This document discusses locking plate technology for fracture fixation. Some key points include: - Locking plates provide fixed-angle stability between screws and plate through threaded screw holes. - They allow for angular stability, increased pullout strength, and preservation of blood supply compared to conventional plates. - Indications include osteoporotic, periarticular, and comminuted fractures. Plates can be used in compression, neutralization, bridging, or combination modes. - Proper surgical planning, screw placement, and technique are important to avoid complications like loss of reduction, screw protrusion, or plate/screw failure.

1. .

2.  Fracture fixation devices with threaded screw
holes, which allow screws to thread to the plate
and function as fixed angle device.
 Any plate that allows the insertion of fixed angle or
angular stable screws or pegs can be used as a
locking plate.

3.  Follow the principle of ext.fixator
 INTERNAL FIXATOR
 Stability is maintained at angular stable screw
plate interface.
 Single beam construct.
 Pullout strength of locking screws higher than that
of conv. screws

4.  Has a combination hole whereby
conventional cortical screws can be applied
to achieve compression or locking head
screws can be applied for angular stability.
 No loss of primary or secondary #
reduction.
 No necrosis (stress shielding) under the
plate.
 Preservation of periosteal blood supply 
decrease in infection.

5.  Increased stability, less soft tissue dissection 
enhanced # healing
 Strain at the # site is optimized so secondary bone
healing with callus formation.
 Allows the use of unicortical screws
 Higher resistance to infection, faster union and
lower refractures.

6.  More expansive
 More difficult to use to help achieve an adequate
reduction.[speciality p]
 Do not improve reduction and cannot help a
poorly reduced # fracture to heal.

8.  Fractures associated with higher risk of loss of
reduction and plate or screw failure.
 Unsolved or problem fractures
1. Comm. Intraarticular #
2. Short segment periarticular #
3. Osteopenic bone #.

9.  According to mode of application of the plate.
 All indications are based on this four principles.
1. Compression P
2. Neutralisation P
3. Bridging P
4. Combination P

10. Mode of application  compression or neutralization
principle.
Compression P  osteoporotic forearm #
Neutralisation P  osteoporotic ankle #. [first lag
then lock].

11.  Mode of application  bridging or combination
principle.
 Proximal & distal humerus, distal radius, proximal
tibia.

12. .Applied , according to Combination principle.
Lag screws for articular fixation, locking head
screws for metaphyseal bridging.
Distal femur & tibia.

13. 4. Comminuted shaft fractures
mode of application  bridging principle [locked
internal fixator].
Shaft of femur, tibia, humerus.

14.  Using locked internal fixator technique for simple #
that requires interfragmental compression.
 Using minimally invasive percutaneous plate
fixation tech for simple fractures [violates concept
of # gap width in relation to strain  nonunion.

16.  Using locking internal fixator tech for fixing
displaced intraarticular # [Malunion, arthritis].
 Relatively C.I for # which can be satisfactorily
fixed with conventional plates.

17.  Secondary loss of reduction with varus collapse
as result of inadequate screw length and
inappropriate fixation of locking head screws in
plates.

19.  Failure of interface between locking head screws
and threaded plate holes occurs if screws are
inserted imperfect angle and torque limiting screw
drivers not used.

20.  Increased strain in a construct with too much
stiffness and exposure to high rotational forces will
lead either to breakage of plate in D.C part of
combihole which is the weakest part of the
construct or more rarely failure at screw plate
interface with breakage of screws.

22.  Locking screws cannot recede back wards as a
conventional screws can.So if longer screws are
used in the head part of the periarticular # ,chance
of protrusion of the screws in to the Jt.

24.  Formal preop planning is a must.
1. Sequence of screw placement
2. Length of screw
3. Position of plate
4. Surgical approach.
• Help to reduce the guess work and increase the
technical success

25.  Correct positioning of the Pt esp, in MIPPO
technique.
 Surgeon should also have preop plan for #
reduction.

26.  L.P offers minimal opportunity for screw
angulation. [> 5* angulation  failure.
 Screw should be perfectly lined lined up with the
axis of the screw threads in the plates. [otherwise
cross threading or cold welding will occurs]
 Malaligned screw threads  loose screws and
loss of reduction.

28.  In order to achieve a large area of stress
distribution on the plate ,at least three or four
holes should be left empty, at the level of the #.]
 Unicortical Screws should be of optimal length as
short s.  failure, long s.  push off from the far
cortex thus destroying the tapped, near cortex.

30.  Bicortical or unicortical
 self drilling / Self tapping or self taping
 Pullout resistance of unicortical locking screws is
almost identical to that of similar diameter
bicortical conventional screws and about 70% of
bicortical L.S.

31.  Locking screw heads are less likely to break since
difference between core diameter of the screw
shaft head is much smaller than conv.S.
 Nevertheless they can break in case of chronic
instability and increased strain as a result of
rotational forces.

33.  Usage of torque limiting screw device so threads
cannot be stripped or over-tightened. Even then
happens in MIPPO due to difficulty in judging the
orientation without direct visualization.
 Purchase of the screw in the bone cannot be felt,
L.S always feel tight.

34.  Two factors are essential in decision making;
1. Quality of the cortical bone
2. Extent of rotational forces applied to the cortical
bone.

35.  In a good quality cortical bone, the working length
of a Unicortical screw provides sufficient pullout
strength.
 In metaphyseal and osteoporotic ,due to thin
cortex always better to use bicortical screws.

36.  As a general rule self drilling / self tapping screws
are used in a unicortical fashion , for MIPPO
technique.
 Self drilling screws [sharp tips] can cause
neurovascular damage or soft tissue damage
across the far cortex.

37.  Bicortical screws should be used for # which are
exposed to high rotational forces like SOH.

38.  For long bone comminuted #, B.P used must be of
longer length with fewer screws to used.
 For periarticular # few screws are needed for
diaphysis and more screws are needed for
articular surface recon.

39.  In general length of the plate should be two times
the length of the fracture zone.
 Screws should be evenly spread and ideally there
should be one empty hole between each pair of
holes filled with screws.
 To avoid local stress conc, 3 / 4 holes should be
left empty at the level of #.

40.  Locking plates, particularly the specialized so-
called all-locking plates, require an approach to
fracture reduction that is completely different from
what is already practiced.
• One should consider initially using combination
plates, that allows traditional reduction tech.