Principles Of Plating
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Submitted by A.PRAKASH BVN 03038 FINALBVSC
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Based on Presence of communicating external wound.(open & closed) Extent of damage( complete , greenstick,fissure fracture) Direction and location of fracture (transverse, oblique, spiral, communited, multiple, impacted, avulsion, unicondylar, bicondylar fracture. Stable and unstable fracture.
Tension
Fracture Forces
Bending Shear Rotation
Compression
SH EA R Te ns ile an d com pres sive fo rce s ac t pe rpen di cu lar or n or mal to a struc ture' s surf ac e
Principles of Internal Fixation
The Goals of fracture repair are
Promote/enhance/allow bone healing Atraumatic technique Good reduction/alignment Stable fixation Early return to full function******
Principles of Internal Fixation
Open reduction
Surgical exposure of the fracture site for fixation Fixation is usually internal
Closed reduction
Fracture site is not opened External fixation (casts, splints, etc.) Becoming more popular with advanced imaging
Principles of Internal Fixation
Advantages of internal fixation
Rigid fixation usually Allows weight bearing during healing Health of the limb and joints Increases the circulation Promotes healing
Hidden implants
No extensive care
Principles of Internal Fixation
Disadvantages of internal fixation
Invasive Potential to slow healing Infection Longer procedure Higher cost
Principles of Internal Fixation
Factors affecting fracture repair
Type of fracture (simple/comminuted) Anatomical area Articular Which limb Where on the bone
Extent of soft-tissue damage Duration of fracture
Principles of Internal Fixation
Factures affecting fracture repair
Animal’s age, weight and temperament Owner’s finances Available aftercare Equipment available Surgeon’s experience
Plates come in a wide variety of shapes and sizes
Screws
Cortical Screws
More threads, low pitch, less thread depth Only fully threaded Used for cortical bone
Cancellous Screws
Less threads, steep pitch, wide thread Fully and partially
Screws
Used to secure bone plates to bone Used as primary means of fracture repair Used to hold fracture fragments in place Used to compress fracture fragments Used to form prosthetic ligaments
Screws
Lag principle
Used to compress fracture fragments Used to hold plates on bone Threads only engage far cortex
(Or they don’t engage the plate)
Can be accomplished with Partially threaded screw Over drilling near cortex Articular fractures Sacroiliac luxations
Bone Plates
Bone plates and screws offer versatile method of fracture of stabilization. Necessary for many fractures. Requires specialized equipment and training. Not readily available in many practices. More expensive than pinning.
Plates
Plate placement
Reconstruct the bone Contour plate Drill, measure, and tap screw holes (one by one) Apply screws from the fracture site out, alternating bone fragments Engage at least six cortices per a major bone fragment
More for comminuted fractures if possible
Bone Plates
Counteract
Tension Compression Shear Bending Rotational forces
Bone plates should be placed on the tension side of the bone
Tension side of the bone
Femur
Tibia*
Craniolateral Craniolateral
Humerus
Craniolateral
Radius
Ulna*
Cranial Caudal
Mandible*
dorsal
Some are not plated on the tension side due to impracticality and added difficulty
Compression
Mechanical compression added to the fracture site. The weight-bearing load is shared by both the plate and the bone. Primary bone healing usually results. Plate is applied eccentrically.
Neutralization
Plate protects primary repair from weight-bearing forces The weight-bearing load is shared by both the plate and the bone Stabilize with series of lag screws and cerclege wires. Numer of cortices is allowed is six.
Buttress
Spans a gap to prevent collapse of a fracture All of the weightbearing forces are transmitted through the plate Minimum of cortices applied is 8. For optimal strength use broad plate and stacked vcp plates..
Plates
Dynamic compression plates
Allows compression of major bone fragments
External compression
Screws must be LOADED in order to get compression (eccentric placement in screw hole) Plate can function in compression, neutralization, and as a buttress plate depending on how the screws are applied
1) Load Drill Guide: Provides 1 mm compression, screws are placed eccentrically 2) Neutral Drill Guide: Places the drill hole centrally, thus little displacement is provided.
Removing Implants
In general, it is recommended that all orthopedic implants be removed
In practice, however, we rarely remove orthopedic implants
Removing Implants
Why don’t we remove them
Cost Post-op confinement required Traumatic surgery Anesthesia risk Potential for refracture
Removing Implants
When to recommend removal
Interferes with function Loosening or breakage Infection Thermal conduction Biological reaction to implants Young dogs?????
AGE 1. 2. 3. 4.
Under 3 months 3-6 months 6-12 months Over 1 year
Post operative time for Plate removal 4 weeks 2-3 months 3-5 months 5-14 months
Removing Implants
Radiographs should document healing prior to removal
Warn owners about potential for bone breakage
Unless implant failure
Cage rest required after plate removal
Good idea to culture implants
Plating is superior over other method
IM pins are cheaper than plates and interfere with blood supply less Little equipment is required for pin placement IM pins can migrate, especially if motion is present IM pins are not ideal for comminuted or transverse fractures
Advantages of one over another Interlocking nails counteract all fracture forces and may do it better than plates
Interlocking nails do require a lot of equipment and some expertise to place them, but are cheaper than plates
Interlocking nails are limited by the
Plating advantage
Plates counteract all fracture forces Plates are versatile and can be applied to many fracture types and animal sizes Plating requires some expertise and expensive equipment Plating requires an aggressive surgical approach in most instances Plates may interfere with blood supply more than any of the other
Advantages of one over another
Open approaches can delay fracture healing and predispose to infection
Plates/screws Interlocking nails
Closed approaches can be used with
IM pins
External fixator
Interlocking nails require a limited approach
2.
