3. Definition
Locked plating is a screw and
plate construct in which the
screw engages special coupling
holes in the plate with a
mechanism which secures a
fixed angle between the two.
New variable angle locked plates
4. 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
– Misuses of locked plating
5. Mechanics of locked plating
Traditional plates rely on
friction between the plate and
the bone achieved by
terminally tightening of screws
through the plate to the bone.
(Bone screw interface)
In locked plates, the screw head
is locked in the plate by
coupling of the threaded
chamber on the plate and the
threads in the screw head.
(plate screw interface)
6. Failure
With non-locking fixation, failure of
fixation may initiate with toggle of
the screw in the bone screw interface
with subsequent loss of compression
between the plate and bone
(sequential failure)
In locking screw fixation, a
monobloc effect is produced, with
all the screws forcing at the same
time
7. Surgical Technique
Anatomic reduction of the articular surface (if intra-
articular)
Absolute stability by LAG First
Alignment of metaphyseal #.
Lock.
After the second locked screw, no change can be made
15. Locked Plating Advantages
Increased rigidity.
May permit fixation with less stripping of soft tissues
(MIPO) also do not disrupt the underlying bone perfusion.
Helpful in osteoporotic bone.
More screws in small area (Divergent).
Screw insertion doesn’t alter the reduction.
