Bone

marrow

edema-like

lesions

change

in

volume

in

the

majority

of

patients

with

osteoarthritis

associations

with

clinical

features

It

has

been

suggested

that

bone

marrow

edema-like

-LRB-

BME

-RRB-

lesions

in

the

knee

are

associated

with

progression

of

osteoarthritis

-LRB-

OA

-RRB-

The

purpose

of

our

study

in

patients

with

OA

was

to

evaluate

prospectively

changes

of

BME

lesions

over

years

and

their

relationship

with

clinical

features

Magnetic

resonance

-LRB-

MR

-RRB-

images

of

the

knee

were

obtained

from

patients

-LRB-

male

aged

years

mean

age

years

-RRB-

who

had

been

diagnosed

with

familial

symptomatic

OA

at

multiple

joint

sites

MR

images

were

made

at

baseline

and

at

years

follow-up

BME

lesions

in

years

were

associated

with

clinical

features

assessed

by

Western

Ontario

and

McMaster

Universities

Osteoarthritis

-LRB-

WOMAC

-RRB-

scores

A

total

of

BME

lesions

were

recorded

Total

size

of

BME

lesions

changed

in

patients

-LRB-

-RRB-

Size

of

individual

lesions

changed

in

foci

-LRB-

-RRB-

new

lesions

appeared

in

-LRB-

-RRB-

existing

lesions

disappeared

in

-LRB-

-RRB-

increased

in

size

in

-LRB-

-RRB-

and

decreased

in

size

in

-LRB-

-RRB-

lesions

Increase

or

decrease

of

BME

lesions

over

a

time

period

was

not

associated

with

severity

of

WOMAC

scores

BME

lesions

fluctuated

in

the

majority

of

patients

with

OA

over

a

time

period

These

changes

were

not

associated

with

severity

of

WOMAC

scores

at

the

study

end

point

Introduction

Knee

osteoarthritis

-LRB-

OA

-RRB-

is

a

chronic

progressive

joint

disease

leading

to

pain

and

loss

of

function

in

a

considerable

proportion

of

patients

with

great

impact

and

consequences

in

the

ageing

population

of

the

industrialized

world

Disease

markers

need

to

be

identified

in

order

to

predict

and

quantify

progression

One

possible

marker

in

OA

is

the

so-called

bone

marrow

edema-like

-LRB-

BME

-RRB-

lesions

-LSB-

-RSB-

Unfortunately

the

role

of

BME

in

OA

remains

controversial

as

contradictory

results

have

been

reported

BME

detected

with

magnetic

resonance

-LRB-

MR

-RRB-

imaging

has

been

associated

with

clinical

symptoms

in

patients

with

OA

-LSB-

-RSB-

However

other

studies

reported

no

association

between

BME

lesions

and

clinical

symptoms

-LSB-

-RSB-

Further

the

role

of

BME

as

a

marker

for

progression

of

OA

is

open

to

discussion

In

a

study

by

Felson

et

al.

-LSB-

-RSB-

BME

was

associated

with

progression

of

OA

as

assessed

by

joint

space

narrowing

on

conventional

radiographs

On

the

other

hand

in

a

study

by

Phan

et

al.

-LSB-

-RSB-

changes

in

BME

did

not

significantly

change

with

progression

of

disease

assessed

by

Western

Ontario

and

McMaster

Universities

Osteoarthritis

-LRB-

WOMAC

-RRB-

scores

Since

these

contradictory

results

regarding

the

association

between

BME

and

clinical

features

have

been

reported

the

purpose

of

our

study

was

to

evaluate

changes

in

BME

lesions

over

a

period

and

associate

them

with

clinical

features

Patients

and

methods

Patients

The

present

prospective

study

is

part

of

the

ongoing

GARP

-LRB-

Genetics

Osteoarthritis

and

Progression

-RRB-

study

-LSB-

-RSB-

The

primary

goal

of

the

GARP

study

is

the

identification

of

genetic

susceptibility

determinants

to

OA

and

disease

progression

in

middle-aged

sibling

pairs

with

OA

at

multiple

joint

sites

MR

image

sets

of

the

knee

were

obtained

in

patients

at

study

entry

and

after

years

-LSB-

-RSB-

Only

one

knee

the

most

symptomatic

was

imaged

per

patient

In

the

present

study

-LRB-

-RRB-

of

the

patients

had

symptomatic

knee

OA

in

their

imaged

knee

defined

as

pain

or

stiffness

on

most

days

in

the

month

prior

to

study

entry

and

osteophytes

on

radiographs

As

the

purpose

of

the

MR

study

was

to

assess

progression

of

OA

no

images

were

made

of

a

knee

that

already

had

a

maximum

Kellgren

and

Lawrence

score

of

grade

-LSB-

-RSB-

Clinical

assessment

Clinical

data

were

assessed

by

WOMAC

to

assess

pain

stiffness

and

functional

impairment

of

the

imaged

knee

at

the

time

point

not

at

baseline

-LSB-

-RSB-

MR

acquisition

Knees

were

imaged

using

a

transmit-receive

four-channel

knee

coil

in

a

superconducting

magnet

-LRB-

Philips

Medical

Systems

Best

the

Netherlands

-RRB-

Each

examination

consisted

of

coronal

proton

density

and

dual

spin

echo

-LRB-

SE

-RRB-

images

-LRB-

with

repetition

time

-LRB-

TR

-RRB-

of

ms

echo

time

-LRB-

TE

-RRB-

of

ms

number

of

excitations

per

data

line

-LRB-

NEX

-RRB-

mm

slice

thickness

mm

intersection

gap

mm

field

of

view

-LRB-

FOV

-RRB-

acquisition

matrix

slices

-RRB-

sagittal

proton

density

and

dual

SE

images

-LRB-

TR

ms

TE

ms

NEX

mm

slice

thickness

mm

intersection

gap

mm

-LRB-

FOV

-RRB-

acquisition

matrix

slices

-RRB-

sagittal

spoiled

gradient

echo

-LRB-

GE

-RRB-

frequency

selective

fat

suppressed

images

-LRB-

TR

ms

TE

ms

NEX

flip

angle

mm

slice

thickness

slice

overlap

mm

no

gap

mm

-LRB-

FOV

-RRB-

acquisition

matrix

slices

-RRB-

and

axial

proton

density

and

turbo

spin

echo

-LRB-

TSE

-RRB-

fat

suppressed

images

-LRB-

TR

ms

TE

ms

NEX

mm

slice

thickness

no

gap

mm

-LRB-

FOV

-RRB-

acquisition

matrix

slices

-RRB-

Total

acquisition

time

-LRB-

including

the

initial

survey

sequence

-RRB-

was

min

MR

interpretation

All

MR

images

were

analyzed

in

known

chronological

order

by

means

of

consensus

between

three

experienced

readers

using

a

comprehensive

score

form

-LSB-

-RSB-

During

the

assessment

the

readers

were

blinded

to

radiographic

results

patient

symptoms

and

patient

age

In

cases

of

disagreement

between

the

readers

the

more

conservative

less

severe

score

was

recorded

BME

or

cysic

lesions

was

assigned

to

any

one

or

more

of

the

following

anatomic

locations

the

crista

patellae

medial

or

lateral

patellar

facets

the

medial

or

lateral

trochlear

articular

facets

the

medial

or

lateral

femoral

condyles

the

medial

or

lateral

tibial

plateaux

BME

lesions

were

defined

as

an

ill-defined

area

of

increased

signal

intensity

on

images

in

the

subchondral

bone

extending

away

from

the

articular

surface

over

a

variable

distance

-LSB-

-RSB-

The

lesions

were

graded

as

follows

grade

absent

grade

minimal

-LRB-

diameter

mm

-RRB-

grade

moderate

-LRB-

diameter

mm

mm

-RRB-

grade

severe

-LRB-

diameter

mm

-RRB-

The

maximum

two-dimensional

diameter

was

measured

to

grade

the

lesion

A

total

BME

score

of

the

knee

was

calculated

by

adding

all

grades

of

each

BME

lesion

in

the

knee

Maximum

possible

knee

score

was

-LRB-

grade

times

nine

anatomic

locations

-RRB-

In

the

total

study

a

maximum

of

BME

lesions

-LRB-

patients

times

nine

anatomic

locations

-RRB-

could

be

scored

Subchondral

cysts

were

defined

as

well-defined

foci

of

high

signal

intensity

with

low

signal

intensity

margins

on

images

in

the

bone

underlying

the

joint

cartilage

Their

greatest

dimension

was

measured

and

they

were

graded

as

follows

grade

absent

grade

minimal

-LRB-

mm

-RRB-

grade

moderate

-LRB-

mm

-RRB-

grade

severe

-LRB-

mm

-RRB-

A

total

score

of

the

knee

was

calculated

by

adding

all

grades

of

each

cystic

lesion

in

the

knee

Maximum

possible

knee

score

was

-LRB-

grade

times

nine

anatomic

locations

-RRB-

In

the

total

study

a

maximum

of

cystic

lesions

-LRB-

patients

times

nine

anatomic

locations

-RRB-

could

be

scored

Statistical

analysis

Odds

ratios

-LRB-

ORs

-RRB-

with

confidence

intervals

-LRB-

CIs

-RRB-

were

used

to

show

any

association

between

BME

size

changes

with

cystic

size

changes

The

difference

in

WOMAC

scores

between

patients

without

BME

lesions

-LRB-

group

A

-RRB-

and

patients

with

BME

lesions

-LRB-

group

B

unchanged

BME

lesions

over

years

group

C

increasing

size

of

BME

lesions

over

years

group

D

decreasing

size

of

BME

lesions

over

years

-RRB-

was

calculated

by

linear

mixed

models

in

SPSS

for

Windows

version

-LRB-

SPSS

Chicago

Ill.

