External coaptation of fractures - SA and LA Flashcards Preview

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Flashcards in External coaptation of fractures - SA and LA Deck (62)
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Roles of external coaptation

- temporary support or first aid
- secondary support after sx
- primary support and stabilisation for selected fractures


What are the fracture forces? 4

- bending
- rotation
- compression/ shear
- distraction


List 6 different fracture configurations

- transverse
- oblique
- comminuted
- spiral
- avulsion
- compression


What to consider when deciding external coaptation

- consider forces acting on fracture


How are bending and rotational forces neutralised?

- by cast
- as long as the joints above and below the fx are immobilised


How can compression/ shear be neutralised??

difficult to neutralise with a cast


T/F: distraction forces are caused by mm tension and are poorly neutralised by external coaptation

True (e.g. olecranon fractures)


When - external coaptation

- best for closed, minimally displaced stable fx
- pair of bones (e.g. tibia/fibula)
- young animal with high healing potential
- 50% contact rule (i.e. bone fragments should be in contact at least 50%)


List steps of external coaptation

- when
- reduction
- alignment
- standing position
- joint above and below


Outline reduction in process of external coaptation

- heavy sedation or GA
- repeat rads to ensure apposition remains for healing
- adequate reduction varies b/w patients (juveniles tolerate greater displacement without developing delayed or non-union)
- 50% contact rule


Describe alignment in process of external coaptation

- perfect reduction often not achieved
- proper joint alignment MUST be achieved
- failure to align major bone fragments to joints of limbs --> rotational or angular malunion
- cause functional gait abnormality, painful lameness from secondary OA


How should external coaptation be applied?

- applied to maintain the limb in a normal standing positiion
- allows animal to 'bear weight' when splint is in place and after removal


What are the guidelines for the joint above/below in external coaptation?

- both must be immobilised
- most conventional splints and casts cannot be used above stifle/elbow
- spica splints can be constructed to immobilise the hip or shoulder
- most are severely displaced


How often is external coaptation used?

- infrequent in SA (difficult to manage, severe complications possible, often there is a better way to tx the patient)
- it is only occasionally used to manage fx
- fairly commonly used for support after sx, especially after arthrodesis


List 8 types of external coaptatin

- Robert Jones bandage
- Modified RJ bandage (less cotton padding used)
- reinforced RJ bandage
- splinted
- bivalved cast (allows frequent changes without)
- spica splint (shoulder, hip)
- Schroeder-Thomas
- Walking bar (aluminium bar at end of cast)


List components of the external coaptation dressing

- primary layer
- secondary layer
- tertiary layer
- +/- stirrups


Function - primary layer - example

- to cover and protect skin
- absorb discharge
- variety: e.g. melolin


Function - secondary layer - example

- absorption
- provides support
- provides pressure
- keeps primary layer in one place
* roll cotton (don't allow direct contact with wounds)
* cast padding (less bulky, conforms better)
- conforming gauze is wrapped over this 'padding layer' to provide stability and occasionally compression


Use - casting tape

- applied over a light secondary layer
- fine balance: too little padding may --> cast rubs/sores, too much padding will allow movement of bone fragments and delay healing


Function - tertiary layer - examples

- holds inner layers together
- fixes inner layers to bandaged part
- barrier against physical abrasion
- barrier against environmental contaminants
- several types but elastic conforming bandage most common; allows application of consistent pressure to outer layer


When do you need to change a bandage?

when tertiary layer is wet as won't keep the water out


Advantages - external coaptation - 2

- relatively cheap (if no complications)
- avoids sx


Disadvantages - external coaptation

- only appropriate for stable, minimally displaced fx
- may result in bone/ limb malalingment
- serious complications possible
- complications are more expensive/ difficult to tx than original fx
- difficult to manage (casts slip, get wet, animals remove them)


Complications - external coaptation

- distal soft tissue swelling
- distal limb oedema
- skin rubs
- skin ulceration
- skin necrosis
- soft tissue necrosis
- slippage of cast
- with severe complications, amputation often only option


How to minimise risk of complications of external coaptation

- use coaptation only if necessary
- plenty of padding (esp over bony prominences)
- change dressing frequently
- change or remove dressing if any concerns
- educate owner to monitor dressing (smell)
- avoid dressing if good alternative


Is a transverse fx suitable for casting?

Yes - it is stable to compression


How long will fx in young animal take to heal?

3-4 wks (check with repeat rads.)


How long do you leave a cast on a fracture?

until the bone has healed


How are fractures that extend into a joint classified?

Salter-Harris classification


How can you manage a fracture that requires sx prior to sx?

- rest
- restrict activity (cage)
- opioid analgesia
- +/- cold compress (if tolerated)
- +/- sling