3.
4.
5.
Based on Presence of communicating external wound.(open & closed) Extent of damage( complete , greenstick,fissure fracture) Direction and location of fracture (transverse, oblique, spiral, communited, multiple, impacted, avulsion, unicondylar, bicondylar fracture. Stable and unstable fracture.
Tension
Fracture Forces
Bending Shear Rotation
Compression
SH EA R Te ns ile an d com pres sive fo rce s ac t pe rpen di cu lar or n or mal to a struc ture' s surf ac e
Principles of Internal Fixation
The Goals of fracture repair are
Promote/enhance/allow bone healing Atraumatic technique Good reduction/alignment Stable fixation Early return to full function******
Principles of Internal Fixation
Open reduction
Surgical exposure of the fracture site for fixation Fixation is usually internal
Closed reduction
Fracture site is not opened External fixation (casts, splints, etc.) Becoming more popular with advanced imaging
Principles of Internal Fixation
Advantages of internal fixation
Rigid fixation usually Allows weight bearing during healing Health of the limb and joints Increases the circulation Promotes healing
Hidden implants
No extensive care
Principles of Internal Fixation
Disadvantages of internal fixation
Invasive Potential to slow healing Infection Longer procedure Higher cost
Principles of Internal Fixation
Factors affecting fracture repair
Type of fracture (simple/comminuted) Anatomical area Articular Which limb Where on the bone
Extent of soft-tissue damage Duration of fracture
Principles of Internal Fixation
Factures affecting fracture repair
Animal’s age, weight and temperament Owner’s finances Available aftercare Equipment available Surgeon’s experience
Plates come in a wide variety of shapes and sizes
Screws
Cortical Screws
More threads, low pitch, less thread depth Only fully threaded Used for cortical bone
Cancellous Screws
Less threads, steep pitch, wide thread Fully and partially
Screws
Used to secure bone plates to bone Used as primary means of fracture repair Used to hold fracture fragments in place Used to compress fracture fragments Used to form prosthetic ligaments
Screws
Lag principle
Used to compress fracture fragments Used to hold plates on bone Threads only engage far cortex
(Or they don’t engage the plate)
Can be accomplished with Partially threaded screw Over drilling near cortex Articular fractures Sacroiliac luxations
Bone Plates
Bone plates and screws offer versatile method of fracture of stabilization. Necessary for many fractures. Requires specialized equipment and training. Not readily available in many practices. More expensive than pinning.
Plates
Plate placement
Reconstruct the bone Contour plate Drill, measure, and tap screw holes (one by one) Apply screws from the fracture site out, alternating bone fragments Engage at least six cortices per a major bone fragment
More for comminuted fractures if possible
Bone Plates
Counteract
Tension Compression Shear Bending Rotational forces
Bone plates should be placed on the tension side of the bone
Tension side of the bone
Femur
Tibia*
Craniolateral Craniolateral
Humerus
Craniolateral
Radius
Ulna*
Cranial Caudal
Mandible*
dorsal
Some are not plated on the tension side due to impracticality and added difficulty
Compression
Mechanical compression added to the fracture site. The weight-bearing load is shared by both the plate and the bone. Primary bone healing usually results. Plate is applied eccentrically.
Neutralization
Plate protects primary repair from weight-bearing forces The weight-bearing load is shared by both the plate and the bone Stabilize with series of lag screws and cerclege wires. Numer of cortices is allowed is six.
Buttress
Spans a gap to prevent collapse of a fracture All of the weightbearing forces are transmitted through the plate Minimum of cortices applied is 8. For optimal strength use broad plate and stacked vcp plates..
Plates
Dynamic compression plates
Allows compression of major bone fragments
External compression
Screws must be LOADED in order to get compression (eccentric placement in screw hole) Plate can function in compression, neutralization, and as a buttress plate depending on how the screws are applied
1) Load Drill Guide: Provides 1 mm compression, screws are placed eccentrically 2) Neutral Drill Guide: Places the drill hole centrally, thus little displacement is provided.
Removing Implants
In general, it is recommended that all orthopedic implants be removed
In practice, however, we rarely remove orthopedic implants
Removing Implants
Why don’t we remove them
Cost Post-op confinement required Traumatic surgery Anesthesia risk Potential for refracture
Removing Implants
When to recommend removal
Interferes with function Loosening or breakage Infection Thermal conduction Biological reaction to implants Young dogs?????
AGE 1. 2. 3. 4.
Under 3 months 3-6 months 6-12 months Over 1 year
Post operative time for Plate removal 4 weeks 2-3 months 3-5 months 5-14 months
Removing Implants
Radiographs should document healing prior to removal
Warn owners about potential for bone breakage
Unless implant failure
Cage rest required after plate removal
Good idea to culture implants
Plating is superior over other method
IM pins are cheaper than plates and interfere with blood supply less Little equipment is required for pin placement IM pins can migrate, especially if motion is present IM pins are not ideal for comminuted or transverse fractures
Advantages of one over another Interlocking nails counteract all fracture forces and may do it better than plates
Interlocking nails do require a lot of equipment and some expertise to place them, but are cheaper than plates
Interlocking nails are limited by the
Plating advantage
Plates counteract all fracture forces Plates are versatile and can be applied to many fracture types and animal sizes Plating requires some expertise and expensive equipment Plating requires an aggressive surgical approach in most instances Plates may interfere with blood supply more than any of the other
Advantages of one over another
Open approaches can delay fracture healing and predispose to infection
Plates/screws Interlocking nails
Closed approaches can be used with
IM pins
External fixator
Interlocking nails require a limited approach
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