-RRB-

with

a

random

intercept

to

adjust

for

the

familial

effect

within

sib

pairs

Adjustments

were

made

for

age

sex

and

body

mass

index

-LRB-

BMI

-RRB-

Estimates

of

fixed

effects

were

reported

with

CIs

Results

In

total

patients

were

monitored

over

a

period

of

years

-LRB-

Table

-RRB-

Forty-six

-LRB-

-RRB-

patients

did

not

have

BME

lesions

thus

patients

-LRB-

-RRB-

had

one

or

more

BME

lesions

at

any

time

point

In

-LRB-

-RRB-

of

patients

BME

scores

did

not

fluctuate

whereas

they

changed

in

the

other

-LRB-

-RRB-

patients

The

total

BME

score

per

individual

patient

increased

in

-LRB-

-RRB-

patients

It

decreased

in

patients

-LRB-

-RRB-

and

total

BME

score

remained

unchanged

in

nine

-LRB-

-RRB-

patients

Individual

BME

scores

did

change

in

this

last

group

without

resulting

in

a

change

of

the

total

BME

score

A

total

of

BME

lesions

were

detected

from

a

possible

total

of

lesions

-LRB-

Table

-RRB-

One

hundred

and

forty-seven

-LRB-

-RRB-

BME

lesions

changed

new

lesions

appeared

on

the

second

MR

-LRB-

-RRB-

-LRB-

-RRB-

increased

-LRB-

-RRB-

decreased

in

size

and

-LRB-

-RRB-

were

no

longer

visible

on

the

second

MR

scan

-LRB-

Fig.

-RRB-

It

was

noted

that

more

lesions

appeared

or

increased

than

decreased

or

disappeared

Table

characteristics

-LRB-

n

-RRB-

At

baselineAge

years

median

-LRB-

range

-RRB-

-LRB-

-RRB-

Female

sex

-LRB-

-RRB-

-LRB-

-RRB-

Body

mass

index

-LRB-

-RRB-

median

-LRB-

range

-RRB-

-LRB-

-RRB-

Symptomatic

knee

OA

n

-LRB-

-RRB-

-LRB-

-RRB-

Kellgren

Lawrence

Score

No.

yearsBone

marrow

edema-like

lesions

n

-LRB-

-RRB-

-LRB-

-RRB-

Grade

n

-LRB-

-RRB-

-LRB-

-RRB-

Grade

yearsWOMAC

Pain

scores

median

-LRB-

range

-RRB-

-LRB-

-RRB-

WOMAC

Stiffness

scores

median

-LRB-

range

-RRB-

-LRB-

-RRB-

WOMAC

Function

scores

median

-LRB-

range

-RRB-

-LRB-

-RRB-

aDefined

as

pain

or

stiffness

on

most

days

of

the

month

prior

to

study

entry

in

combination

with

osteophytes

on

radiographsbDuring

yearscMaximal

grade

per

patientdn

and

BME

lesions

per

patient

changing

over

years

in

patients

-LRB-

n

-RRB-

BME

lesionsNo

BMENo

changeIncreaseDecreaseTotalCystsNo

No

Fig.

d

Axial

turbo

spin

echo

fat

suppressed

images

Increase

-LRB-

a

at

baseline

b

after

two

years

-RRB-

in

size

of

bone

marrow

edema-like

lesions

over

years

at

the

crista

patella

-LRB-

arrow

-RRB-

and

at

the

medial

femoral

condyle

-LRB-

arrowhead

-RRB-

Decrease

-LRB-

c

at

baseline

d

after

two

years

-RRB-

in

size

of

bone

marrow

edema-like

lesions

over

years

at

the

crista

and

medial

part

of

the

patella

-LRB-

open

arrowhead

-RRB-

One

hundred

-LRB-

-RRB-

patients

had

one

or

more

cystic

lesions

at

any

time

In

patients

-LRB-

-RRB-

total

cystic

score

did

not

fluctuate

over

time

whereas

in

the

other

patients

-LRB-

-RRB-

the

total

cystic

score

changed

in

size

In

of

these

patients

-LRB-

-RRB-

the

cystic

score

increased

it

decreased

in

patients

-LRB-

-RRB-

and

the

total

cystic

score

remained

unchanged

irrespective

of

changes

on

the

level

of

individual

cysts

in

two

patients

-LRB-

-RRB-

A

total

of

cystic

lesions

were

detected

from

a

possible

total

of

sites

-LRB-

Table

-RRB-

Seventy

cystic

lesions

-LRB-

-RRB-

changed

new

cysts

appeared

on

the

second

MR

-LRB-

-RRB-

-LRB-

-RRB-

increased

six

-LRB-

-RRB-

decreased

in

size

and

-LRB-

-RRB-

were

no

longer

visible

on

the

second

MR

-LRB-

Fig.

-RRB-

Fig.

bAxial

turbo

spin

echo

fat

suppressed

images

Disappearing

cyst

at

the

lateral

femoral

condyle

-LRB-

arrow

-RRB-

a

At

baseline

b

after

years

Cystic

and

BME

lesions

were

both

present

in

the

same

anatomic

location

-LRB-

associated

lesions

-RRB-

in

cases

A

change

of

BME

lesions

or

cystic

lesions

was

associated

with

a

change

in

size

of

an

adjacent

cystic

or

BME

lesion

-LRB-

OR

CI

-RRB-

In

cases

both

BME

lesions

and

cystic

lesions

changed

When

cystic

and

BME

lesions

were

both

present

in

the

same

anatomic

location

size

changes

-LRB-

increase

or

decrease

-RRB-

were

in

same

direction

-LRB-

OR

CI

-RRB-

-LRB-

Table

-RRB-

One

hundred

and

fifty-seven

-LRB-

-RRB-

patients

completed

a

WOMAC

questionnaire

of

the

imaged

knee

at

years

The

WOMAC

pain

and

function

scores

for

patients

without

and

with

BME

lesions

over

years

are

shown

in

Fig.

and

b

respectively

The

mean

WOMAC

scores

did

not

differ

between

the

different

patient

groups

even

when

BME

lesions

completely

disappeared

lower

WOMAC

scores

were

not

recorded

The

mean

difference

in

WOMAC

pain

scores

between

patients

with

unchanged

BME

lesions

with

increasing

BME

lesions

and

with

decreasing

BME

lesions

compared

with

patients

without

BME

lesions

were

-LRB-

to

-RRB-

-LRB-

to

-RRB-

and

-LRB-

to

-RRB-

respectively

-LRB-

Fig.

-RRB-

The

mean

difference

in

WOMAC

function

scores

between

patients

with

unchanged

BME

lesions

with

increasing

BME

lesions

and

with

decreasing

BME

lesions

compared

to

patients

without

BME

lesions

were

-LRB-

to

-RRB-

-LRB-

to

-RRB-

and

-LRB-

to

-RRB-

respectively

-LRB-

Fig.

-RRB-

Fig.

between

WOMAC

pain

-LRB-

a

-RRB-

or

function

-LRB-

b

-RRB-

scores

and

bone

marrow

edema-like

lesions

Group

A

patients

with

no

bone

marrow

edema-like

lesions

Group

B

patients

in

whom

bone

marrow

edema-like

lesions

did

not

change

over

years

Group

C

patients

in

whom

bone

marrow

edema-like

lesions

increased

in

size

over

years

Group

D

patients

in

whom

bone

marrow

edema-like

lesions

decreased

in

size

over

years

Box

plots

show

the

median

interquartile

range

minimum

and

maximum

values

Discussion

The

majority

-LRB-

-RRB-

of

patients

with

familial

OA

at

multiple

sites

have

BME

lesions

visualized

when

two

sequential

MR

scans

are

made

with

a

time

interval

In

the

majority

-LRB-

-RRB-

of

these

patients

with

BME

lesions

the

total

size

of

BME

changed

over

this

time

period

Our

study

also

demonstrates

that

cysts

and

BME

fluctuations

are

associated

However

no

association

existed

between

changes

in

BME

lesions

and

severity

of

WOMAC

scores

after

years

The

finding

that

BME

lesions

fluctuate

in

of

the

patients

indicates

that

BME

is

part

of

a

dynamic

process

in

OA

BME

is

not

a

constant

finding

as

opposed

to

hyaline

cartilage

loss

for

example

Thus

it

is

important

to

realize

that

the

finding

of

BME

lesions

in

patients

with

OA

represents

only

a

single

snapshot

in

time

The

variability

of

BME

lesions

has

been

noted

before

-LSB-

-RSB-

It

is

also

interesting

and

important

to

note

that

of

BME

lesions

disappear

completely

This

is

particularly

noteworthy

if

BME

is

to

be

used

as

an

inclusion

criterion

outcome

parameter

or

surrogate

endpoint

in

drug

trials

or

clinical

outcome

studies

The

second

finding

of

the

present

study

is

that

when

cystic

lesions

and

BME

lesions

are

in

close

proximity

the

direction

in

which

they

change

is

identical

This

is

an

interesting

finding

as

the

role

of

cysts

in

OA

is

unclear

Their

exact

pathophysiology

is

uncertain

as

is

their

prognostic

significance

A

recent

study

by

Carrino

et

al.

