Plates-form and function

AO principles

1. Pre Basic Course
Plates - form and function
Dr Sudarshan Bhandary

2. Plate : Form and Function
•To understand how changes in the design of
plates has evolved to meet the needs of the
patient
•To understand how you can use a plate in
several different ways to achieve different
types of fixation

3. Plate : Form and Function
•Absolute stability challenged by biological
fixation
•Osteosynthesis with plates has a firm place in #
treatment
•Articular #s require stable fixation
•Compromise of cortical blood supply a major
drawback of conventional plating

4. Plate : Form
•DCP
•Reconstruction plate
•Semitubular - 1/3
rd
Tubular Plate
•LC-DCP
•PC-FIX
•LCP
•LISS

5. DCP - 3.5 and 4.5
•First introduced in 1969 by Danis
•Revolutionary concept of compression plating
•Featured a new hole designed for axial compression
•Broad 4.5 for Femur & Narrow 4.5 for Humerus &
Tibia
•DCP 3.5 for Forearm, Fibula, Pelvis & Clavicle

6. •The screw hole in DCP is like a portion of an inclined
& angled cylinder
•When the screw is tightened it results in a movement
of bone fragment in relation to the plate

7. •Screw holes allow 1mm
compression
•Additional compression with
1 more eccentric screw before
locking first screw
•Oval shape allows 25*
inclination in longitudinal &
7* in transverse plane

8. Technique of application
3 drill guides
a)Concentric (Neutral) - Green collar - 0.1 mm offset
b)Eccentric (Load) - Gold collar - 1 mm offset
c)Universal for buttress mode

9. Problems with DCP
•Unstable fixation leads to fatigue & failure
•Strict adherence to principles of compression
•Compromised blood supply due to intimate
contact with underlying cortex
•“Refractures” after plate removal

10. LC-DCP
•Represents a design change
•Overcome problems with DCP
•Plate footprint reduced
•Minimized kinking at screw holes
•Allows more inclination of screw in
longitudinal plane

11. Technique of application
•New spring loaded drill guide
•Without pressure - Eccentric hole
•With pressure - Neutral

12. Tubular plates
•3.5 system - 1/3
rd
Tubular
•4.5 system - Semitubular
•Limited stability
•Collared hole
•Lateral malleolus
•Distal ulna / Olecranon
•Distal humerus

13. Reconstruction plates
•Deep notches between holes
•Accurate contouring in any
plane
•Pelvis
•Acetabulum
•Distal humerus
•Clavicle
•Olecranon

14. New Systems
•Abolish ill effects of plate to bone contact
•Concept of “Internal Fixator”
•PC - FIX = First implant designed
•Self tapping, unicortical, one length screws
•Locking head

15. LCP – Locking Compression Plate

16. L C P
•Latest in the evolution
•“ Internal fixator ”
•Combination of locking
screw with conventional
screw
•Extraperiosteal
location of plate

17. LCP
•Fixed angle stability
•Unicortical fixation
option
•Load & neutral position
of screws
•Conical screw head
•Large diameter

18. LISS-Less Invasive Stabilization System

19. LISS

20. Plate: Function

21. Principles of rigid internal fixation with plates
•Neutralization Plate
•Compression plate
•Buttress Plate
•Bridge Plate
•Tension Band Plate

22. Neutralisation Plate
•Used with lag screws , plate is
protective
•Neutralises the weight bearing forces
to protect the lag screws from axial
loading
•Lag screw generates forces of 3000 N

24. Compression plating
Techniques
•With dynamic compression principle
(DCP/LC-DCP)
•With tension devise
•By contouring plate
•Additional lag screw thro plate

25. Compression plating
•Compression through plate
- DC / LC-DC
•Compression with tension
devise

26. Compression with external devise

29. Contouring Plates
•To fit anatomy of bone
•Bending pliers
•Weakens plate

30. Buttress Plate
•Used when the fracture will only displace in one
direction.
•Only useful in metaphyseal fractures
•Applied so as to resist one deforming force

35. AO Organisation
☻Philosophies and techniques of treatment will
change with time
☻ The philosophy that we exist to improve the
care given to our patients will last forever

36. THANK YOU