1. Locked Plating Thomas F. Higgins, MD; Sean E. Nork, MD;
James P. Stannard, MD; and Philip J. Kregor, MD
Created October 2006 and Revised October 2011

2. Locked Plating
Thomas F. Higgins, MD

3. Definition
Locked plating, for the purposes of this talk, is a screw and plate construct for the purposes of osteosynthesis, in which the screw engages the plate with a mechanism which secures a fixed angle between the two.

4. History
Locked plating, improvised in various ways for years, and in development for many years, came into widespread commercial availability and clinical use in the United States between 1998 and 2002.

5. Five stages of new Medical Technology
Experimentation
Skepticism
Fevered enthusiasm / overuse
Complications and despair
Judicious use

6. Hopefully, the pendulum is now swinging toward a better understanding of locked plating and judicious use

7. Like much new medical technology, the employment of locked plating was complicated by a lack of a thorough understanding of indications and mechanism of action

8. The ideal recipe for implant and construct stiffness is still not fully understood. Where maximizing construct stiffness was once the ultimate goal, locked plating has likely created some situations where constructs have, in fact, become TOO stiff.

9. The correct employment of locked plating techniques necessitates understanding the following:
Mechanism of action of locked plating
Differences from non-locked plating
Indications for locked plating
Contra-indications / misuses of locked plating

10. Gauthier et al, Injury 2003, Vol 34 Supplement 2, pp. B63-76
Recommended Reading
Gauthier et al, Injury 2003, Vol 34 Supplement 2, pp. B63-76

11. Mechanics of locked plating

12. Traditional (non-locking) plates rely on friction between the plate and the bone achieved by terminally tightening of screws passed through the plate to the bone.
Locked plating does not require that the plate be compressed to the bone, as the interface between the plate and screw is secured without this plate-bone compression

13. With non-locking fixation, failure of fixation may initiate with toggle between the screw and plate, subsequent loss of compression between the plate and bone

14. Correct and incorrect sequencing in the application of locked plating

15. Surgical Technique Reduce the joint (if applicable)
LAG First (Lag, then Lock)
Re-confirm alignment
Lock
After the second locked screw, no change can be made

16. The next twelve slides should be viewed as a “slide show”
The next twelve slides should be viewed as a “slide show”. The screws with green “x”’s represent locking screws, and the screws without “x”’s are non-locking.

17. Lab Exercise Metaphyseal Fixation (Animation)
(In slide show-Bone first shown with no screws showing reduced condyles)
First, insert middle conical screw to obtain additional compression
Add locking screws to solidify and create fixed angle device
Metaphyseal
Fixation

18. Lab Exercise Metaphyseal Fixation (Animation)
Remove middle conical screw and replace with locking screw
Metaphyseal
Fixation

19. Lab Exercise
(Animation)
Metaphyseal
Fixation

20. Lab Exercise Metaphyseal Reduction of Shaft Fixation (Animation)
Now time to coapt plate to shaft
1st screw locked to plate
2nd screw put in load position
3rd screw put in neutral
Fragment will not reduce due to the locked screw
Metaphyseal
Fixation
Reduction of Shaft

21. Lab Exercise Metaphyseal Reduction of Shaft Fixation (Animation)
1st Screw as traditional 4.5 cortical screw
Tightened down the bone reduces to the plate
3rd screw as locking screw- eliminates the possibly of toggle and thereby eliminates loosening and shortening
Biomechanics especially relevant in osteopenic bone
Metaphyseal
Fixation
Reduction of Shaft

22. Metaphyseal Reduction of Shaft Fixation (Animation)
Load position to compress fracture
Metaphyseal
Fixation
Reduction of Shaft

23. Metaphyseal Reduction of Shaft Fixation (Animation)
Axial alignment achieved
Metaphyseal
Fixation
Reduction of Shaft

24. Metaphyseal Reduction of Shaft Fixation (Animation)
2nd screw as traditional 4.5 cortical screw reduces bone to plate
Metaphyseal
Fixation
Reduction of Shaft

25. Metaphyseal Reduction of Shaft Fixation (Animation)
Axial alignment achieved
Metaphyseal
Fixation
Reduction of Shaft

26. (Animation)
Axial Loading
Metaphyseal
Fixation
Reduction of Shaft

27. Metaphyseal Reduction of Shaft Fixation (Animation)
Axial loading-Toggle because present construct is relying on friction
Metaphyseal
Fixation
Reduction of Shaft

28. Metaphyseal Reduction of Shaft Fixation (Animation)
3rd screw as locking screw- eliminates the possibly of toggle and thereby eliminates loosening and shortening
Metaphyseal
Fixation
Reduction of Shaft

29. Locked Plating Advantages
Increased rigidity
Decreased toggle
Potential use as a reduction tool
May permit fixation with less stripping of soft tissues
May be helpful in osteoporotic bone

30. Locked Plating Disadvantages
Very expensive
Constructs may be too rigid
Some percutaneous applications be self-drilling
That must be unicortical or strips near cortex
No tactile feedback on bone purchase
They “allow you to stop thinking”
Reduction must still be achieved, it is not magically achieved by locking implant

31. List of Indications for Locking
(Framework)

32. Indications for Locking
Biological Fixation
Spanning Comminution (bridging)
Percutaneous Techniques in selected indications
Implant as reduction tool
Metaphyseal / Bicondylar Articular Fractures
Short Articular Segment
Periprosthetic Fractures
Osteoporosis

33. Biological Fixation
Without necessitating compression of the plate to the bone to achieve fixation, locked plating may be applied percutaneously, or with less damage to the vascularized tissue immediately adjacent the bone.

