1. No category

op
ed
i
Evolution of
Plate Design and Function
rt
-Indications for Locked Plating-
ya
O
Uğur GÖNÇ, MD
Ç
an
ka
Çankaya Hospital
Dept. Orthopedics and Traumatology
Ankara, TURKEY
AO Trauma Advanced Course
Krakow, 2014
ed
i
Learning Outcomes
op
• Spectrum of fixation methods using different plates
O
– Biomechanical considerations
rt
• Evolution of plates
ya
• Mechanics of locking head screws
ka
• Indications for locked plating
Ç
an
• Correct application of locked plating
Ç
an
ka
ya
O
rt
op
ed
i
Historical implants
ed
i
Original AO Principles (1958)
op
1. Anatomical direct reduction
O
ya
– Stable internal fixation
rt
2. Rigid fixation with fracture compression
ka
3. Preservation of blood supply and soft tissues
Ç
an
4. Early active pain-free mobilization
ed
i
Lag screw
Ç
an
ka
ya
O
rt
op
The lag screw is the basic tool used to create
interfragmentary compression
Round-hole plate (1958)
Ç
an
ka
ya
O
rt
op
ed
i
Axial compression could only be obtained using the
external compression device
Dynamic compression plate (DCP)
Ç
an
ka
ya
O
rt
op
ed
i
“Still—don’t forget”
Dynamic compression
plate
External tension device
ed
i
Plate Function
Ç
an
ka
ya
• Tension band
O
• Buttress – antiglade
rt
• Protection – neutralization
op
• Compression
absolute
stability
ed
Absolute stability
op
Direct healing
Transverse or oblique 2-part fractures
ka
ya
O
rt
Screws compress plate to bone
Ç
an
•
•
•
•
i
Compression plate
Ç
an
ka
ya
O
rt
op
ed
i
Compression plate
ed
i
Neutralization Plate
Ç
an
ka
ya
O
rt
•  rotational and axial forces
op
• Protects interfragmantery lag screw(s)
op
• Displacement in one direction
ya
O
rt
• Resists axial loading
(antigliding)
ka
• Metaphyseal fractures
(“B” type partial articular)
Ç
an
ed
i
Buttress Plate
Ç
an
ya
ka
op
rt
O
ed
i
op
ed
i
Tension Band Plating
O
• Plate on tension (convex) side
rt
• Eccenterically loaded bone
Ç
an
ka
ya
• Compression at concave side
ka
ya
Lag screw through plate
O
rt
op
ed
i
Wedge Fractures
Ç
an
More soft tissue
stripping
Lag screw and neutralization
ed
i
Comminuted Fractures ?
op
• Require substantial soft tissue disruption
Ç
an
ka
ya
O
rt
• Bone grafting on contralateral side
ed
i
Problems with Absolute Stability
• Delayed union
op
• Too extensive surgery
• Periosteal stripping
• Implant failure
• Nonunion
O
rt
• Soft tissue damage
Ç
an
ka
ya
• Too many implants
• Wound problems and
Infection
ed
i
Biological Solutions
Ç
an
ka
ya
O
• New surgical techniques
rt
op
• New plate designs
ed
i
Traditional Compression Plate
Ç
an
ka
ya
O
rt
op
Plate pressure - necrosis
Ç
an
ka
ya
1991
O
rt
op
ed
i
Limited contact DCP (LC-DCP)
ed
i
Plate Design
op
• Gradual evolution
O
rt
• Minimize detrimental effects on bone
Ç
an
ka
ya
DCP
LC-DCP
PC-Fix
ed
i
Point-contact fixator (PC-Fix)
Ç
an
ka
ya
O
rt
op
An evolutionary breakthrough
ed
i
New Surgical Techniques
op
• Relative stability concept
rt
• Bridge plating
Ç
an
ka
ya
– İndirect reduction
– Percutaneous plating
O
• Minimally invasive surgery
Ç
an
ka
ya
O
rt
op
ed
i
Bridging Techniques
op
Internal extramedullary splinting
ed
i
Bridging Plating
O
rt
• Long plate
Ç
an
ka
ya
• Less screw
op
• Functional reduction to restore
O
rt
– Alignment
– Length
– Rotation
Ç
an
ka
ya
• No anatomical reduction of the
fragments
ed
i
Indirect Reduction
Ç
an
ya
ka
op
rt
O
ed
i
MIPO
Ç
an
ya
ka
op
rt
O
ed
i
Distal Tibia
Ç
an
ya
ka
op
rt
O
ed
i
Distal Tibia
Ç
an
ya
ka
op
rt
O
ed
i
Distal Tibia
Ç
an
ya
ka
op
rt
O
ed
i
Distal Tibia
Ç
an
ya
ka
op
rt
O
ed
i
rt
op
ed
i
Spectrum of stability
• Some motion
• Relative stability
Ç
an
Compression
Neutralization
Buttress
Tension band
ka
ya
O
• No motion
• Absolute stability
Bridge
• Excessive
motion
• No stability
ed
i
AO Principles now !
ya
2. Adequate fixation
articular, simple fractures, forearm
comminuted meta-diaphyseal fractures
rt


