应变理论在骨折愈合中的临床应用课件

应变理论在骨折愈合中的临床应用一点粗浅的了解2011-03-30n

骨折愈合的分型n

应变的概念n

基于Perren应变理论的一些AO理念n

附：微动促进骨折愈合的一项研究要点n

Fracture

healing

can

n

骨折愈合分为2种类型be

divided

into

twotypes:n

通过内塑形的一期或直接愈合n

通过骨痂形成的二期或间接愈合nprimary

or

directhealing

by

internalremodeling;n

secondary

or

indirecthealing

by

callusformation直接愈合仅发生在绝对稳定固定时，它是骨单位重建的生物过程n

occurs

only

with

absolutestability

and

is

a

biologicalprocess

of

osteonal

boneremodelingnn绝对稳定使骨折部位的修复组织在生理负荷下的应变完全消除n

将应变减少到临界值以下可以减少骨痂形成的刺激，使骨折的愈合没有出现肉眼可见的骨痂间接愈合n

occurs

with

relativestability

(flexible

fixationmethods).

It

is

verysimilar

to

the

process

ofembryological

bonedevelopment

andn

发生于相对稳定固定时（弹性固定方法），包括膜内成骨和软骨成骨n

除了加压技术外，所有的固定方法均可视为弹性固定，提供相对稳定性。其特点是骨痂形成includes

bothnintramembraneous

andendochondral

boneformation.

In

diaphysealfractures,

it

ischaracterized

by

theformation

of

callus.n

Bone

healing

can

bedivided

into

four

stages:n

inflammation;骨折间接愈合的四个阶段nn

炎性期n

soft

callus

formation;n

hard

callus

formation;n

remodeling.n

软骨痂形成期n

硬骨痂形成期n

重塑形期n

Interfragmentarymovement

stimulatesthe

formation

of

acallus

and

accelerateshealing骨痂形成需要一定程度的力学刺激nn骨折块之间的相对活动可刺激骨痂的形成，加速骨折的愈合Perren’s

strain

theoryn

The

manner

in

whichmechanical

factorsPerren应变理论解释了机械力学因素对于骨折愈合的影响ninfluence

fracture

healingis

explained

by

Perren’sstrain

theory.n

Perren

SM,

Cordey

J(1980)

The

concept

ofinterfragmentary

strain.Berlin

Heidelberg

NewYork:

Springer-Verlag.Perren's

strain

theoryPerren应变理论n

Motion

at

the

fracture

骨折端的活动引起的nresults

in

deformation

形变会在骨折端肉芽producing

strain

in

the

组织中产生应变granulation

tissue

atthe

fracture

site.Strain-应变n

Strain

is

the

deformationof

a

material

when

an

在应力作用下，材料在单位长度内发生的形变given

force

is

applied.n

对材料施加应力后其长度发生的变化n

Normal

strain

is

thechange

in

length

(Δ

l)

incomparison

to

originallength

(l)when

a

givenload

is

applied.

Thus,

ithas

no

dimensions

and

isoften

expressed

as

apercentage.n

没有单位，通常用百分比表示n

ε=（L-L。）/L。n

ε=

δL/Ln

The

amount

of

deformation

that

a

tissuecan

tolerate

and

still

function

variesgreatly.

Intact

bone

has

a

normal

straintolerance

of

2%

(before

it

fractures),whereas

granulation

tissue

has

a

straintolerance

of

100%.n

组织在功能正常状态下可耐受的变形程度有很大的变化范围n

完整骨骼的正常应变程度为2%（骨折发生前）n

肉芽组织的应变能力为100%n

在早期，当骨痂主要成分为软组织时，骨折端耐受畸形或组织应变的强度要大于后期的骨性骨痂只有当局部的应变小于编织骨所能耐受的程度，远近端的骨痂才能发生骨性连接n

Bony

bridging

between

thedistal

and

proximal

callus

canonly

occur

when

local

strain(ie,

deformation)

