Fracture fixation principles and choice of implants

badwaterreflectiveΠολεοδομικά Έργα

29 Νοε 2013 (πριν από 3 χρόνια και 6 μήνες)

141 εμφανίσεις

Fracture fixation

p
rinciples and choice of implants

AO principles of fracture management

Anatomic reduction

Fracture reduction and fixation to restore functional anatomical relationships.


Stable fixation

Stability by rigid fixation or
splintage
, as the personality of the fracture and the injury
requires.


Preservation of blood supply

Preservation of the blood supply to soft tissue and bone by careful handling and
gentle reduction techniques.


Early mobilization

Early and safe mobilization of the part and patient.

Principles of fracture management

Absolute Stability

Relative Stability

Principles of fracture management

Absolute Stability

Relative Stability

-
Direct Healing, (Primary)

-
No callous

-
No gap between the fracture
segments


Ex


Forearm and Intra
-
articular

Principles of fracture management

Absolute Stability

Relative Stability

-
Indirect Healing (Secondary),
with callous


Ex


Fractures other than intra
-
articular and forearm


Principles of fracture management

Absolute Stability

Relative Stability

-
Indirect Healing (Secondary),
with callous


Ex


Fractures other than intra
-
articular and forearm


-
Direct Healing, (Primary)

-
No callous

-
No gap between the fracture
segments


Ex


Forearm and Intra
-
articular

Preservation
of Blood Supply:


Limited contact stabilizes fracture
without plate
-
to
-
bone compression


Tapered tip allows
submuscular

(percutaneous)
plate

insertion, decreasing tissue destruction




DJ 4213

Early
Active Pain Free Mobilization:


A more stable construct = earlier return to
ADL

Evolution of Plates


DCP


Dynamic Compression Plate



LC
-
DCP


Limited Contact
Dynamic Compression Plate



LCP


Locking Compression Plate

Types of Screws

Cortical

Cancellous


Fully Treaded

Partially Treaded

Cannulaed

Locking

Conventional

Screw & Plate

Locked

Screw & Plate

Types of Internal Fixation


1
. Lag screws

2. Plates

3. Intramedullary Nails

4. Tension Band
Wiring

-
Stability
is achieved by compression & bone
contact


-
Load
transfer occurs directly from fragment to
fragment & not via the
implant


-
Should
be placed perpendicular to the fracture
line


-
Screw
can apply
2000
-
4000N


-

Drilling
& insertion of a lag screw stimulates
bone
formation around the threads
& maximum
strength is
reached at 6
-
8 weeks & at all times
remeins

higher
than
when inserted

Types of Internal Fixation


1
. Lag screws

2. Plates

3. Intramedullary Nails

4. Tension Band Wiring

Types of Internal Fixation


1
. Lag screws

2. Plates

3. Intramedullary Nails

4. Tension Band Wiring

Seven
types


a.
Neutralisation plate

b.
Compression plate

c
.
Buttress plate

d.
Bridging plate/ wave plate

e.
Antiglide

plate

f.
Tension
-
band plate

h.
Spring plate

Types of Internal Fixation


1
. Lag screws

2. Plates

3. Intramedullary Nails

4. Tension Band Wiring

Seven
types


a
.
Neutralisation plate

2. Compression plate

3. Buttress plate

4. Bridging plate/ wave plate

5.
Antiglide

plate

6. Tension
-
band plate

7. Spring plate

Protect
lag screws from bending, shear, &
rotation


Eg
. lateral malleolus fracture

Types of Internal Fixation


1
. Lag screws

2. Plates

3. Intramedullary Nails

4. Tension Band Wiring

Seven
types


a.
Neutralisation plate

b.
Compression plate

c
.
Buttress plate

d.
Bridging plate/ wave plate

e.
Antiglide

plate

f.
Tension
-
band plate

h.
Spring plate

-

Applied
to tension side of eccentrically loaded bone

-

Can
produce 600N compression

(
cf. 2000
-
4000N compression with lag screw)

-

Plate
should be
over bent
to produce compression on
-

F
ar
side as well as near cortex

-

Inner
screws applied first


Eg
. transverse or short oblique radial fracture

Types of Internal Fixation


1
. Lag screws

2. Plates

3. Intramedullary Nails

4. Tension Band Wiring

Seven
types


a.
Neutralisation plate

b.
Compression plate

c
.
Buttress plate

d.
Bridging plate/ wave plate

e.
Antiglide

plate

f.
Tension
-
band plate

h.
Spring plate

Physically protects underlying thin cortex

Often for
metaphyseal

fractures


Eg
.
tibial

plateau & distal radius fractures

Types of Internal Fixation


1
. Lag screws

2. Plates

3. Intramedullary Nails

4. Tension Band Wiring

Seven
types


a.
Neutralisation plate

b.
Compression plate

c
.
Buttress plate

d.
Bridging
plate

e.
Antiglide

plate

f.
Tension
-
band plate

h.
Spring plate

Treatment of
multi
-
fragmented
fractures

Bridge segment of
comminution

with indirect
reduction & minimal disruption to blood supply

Compression occasionally
possible


Eg.
Comminuted Ulnar/ Humerus
fracture

Types of Internal Fixation


1
. Lag screws

2. Plates

3. Intramedullary Nails

4. Tension Band Wiring

Seven
types


a.
Neutralisation plate

b.
Compression plate

c
.
Buttress plate

d.
Bridging plate/ wave plate

e.
Antiglide

plate

f.
Tension
-
band plate

h.
Spring plate

Secured at apex of fragment of oblique fracture to
physically block shortening or
displacement