-LSB-

-RSB-

also

showed

a

change

in

cyst

size

was

accompanied

by

a

change

in

oedema-like

signal

size

That

study

also

showed

subchondral

cysts

developing

in

pre-existing

regions

of

subchondral

bone

marrow

oedema-like

signal

The

third

finding

is

that

changes

in

BME

lesions

did

not

correlate

with

severity

of

WOMAC

scores

Patients

in

whom

BME

increased

did

not

have

a

higher

WOMAC

score

than

patients

with

a

decrease

in

BME

size

Even

when

BME

completely

disappeared

lower

WOMAC

scores

were

not

recorded

Previous

work

has

demonstrated

that

pain

as

assessed

by

WOMAC

scores

was

not

related

significantly

to

changes

in

BME

lesions

-LSB-

-RSB-

However

in

the

studies

by

Felson

et

al.

-LSB-

-RSB-

BME

was

associated

with

progressive

radiographic

knee

OA

and

pain

Cross

sectional

associations

between

BME

lesions

and

clinical

findings

remain

controversial

-LSB-

-RSB-

Hence

a

lack

of

clarity

about

the

relationship

between

changes

in

BME

lesions

and

WOMAC

scores

is

not

surprising

Phan

et

al.

-LSB-

-RSB-

have

suggested

that

the

complexity

of

pain

physiology

and

the

difficulty

of

pain

evaluation

may

explain

these

findings

as

well

as

the

fact

that

patients

experience

pain

differently

Another

important

factor

might

be

the

stage

of

OA

in

the

patients

being

studied

For

instance

pain

might

be

associated

with

BME

lesions

in

a

more

developed

stage

of

the

disease

and

less

so

earlier

on

Knee

OA

studied

in

the

population

by

Felson

-LSB-

-RSB-

was

more

advanced

than

the

GARP

population

-LSB-

-RSB-

Also

Felson

's

population

consisted

of

patients

with

knee

OA

only

whereas

the

GARP

population

is

focused

on

patients

with

familial

OA

at

multiple

sites

A

considerable

proportion

of

patients

in

the

present

study

did

not

have

symptomatic

radiographic

knee

OA

in

the

imaged

knee

and

consequently

average

WOMAC

scores

in

the

present

population

were

low

-LRB-

Table

-RRB-

Nevertheless

associations

between

BME

lesions

and

clinical

findings

are

controversial

and

BME

lesions

may

be

excluded

ultimately

as

a

factor

in

pain

sensation

The

present

study

has

a

number

of

limitations

Firstly

not

all

patients

with

a

complete

MRI

follow-up

completed

the

WOMAC

signal

knee

Secondly

the

inclusion

of

patients

who

were

first-degree

relatives

may

have

introduced

an

artefact

However

linear

regression

analysis

with

robust

standard

errors

that

clustered

on

pairs

excluded

this

possibility

Thirdly

although

referred

pain

from

the

hip

may

have

been

a

confounder

hip

OA

occurred

in

only

of

the

patients

and

was

not

thought

a

contributory

factor

Fourthly

years

of

follow-up

may

be

too

short

for

an

early

OA

population

However

we

did

find

a

considerable

change

in

size

of

both

cystic

and

BME

lesions

Finally

the

term

BME

used

in

this

article

probably

should

be

described

more

properly

as

ill

defined

signal

intensity

abnormalities

as

the

so-called

BME

pattern

in

OA

knees

represents

on

histological

examination

nonspecific

abnormalities

such

as

bone

marrow

necrosis

bone

marrow

fibrosis

trabecular

abnormalities

and

only

a

small

amount

of

bone

marrow

oedema

-LSB-

-RSB-

Nevertheless

the

term

BME

is

a

commonly

accepted

identity

and

widely

used

in

the

OA

literature

-LSB-

-RSB-

In

conclusion

BME

lesions

are

shown

to

be

a

variable

parameter

when

followed

over

time

in

patients

with

knee

OA

and

are

not

predictive

of

pain

O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O B O O O O O O O B O O O O O O O O O O B O O O O O O B O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O B O O O O O O O B O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O B O O B O O O O O O O O B O O O O O O O O O O O O O O B O O O O O O O O B O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O B O O O O O O O O O O O B O B O O O O O O O O O O B O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O B O O O O O O B O O O O O O O O O O O O O O O O B O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O B O O O O O O O O O O O B O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O B O O O O O O O O O O B O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O B B O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O B O O O O O O O O B O O O B O O O B O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O B O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O B O O O O B O O O O O O O O B O O O O O O B O O O O O O O O O O O B O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O B O O O O O O O O O O O O O O O B O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O B O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O B O O O O O B O O O O O O O O O B O O O O O O O O O O O O O O O O B O O O O O O O O O O O O B O O O O O B O O O O O O O O O B O O O O O O B O O O O B O O O O B O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O B O O O O B O O O O B O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O B O O O O O O O O O O O O O O B O O O O O O O O O O O O B O O O O B O O O O O O O O O B O O O O O O O O O O O B O O O O O O O B O B O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O B O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O B O O O O O B O O O O O O B O O O O O O O B O O O O B O O O O B O O O O O O O O O O O O O O O B O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O B O O O O O B B O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O B O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O B B O O O O O O O O O O O O O O O O O O O O O O O O O O O O B B O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O B B O O O B O O O O B O O O O O O O O O O O O O O O O B O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O B O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O B O O O O O O B O O O O O O O O O O O O O O O O O O O O O O B O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O B O O O O O O O O B O O O O O O O O O O O O O O O B B O O O O O O O


MR

imaging

in

sports-related

glenohumeral

instability

Sports-related

shoulder

pain

and

injuries

represent

a

common

problem

In

this

context

glenohumeral

instability

is

currently

believed

to

play

a

central

role

either

as

a

recognized

or

as

an

unrecognized

condition

Shoulder

instabilities

can

roughly

be

divided

into

traumatic

atraumatic

and

microtraumatic

glenohumeral

instabilities

In

athletes

atraumatic

and

microtraumatic

instabilities

can

lead

to

secondary

impingement

syndromes

and

chronic

damage

to

intraarticular

structures

Magnetic

resonance

-LRB-

MR

-RRB-

arthrography

is

superior

to

conventional

MR

imaging

in

the

diagnosis

of

labro-ligamentous

injuries

intrinsic

impingement

and

SLAP

-LRB-

superior

labral

anteroposterior

-RRB-

lesions

and

thus

represents

the

most

informative

imaging

modality

in

the

overall

assessment

of

glenohumeral

instability

This

article

reviews

the

imaging

criteria

for

the

detection

and

classification

of

instability-related

injuries

in

athletes

with

special

emphasis

on

the

influence

of

MR

findings

on

therapeutic

decisions

Introduction

In

the

last

decade

understanding

of

the

biomechanics

and

pathophysiology

of

the

athletic

shoulder

has

significantly

improved

Especially

in

overhead

athletes

and

throwers

several

pathologic

mechanisms

have

been

identified

which

could

not

be

explained

by

the

traditional

concepts

of

instability

and

impingement

With

an

expanded

definition

glenohumeral

instability

is

now

believed

to

play

the

crucial

role

in

the

etiology

of

the

painful

athletic

shoulder

Instability

related

to

sports

is

not

infrequently

unrecognized

and

initiates

a

vicious

circle

of

secondary

impingement

muscular

dysfunction

and

damage

to

intraarticular

structures

that

can

be

devastating

and

may

end

the

athlete

's

career

-LSB-

-RSB-

The

term

instability

constitutes

a

spectrum

of

disorders

which

includes

hyperlaxity

subluxation

and

dislocation

Principally

glenohumeral

instability

can

be

classified

according

to

its

etiology

degree

frequency

and

direction

The

classic

categorization

of

affected

individuals

into

two

groups

with

traumatic

and

atraumatic

instability

represented

by

the

mnemonics

TUBS

and

AMBRII

has

been

supplemented

by

a

further

grouping

that

is

mainly

comprised

of

overhead

athletes

with

so-called

microinstability

-LRB-

microtraumatic

instability

-RRB-

and

that

has

been

labelled

with

the

acronym

AIOS

-LRB-

Table

-RRB-

However

it

should

be

emphasized

that

congenital

or

acquired

hyperlaxity

microinstability

and

traumatic

instability

can

overlap

particularly

in

athletes

engaged

in

overhead

sports

-LSB-

-RSB-

Table

for

classification

of

glenohumeral

instabilityTUBSAMBRIIAIOSTraumaticAtraumaticAcquiredUnidirectionalMultidirectionalInstabilityBankart