is

less

thanthe

forming

woven

bone

cantolerate.nn

因此，当骨折端的活动过大时，硬骨痂无法桥接骨折端n

Thus,

hard

callus

will

notbridge

a

fracture

gap

when

themovement

between

thefracture

ends

is

too

great在骨折愈合的后期，过n度的负荷使骨折块发生过多的活动不利于骨折的愈合n

Thus,

overloading

of

thefracture

with

too

muchinterfragmentary

movementlater

in

the

healing

process

isnot

well

toleratedn

Callus

formation

will

nottake

place

when

thestrain

is

too

low但是，当应变过小时骨痂无法形成nn

当固定装置过于坚硬或骨折间隙过宽时，会产生低应变的环境，此时可发生骨折不愈合或延迟愈合n

A

low-strain

environmentwill

be

produced

if

thefixation

device

is

too

stiff,or

if

the

fracture

gap

istoo

wide

.

Delayedhealing

and

nonunion

willresult根据Perren’s

strain

theoryn

the

strain

is

the

higher

the骨折间隙越小，应变越大nsmaller

the

gap

is.n

The

same

deformingforce

produces

morestrain

at

the

site

of

asimple

fracture

than

atn

相同的应力作用于简单骨折和粉碎骨折，其中简单骨折产生的that

of

a

multifragmentary

应变较大fracture.n

Multifragmentary

fractures

toleratemore

motion

between

the

twomain

fragments

because

theoverall

movement

is

shared

byseveral

fracture

planes,

whichreduces

the

tissue

strain

or粉碎骨折可耐受两个主要骨折块之间有更大范围的活动nn因为其总的活动被不同的骨折平面所分担，因此减少了骨折间隙中组织的应变deformation

at

the

fracture

gap.n

A

perfectly

reducedsimple

fracture

(smallgap)

stabilized

undercompression

(absolutestability

and

low

strain)heals

without

externalcallus

(direct

healing).简单骨折（间隙小）解剖复位加压固定（绝对稳定，低应变）后，骨折发生无外骨痂的愈合（直接愈合）nn

A

simple

fracture

(small

gap)fixed

with

a

bridging

plate(relative

stability)

is

exposed

tomovement

(high

strain).简单骨折（间隙小）用桥接钢板（相对稳定）固定后，骨折端的活动导致高应变，骨折愈合延迟甚至不愈合nFracture

healing

is

delayed

orwill

not

occur

at

alln

Today

there

is

clinicalexperience

and已有临床和实验室证据表明弹性固定可刺激骨痂的形成，从而促进骨折的愈合nnexperimental

proof

thatflexible

fixation

canstimulate

callus

formation,thereby

acceleratingfracture

healing

.骨干骨折后，使用随内钉、外固定架、桥接钢板固定可观察到这一现象nThis

can

be

observed

indiaphyseal

fracturessplinted

by

intramedullarynails,

external

fixators,

orbridging

platesn

In

a

complex

fracture

(largegap)

fixed

with

a

bridging

plate(relative

stability)

the

strain

willbe

low

in

spite

of

movement,and

fracture

healing

will

occurwith

callus

formation

(indirectbone

healing).复杂骨折（间隙大）用桥接钢板（相对稳定）固定后，骨折端虽有活动，但应变低，骨折发生有骨痂形成的愈合（间接愈合）n外部机械刺激对应用弹性外固定固定的骨干截骨模型愈合作用的研究Backgroundn

It

is

generally

accepted

that

smallinterfragmentary

movements

(IFMs)

yieldbetter

bone

healing

results

than

largerIFMs

(

>

1

mm).n

However,

the

optimal

size

of

IFM

within

thel-mm

range

remains

undetermined.Objectiven

The

purpose

of

this

study

was

toinvestigate

the

effect

of

an

externallyapplied

mechanical

stimulus

on

fracturehealing

under

flexible

fixation.Designn

Stimulation

of

fracture

healing

undervarious

conditions

of

interfragmentarymovement

in

an

in

vivo

fracture

model

on41

sheepMethodsn

Standardized

transverse

osteotomy

of

3mm

gap

size

in

the

left

ovine

tibia

wasfixed

with

an

unilateral

external

fixator.n

To

perform

controlled

axial

micromovement,

acustom-desig