Anatomical
Functional
O
•
•
op
1. Reduction
ka
– Absolute or relative stability depending on the fracture pattern
Ç
an
3. Preservation of blood supply and soft tissues
4. Early active pain-free mobilization
ed
i
LISS
“Less Invasive Stabilization System”
op
• Designed for MIPO
Ç
an
ka
ya
O
rt
• Internal fixator
LISS - DF
LISS - PLT
ed
i
LISS
Ç
an
ka
ya
rt
O
• Self-drilling, self-tapping
op
• Locking head screw
Ç
an
ya
ka
op
rt
O
ed
i
LISS - DF
Ç
an
ya
ka
op
rt
O
ed
i
LISS - DF
Ç
an
ya
ka
op
rt
O
ed
i
LISS - DF
Ç
an
ya
ka
op
rt
O
ed
i
ed
i
Locking Compression Plate (LCP)
op
Combination hole
Ç
an
ka
ya
O
rt
dynamic
compression
unit
conical and
threaded
unit
rt
op
Locking head screws (LHS)
Self-tapping LHS
Self-drilling, self-tapping LHS
Ç
an
ka
ya
O
Conventional screws
Cortex screw (with or without shaft)
Cancellous bone screw (with or
without shaft)
ed
i
Different types of screws
Difference of Function
Locked plate
Ç
an
ka
ya
O
rt
op
ed
i
Compression plate
Force Transmission by
Bone to Plate Friction
Force Transmission through
Locking Head Screw
Ç
an
ka
ya
O
rt
op
ed
i
Non-contact Plate
Locked plate does not compress underlying bone !!
op
• No compression of periosteum
ed
i
Advantages of LHS
rt
– Protects blood supply
ya
O
• Angular stability
• Better anchorage in osteoporotic bone
Ç
an
ka
– Less primary destruction of thread in the bone
– Higher resistance against bending forces
ed
i
Conventional Screws in Osteoporosis
Ç
an
ka
ya
O
rt
op
Failure at screwplate interface
sequential failure of screws
Small area of
bone loss
ed
i
LHS in Osteoporosis
Ç
an
ka
ya
O
rt
op
LHS and plate
functions as one unit
Larger area of
resistance
ya
O
rt
op
ed
i
LHS-Plate Unit
Ç
an
ka
Pull out force
Ç
an
ka
ya
O
rt
op
ed
i
LHS-Plate Unit
Pull out strength 
ed
i
No Bony Contact
op
• Preserved periosteal
Ç
an
ka
ya
O
rt
circulation
ed
i
Primary Loss of Reduction
op
• No compression of the plate
ya
metaphyseal region
O
• No contouring necessary in
rt
to the bone
Ç
an
ka
• Advantageous in MIPO
ed
i
Secondary Loss of Reduction
op
• Angular stability
Ç
an
ka
ya
• Osteoporotic fractures
O
fragments
rt
• Short epi-metaphyseal
ed
i
Application of LCP
rt
op
• When ?
ya
ka
Ç
an
• How ?
O
• Where ?
• Anatomical region
ed
i
When ?

