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Flashcards in Fracture management 2 Deck (55)
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Explain non-locking plate contouring

- Required to create bone-plate friction
- Contour plate to the shape of the bone
- Use bending iron or press


Explain the use of dynamic compression plates

- Apply axial compression to transverse fracture
- Aim for primary bone union (contact healing)


Explain the use of compression screws in plates

- Screw either side of fracture fixed
- Screw inserted eccentrically
- As tightened, head shift down towards centre, pulls bone with it towards the fracture therefore compressing the fracture site
- Compression screws placed first, then neutralisation screws placed (place one positional first to hold plate in place


Explain the use of neutral screws in plates

- As tightened pull plate onto bone
- Do not move in plate hole and do not move bone


How many screw head movements and how many compression screws can be use in plates?

- Maximum of 2 screw head movements per plate hole
- Maximum of 2 compression screws, rest all neutral screws


Explain the function of neutralisation plates

- Used where other implants are used to reconstruct the fracture e.g. K wire, cerclage wire
- Used to stabilise against (neutralise) some forces and allow weight bearing on bone
- Bone takes some load


Explain the function of bridging plates

- Used where fracture is not reconstructed and bone unable to take any load, unstable to all forces
- Plate must take load, spans the fracture gap
- Use larger plate and auxillary fixation device e.g. IM pin


What is the main risk with bridging plates?

Plate failure in particular in mid section


What are the advantages and disadvantages of plate application for fracture repair?

- Good for fracture reduction/internal fixation
- But requires dissection and high biological cost: trauma to bone, disruption to soft tissue attachment and blood supply


Explain the use of locking plates

- Screw head locks into plate, have thread on head of screw and plate
- Implant stability provided by locking mechanism


Outline the advantages of locking plates

- Implant stability not dependent on bone quality
- Good purchase in poor quality bone
- Does not compress plate onto bone so no periosteal vascular disturbance
- Exact contouring not necessary
- Able to resist higher loads
- No chance of screw/thread stripping


Explain how plate failure most common occurs

- Exposure to cyclical bending due to trans cortex not being in tact (trans cortex must resist bending)
- Non-reconstructed fractures higher chance of bending
- Most common fail through screw hole


What is an external skeletal fixator device?

A device that fixes bone using pins inserted into the bone, external to skin and bone


Name the different frame times for ESFs

- Linear (most common)
- Circular
- Free form (putty/epoxy)
- Hybrid


Describe linear ESFs

- Longitudinal connecting bars
- Clamps attaching to pins inserted into bone
- Versatile
- Limited surgical incision so low biological cost


Name the different types of linear ESFs (5) in order from weakest to strongest

- Type IA
- Type IB
- Type II modified (IIB)
- Type II (IIA)
- Type III


Describe type IA linear ESFs (structure, insertion, pins, risks)

- Uniplanar and unilateral
- Safe corridor insertion through clean skin site
- Do not exceed 30% of bone diameter
- Plain and threaded pins used
- Tip threads and positive threads prevent breakage due to bending
- Pin tract infection risk


Describe type IB linear ESFs (structure, insertion, pins, risks)

- Biplanar (craniocaudal and mediolateral plane) and unilateral (one side of each plane)
- SAfe corridor insertion through clean skin site
- Do not exceed 30% of bone diameter
- Plain and threaded pins used, tip threads and positive threads prevent breakage due to bending
- Consideration of pin tract infection


Describe type IIB linear ESFs (structure, pins)

- Uniplanar, bilateral (2 sides of bone)
- Full pins top and bottom, half pins in between


Describe type IIA linear ESFs (structure, pins, risks)

- Bilateral and uniplanar
- Full pins throughout
- Technically difficult


Describe type III linear ESFs (structure, disadvantages)

- Biplanar, bilateral
- Excessively complicated, large, rarely used


Describe the structure of circular ESFs

Thin wires suspended by rings surrounding the limb


Outline the advantages and disadvatages of circular ESFs

- More versatile
- More applications
- Good for complex fracture applications

- More complex
- More demanding


Outline the advantages and disadvantages of free form/epoxy putty ESFs

- Very adaptable, bespoke frame
- Clamps and bars replaced by resin or epoxy putty

- Messy, cannot adjust post-op, tricky to de-stage


Describe hybrid ESFs and give a common example

- Combination of various fixator types
- Typically circular ESF distally + linear ESF proximally


Compare the healing achieved with ESFs and bone plates

- Bone plates have slower healing, primary bone union
- ESFs use secondary bone healing and heal twice as quickly, used for non-reconstructable/comminuted fracture


Describe the basic application of ESFs

- Pins designed for purpose, can have negative and positive profile
- 2 placed at either end of bone, external connecting bar placed
- Pins clamped in position whilst examining limb for length and orientation of the two joints
- Further pins placed to strengthen the construct with 2 close to the fracture
- Some limited ability to alter alignment after pins placed


Outline the main disadvantages of ESFs

- Do not get accurate fracture reduction
- Pins loosen
- Pin tract discharge common
- Complications almost guaranteed due to catching of structure
- Frequently have problems with bone healing due to technique or pin loosening
- Avoid ESF where possible as internal more reliable


In what conditions are splints required?

- Unstable fractures
- Unstable tendon injuries


When an injury is in region 1 of an equine limb, describe the correct splint placement

- Need to align the dorsal cortices
- Place splint dorsally
- Use commercial splints