Eg
. Weber B ankle fracture with posterior plate

Types of Internal Fixation


1
. Lag screws

2. Plates

3. Intramedullary Nails

4. Tension Band Wiring

Seven
types


a.
Neutralisation plate

b.
Compression plate

c
.
Buttress plate

d.
Bridging plate/ wave plate

e.
Antiglide

plate

f.
Tension
-
band plate

h.
Spring plate

Same principle as TBW with application on tensile
surface of eccentrically loaded bone & conversion of
tension forces to compression
forces


Eg
. olecranon plate

Types of Internal Fixation


1
. Lag screws

2. Plates

3. Intramedullary Nails

4. Tension Band Wiring

Seven
types


a.
Neutralisation plate

b.
Compression plate

c
.
Buttress plate

d.
Bridging plate/ wave plate

e.
Antiglide

plate

f.
Tension
-
band plate

h.
Spring plate

When do Locking Plates Work Best?

When conventional screw purchase may
be poor:



Osteopenic

bone



Metaphyseal

areas



Periprosthetic

fractures



Failed fixation/nonunion



Screw
strippage



Types of Internal Fixation


1
. Lag screws

2. Plates

3. Intramedullary Nails

4. Tension Band Wiring

Seven
types


a.
Neutralisation plate

b.
Compression plate

c
.
Buttress plate

d.
Bridging plate/ wave plate

e.
Antiglide

plate

f.
Tension
-
band plate

h.
Spring plate

How Many Cortices


Humerus
6

Radius & ulna 5

Femur
8

Tibia 6

Types of Internal Fixation


1
. Lag screws

2. Plates

3. Intramedullary Nails

4. Tension Band Wiring

Fixation of
diaphyseal

fractures of long bones


Types


-

Reamed
vs

Unreamed


-

Cylindrical
vs

Slotted


-

Locked
vs

Unlocked


-

Anterograde
vs

Retrograde


Types of Internal Fixation


1
. Lag screws

2. Plates

3. Intramedullary Nails

4. Tension Band Wiring

-

Relies
upon compression by the dynamic component of the functional load

-

Conversion
of tension forces to compression forces

-

Allows
some load
-
induced movement

-

Patella
& olecranon fractures

Bioabsorbable
Materials


Poly
-
lactic acid (PLA)

Not induce bone reaction

~ 2 years to resorb

Screws & wires
available


Poly
-
glycolic acid (PGA)

Associated with cyst
formation

-

Screw
pitch:


-

pitch of a screw is the distance between the threads, and the lead is distance thru

which
a screw advances with one turn;


-

Tensile
strength:
(resistance to breaking)


-

depends on root diameter (diameter of the screw between the threads)


-

Pull
out strength:


-

depends on the outside diameter of the threads;


-

does not depend on the number of threads per inch has no effect on pull out

strength
of screw, provided 5 or 6 threads are in cortex;


-

shear strength:


-

is proportional to the cube of the root diameter, and tensile strength is proportional

to
the square;


-

Tapping
vs. non tapping screws:


-

tap is designed in such a way that it is not only much sharper than thread of the

screw
, but also has a more efficient mechanism of clearing bone debris, which

therefore
does not accumulate and clog its threads;


Screw sizes


-

1.5 mm screws:


-

1.5 mm sized screw requires 1.1 mm drill bit


-

used for phalangeal
frx
;


-

2.0 mm screws:


-

2.0 mm sized screw requires 1.5 mm drill bit


-

used for phalangeal
frx

in larger patients;


-

usef

for metacarpal
frx
;


-

2.7 mm screws:


-

used for metacarpal
frx
;


-

2.7 mm sized screw requires 2.0 mm drill bit


-

AO 3.5 mm screw:


-

core diameter of 2.4 mm and requires a 2.5 mm drill bit;


-

Cancellous

Bone Screws: 4.0 mm


-

4.5 mm cortical screw:


-

Bioabsorbable

Screw Fixation in
Coracoclavicular

Ligament Reconstruction


-

Cancellous

Bone Screws
:



-

4.5
and 6.5 mm,
malleolar

screw made of stainless steel all have same core
diameter of 3.0 mm;


-

3.2 mm drill bit is used to predrill thread holes for each of these screws;

Screw Functions

1)
Lag

2)
Plate holding

3)
Locking screws

4)
Buttress /Anti
-
glide

5)
Anchoring Screw


Tension band

6)
Distraction

7)
Reduction

8)
Polar

9)
Position

Screw Functions

1)
Lag

2)
Plate holding

3)
Locking screws

4)
Buttress /Anti
-
glide

5)
Anchoring Screw


Tension band

6)
Distraction

7)
Reduction

8)
Polar

9)
Position

Thank you