Periarticular / metaphyseal fx
• Fracture pattern
op
– Not suitable for IM nail

ka
rt
ya

O
• Bone quality
Comminuted fx
Ç
an
• Surgical technique
• Special situations


– Bridge plating  relative stability
Osteoporosis
– Angular stability
MIPO
– No 10 loss of reduction
Periprosthetic fx
– Monocortical screw
op
Surgical technique
Ç
an
ka
ya
O
rt
Implants
ed
i
Do not mix things up!
Biomechanical principles
i
LCP for Absolute Stability
Ç
an
ka
ya
O
rt
op
ed
As a conventional plate, using conventional screws
Good bone quality
Ç
an
ed
ka
ya
O
rt
op
For poor bone quality
i
LCP for Absolute Stability
LHS for protection in osteoporotic bone especially in upper extremity
Ç
an
ya
ka
op
rt
O
CS 1
CS 2
ed
i
ed
i
Neutralization
op
• Free lag screws
– Absolute stability
O
rt
• Neutralization with locked plate
Ç
an
ka
ya
– Less periosteal compression
– No plate contouring
– Angular stability in poor bone
ka
ya
O
rt
op
Bridging plating
ed
i
LCP for Relative Stability
Ç
an
As an internal fixator, using locking head screws
op
rt
O
ya
ka
Proksimal humerus
Humeral shaft
Distal humerus
Distal radius
Proximal femur
Distal femur
Proximal tibia
Distal tibia
Hand
Foot
Ç
an
•
•
•
•
•
•
•
•
•
•
ed
i
Where ?
ed
i
Anatomically Preshaped Plates
O
rt
op
Standard plates
Ç
an
ka
ya
Special and anatomically preshaped plates
ed
i
Proximal Humerus
• Poor bone quality
rt
op
– Angular stability
– LHS in different directions
Ç
an
ka
ya
O
• MIPO
Ç
an
ka
ya
O
rt
op
ed
i
Proximal Humerus
MIPO technique
ed
i
Humeral Shaft
• MIPO
Ç
an
ka
ya
O
rt
op
• Rotational stability
ed
i
Distal Humerus
op
• Anatomically preshaped plates
• Short distal fragments
Ç
an
ka
ya
O
rt
– Angular stability
ed
i
Distal Radius
• Volar plating
Ç
an
ka
ya
O
rt
op
– Short segment
– Dorsal comminution
– Osteoporosis
ed
i
Lower Extremity
• Periarticular / metaphyseal fx
O
rt
op
– Short segment
– Osteoporosis
– Comminution
Ç
an
• MIPO
ka
– Relative stability
ya
• Bridging plating
Ç
an
ya
ka
op
rt
O
ed
i
Ç
an
ya
ka
op
rt
O
ed
i
MIPO
ed
i
Intraarticular Involvement
• Intraarticular component
Ç
an
ka
O
ya
– Bridging  relative stability
rt
• Metaphyseal component
op
– Lag screw  absolute stability
op
ed
i
Intraarticular Involvement
rt
Absolute
O
Relative
Ç
an
ka
ya
Relative
Absolute
Ç
an
ka
ya
O
rt
op
ed
i
Periprosthetic Fractures
ed
i
Diaphyseal Fractures
rt
O
• Multiple injured patients
op
When you cannot use IM nailing
ya
• Open physis
Ç
an
ka
• Narrow canal
Ç
an
ya
ka
op
rt
O
ed
i
Polytrauma
Ç
an
ya
ka
op
rt
O
ed
i
Pediatric
Ç
an
ya
ka
op
rt
O
ed
i
Narrow Canal
ed
i
How ?
ka
rt
O
ya
Plate length
Screw positon
Number of screws
Screw length
Ç
an
•
•
•
•
op
Pre-operative planning
Ç
an
ka
ya
O
rt
op
ed
i
Plate Length
Long lever arm
ya
O
rt
ed
op
Higher stress
i
Screw Position
Ç
an
ka
Maximum stress
Ç
an
ka
ya
O
rt
op
ed
i
Avoid short “middle”
ed
i
Implant Choice
• Plate length
rt
op
– Comminuted  2 or 3 X fx length
– Simple  8 or 10 X fx length
O
• 3 - 4 empty holes
ya
• Number of screws
ka
– Lower ex.  2 - 3 in each segment
– Upper ex.  3 - 4 in each segment
Ç
an
• Plate-screw density 0.40
• Anatomical plates in metaphysis
Plate length
Fx zone
ed
i
Hybrid use of screws
op
• Intraarticular fractures
rt
– Absolute stability
O
• Reduction
ka
ya
– Anatomically preshaped plates
– Big butterly fragment
• Articular orientation of fixed
Ç
an
angled screw
O
rt
op
ed
i
Hybrid use of screws
Ç
an
ka
ya
Lag before locked
Ç
an
ka
ya
O
rt
op
ed
i
Avoid monocortical screws
i
Working Length
ka
Ç
an
insufficient
working length
rt
O
ya
good bone
quality
op
ed
sufficient
working length
osteoporotic
bone
ed
i
Malreduction
op
• Locked plates don’t help
Ç
an
ka
ya
O
• Careful indirect reduction
rt
reduction !!
op
• Plate name ≠ plate function
ed
i
Take home messages
rt
• Any plate can be used in many ways
O
• Plate function is dependent upon:
ya
 Design
Ç
an
ka
 Method of application
ed
i
Take home messages
op
• Evolution of plates: mechanics  biology
• Comminuted fractures
rt
 Bridging plating  biological fixation
O
• Locked plating
 Planning !!
ka
ya
 Osteoporosis; short metaphyseal segments
 MIPO
Ç
an
 Understanding the principles
 Good functional reduction
 Correct choice of implant and application