lesionBilateralOverstressSurgeryRehabilitationSurgeryInferior

capsular

shift

-LRB-

Rotator

-RRB-

Interval

closure

With

reference

to

the

complex

relationships

beween

instability

and

impingement

in

overhead

athletes

Jobe

and

co-workers

developed

a

classification

system

-LRB-

Table

-RRB-

with

four

groups

of

pathologic

conditions

-LSB-

-RSB-

Whereas

groups

and

represent

clearly

defined

entities

with

either

impingement

or

instability

groups

and

include

pathologies

in

which

both

mechanisms

coexist

Group

corresponds

to

classic

subacromial

impingement

which

appears

to

be

relatively

rare

in

athletes

especially

in

younger

individuals

Group

refers

to

microinstability

caused

by

repetitive

microtraumatization

of

the

capsulo-labral

structures

as

the

main

pathologic

process

leading

to

secondary

impingement

syndromes

such

as

posterosuperior

impingement

Group

equals

the

AMBRII

group

with

athletes

that

have

congenital

hyperlaxity

of

both

shoulders

as

well

as

of

other

joints

Group

finally

includes

pure

traumatic

instabilities

without

secondary

impingement

as

seen

in

the

TUBS

group

In

the

majority

of

athletes

traumatic

instability

occurs

in

an

anterior

direction

sports-related

posterior

macroinstability

is

very

rare

-LSB-

-RSB-

Table

classification

of

instability

and

impingement

in

the

athletic

shoulder

-LSB-

-RSB-

GroupPathologyEtiologyPattern

of

impingementSubacromial

stenosisRotator

cuff

lesionsNo

instabilityRepetitive

microtraumaLabro-ligamentous

lesionsSecondary

impingementRotator

cuff

lesionsSLAP

lesionsPosterosuperior

instabilityGeneralized

hyperlaxityLarge

capsular

volumeSecondary

impingementRotator

cuff

lesionsLabral

instabilityAcute

trauma

-LRB-

dislocation

-RRB-

Labro-ligamentous

injuriesNo

impingementSLAP

lesions

Magnetic

resonance

-LRB-

MR

-RRB-

imaging

plays

an

important

role

in

the

diagnostic

work-up

of

the

painful

athletic

shoulder

and

with

advanced

techniques

has

in

many

instances

already

replaced

diagnostic

arthroscopy

This

article

discusses

the

role

of

MR

imaging

and

MR

arthrography

in

the

context

of

the

most

common

forms

of

sports-related

glenohumeral

instability

and

presents

the

typical

MR

arthrographic

appearance

of

their

corresponding

intraarticular

lesions

and

patterns

of

injury

Technical

considerations

Particularly

in

athletes

MR

arthrography

has

been

advocated

for

accurate

depiction

of

labro-ligamentous

injuries

as

well

as

rotator

cuff

pathology

-LSB-

-RSB-

With

the

exception

of

examinations

following

acute

shoulder

dislocation

where

joint

effusion

or

hemorrhage

serve

as

natural

contrast

media

at

our

institution

MR

arthrography

is

performed

on

a

routine

basis

in

individuals

with

clinical

evidence

of

shoulder

instability

and

in

athletes

with

unclear

shoulder

pain

For

intraarticular

injection

of

contrast

media

several

different

techniques

have

been

described

that

can

all

successfully

be

employed

in

MR

arthrography

-LSB-

-RSB-

We

inject

ml

of

a

mmol/l

solution

of

a

gadolinium

chelate

following

fluoroscopically

guided

puncture

of

the

glenohumeral

joint

via

a

classic

anterior

approach

and

verification

of

the

intraarticular

position

of

the

needle

tip

by

application

of

a

small

amount

of

iodinated

contrast

media

With

the

use

of

a

dedicated

shoulder

coil

transverse

coronal

oblique

and

sagittal

oblique

spin-echo

-LRB-

SE

-RRB-

sequences

are

then

obtained

Fat-suppression

is

routinely

applied

in

the

coronal

oblique

plane

but

not

necessarily

in

the

transverse

and

sagittal

oblique

planes

The

examination

is

supplemented

by

acquisition

of

a

coronal

oblique

intermediate

weighted

-LRB-

echo

time

ms

-RRB-

turbo

spin-echo

-LRB-

TSE

-RRB-

sequence

with

spectral

fat-saturation

In

patients

with

anterior

instability

or

suspected

posterosuperior

glenoid

impingement

we

generally

add

a

SE

and/or

an

intermediate

weighted

TSE

sequence

in

the

ABER

-LRB-

abduction

and

external

rotation

-RRB-

position

achieved

by

transverse

oblique

orientation

of

the

images

along

the

long

axis

of

the

humerus

after

flexing

the

elbow

and

placing

the

patient

's

hand

behind

his

head

or

neck

-LRB-

Fig.

-RRB-

-LSB-

-RSB-

Geometric

parameters

are

identical

for

all

pulse

sequences

with

a

section

thickness

of

mm

and

an

in

plane

resolution

of

mm

Fig.

bABER

position

normal

findings

a

Coronal

localizer

image

of

the

shoulder

obtained

in

abduction

and

external

rotation

shows

correct

orientation

of

transverse

oblique

sections

aligned

with

the

humeral

shaft

b

Resulting

transverse

oblique

MR

arthrogram

demonstrates

normal

appearance

of

anteroinferior

labrum

-LRB-

white

arrow

-RRB-

with

taut

IGHL

-LRB-

arrowheads

-RRB-

posterosuperior

labrum

-LRB-

black

arrow

-RRB-

and

supraspinatus

tendon

-LRB-

-RRB-

-LRB-

T

greater

tuberosity

of

humeral

head

-RRB-

The

non-enhanced

MR

imaging

protocol

performed

after

acute

shoulder

dislocation

includes

a

coronal

oblique

SE

sequence

coronal

oblique

and

transverse

intermediate

weighted

TSE

sequences

with

fat-saturation

and

a

sagittal

oblique

TSE

sequence

with

the

same

geometric

parameters

as

mentioned

above

Traumatic

glenohumeral

instability

Traumatic

glenohumeral

instability

is

typically

initiated

by

a

specific

traumatic

event

followed

by

other

episodes

of

dislocation

or

subluxation

with

a

unidirectional

pattern

-LSB-

-RSB-

In

the

vast

majority

of

athletes

traumatic

instability

occurs

in

an

anteroinferior

direction

when

a

sudden

force

overwhelms

the

anterior

capsular

structures

while

the

athlete

's

arm

is

in

an

abducted

externally

rotated

and

extended

position

-LSB-

-RSB-

The

resulting

combination

of

injuries

represents

the

source

of

chronic

instability

particularly

those

involving

the

inferior

glenohumeral

ligament

-LRB-

IGHL

-RRB-

which

according

to

the

current

opinion

is

the

most

important

passive

stabilizer

of

the

shoulder

joint

The

IGHL

is

formed

by

an

anterior

and

a

posterior

band

which

represent

condensations

of

the

capsule

running

from

the

inferior

labrum

to

the

humeral

neck

The

anteroinferior

labrum

and

the

anterior

band

of

the

IGHL

together

form

the

anteroinferior

labro-ligamentous

complex

The

labrum

is

thought

to

serve

more

as

an

insertion

site

for

the

IGHL

than

to

provide

stability

to

the

glenohumeral

joint

by

deepening

the

glenoid

fossa

-LSB-

-RSB-

Although

generally

common

in

sports

this

type

of

instability

is

rarely

observed

in

throwers

or

overhead

athletes

but

if

present

can

cause

secondary

damage

to

the

rotator

cuff

and

the

superior

and

posterior

labrum

-LSB-

-RSB-

Labro-ligamentous

injuries

The

high

diagnostic

accuracy

of

MR

arthrography

in

the

detection

of

labro-ligamentous

lesions

has

been

demonstrated

in

several

studies

MR

arthrography

identifies

labral

tears

with

a

sensitivity

of

and

a

specificity

of

-LSB-

-RSB-

For

the

detection

of

lesions

of

the

superior

middle

and

inferior

glenohumeral

ligaments

Chandnani

and

co-workers

reported

sensitivities

and

specificities

of

-LSB-

-RSB-

The

sensitivities

and

specificities

of

unenhanced

MR

imaging

for

the

diagnosis

of

labro-ligamentous

injuries

vary

widely

in

the

literature

Although

a

direct

comparison

with

MR

arthrography

has

not

yet

been

performed

in

a

larger

series

we

regard

the

role

of

standard

MR

imaging

in

the

diagnostic

work-up

of

shoulder

instability

as

questionable

particularly

with

a

view

to

chronic

cases

and

the

depiction

of

associated

pathology

-LSB-

-RSB-

The

advantages

of

MR

arthrography

are

obvious

and

result

from

capsular

distension

with

separation

of

anatomic

structures

and

improved

delineation

of

tears

following

entrance

of

contrast

media

-LSB-

-RSB-

MR

arthrography

thereby

allows

more

confident

distinction

of

pathologic

conditions

from

the

common

anatomic

variations

of

labral

morphology

as

well

as

from

congenital

variants

of

the

glenohumeral

ligaments

and

the

labro-ligamentous

unit

such

as

the

Buford

complex

-LSB-

-RSB-

Furthermore

the

imaging

appearance

of

Bankart

variant

lesions

has

been

described

only

with

MR

arthrography

-LSB-

-RSB-

Few

studies

have

directly

compared

MR

arthrography

and

computed

tomography

-LRB-

CT

-RRB-

arthrography

in

the

diagnosis

of

labro-ligamentous

injuries

The

results

suggest

that

with

the

exception

of

bony

changes

CT

arthrography

is

less

sensitive

than

MR

arthrography

-LSB-

-RSB-

However

CT

arthrography

with

the

use

of

new

multidetector

techniques

has

not

yet

been

fully

evaluated

in

the

shoulder

First

results

indicate

that

due

to

its

capability

of

isotropic

data

acquisition

it

will

probably

perform

equivalent

to

MR

arthrography

-LSB-

-RSB-

Since

modern

surgical

stabilization

procedures

aim

at

restoration

of

normal

anatomy

a

more

differentiated

view

at

labro-ligamentous

injuries

has

developed

in

the

recent

years

and

several

variants

of

traumatic

lesions

of

the

anteroinferior

labrum

and/or

capsular

structures

have

been

described

The

following

types

of

lesions

should

be

distinguished

-LRB-

Fig.

-RRB-

Fig.

fClassification

of

Bankart

and

Bankart

variant

lesions

a

Bankart

lesion

b

bony

Bankart

lesion

c

Perthes

lesion

d

ALPSA

-LRB-

anterior

labro-ligamentous

periosteal

sleeve

avulsion

-RRB-

lesion

e

GLAD

-LRB-

glenolabral

articular

disruption

-RRB-

lesion

f

HAGL

-LRB-

humeral

avulsion

of

glenohumeral

ligaments

-RRB-

lesion

-LRB-

LLC

anteroinferior

labro-ligamentous

complex

P

scapular

periosteum

HH

humeral

head

AC

articular

cartilage

of

glenoid

IGHL

inferior

glenohumeral

ligament

-RRB-

Bankart

lesion

The

classic

labral

injury

described

by

Bankart

-LRB-

Fig.

