Peggers’ Super Summary of External Fixation & DCO

Indications:

PATIENT FACTORS

Organ Injury

  • Thoracic trauma
  • Polytrauma
  • HI or raised ICP

Hamodynamic instability

  • Systolic Bp <100mmhg
  • Use of catecholamines
  • Anuria
  • Transfusion > 25 units of blood

Terrible Traid

  • Acidosis
  • Hypothermia
  • Coagulopathy

Bloods

  • IL 6 > 800pg/dl
  • Lactate levels >2.5

FRACTURE FACTORS

  • Limb deformity not reduced by non operative techniques out of hours
  • Limb shortening or skin compromise due to tenting
  • Soft tissue damage or skin blisters
  • Complicated Comminuted intra-articular fracture

Deciding ETC vs DCO:

  • Stable - ETC
  • Boarderline - ?? Factors aiding choice include
  • ISS > 40
  • ISS > 20 + thoracic trauma
  • pH < 7.24
  • Temperature <350
  • Transfusion > 10 RBC
  • Coagulopathy
  • IL-6
  • Unstable - DCO
  • Extremis - DCO

Biomechanics

  • Monolateral fixation and 60-70% of load is supported by near cortex
  • Bending rigidity is ∞ pin diameter 4
  • 2 screws per segment (adding a 3rd makes no difference)
  • Decrease ‘working length’ of the screws i.e. bone to bar distance
  • Near to fracture site screws far away from each other i.e. shorten working length of bar
  • Add more bars increases stability
  • Increase planes increases stability

Preoperative planning

  • Pin diameter should not exceed 20% of bone diameter
  • Safe corridors
  • Spanning or non-spanning of joints

Anatomy Safe Corridors:

NB Avoid 2-3 cm around joints to avoid synovium thus intra-articular joint penetration

PELVIS

  • ASIS horizontal stab incisions down to bone
  • Lateral cutaneous femoral nerve
  • Hip joint
  • Supra-acetabular pin placement
  • Risk of injuring femoral vessels
  • Lateral femoral cutaneous nerve
  • Sciatic notch
  • Hip joint

FEMUR

  • Anterior to 900 laterally

TIBIA

  • Subcutaneous boarder anteromedially to the tibial spine running perpendicularly to subcutaneous boarder of the tibia.
  • The more distally placed schanz pin needs to be more medially in a 900 arc

FOOT

  • 2.5cm proximal and anterior to calcaneum through and through
  • Medial and in the centre of great toe (1st) MT via open placement

HUMERUS

  • Proximal 1/2 blind pin placement into lateral humerus
  • Distal ½ Open placement laterally to avoid radial nerve

FOREARM

  • Proximal half subcutaneous ulnar posteriorly
  • Distal 1/2 Into Radius via open placement between ECRL/B interval
  • To Avoid superficial radial nerve
  • Dorsal hand pins are inserted either side of listers tubercle or EPL (4rd compartment) via open placement

HAND

  • Index Metacarpal 450 to the long axis dorsal radial angle viaopen placementdistal to the interosseous muscle in proximal 2/3rds of the MC bone - Avoid radial artery and superficial radial nerve aim in the middle to avoid extensor hood or joint

External fixation principles:

  • Near-far technique
  • Open placement in ‘danger’ areas
  • Single pin clamps
  • Avoid pins in peri-articular regions
  • Avoid robs over # site; obscure reduction on x ray
  • REDUCE FRACTURE DISPLACEMENT

Pelvic Fractures:

INDIACATIONS OF PELVIC FRACTURE

  • Seeing bruising to thighs, flanks or blood at meatus
  • Movement on pelvic springing

CLASSIFICATION –

1)Burgess & Young

  • AP Compression–partially stable
  • Pubic Diastasis gap >1cm
  • >2.5cm = SIJ thus posterior injury
  • Lateral Compression – partially stable
  • Vertical Shear - unstable
  • Combination

2)J Orthopaedic Sugery (Am) 1996

  • Type A – stable
  • Type B – Partially stable
  • Type C – Unstable (LC III, APC III, VS)

MANAGEMENT

  • 75% have massive haemorrhage
  • 25% have urological injuries
  • 20% have abdominal injuries

HAEMORHAGE SOURCE:

  • Arterial
  • Gluteal
  • Lateral sacral
  • Obturator
  • pudendal
  • Venous
  • Posterior venous plexus
  • # cancellous bone

NB indications for EX-FIX is uncontrolled haemorrhage and unstable pelvis

Arterial bleeding is only present in 10% of cases thus arteriography is not indicated in UNSTABLE PATIENTS

Katish et al J Trauma 1973

Indication for angiography persisting haemodynamic instability after pelvic stabilisation without evidence of abdominal or thoracic haemorrhage

Pelvic Fracture summary:

Mechanical / Haemodynamic / Treatment
Stable / Stable / No treatment
Stable / Unstable / Probably not pelvic – look for other source
Unstable / Stable / No Urgent pelvic treatment needed
Unstable / Unstable / URGENT pelvic stabilisation AND look for other bleeding sources

Equipment:

  • Instrument and dissection set
  • External fixators set
  • AO
  • Orthofix
  • Smith & Nephew
  • Schanz pins
  • II + Radiolucent operating table
  • If unstable pelvis need vascular and general surgeons

Algorithm for pelvic Fracture:

Burgess & Young Detailed:

LC / Pubic rami and sacral # / Associated iliac # / Contralateral open book
Blood loss in 24hrs* / 2.4 / 2.8 / 5.7
APC / Anterior diastasis ligaments intact / Isolated anterior ligament injury / Anterior and posterior ligament injury
Blood loss in 24hrs* / 6.4 / 20.5
VS / Disruption of anterior & posterior elements
Blood loss in 24hrs* / 7.8

*Burgess et al J Trauma 1990

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