MSK Flashcards
What Cells make up bones
osteoblasts, osteoclasts, osteocytes and Oligodendrocyte progenitor cells (OPCs)
What makes up the Matrix of bones
Organic = osteoid (40%)
Collagen Type I - Resists tension, twisting and bending
Inorganic (60%)
Calcium hydroxyapatite - Resists compressive forces
What is Woven Bone
Disorganised bone that forms the embryonic skeleton and fracture callus.
What is Lamellar Bone
Mature bone that can be one of two types:
Cortical/compact: dense outer layer
Cancellous/trabecular: porous central laye
How can bones form
Intramembranous Ossification or Endochondral Ossification
What is Intramembranous Ossification
Direct ossification of mesenchymal bone models formed during embryonic development.
e.g. Skull bones, mandible and clavicle
What is Endochondral Ossification
Mesenchyme goes to cartilage goes to bone
e.g. Most bones ossify this way
What are the main stages of Fracture Healing
Reactive Phase
o Bleeding
Reparative Phase
Inflammation
Remodelling Phase
o Proliferation
o Consolidation
What is the Reactive Phase of fracture repair and how long does it last?
Bleeding into fracture site fgrms haematoma
Inflammation - cytokine, GF and vasoactive mediator release leads to recruitment of leukocytes and fibroblasts forming granulation tissue
From injury to 48hrs
What is the Reparative Phase of fracture repair and how long does it last?
Proliferation of osteoblasts and fibroblasts forms cartilage and woven bone production leading to callus formation.
Consolidation (endochondral ossification) of woven bone forms lamellar bone
2 days to 2 weeks
What is the Remodelling Phase of fracture repair and how long does it last?
Remodelling of lamellar bone to cope with the mechanical forces applied to it (Wolff’s Law: “form follows function”)
1wk – 7yrs
What is the healing time of a Closed Fracture
3wks
What is the healing time of a paediatric Fracture
3wks
What is the healing time of a metaphyseal Fracture
3wks
What is the healing time of an upper limb Fracture
3wks
What is the healing time of an Adult Fracture
6wks
What is the healing time of a Lower limb Fracture
6wks
What is the healing time of a Diaphyseal Fracture
6wks
What is the healing time of an Open Fracture
6wks
What is the rule for healing time of wounds
Normal fractures take 3 weeks to heal. Any complicating factor, e.g. Adult bone, open wound etc doubles healing time
What are the main classifications of fractures
Traumatic
Stress
Pathological
What are the types of Traumatic fracture
Direct: e.g. assault with metal bar
Indirect: e.g. Fall on outstretched hand (FOOSH) leads to clavicle fracture
Avulsion
What is a Stress Fracture
Bone fatigue due to repetitive strain causes fracture E.g. foot fractures in marathon runners
What is a Pathological Fracture
Normal forces applied but bone is diseased
Local causes: tumours
General causes: osteoporosis, Cushing’s, Paget’s
What is the system of describing a fracture
PAID
o Demographics
o Pt. details
o Date radiograph taken
o Orientation and content of image
o Pattern o Transverse o Oblique o Spiral o Multifragmentary o Crush o Greenstick o Avulsion
Anatomical Location
Intra- / extra-articular
o Dislocation or subluxation
Deformity (distal relative to proximal) o Translation o Angulation or tilt o Rotation o Impaction (→shortening)
Soft Tissues
o Open or closed
o Neurovascular status
o Compartment syndrome
Specific Fractyre Details
o Salter-Harris
o Garden
o Colles’, Smith’s, Galeazzi, Monteggia
What features must a radio-graph of a fracture have?
Radiographs must be orthogonal (at right angles): request AP and lat. films.
Need images of joint above and joint below
What are the stages of Fracture Management
4Rs Resuscitation Reduction Restriction Rehabilitation
What are the steps of Resuscitation in fracture management
Follow Advanced Trauma Life Support guidelines
Assess C-spine, chest then pelvis
Fractures usually assessed in second assessment
Assess neurovascular status and look for dislocations
Consider reduction and splinting before imaging - leads to reduced pain, bleeding and risk of neurovascular injury
X-ray once stable
What is the treatment of open fractures
6 A’s
Analgesia: Morphine + Midazolam
Assess: NV status, soft tissues, photograph
Antisepsis: wound swab, copious irrigation, cover with betadine-soaked dressing.