-RRB-

is

a

complete

detachment

of

the

anteroinferior

labro-ligamentous

complex

from

the

glenoid

associated

with

a

rupture

of

the

scapular

periosteum

-LSB-

-RSB-

The

Bankart

lesion

represents

the

most

common

form

of

labro-ligamentous

injury

in

patients

with

first-time

traumatic

dislocations

of

the

shoulder

-LSB-

-RSB-

Due

to

the

lost

contact

with

the

periosteum

the

lesion

shows

no

tendency

to

heal

Surgical

treatment

is

by

reattachment

of

the

labro-ligamentous

complex

to

the

glenoid

either

arthroscopically

or

during

an

open

procedure

-LRB-

Bankart

repair

-RRB-

-LSB-

-RSB-

MR

arthrography

-LRB-

Fig.

-RRB-

typically

shows

a

deformed

anteroinferior

labrum

which

is

completely

separated

from

the

glenoid

and

therefore

is

floating

in

the

anterior

capsular

recess

adherent

to

the

anterior

band

of

the

IGHL

-LSB-

-RSB-

In

many

cases

the

torn

periosteum

can

be

visualized

by

transverse

MR

arthrograms

Fig.

cBankart

lesion

a

Transverse

and

b

coronal

oblique

MR

arthrograms

show

complete

detachment

of

the

anteroinferior

labrum

-LRB-

arrows

-RRB-

which

floats

within

the

anterior

capsular

recess

but

remains

attached

to

the

IGHL

-LRB-

arrowheads

-RRB-

c

Fat-suppressed

MR

arthrogram

obtained

in

ABER

position

reveals

separation

of

the

anteroinferior

labrum

from

the

glenoid

edge

as

well

as

disruption

of

the

periosteum

-LRB-

arrow

-RRB-

Note

taut

IGHL

adherent

to

the

labrum

-LRB-

arrowhead

-RRB-

Bony

Bankart

lesion

In

a

bony

Bankart

lesion

-LRB-

Fig.

-RRB-

an

osseous

fragment

of

variable

size

is

avulsed

from

the

anteroinferior

glenoid

together

with

the

labro-ligamentous

complex

The

size

of

the

fragment

influences

the

therapeutic

concept

since

larger

glenoidal

defects

can

give

rise

to

recurrent

instability

after

stabilizing

soft

tissue

procedures

such

as

the

Bankart

procedure

particularly

in

contact

athletes

-LSB-

-RSB-

In

a

study

with

cadaveric

specimens

and

experimentally

created

defects

of

the

glenoid

rim

the

critical

fragment

size

was

mm

in

average

width

-LSB-

-RSB-

Burkhardt

and

De

Beer

coined

the

term

inverted

peer

to

describe

the

visual

impression

of

a

significant

bone

defect

of

the

glenoid

at

arthroscopy

The

inverted

peer

geometry

is

the

reverse

of

the

normal

peer-shaped

glenoid

which

means

that

its

anteroposterior

diameter

below

the

midglenoid

notch

is

smaller

than

that

above

it

-LSB-

-RSB-

This

configuration

usually

precludes

arthroscopic

repair

and

represents

an

indication

for

fragment

refixation

or

bone

grafting

MR

arthrography

is

less

accurate

in

depiction

of

bony

Bankart

lesions

compared

with

CT

or

CT

arthrography

-LSB-

-RSB-

Smaller

osseous

fragments

can

easily

be

overlooked

particularly

if

fat

suppression

is

used

whereas

glenoid

fractures

with

larger

fragments

can

usually

be

diagnosed

with

sufficient

confidence

Sagittal

oblique

images

are

useful

to

estimate

the

geometry

of

the

glenoid

-LRB-

Fig.

-RRB-

Fig.

dBony

Bankart

lesion

a

Coronal

oblique

and

b

transverse

MR

arthrograms

show

avulsion

of

a

large

osseous

fragment

-LRB-

arrowheads

-RRB-

from

the

glenoid

together

with

the

attaching

anteroinferior

labrum

and

IGHL

-LRB-

arrow

-RRB-

c

Sagittal

oblique

MR

arthrogram

demonstrates

inverted

peer

geometry

of

glenoid

in

presence

of

a

relevant

bony

Bankart

lesion

-LRB-

arrowhead

-RRB-

Note

smaller

anteroposterior

diameter

of

glenoid

below

-LRB-

-RRB-

midglenoid

notch

than

above

-LRB-

-RRB-

it

For

comparison

normal

peer-shaped

configuration

of

glenoid

is

shown

on

d

sagittal

oblique

MR

arthrogram

from

individual

with

stable

shoulder

-LRB-

C

coracoid

process

-RRB-

Perthes

lesion

The

Perthes

lesion

-LRB-

Fig.

-RRB-

is

a

variant

of

the

Bankart

lesion

which

also

occurs

in

patients

with

acute

anterior

instability

In

the

Perthes

lesion

the

anteroinferior

labro-ligamentous

complex

is

detached

from

the

glenoid

but

unlike

in

the

injury

described

by

Bankart

the

periosteum

remains

intact

and

is

stripped

anteromedially

-LSB-

-RSB-

Therefore

unless

only

loosely

attached

the

labrum

may

remain

in

its

normal

anatomic

position

The

integrity

of

the

periosteum

allows

partial

healing

of

the

labrum

which

might

also

become

resynovialized

and

thus

although

incompetent

can

look

normal

on

arthroscopic

inspection

Because

scar

tissue

may

prevent

contrast

media

from

entering

the

labral

tear

nondisplaced

Perthes

lesions

can

be

difficult

to

detect

on

MR

arthrography

as

well

-LSB-

-RSB-

MR

arthrograms

obtained

in

the

ABER

position

have

been

reported

to

be

more

sensitive

in

the

diagnosis

of

Perthes

lesions

compared

with

conventional

transverse

MR

arthrograms

although

these

results

are

based

on

a

relatively

small

series

of

patients

-LSB-

-RSB-

In

our

experience

the

ABER

position

can

at

times

help

to

visualize

nondisplaced

Perthes

lesions

by

separating

the

base

of

the

anteroinferior

labrum

from

the

glenoid

and

consecutively

allowing

the

entrance

of

contrast

media

On

the

other

hand

displaced

or

slightly

displaced

lesions

can

be

realigned

with

the

glenoid

and

therefore

be

less

conspicuous

on

ABER

images

than

on

transverse

images

obtained

in

neutral

position

-LRB-

Fig.

-RRB-

Fig.

bPerthes

lesion

a

Transverse

fat-suppressed

MR

arthrogram

shows

detachment

and

slight

displacement

of

the

anteroinferior

labro-ligamentous

complex

-LRB-

arrow

-RRB-

and

stripping

of

the

intact

scapular

periosteum

-LRB-

arrowhead

-RRB-

On

b

corresponding

MR

arthrogram

obtained

in

ABER

position

the

anteroinferior

labrum

is

realigned

with

the

glenoid

edge

by

the

taut

IGHL

-LRB-

arrowhead

-RRB-

Although

the

tear

is

still

demarcated

by

contrast

media

-LRB-

arrow

-RRB-

it

is

less

conspicuous

than

on

the

conventional

transverse

section

in

this

case

-LRB-

M

middle

glenohumeral

ligament

ALPSA

lesion

The

ALPSA

-LRB-

anterior

labro-ligamentous

periosteal

sleeve

avulsion

-RRB-

lesion

-LRB-

Fig.

-RRB-

has

also

been

termed

medialized

Bankart

lesion

and

is

more

common

in

patients

with

recurrent

than

with

first-time

traumatic

dislocations

of

the

shoulder

-LSB-

-RSB-

It

represents

an

anteroinferior

labral

avulsion

that

leads

to

medial

displacement

and

inferior

rotation

of

the

labro-ligamentous

complex

together

with

the

intact

periosteum

in

a

sleeve-like

fashion

thereby

causing

incompetence

of

the

IGHL

and

consecutively

anterior

instability

The

labrum

may

eventually

heal

and

be

resynovialized

in

this

abnormal

position

-LSB-

-RSB-

Transformation

of

the

ALPSA

lesion

into

a

Bankart

lesion

by

dissection

of

the

complex

from

the

glenoid

followed

by

anatomic

refixation

-LRB-

Bankart

repair

-RRB-

has

been

recommended

as

the

treatment

of

choice

-LSB-

-RSB-

MR

arthrography

-LRB-

Fig.

-RRB-

shows

the

typical

medial

and

inferior

displacement

of

the

deformed

labro-ligamentous

complex

which

is

best

seen

on

transverse

and

coronal

oblique

images

Contrast

medium

often

outlines

a

crease

or

cleft

between

the

glenoid

and

the

nodular

shaped

fibrous

tissue

on

the

glenoid

neck

whereas

the

glenoid

edge

typically

lacks

a

normal

labral

structure

-LSB-

-RSB-

Familiarity

with

these

signs

can

prevent

misinterpretation

of

the

ALPSA

lesion

as

an

anatomic

variant

in

cases

with

only

slight

displacement

of

the

labrum

Fig.

bALPSA

lesion

a

Coronal

oblique

and

b

transverse

MR

arthrograms

demonstrate

a

nodular

shaped

anteroinferior

labroligamentous

complex

-LRB-

arrows

-RRB-

that

is

displaced

medially

and

inferiorly

on

the

scapular

neck

Note

cleft

-LRB-

arrowheads

-RRB-

between

fibrous

tissue

and

glenoid

GLAD

lesion

The

GLAD

-LRB-

glenolabral

articular

disruption

-RRB-

lesion

-LRB-

Fig.

