Fracture management 2 Flashcards
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
When an injury is in region 2 of an equine limb, describe the correct splint placement
Splint placed laterally and caudally
When an injury is in region 3 of an equine limb, describe the correct splint placement
Splint should be placed laterally (and medially if possible)
When in injury is in region 4 of an equine limb, describe the correct splint placement
Only possible in the forelimb, need to stabilise the carpus, some may be better without splints as the joint above cannot be stabilised
Outline the main uses of coaptation
- Temporary support or first aid before definitive procedure is performed
- Reduce post operative swelling
- Provide additional support following surgical intervention
- To help protect wounds
What factors must be taken into consideration to determine if external coaptation is appropriate?
- Location
- Type of fracture
- Fracture reduction
- Breed and age
What is the basic principle of external coaptation?
To immobilise the joint above and below the site of fracture
What location of fractures are most suited to external coaptation? What is the exception?
- Fractures distal to the elbow and stifle
- Fractures proximal to these sights have high risk of bandage slippage which may increase stress on fracture site
- Articular and growth plate fractures: best managed with open reduction and internal fixation
What forces is external coaptation resistant to?
Bending and some resistance to rotation
Which types fractures are well suited to external coaptation?
- Transverse fractures best suited
- Simple oblique or spiral fractures that are stable after reduction
Outline the fracture reduction requirements when using external coaptation
- Minimally displced best
- Ends of fracture need to overlap by at least 50% in both orthogonal views to achieve healing
- Goal must always be perfect reduction
Compare and explain the suitability of juveniles vs adults to external coaptation
- Juvenile better than adults
- Good healing potential, able to form bridging callus in short period of time
In which location should external coaptation be avoided and why?
- Fractures of distal radius and ulna (esp. toy breeds)
- High incidence of delayed union due to poor blood supply to the area
Outline the complications that may occur with external coaptation
- Poor application
- Non-union due to poor stabilisation
- Excessive pressure on limb
- Excessive movement of bandage (rub, sores, swelling)
Briefly outline the application of a cast in small animals
- Rigid material completely surrounding limb
- Use Robert-Jones bandage for temporary support
- Only apply case once swelling subsided
- Use synthetic casting tapes
- Can make bivalving casts
- Any prominent areas should have additional padding surrounding it (i.e. doughnut shape) in order to make the area level
- Radiograph following application to ensure adequate fracture reduction
When might a modified Robert Jones bandage be used and what is meant by this?
- Replace cotton wool layer with light cast padding
- Does not provide fracture support, but can be benneficial following internal fixation to reduce swelling of soft tissues
Outline the method for applying a Robert Jones bandage
- Tape stirrups from above carpus/tarsus to beyond the toes
- Cotton wool layer to level of the mid-humerus/femur, leave nails of 2 middle toes visible
- Wrap conforming gauze over cotton wool, even pressure
- Repeat cotton wool and gauze layers twice, each time compress cotton wool
- Invert tape stirrups, adhere to outside of gauze
- Apply cohesive bandage layer
When would a Robert Jones bandage be appropriate?
- Temporary support to injured limb
When is the use of splints indicated in small animals?
Only for distal limb injuries, should not be used to stabilise more proximal fractures of the radius and tibia
Outline the application of a splint and explain why this is done
- Less padding to reduce motion between splint and skin
- Splint positioned over secondary layer and held in place with additional layer of gauze
- Final layer of adhesive tape/cohesive bandage
What are velpaeu slings used for?
Thoracic limbs, immobilise fractures and joints more proximally
What are Ehmer slings used for?
Pelvic limbs, immobilise fractures and joints more proximally
What are the disadvantages of slings?
- Difficult to place and maintain without slipping
- Potential to cause skin necrosis over feet if not carefully monitored
Outline the monitoring and treatment of a cast or splint for fracture and post-op support
- For fracture support: check weekly, change padding and inspect limb every 2 weeks
- For post-surgical support: change padding and inspect weekly
When should a Robert Jones bandage be changed for fracture support and general limb support?
- Fracture: change every 2-3 days
- General limb support: change weekly
Outline what checks should be performed for cast/bandages by the owner and how often?
- Check twice daily
- Check toes carefully for heat, swelling, pain
- Check pads and nails to ensure normal colour
- Check top of dressing for pain swelling
- Check skin above cast/bandage for increased redness, sores, swelling
- Check cast/bandage for bad smell
