprout penetrating bands of Bungner
- Successful nerve regeneration / Unsuccessful (disorganised axonal sprouts, nerve may not find its path to successfully regenerate –> atrophied muscle)
Complications:
- Amputation stump (traumatic) neuroma
- -> not true tumour
- -> hypersensitive and painful
- -> caused by regeneration front of nerve
15
Q
Basics in managing soft tissue injury
A
- Preserve blood supply to edges
- Minimally invasive surgery
Problems caused by surgeon:
- iatrogenic necrosis
- wound too tight
- excessive retraction
- undermined skin flaps
- thermal necrosis (electrocautery, high-speed power tools: drills)
- rough handling
- extensive dissection