-RRB-

as

described

by

Neviaser

is

a

superficial

tear

of

the

anteroinferior

labrum

in

combination

with

an

articular

cartilage

lesion

of

the

anterior

inferior

quadrant

of

the

glenoid

The

injury

is

thought

to

result

from

glenohumeral

impaction

while

the

arm

is

abducted

and

externally

rotated

Persistent

anterior

shoulder

pain

after

a

fall

onto

an

outstretched

arm

is

the

most

common

clinical

presentation

and

arthroscopic

debridement

has

been

proposed

as

the

treatment

of

choice

-LSB-

-RSB-

The

labral

component

of

the

abnormality

typically

represents

an

inferior

based

flap

tear

without

evidence

of

capsulo-periosteal

stripping

Since

the

anterior

fibers

of

the

IGHL

remain

strongly

attached

to

the

labrum

and

glenoid

the

GLAD

lesion

is

usually

not

associated

with

anterior

instability

The

degree

of

articular

cartilage

damage

is

variable

and

ranges

from

softening

and

fibrillation

to

deep

surface

defects

with

loose

fragments

of

cartilage

which

might

remain

attached

to

the

anterior

labrum

and

can

be

undermined

by

contrast

media

on

MR

arthrography

-LRB-

Fig.

-RRB-

-LSB-

-RSB-

Particularly

if

the

chondral

lesion

is

small

and

therefore

hardly

visible

on

MR

imaging

the

GLAD

lesion

can

look

similar

to

instability-related

labral

injuries

It

is

therefore

important

to

note

that

the

labrum

is

nondisplaced

and

both

the

IGHL

as

well

as

the

periosteum

are

intact

Fig.

lesion

Transverse

MR

arthrogram

shows

a

nondisplaced

tear

of

the

anterior

labrum

-LRB-

arrow

-RRB-

associated

with

a

full-thickness

chondral

defect

of

the

anterior

glenoid

-LRB-

arrowhead

-RRB-

A

small

fragment

of

hyaline

cartilage

adheres

to

the

torn

labrum

HAGL

lesion

In

contrast

to

the

Bankart

lesion

and

its

variants

the

HAGL

-LRB-

humeral

avulsion

of

glenohumeral

ligaments

-RRB-

lesion

-LRB-

Fig.

-RRB-

does

not

involve

the

labro-ligamentous

complex

at

the

glenoid

but

represents

an

isolated

tear

of

the

IGHL

at

its

humeral

insertion

following

vigorous

shoulder

dislocation

-LSB-

-RSB-

The

injury

is

associated

with

anterior

instability

and

represents

a

pitfall

at

arthroscopy

as

well

as

open

shoulder

surgery

since

it

can

be

overlooked

if

the

area

of

the

humeral

neck

is

not

specifically

searched

for

this

finding

-LSB-

-RSB-

The

majority

of

patients

in

whom

a

HAGL

lesion

is

detected

are

male

and

are

involved

in

contact

sports

such

as

rugby

-LRB-

American

-RRB-

football

or

ice

hockey

-LSB-

-RSB-

The

injury

therefore

is

thought

to

be

relatively

rare

in

countries

where

these

kinds

of

sport

are

unpopular

Treatment

is

by

surgical

reattachment

of

the

IGHL

to

its

humeral

insertion

-LSB-

-RSB-

Particularly

in

subacute

cases

with

absence

of

joint

effusion

the

HAGL

lesion

can

only

be

diagnosed

with

confidence

if

MR

arthrography

is

used

As

a

sequel

of

humeral

avulsion

the

IGHL

is

seen

as

a

J-shaped

rather

than

a

U-shaped

structure

on

coronal

oblique

arthrograms

and

contrast

extravasation

can

occur

at

its

insertion

site

-LRB-

Fig.

-RRB-

Acute

injuries

are

usually

associated

with

edematous

changes

of

the

soft

tissues

anterior

to

the

humeral

neck

-LSB-

-RSB-

Approximately

of

HAGL

lesions

occur

with

avulsion

of

a

bony

fragment

from

the

humerus

-LRB-

bony

HAGL

BHAGL

-RRB-

-LSB-

-RSB-

On

rare

occasions

the

HAGL

lesion

can

be

associated

with

a

classic

Bankart

lesion

Due

to

the

complete

isolation

of

the

anterior

band

of

the

IGHL

which

results

from

this

combination

of

injuries

the

lesion

has

been

described

as

the

floating

AIGHL

-LSB-

-RSB-

Other

associated

injuries

include

subscapularis

tears

and

Hill-Sachs

defects

as

well

as

other

osteochondral

lesions

-LSB-

-RSB-

Fig.

bHAGL

lesion

a

Coronal

oblique

fat-suppressed

MR

arthrogram

and

b

corresponding

intermediate

weighted

TSE

image

demonstrate

avulsion

of

the

IGHL

at

its

humeral

insertion

causing

a

J-shaped

configuration

of

the

axillary

recess

-LRB-

arrowheads

-RRB-

Contrast

extravasation

can

be

seen

at

the

site

of

the

tear

-LRB-

arrows

-RRB-

Bone

marrow

edema

within

humeral

head

-LRB-

-RRB-

was

caused

by

acute

Hill-Sachs

defect

-LRB-

not

shown

-RRB-

Particularly

in

athletes

the

decision

whether

an

arthroscopic

or

an

open

procedure

should

be

performed

to

achieve

the

most

favourable

outcome

can

be

very

difficult

and

is

subject

to

a

controverse

discussion

Criteria

in

favour

of

open

rather

than

arthroscopic

surgery

include

engagement

in

contact

sports

presence

of

a

relevant

glenoid

defect

and/or

Hill-Sachs

defect

a

HAGL

lesion

and

poor

quality

of

the

labro-ligamentous

complex

-LSB-

-RSB-

A

recent

study

could

demonstrate

the

potential

of

MR

arthrography

in

classification

of

anteroinferior

labro-ligamentous

injuries

with

a

view

to

therapeutic

decisions

-LSB-

-RSB-

With

arthroscopy

as

the

gold

standard

Bankart

and

Bankart

variant

lesions

could

be

correctly

classified

with

a

sensitivity

of

a

specificity

of

and

an

accuracy

of

Furthermore

MR

arthrography

was

capable

of

identification

of

injuries

with

poor

quality

of

the

anterior

labrum

and

IGHL

which

in

high

concordance

with

arthroscopy

could

not

be

assigned

to

one

of

the

specific

types

of

lesions

mentioned

above

All

of

these

nonclassifiable

lesions

with

degenerative

changes

and

scar

tissue

formation

were

observed

in

patients

with

chronic

anterior

instability

On

MR

arthrography

-LRB-

Fig.

-RRB-

these

injuries

are

characterized

by

a

swollen

inferior

glenohumeral

ligament

complex

without

distinct

depiction

of

the

labrum

IGHL

and

scapular

periosteum

-LSB-

-RSB-

Fig.

anteroinferior

labro-ligamentous

injury

Transverse

MR

arthrogram

shows

markedly

deformed

and

enlarged

labro-ligamentous

complex

without

differentiability

of

labrum

IGHL

and

scapular

periosteum

The

lesion

was

associated

with

chronic

anteroinferior

instability

Hill-Sachs

defect

The

Hill-Sachs

defect

represents

a

compression

injury

of

the

posterolateral

humeral

head

which

develops

during

anteroinferior

dislocation

as

the

relatively

large

and

soft

humeral

head

impacts

against

the

comparatively

small

and

hard

bony

glenoid

-LSB-

-RSB-

The

incidence

of

the

lesion

at

arthroscopy

varies

considerably

from

to

among

different

series

of

patients

with

first-time

traumatic

dislocations

-LSB-

-RSB-

The

depth

and

size

of

a

Hill-Sachs

lesion

ranging

from

shallow

chondral

defects

to

deep

osteochondral

impaction

fractures

is

thought

to

reflect

the

tightness

of

the

joint

capsule

-LSB-

-RSB-

In

athletes

with

hyperlaxity

at

the

time

of

the

first

shoulder

dislocation

the

humeral

injury

therefore

typically

is

small

or

absent

Osteochondral

Hill-Sachs

defects

that

involve

less

than

one

third

of

the

circumference

of

the

humeral

head

are

usually

regarded

as

prognostically

irrelevant

Larger

lesions

especially

if

oriented

with

their

long

axis

parallel

to

the

glenoid

can

engage

the

anterior

corner

of

the

glenoid

in

abduction

and

external

rotation

and

thus

lead

to

repeated

subluxations

or

redislocations

-LRB-

engaging

Hill-Sachs

defect

-RRB-

-LSB-

-RSB-

On

transverse

MR

images

the

Hill-Sachs

defect

is

typically

seen

at

or

slightly

above

the

level

of

the

coracoid

process

-LRB-

Fig.

