1) Different types of plates function to produce absolute stability through interfragmentary compression, including compression plates, tension band plates, and buttress plates. 2) Absolute stability is achieved when fracture surfaces do not displace under functional loads, which requires neutralizing all forces through interfragmentary compression. 3) The key to absolute stability is using lag screws in combination with plates to provide interfragmentary compression between fracture fragments.

1. Muhammed Nazeer MS,FRCS

2. • To learn how absolute stability can be obtained using
plates
• To differentiate between plate name and function
• To learn how different types of plate function can
produce absolute stability
• To show how to reduce the biological price of rigid
fixation using plates
2

3. 3

4. • Refers to shape or design
• Catalogue name
4

5. 5
• “Surfaces of the fracture do not displace under
functional load”
• Can only be achieved by interfragmentary
compression
Absolute stability
• A plate by itself rarely provides absolute stability
• The key tool of absolute stability is the lag screw

6.  Compression must sufficiently neutralize all
forces[bending, tension, shear and rotation]
6

7.  The surgeon not the designer of
the plate determines how a plate will
function and how it will be applied
7

8. • Neutralization[Protection] plate
• Compression plate
• Tension band plate
• Buttress plate
• Bridge plate—relative stability
8

9. • Reduces torsional and axial forces on interfragmentary
compression screw(s)
• Always used with lag screws
• Requires anatomical reduction
9

10. 10

11. • Requires a transverse or short oblique fracture pattern
• Requires a simple fracture pattern
• Requires perfect plate contouring
11

12. 12
Compression plate:
eccentric DC (dynamic compression) hole
Removable device:
compression device
Interfragmentary compression by plate

13. 13

14. 14
Axial compression with removable
compression device
Metaphysis: plate contoured but
slightly less (shorter) than bone,
bone is pulled towards plate
Diaphysis: in order to compress
Opposite cortex plate must be prebent

15. 15

16. 16

17.  A plate applied to the tension side of a bone so
that tension forces on the plate side of the bone are
converted to compression forces on the opposite
cortex
17

18. 18

19. • Only works if you have a true tension side
• Only works if opposite cortex is intact
• Converts tension forces to compression forces on
opposite cortex
19

20. 20
Absolute stability: tension band principle
In the eccentrically loaded femur the tension side is always
lateral.
A plate MUST be placed on convex (tension) side to counteract
distraction forces.
However there must also be a medial bony buttress, if
missing, the plate will break due to fatigue.

21. 21
Plate on concave side distracts fracture
Absolute stability: tension band principle

22. 22

23. 23

24. •Resist axial load by applying force at 90 degree to the axis of
potential deformity
•Metaphyseal tibial plateau split fractures
24

25. • Used when the fracture will only displace in one direction
• Only useful in metaphyseal fractures
• Applied so as to resist one deforming force
25

26. 26

27. 27

28. 28

29. 29

30.  Plate may be a reduction tool
30

31. 31
Direct (primary) bone healing without
visible, external callus

32. 32
Absolute stability
only after rigid fixation with
interfragmentary compression
Internal remodelling
replaces dead structures
Fracture gradually disappears
Minimal periosteal callus
Direct (primary) fracture healing

33. 33
Hazards of absolute stability
Too aggressive exposure, periosteal stripping
Lack of respect for vascularity of all tissues
Poor soft-tissue care
Too much metal
Too stiff construct
Slow healing
Catastrophies

34. Careful technique →
interfragmentary compression →
absolute stability
Errors in technique and principles →
complications
• Delayed healing
• Implant failures
• Nonunions
• Wound complications and infections
34

35. 35

36. 36

37. • Cortical blood supply damage—potential problem
• Devascularization and transient osteoporosis beneath plate
37

38. • Change the design of the plate
• Change the surgical technique
38

39. 39
• Plates rely on friction between the plate and bone to
achieve stability
• The bone under the plate will always suffer a degree
of vascular damage
• The smaller the footprint of the plate the less the
damage will be

40. • Gradual evolution of plate design
• Minimize detrimental effects on bone
40
DCP
LC-DCP
PC-Fix
LCP

41. Preservation of the soft-tissue envelope profoundly
affects bone healing
41

42. • Always preserve soft tissues
• Use the least amount of metal
• Percutaneous approaches
• MIPO (minimally invasive plate osteosynthesis)
42

43. 43
Biological fixation & absolute stability?
• Balance between surgical fracture stabilization and
the insult to the biology caused by the technique
• A demanding surgical technique requiring much
experience and the correct indications

44. 44
Absolute stability of
conventional plating
Biologic damage of surgical
dissection and open
reduction

45.  Respect for soft-tissue envelope surrounding fractures is
essential
45
Caution! Open
carefully,
intraarticular fracture
inside
No returns
or second
chances
Handle
with
care

46. 46
Fractures requiring anatomical reduction and early functional aftercare
• articular fractures
• forearm fractures: closed/open
Fractures not suited for relative stability
• simple (type A) metaphyseal fracture
•Function of the plate is not the design but the surgeons technique
Utmost care for the vascularity of soft tissues, periosteum, and bone!
Take home message