MSK

Question 1

What Cells make up bones

Answer 1

osteoblasts, osteoclasts, osteocytes and Oligodendrocyte progenitor cells (OPCs)

Question 2

What makes up the Matrix of bones

Answer 2

Organic = osteoid (40%)
Collagen Type I - Resists tension, twisting and bending

Inorganic (60%)
Calcium hydroxyapatite - Resists compressive forces

Question 3

What is Woven Bone

Answer 3

Disorganised bone that forms the embryonic skeleton and fracture callus.

Question 4

What is Lamellar Bone

Answer 4

Mature bone that can be one of two types:

Cortical/compact: dense outer layer
Cancellous/trabecular: porous central laye

Question 5

How can bones form

Answer 5

Intramembranous Ossification or Endochondral Ossification

Question 6

What is Intramembranous Ossification

Answer 6

Direct ossification of mesenchymal bone models formed during embryonic development.

e.g. Skull bones, mandible and clavicle

Question 7

What is Endochondral Ossification

Answer 7

Mesenchyme goes to cartilage goes to bone

e.g. Most bones ossify this way

Question 8

What are the main stages of Fracture Healing

Answer 8

Reactive Phase
o Bleeding
Reparative Phase
Inflammation

Remodelling Phase
o Proliferation
o Consolidation

Question 9

What is the Reactive Phase of fracture repair and how long does it last?

Answer 9

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

Question 10

What is the Reparative Phase of fracture repair and how long does it last?

Answer 10

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

Question 11

What is the Remodelling Phase of fracture repair and how long does it last?

Answer 11

Remodelling of lamellar bone to cope with the mechanical forces applied to it (Wolff’s Law: “form follows function”)

1wk – 7yrs

Question 12

What is the healing time of a Closed Fracture

Answer 12

3wks

Question 13

What is the healing time of a paediatric Fracture

Answer 13

3wks

Question 14

What is the healing time of a metaphyseal Fracture

Answer 14

3wks

Question 15

What is the healing time of an upper limb Fracture

Answer 15

3wks

Question 16

What is the healing time of an Adult Fracture

Answer 16

6wks

Question 17

What is the healing time of a Lower limb Fracture

Answer 17

6wks

Question 18

What is the healing time of a Diaphyseal Fracture

Answer 18

6wks

Question 19

What is the healing time of an Open Fracture

Answer 19

6wks

Question 20

What is the rule for healing time of wounds

Answer 20

Normal fractures take 3 weeks to heal. Any complicating factor, e.g. Adult bone, open wound etc doubles healing time

Question 21

What are the main classifications of fractures

Answer 21

Traumatic
Stress
Pathological

Question 22

What are the types of Traumatic fracture

Answer 22

Direct: e.g. assault with metal bar
Indirect: e.g. Fall on outstretched hand (FOOSH) leads to clavicle fracture
Avulsion

Question 23

What is a Stress Fracture

Answer 23

Bone fatigue due to repetitive strain causes fracture E.g. foot fractures in marathon runners

Question 24

What is a Pathological Fracture

Answer 24

Normal forces applied but bone is diseased

Local causes: tumours
General causes: osteoporosis, Cushing’s, Paget’s

Question 25

What is the system of describing a fracture

Answer 25

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

Question 26

What features must a radio-graph of a fracture have?

Answer 26

Radiographs must be orthogonal (at right angles): request AP and lat. films. Need images of joint above and joint below

Question 27

What are the stages of Fracture Management

Answer 27

``` 4Rs Resuscitation Reduction Restriction Rehabilitation ```

Question 28

What are the steps of Resuscitation in fracture management

Answer 28

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

Question 29

What is the treatment of open fractures

Answer 29

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

Question 30

What is the classification of Open fractures

Answer 30

Gustillo Classification 1. Wound <1cm in length 2. Wound ≥1cm with minimal soft tissue damage 3. Extensive soft tissue damage

Question 31

What is the most dangerous complication of open fractures and how is it treated

Answer 31

Clostridium perfringes Wound infections and gas gangrene ± shock and renal failure Rx: debride, benzylpeniclin + clindamycin

Question 32

What are the principles and methods of Reduction in fracture management

Answer 32

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 ```

Question 33

What are the principles and methods of Restriction in fracture management

Answer 33

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

Question 34

What are the principles and methods of Rehabilitation in fracture management

Answer 34

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

Question 35

General Complications of Fractures

Answer 35

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) ```

Question 36

Specific Complications of Fractures

Answer 36

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 ```

Question 37

What are the 3 main types of Neurological Complication of a fracture

Answer 37

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

Question 38

What is the common palsy associated with Ant. shoulder dislocation/Humeral surgical neck frcture

Answer 38

Axillary Nerve Palsy Numb chevron Weak abduction