-RRB-

False

positive

diagnoses

can

occur

due

to

misinterpretation

of

a

normal

anatomic

groove

at

the

posterolateral

humerus

which

can

often

be

found

caudad

to

that

position

-LSB-

-RSB-

In

acute

or

subacute

cases

with

edema

of

adjacent

bone

marrow

the

impaction

injury

can

easily

be

detected

on

fat-suppressed

or

STIR

images

Chronic

lesions

particularly

if

small

are

often

better

visualized

by

CT

-LSB-

-RSB-

However

clinically

significant

osteochondral

defects

are

sufficiently

demonstrable

by

MR

and

rarely

necessitate

further

imaging

Fig.

cHill-Sachs

defect

MR

appearance

a

Acute

lesion

transverse

fat-suppressed

intermediate

weighted

TSE

image

shows

impaction

of

the

posterolateral

humeral

head

-LRB-

arrowhead

-RRB-

with

adjacent

bone

marrow

edema

following

acute

anteroinferior

dislocation

b

c

Chronic

lesions

b

transverse

fat-suppressed

and

c

transverse

MR

arthrograms

obtained

in

two

different

patients

several

months

after

anteroinferior

dislocation

depict

circumscribed

-LRB-

b

-RRB-

and

extensive

-LRB-

c

-RRB-

osteochondral

defects

-LRB-

arrowheads

-RRB-

of

the

humeral

head

-LRB-

C

tip

of

coracoid

process

-RRB-

Atraumatic

glenohumeral

instability

Atraumatic

glenohumeral

instability

is

typically

multidirectional

and

usually

evident

in

individuals

with

congenital

hypermobility

syndrome

The

diagnosis

is

predominantly

based

on

the

clinical

examination

which

uncovers

bilateral

affection

of

the

shoulders

in

association

with

generalized

hyperlaxity

of

ligaments

and

joints

-LSB-

-RSB-

The

increased

baseline

laxity

of

the

shoulder

seen

in

athletes

with

generalized

hypermobility

is

advantageous

for

several

types

of

sports

but

at

the

same

time

harbors

a

high

risk

of

long-term

injury

with

damage

of

intra

and

periarticular

structures

-LSB-

-RSB-

If

conservative

management

fails

multidirectional

instability

is

usually

treated

surgically

by

inferior

capsular

shift

and

closure

of

the

rotator

interval

-LSB-

-RSB-

There

are

no

specific

findings

to

diagnose

atraumatic

glenohumeral

instability

by

MR

imaging

or

MR

arthrography

-LSB-

-RSB-

In

most

non-athletic

AMBRII

patients

MR

arthrography

shows

an

increased

capsular

volume

but

no

or

little

substantial

alterations

of

the

intraarticular

structures

In

athletes

laxity

of

the

capsule

is

frequently

associated

with

secondary

damage

to

the

labrum

and

the

rotator

cuff

-LSB-

-RSB-

The

labrum

may

be

hypoplastic

or

torn

but

can

as

well

appear

swollen

and

increased

in

signal

intensity

due

to

more

or

less

extensive

degenerative

change

-LRB-

Fig.

-RRB-

Further

morphologic

alterations

can

involve

the

biceps

anchor

and

the

articular

surface

of

the

rotator

cuff

-LSB-

-RSB-

MR

arthrography

can

help

with

therapeutic

decisions

by

identification

or

exclusion

of

significant

intraarticular

pathology

that

might

represent

an

indication

for

surgical

repair

in

addition

to

capsular

reduction

Fig.

bAtraumatic

glenohumeral

instability

labral

degeneration

a

Transverse

fat-suppressed

and

b

corresponding

sagittal

oblique

MR

arthrograms

reveal

markedly

swollen

and

enhanced

but

nondisplaced

anterior

glenoid

labrum

in

an

athlete

with

multidirectional

shoulder

instability

Extensive

labral

degeneration

was

verified

by

arthroscopy

-LRB-

not

shown

-RRB-

Microtraumatic

glenohumeral

instability

Microtraumatic

glenohumeral

instability

is

thought

to

result

from

chronic

traumatization

of

the

capsular

structures

in

throwers

and

overhead

athletes

such

as

tennis

players

swimmers

and

handball

players

In

contrast

to

atraumatic

glenohumeral

instability

microinstability

is

typically

seen

unilaterally

only

in

the

dominant

shoulder

of

the

athlete

Whereas

repetitive

abduction

and

external

rotation

cause

microtrauma

of

the

anterior

capsule

and

thus

can

provoke

anterior

instability

repetitive

overhead

activity

with

abduction

flexion

and

internal

rotation

might

give

rise

to

posterior

microinstability

as

a

result

of

injury

to

the

posterior

labro-ligamentous

elements

-LSB-

-RSB-

Structural

abnormalities

consecutive

to

microtraumatic

glenohumeral

instability

can

be

depicted

by

MR

arthrography

and

include

laxity

of

the

anterior

or

posterior

capsule

labral

injuries

ranging

from

degeneration

and

fraying

to

tearing

and

detachment

SLAP

-LRB-

superior

labral

anteroposterior

-RRB-

lesions

and

tears

of

the

rotator

cuff

caused

by

secondary

impingement

-LSB-

-RSB-

Posterosuperior

glenoid

impingement

-LRB-

PSI

-RRB-

PSI

is

a

form

of

internal

impingement

which

represents

a

common

problem

in

throwers

and

overhead

athletes

presenting

with

acute

or

chronic

posterior

shoulder

pain

-LSB-

-RSB-

The

basic

observation

was

reported

by

Walch

who

described

impingement

between

the

articular

side

of

the

supraspinatus

tendon

and

the

posterosuperior

edge

of

the

glenoid

evident

in

abduction

and

external

rotation

-LSB-

-RSB-

In

throwers

and

overhead

athletes

PSI

can

lead

to

a

typical

pattern

of

injuries

the

so-called

kissing

lesions

which

includes

corresponding

lesions

of

the

undersurface

of

the

rotator

cuff

the

posterosuperior

labrum

the

greater

tuberosity

and

the

superior

bony

glenoid

-LSB-

-RSB-

The

development

of

PSI

has

been

attributed

to

chronic

injury

-LRB-

repetitive

stretching

-RRB-

of

the

anterior

capsular

structures

particularly

the

IGHL

with

consecutive

anterior

microinstability

which

causes

anterior

subluxation

of

the

humeral

head

in

abduction

and

external

rotation

during

overhead

movements

and

thus

allows

excessive

contact

between

the

rotator

cuff

and

the

posterosuperior

glenoid

-LSB-

-RSB-

However

this

theory

is

not

generally

accepted

Other

authors

described

a

contracture

of

the

posteroinferior

capsule

and

a

posterior

SLAP

lesion

as

the

essential

lesions

for

the

development

of

PSI

in

throwers

-LSB-

-RSB-

Although

the

basic

mechanism

is

still

subject

to

discussion

the

high

coincidence

of

PSI

and

SLAP

lesions

is

undoubted

Furthermore

there

is

apparently

a

huge

overlap

of

clinical

symptoms

in

athletes

with

SLAP

lesions

PSI

or

both

It

is

important

to

stress

that

contact

between

the

undersurface

of

the

rotator

cuff

and

the

posterosuperior

glenoid

as

seen

on

arthroscopy

is

not

pathologic

per

se

Posterosuperior

glenoid

impingement

should

only

be

diagnosed

if

this

contact

is

associated

with

clinical

symptoms

and

corresponding

lesions

of

the

involved

anatomic

structures

-LSB-

-RSB-

Conservative

treatment

is

usually

suited

in

athletes

with

minor

structural

abnormalities

whereas

surgical

debridement

and

repair

-LRB-

eventually

in

combination

with

capsular

plication

-RRB-

are

indicated

in

the

presence

of

relevant

rotator

cuff

and

labral

lesions

MR

imaging

can

be

used

to

confirm

the

diagnosis

of

PSI

and

to

help

with

therapeutic

decisions

by

demonstrating

the

extent

of

articular

damage

Since

MR

arthrography

has

been

shown

to

be

more

accurate

than

conventional

MR

imaging

in

the

detection

of

partial

rotator

cuff

tears

labral

tears

and

SLAP

lesions

it

is

also

regarded

as

the

method

of

choice

in

athletes

with

suspected

PSI

which

is

accompanied

by

a

combination

of

these

abnormalities

-LSB-

-RSB-

MR

arthrograms

-LRB-

Fig.

-RRB-

typically

show

articular-sided

partial

tearing

of

the

supraspinatus

and/or

infraspinatus

tendons

The

supraspinatus

lesion

unlike

in

patients

with

subacromial

impingement

usually

involves

the

posterior

part

of

the

tendon

Damage

to

the

posterosuperior

labrum

ranges

from

degenerative

change

and

fraying

to

tears

and

detachment

and

might

be

associated

with

ganglia

and

SLAP

lesions

Alterations

of

bone

at

the

greater

tuberosity

and

the

superior

glenoid

are

best

demonstrated

by

fat-suppressed

intermediate

or

images

and

include

erosions

bone

marrow

edema

cyst

formation

and

sclerosis

-LSB-

-RSB-

MR

arthrograms

obtained

in

the

ABER

position

-LRB-

Fig.

e

-RRB-

usually

show

contact

between

the

lesions

of

the

rotator

cuff

and

the

superior

labrum/glenoid

and

might

even

reveal

interposition

of

the

supraspinatus

tendon

pinched

between

the

glenoid

and

the

greater

tuberosity

Furthermore

the

ABER

position

is

useful

in

demonstration

of

subluxation

of

the

humeral

head

and

depiction

of

abnormalities

of

the

anterior

capsule

The

anterior

band

of

the

IGHL

can

appear

attenuated

and

elongated

or

might

even

be

torn

-LSB-

-RSB-

Fig.