Alignment: align fracture and splint
Anti-tetanus: check status (booster lasts 10yrs)
Abx - Fluclox 500mg IV/IM + benpen 600mg IV/IM (Or, augmentin 1.2g IV)
Treat with debriment in theatre
What is the classification of Open fractures
Gustillo Classification
- Wound <1cm in length
- Wound ≥1cm with minimal soft tissue damage
- Extensive soft tissue damage
What is the most dangerous complication of open fractures and how is it treated
Clostridium perfringes
Wound infections and gas gangrene
± shock and renal failure
Rx: debride, benzylpeniclin + clindamycin
What are the principles and methods of Reduction in fracture management
Displaced fractures should be reduced -
Unless no effect on outcome, e.g. ribs Aim for anatomical reduction (esp. if articular surfaces involved)
Alignment is more important than opposition
Methods Manipulation / Closed reduction o Under local, regional or general anaesthetic o Traction to dis-impact o Manipulation to align
Traction
o Not typically used now.
o Employed to overcome contraction of large muscles: e.g. femoral fractures
o Skeletal traction vs. skin traction
Open reduction (and internal fixation) o Accurate reduction vs. risks of surgery o Intra-articular fractures o Open fractures o 2 fractures in 1 limb o Failed conservative Management o Bilat identical fractures
What are the principles and methods of Restriction in fracture management
Principles
Inter-fragmentary strain hypothesis dictates that tissue formed at fracture site depends on strain it experiences.
Fixation leads to reduced strain and better bone formation
Fixation also reduces pain while increasing stability and ability to function.
Methods
Non-rigid
o Slings
o Elastic supports
Plaster
o POP
o In first 24-48h use back-slab or split cast due to risk of compartment syndrome
Functional bracing
o Joints free to move but bone shafts supported in cast segments.
Continuous traction
e.g. collar-and-cuff
Ex-Fix
o Fragments held in position by pins/wires which are then connected to an external frame.
o Intervention is away from field of injury.
o Useful in open fractures, burns, tissue loss to allow wound access and reduced infection risk.
o Risk of pin-site infections
Internal fixation
o Pins, plates, screws, IM nails
o Usually perfect anatomical alignment
o Increased stability which Aid early mobilisation
What are the principles and methods of Rehabilitation in fracture management
Principles
Immobility leads to reduced muscle and bone mass and joint stiffness
Need to maximise mobility of uninjured limbs
Quick return to function reduces later morbidity
Methods
o Physiotherapy: exercises to improve mobility
o OT: splints, mobility aids, home modification
o Social services: meals on wheels, home help
General Complications of Fractures
Tissue Damage
o Haemorrhage and shock
o Infection
o Muscle damage leading to rhabdomyolysis
Anaesthesia
o Anaphylaxis
o Damage to teeth
o Aspiration
Prolonged Bed Rest o Chest infection o UTI o Pressure sores and muscle wasting o DVT, PE o Reduced bone mineral density (BMD)
Specific Complications of Fractures
Immediate
Neurovascular damage
Visceral damage
Early
Compartment syn.
Infection (worse if assoc with metalwork)
Fat embolism →Acute respiratory distress syndrome
Late Problems with union Avascualr Necrosis Growth disturbance Post-traumatic osteoarthritis Complex regional pain syndromes Myositis ossificans
What are the 3 main types of Neurological Complication of a fracture
Neuropraxia - Temporary interruption of conduction w/o loss of axonal continuity.
Axonotmesis
o Disruption of nerve axon leads to distal Wallerian degeneration
o Connective tissue framework of nerve preserved
o Regeneration occurs and recovery is possible.
Neurotmesis
o Disruption of entire nerve fibre
o Surgery required and recovery not usually complete
What is the common palsy associated with Ant. shoulder dislocation/Humeral surgical neck frcture
Axillary Nerve Palsy
Numb chevron Weak abduction
