FX repair horses-techniques (Bauck)

Question 1

Factors that determine prognosis

Answer 1

• time/location
• Open vs closed
• soft tissue damage
• Age, breed, weight, temperament
• Number of fractures
• Time
• first-aid
• hospital set-up
  
  • equipment, implants, recovery system, experience of surgeon

Question 2

Condylar fracture means

Answer 2

distal condyle of Metatarsal/matacarpal 3

Question 3

Medial condylar fractures tend to…..

Answer 3

Propogate

-lateral condylar fractures usually don’t

Question 4

Classification of fractures

Answer 4

• Complete vs. incomplete
• Stable vs unstable
  
  • displaced vs nondisplaced
• Open vs. closed
• Configuration
  
  • greenstick
  • transverse
  • oblique
  • spiral
  • comminuted
  • avulsion
  • crush
• Location
  
  • diaphyseal
  • metaphyseal
  • physeal
  • articular

Question 5

Foals

Answer 5

• Faster healing than adults
• Angular limb deformities
  
  • secondary limb deformities
• Salter-Harris fractures
• Casts
  
  • More prone to cast sores
  • tendon laxity if casted long periods

Question 6

Cis cortex

Answer 6

near cortex

Question 7

Trans cortex

Answer 7

far cortex

Question 8

MCP

Answer 8

Metacarpophalangeal joint

Question 9

Stall rest

Answer 9

• Used for
  
  • stress fractures
  • non-displaced pelvic fx
  • Third trochanter, patellar, detoid tubercle
• Risks
  
  • catastrophic propagation

*depends on temperment

Question 10

External Coaptation

Answer 10

• Casts or splints
• Often used as a supplement to
  
  • internal fixation
  • emergency stabilizatoin
• Not used alone

Question 11

External fixation

Answer 11

• distal limb fx only
• Transfixation-pin casts
• external skeletal fixators
• ESFD: external skeletal fixation device

Question 12

Transfixation-pin casts

Answer 12

• Provides additional axial support
  
  • dec rotation
• Indications
  
  • comminuted phalangeal fx
  • distal MC/MT III fx
  • MCP breakdown
• 2-3 cross pins proximal to fx
  
  • incorporated into cast

Question 13

External Skeletal fixators

Answer 13

• Allow immediate weight-bearing
  
  • Access to wounds
• Often don’t provide enough axial support
• used in
  
  • foals
  • non-weight bearing fractures
    
    • ie: mandibular

Question 14

Internal fixation

Answer 14

• Key principles
  
  • anatomical reduction
  • rigid fixation
  • preservation blod supply
  • early mobilization
• Screws and plates
  
  • +/- wire, pins
• Intra-operative imaging

Question 15

Cortex screw

Answer 15

• Features
  
  • Large core diameter
  • Small thread diameter = stronger, more rigid
• Position, implant or lag fashion
• 4.5 ‘work horse’ of equine fx repair

Question 16

Cancellous screw

Answer 16

• Features
  
  • small core diameter
  • Large thread diameter
• Not as common in equine fx repair
• 3.5 cortical screw

Question 17

Screws placed in lag fashion

Answer 17

• Screw head engaged in cis cortex, screw threads engaged in transcortex
• hole drilled in cis cortex
• Smaller hole in transcortex
• Row row row your boat
  
  • DRILL (glide hole)
  • DRIL (thread hole)
  • COUNTERSINK
  • MEASURE
  • TAP
  • SCREW

Question 18

Drilling technique

Answer 18

• 1 mm/s
• slower drill speeds and accumulatio of ‘swath’
  
  • => overheating of bone
  • => bone necrosis
  • => implant failure
• Saline flush acts as lubricant/cooling

Question 19

Tapping

Answer 19

• Creates thread holes in drill holes
• Improves bone-screw interface

Question 20

Plate fixation

Answer 20

• Most common
  
  • DCP: Dynamic compression plate
    
    • squeezes fracture together
  • LC-DCP: Limited Contact; Dynamic compression plate
    
    • can place screws in neutral or compression
    • cutouts make it stronger?!?!
    • eaiser to bend/contour
    • preserves some periosteum
  • LCP: locking compression plate
• Minimum of 4 scres on each side of fx is ideal
• Apply to tension side where possible

Question 21

Plates are strong in …..

Answer 21

tension

Question 22

Plate fixation

LCP

Answer 22

• Locking compression plates
  
  • Inc stiffness and rigidity
  • LCP screws
    
    • bigger core
    • smaller threads
    • inserted perpendicular to plate, not accross fx
  • Can use
    
    • LCP (locking) screws
    • cortical screws
  • Less bone-plate contact required

Question 23

Strongest type of screws biomechanically

Answer 23

LCP screws

Question 24

Implant Removal

Answer 24

• When to remove
  
  • infection/loosening/lameness
  • Return to exercise (if problems)
    
    • Except arthrodesis
• Screws
  
  • generally don’t remove
• Staggered removal

Question 25

Complications

Answer 25

• implant infection
  
  • becomes loose and thus painful
• Catastrophic breakdown
  
  • recovery from anesthesia or post-op
• Osteoarthritis
• Foals
  
  • angular limb deformities
  • flexural limb deformities
• Supporting limb laminitis
  
  • sinking/rotation of P3
  • common
  • life-threatening