34. Obese 33 yo female with bilateral open femur fractures

35. I&D, Spanning external fixation

36. Locking plate is secured to the peri-articular segment, the metaphyseal is not disturbed or dissected, and then the plate is secured to the diaphysis.

37. Plate is fixed to the distal fragment in the correct varus / valgus orientation, through a separate incsion

38. Separate incision permits proximal fixation to the bone

39. Fracture zone is undisturbed, permitting callus formation and secondary healing

40. Both the nailed and plated fractures heal with callus
Bridging fixation on both sides, with locked bridge plating OR with nail, yields callus formation, secondary bone healing, and good alignment at union.

41. Percutaneous Techniques are a form of “biological plating”
(in selected indications)

42. 15 y.o. male

44. This is a functions like a nail: Secondary healing, Relative stability

45. Percutaneous / Submuscular Plating

46. Metaphyseal / Bicondylar Articular Fracture

47. 36 y.o. male skier

48. 36 y.o. male skier

49. With bicondylar involvement, and very small articular segment, locking fixation allows us to secure the joint surface back to the diaphysis in the correct orientation

50. 4 months out

51. Long Standing 6 months

52. Use of Locked Plate as Reduction Tool
Lock plate to articular segment in correct alignment
Provisionally affix plate to diaphysis
Confirm alignment
Secure plate to the diaphysis with non-locking or locking screws

53. Obese 47 y.o. female Open Distal femur fracture

54. Reduce Joint
Reduce jointm then set the correct orientation of the plate on the articular fragment (as with this jg)

55. Make sure it is not flexed or extended on the lateral view (done in this case with jig)

56. After joint reduction, make sure that the plate is correctly aligned to the articular segment. Then connect to diaphysis.

57. Connect reduced joint to Diaphysis

58. Short Articular Segment

59. Open Femur Fracture 27 y.o. male
Motorcycle vs. flatbed truck, then guard rail
Open L femur with segmental loss,
Segmental L tibia

61. Very small remaining articular segment

62. ORIF and cement spacer in metaphysis

63. Well healed after subsequent bone grafting

64. 35 y.o. vs. tractor

65. Femoral neck fracture plus intertrochanteric fracture equals short articular segment

68. Periprosthetic Fractures
(This is also a form of a short articular segment)

69. Obese 64 y.o. female

73. 72 y.o. male TAA Periprosthetic Fracture “Periprosthetic” = Short Articular Segment

75. Osteoporosis

76. 74 y.o. diabetic female

79. Locking Plate Principles
Locking plate is an IMPLANT, not a technique
There are unique techniques
Beware the siren call of M.I.S. (Mal-aligned Implant Surgery)

80. Locking Implants Still Require Reduction

81. Unclear Indications/ Non-indication

82. Compression plating in healthy diaphyseal bone does not require locking

83. 16 y.o. male, healthy bone, non-locking fixation

84. 18 y.o. female, diaphyseal injury. Locking fixation not necessary

85. Partial Articular Fractures “B-type fractures” require buttress, not locking.

86. 24 y.o. male Snowboarder vs. Half-Pipe

89. Beware “too rigid” construct

90. 72 y. o. Rheumatoid female on multiple cytotoxic medications
72 y.o. Rheumatoid female on multiple cytotoxic medications. Ground level fall. Repaired with this locking construct

92. The experience over the last ten years with locking fixation has demonstrated that we now have the ability to make a construct “too strong” or “too stiff”

93. Particularly in
Comminuted metaphyseal fractures, or
Very simple transverse or spiral patterns
rigid immobilization of the fracture may obliterate all motion, and prevent the formation of callus, leading to non-unions.

94. In these patterns, the correct answer may be a wider spread of our fixation, allowing more motion around the fragments, and the formation of a more vigorous healing response

95. Failed varus nonunion revised to this, allowing more motion in the metaphysis and a callus response.

96. One other potential response to the problem of excess stiffness in locking constructs has been so called “far cortical locking”. This entails over-drilling the near cortex and then placing a screw that engages the far cortex and locks in the plate (see diagram, next slide). This may theoretically allow more motion in the construct, and reduce strain at the screw – plate interface. At the time of this publishing, this technology has not been proven clinically, but may have some promise in the future.

97. “Far cortical locking”

98. Locked Plating Mechanics Summary
Understand the biomechanical difference from conventional plating
Understand the limitations
Reduce and lag before locking

99. Locked Plating Indications Summary
Biological Fixation
Plate as a reduction tool
Metaphyseal / Articular Fractures
Short articular segments / periprosthetics
Osteoporosis

100. Locked Plating Huge advance in plating
Must understand biomechanics and what the various constructs accomplish
Need to know and understand the new “rules” of locked plating, as we understand them, and not just apply locked plating blindly
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102. Thank You
If you would like to volunteer as an author for the Resident Slide Project or recommend updates to any of the following slides, please send an to
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