fractures and dislocations

Question 1

selected serious complications

Answer 1

Fat embolism
compartment syndrome
complex regional pain syndrome type 1

Question 2

#

Answer 2

shorthand for fracture

Question 3

why do bones fail

Answer 3

high energy transfer in normal bones
repetitive stress
abnormal bones

Question 4

wolff’s law

Answer 4

laid down where needed removed where not needed

Question 5

emergency orthopaedic management

Answer 5

life saving
reducing pelvic fracture in haemodynamically unstable patient
Complication saving
early and complete diagnosis of injury extent

Question 6

treating soft tissue injury

Answer 6

injury delays fracture healing

Question 7

phases of bone healing

Answer 7

inflammatory (mesenchymal)
reparative (chondral + osseous)
remodelling (osseuos)

Question 8

Immediate
response to
injury

Answer 8

1. Haematoma formation
2. Release of vasoactive mediators (e.g. nitric oxide), cytokines
3. Proliferation of undifferentiated cells - migration, recruitment,
   proliferation, differentiation
4. Invasion by inflammatory cells
   (macrophages, PMNs)
5. Organisation of clot into fibrous tissue by fibroblasts
6. Formation of reparative granuloma
7. Vessel thrombosis and osteocyte death

Question 9

Intra-
membranous
ossification

Answer 9

Differentiation of osteo-progenitor 
     precursor cells into osteoblasts
2. Angiogenesis
3. Collagen deposited along fibrin
     scaffold - new bone matrix 
     synthesis (osteoid from 
     osteoblasts - uncalcified mass = 
     primary callus)
4. Bone formation in periosteum 
      (woven bone) - converts primary 
      external callus into hard
      secondary callus - clinical union

Question 10

callus

Answer 10

Initially fibrous, but disorganised
Biomechanical environment important
Chondroblasts appear later, form cartilage (Type II Collagen)
Later, bone forms by endochondral ossification
Initially woven

Question 11

Endochondral

ossification

Answer 11

1. Bone formation in callus similar 
     to bone formation in growth 
     plate
2. Osteoblasts follow capillary 
     ingrowth
3. Synthesis of osteoid (un-calcified
     mass) – becomes mineralised to 
     give speckled calcification
4. Formation of ‘mixed spiculae’ 
     (immature bone and cartilage)
5. Bridging of fracture gap -
     radiological union

Question 12

Remodelling

Answer 12

osteoblastic & osteoclastic activity
osteoclastic cutting cones
consolidation
remodelling of woven bone
lamellar bone more efficient
cancellous bone remodels at trabecular level
longest stage

Question 13

when fracture healed

Answer 13

patient can bear weight
Xray
remodelling complete

Question 14

systemic

Answer 14

early:
hypovolaemia
crush syndrome
fat embolism
complications
bed rest complications tetanus
Local late problems
avascular necrosis
complications
malunion
implant failure
joint stiffness

Question 15

delayed or non union

Answer 15

inadequate immobilisation
repeated manipulations
anatomical vascular suscruptibility
soft tissue damage

Question 16

avascular necrosis

Answer 16

loss of blood supply
classical fractures- hip, scaphoid, talus
any bone fragment stripped of soft tissue attachments

Question 17

rehabilitation

Answer 17

restoring patient as close to preinjury function level as possible

Question 18

treatment options

Answer 18

rest+ elevation
rest + gravity
semirigid splintage
immobilisation by rigid external splint
functional brace
skin traction
skeletal traction
external fixation
external + internal fixation
percutaneious K wire fixation
ORIF with K wires
ORIF with tension band wiring
internal fixation with sliding nail/screw + plate
spinal rods
bony excision and prosthetic replacement
amputation

Question 19

mangled extremity severrity score

Answer 19

if warm ischaemic time > 6hrs
if tibial nerve is divided
very poor prognosis