ePSI

spectrum

of

findings

on

MR

arthrography

a

Transverse

fat-suppressed

MR

arthrogram

and

b

c

corresponding

coronal

oblique

images

obtained

in

a

tennis

player

with

posterior

shoulder

pain

show

a

posterosuperior

labral

tear

-LRB-

arrow

in

a

-RRB-

associated

with

an

articular-sided

partial

tear

of

the

posterior

aspect

of

the

supraspinatus

tendon

-LRB-

arrowhead

in

b

-RRB-

and

a

SLAP

type

lesion

-LRB-

arrow

in

c

-RRB-

Note

large

volume

of

anterior

capsule

-LRB-

in

a

-RRB-

d

e

MR

arthrograms

obtained

in

ABER

position

from

two

athletes

with

PSI

d

Arthrogram

demonstrates

the

kissing

lesion

pattern

with

corresponding

tears

of

the

posterosuperior

labrum

-LRB-

white

arrow

-RRB-

and

the

undersurface

of

the

supraspinatus

tendon

-LRB-

black

arrowhead

-RRB-

accompanied

by

sclerosis

of

the

greater

tuberosity

of

the

humeral

head

at

the

contact

zone

with

the

glenoid

-LRB-

black

arrow

-RRB-

Note

elongation

of

the

IGHL

-LRB-

white

arrowhead

-RRB-

e

Arthrogram

shows

interposition

of

the

supraspinatus

tendon

-LRB-

-RRB-

between

the

greater

tuberosity

and

the

superior

glenoid

as

well

as

a

tear

of

the

IGHL

-LRB-

arrowhead

-RRB-

with

consecutive

contrast

extravasation

SLAP

lesions

SLAP

lesions

of

the

shoulder

are

common

injuries

in

athletes

which

represent

tears

of

the

superior

glenoid

labrum

that

extend

in

an

anterior

to

posterior

direction

-LSB-

-RSB-

Four

different

types

of

SLAP

lesions

have

been

described

in

the

original

classification

by

Snyder

degenerative

fraying

of

the

superior

labrum

avulsion

of

the

superior

labrum

and

biceps

anchor

from

the

glenoid

bucket-handle

tear

of

the

superior

labrum

with

preserved

biceps

anchor

bucket-handle

tear

of

the

superior

labrum

involving

the

long

head

of

biceps

tendon

-LSB-

-RSB-

This

classification

has

been

expanded

with

several

further

types

of

lesions

which

mainly

represent

combinations

of

the

most

common

form

the

SLAP

type

lesion

with

other

injuries

of

the

labrum

medial

glenohumeral

ligament

or

rotator

cuff

However

only

the

Snyder

classifications

have

found

wide

acceptance

and

most

institutions

categorize

these

injuries

as

type

with

or

without

asscociated

lesions

Whereas

type

and

lesions

are

typically

caused

by

repetitive

torsion

of

the

biceps

anchor

-LRB-

the

so-called

peelback

mechanism

-RRB-

in

throwers

and

overhead

athletes

types

and

lesions

are

thought

to

occurr

more

often

after

a

fall

onto

an

outstretched

arm

or

onto

a

flexed

elbow

-LSB-

-RSB-

Furthermore

type

lesions

are

frequently

observed

in

athletes

with

traumatic

anterior

shoulder

instability

where

they

develop

in

association

with

lesions

of

the

anteroinferior

labro-ligamentous

complex

-LRB-

most

often

a

classic

Bankart

lesion

-RRB-

In

these

cases

the

labro-ligamentous

avulsion

can

be

considered

as

the

main

lesion

with

the

SLAP

lesion

being

an

associated

injury

-LSB-

-RSB-

Surgical

treatment

is

indicated

in

all

types

of

SLAP

lesions

except

type

lesions

which

are

usually

of

no

clinical

relevance

Since

type

and

lesions

impair

the

stabilizing

function

of

the

biceps

insertion

and

therefore

can

provoke

glenohumeral

instability

secondary

impingement

and

rotator

cuff

lesions

they

are

commonly

treated

by

refixation

Type

bucket-handle

tears

are

usually

not

surgically

reattached

but

treated

by

simple

debridement

-LSB-

-RSB-

MR

arthrography

has

proved

to

be

superior

to

conventional

MR

imaging

with

regard

to

the

identification

of

SLAP

lesions

and

has

been

shown

to

be

reliable

in

assessment

of

the

stability

of

the

biceps

anchor

and

the

detection

of

associated

injuries

-LSB-

-RSB-

However

its

ability

to

correctly

classify

the

different

types

of

lesions

is

limited

-LSB-

-RSB-

Most

SLAP

lesions

are

best

depicted

on

MR

arthrograms

oriented

in

the

coronal

oblique

plane

-LRB-

Fig.

-RRB-

Increased

signal

intensity

and/or

surface

irregularity

of

the

superior

labrum

can

be

seen

in

type

lesions

which

however

can

only

infrequently

be

diagnosed

by

MR

imaging

Type

lesions

are

characterized

by

linear

extension

of

contrast

media

into

the

superior

labrum

and

the

biceps

anchor

This

most

common

type

of

SLAP

lesion

also

represents

the

most

problematic

in

terms

of

differential

diagnosis

False

positive

and

false

negative

diagnoses

of

a

SLAP

type

lesion

can

be

caused

by

misinterpretation

of

a

sublabral

recess

as

a

tear

and

vice

versa

-LSB-

-RSB-

The

sublabral

recess

-LRB-

Fig.

-RRB-

is

a

very

common

anatomic

variant

with

an

incidence

of

in

cadaveric

studies

-LSB-

-RSB-

It

represents

a

variably

sized

synovialized

cleft

between

the

superior

labrum

and

the

bony

glenoid

which

is

typically

oriented

medially

and

points

at

the

supraglenoidal

tubercule

-LSB-

-RSB-

The

most

important

criterion

for

the

presence

of

a

SLAP

type

lesion

rather

than

a

sublabral

recess

therefore

is

lateral

or

superior

extension

of

the

tear

If

the

tear

extends

medially

-LRB-

like

a

sublabral

recess

-RRB-

it

often

shows

irregular

margins

and/or

a

relatively

wide

separation

between

the

labrum

and

the

glenoid

In

individuals

with

traumatic

anterior

instability

the

type

lesion

often

originates

from

an

anteroinferior

tear

of

the

labro-ligamentous

complex

that

extends

cranially

up

into

the

superior

labrum

and

the

biceps

anchor

-LRB-

Fig.

-RRB-

-LSB-

-RSB-

Type

lesions

are

characterized

by

a

vertical

and

an

additional

horizontal

contrast

interface

which

separate

the

avulsed

superior

labrum

as

a

triangular-shaped

fragment

from

the

intact

biceps

tendon

In

Type

lesions

the

horizontal

component

of

the

tear

additionally

extends

into

the

long

head

of

biceps

tendon

The

bucket-handle

fragment

therefore

is

composed

of

the

superior

labrum

as

well

as

a

portion

of

the

tendon

and

might

be

more

or

less

displaced

from

the

superior

glenoid

-LSB-

-RSB-

Fig.

dSLAP

lesions

classification

according

to

Snyder

-LSB-

-RSB-

on

coronal

oblique

MR

arthrograms

-LRB-

from

-LSB-

-RSB-

modified

-RRB-

a

SLAP

type

lesion

b

SLAP

type

lesion

c

SLAP

type

lesion

d

SLAP

type

lesion

-LRB-

LBC

labral-bicipital

complex

HH

humeral

head

G

glenoid

-RRB-

Fig.

recess

Coronal

oblique

MR

arthrogram

demonstrates

medially

oriented

cleft

-LRB-

arrowhead

-RRB-

between

the

superior

labrum

and

the

glenoid

outlined

by

contrast

media

which

was

also

diagnosed

as

a

sublabral

recess

with

a

stable

biceps

insertion

on

arthroscopy

-LRB-

not

shown

-RRB-

Note

meniscoid

shape

of

superior

labrum

-LRB-

-RRB-

and

integrity

of

the

biceps

anchor

-LRB-

arrow

-RRB-

Fig.

dSLAP

type

lesion

in

association

with

a

Bankart

lesion

in

traumatic

anterior

glenohumeral

instability

a

Coronal

oblique

fat-suppressed

MR

arthrogram

shows

superior

extension

of

contrast

media

into

the

superior

labrum

and

biceps

anchor

-LRB-

arrowhead

-RRB-

b

Corresponding

sagittal

oblique

MR

arthrogram

reveals

tearing

of

the

entire

anterior

labrum

-LRB-

arrowheads

-RRB-

extending

from

inferior

to

superior

c

d

Corresponding

transverse

MR

arthrograms

demonstrate

detachment

of

the

anterior

labrum

that

continues

as

a

classic

Bankart

lesion

anteroinferiorly

-LRB-

arrows

-RRB-

Conclusion

Sports-related

glenohumeral

instability

is

a

complex

and

in

many

aspects

still

controversial

subject

MR

imaging

can

play

an

important

role

in

evaluation

of

the

athlete

's

shoulder

if

it

aims

at

providing

essential

information

for

therapeutic

decisions

at

eye

level

with

diagnostic

arthroscopy

Therefore

the

radiologist

should

be

familiar

with

the

mechanisms

and

classification

of

injuries

as

well

as

the

advantages

and

limitations

of

his

examination

techniques

At

present

MR

arthrography

represents

the

best

evaluated

and

most

informative

imaging

technique

for

the

assessment

of

shoulder

pathology

in

many

aspects

and

thus

appears

to

be

most

valuable

for

the

diagnostic

work-up

of

glenohumeral

instability

and

unclear

shoulder

pain

in

athletes

O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O 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O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O 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shoulder dislocation
magnetic resonance
mr arthrography