Pekka

U. Farm,

MD

#{149} Heikki

Shoulder Sonographic

Jaroma,

radiography

provide

valuable

information in patients with pected early-stage impingement syndrome. Index

terms:

Bursitis,

41.25

sus-

Shoulder,

ab-

#{149}

nonmalities, 41.25, 41.48 #{149} Shoulder, injuries, 41.48 #{149} Shoulder, US studies, 41.12981

Radiology

#{149} Arvi

1990; 176:845-849

T

HE

impingement

disability.

beneath

C

RSNA,

1990

of Diagnostic

Radi-

S.) and Orthopaedics and SunKuopio University Central 6, 70211 Kuopio, Finland. Re5, 1989; revision requested revision received April 17; acAddress reprint requests to

of the

the

em tuberosity

of the

coracoacromial during abduction

arm

results

rota-

coracoacmomial

acromial

humerus

bursa

hemorrhage

and

ligamentous or elevation

in changes such

the

arch of the

in the

and

collection

in the

bumsa and tendons (i,2). Impingement syndrome is thought to begin in anatomically predisposed shouldens and can progress to degeneration and calcification within the tendons and eventually to bone spun formation at the undersurface of the acmomion and the distal end of the

clavicle. Subacmomial bursitis, tal tendinitis, and rotator cuff

bicipidismup-

tions are common sequelae of this abnormality. Fundamental diagnostic imaging methods in this syndrome include fluomoscopy, amthmogmaphy, subacromiab bumsography, tomography, and in recent years, computed tomogmaphy and magnetic resonance (MR)

imaging.

Subacmomial

in particular,

has

an accurate

diagnostic this not

bunsography,

been disorder

received

purpose

suggested

as

modality

of this

appropriate evaluation

in

(5,6);

howev-

much

attention

paper

is to de-

technique of the

syndrome and of sonographic

PATIENTS Between

phy

department. performed

by

a few

were

221 with

patients and

AND

October underwent

for im-

to discuss find-

cases

followed arthrography

and bilateral

by plain at our

June

1988, shoulder

radiograradiology

each case, a radiologist

sonography (P.U.F.).

videotaped.

was Only

There

were

years). Surgical for 102 patients

women).

correlation (27%) (55

The

group The real-time

mean

age

LS;

grams

Aboka,

were

Tokyo).

interpreted

examination

ton cuff, tendon

latter

All

sono-

prospectively.

technique

intertubercular did not differ

for

the

sulcus, from that

rota-

or biceps used in

studies (8-11) and always included and dynamic portions. Biceps tendiwas diagnosed with sonography

when the

of this

was 42 years (range, 24-45 years). sonograms were obtained with a 7.5-MHz linear-array scanner

(SSD-280

earlier static nitis

18-71

was available men and 47

effusion

surrounded

bicipital

tendon empty

sheath

lesser

tuberosity

in transverse All

scanning,

subdeltoid arm held

bursa was in a neutral

nab or external maximal internal

the patient’s laterally and

same

time,

of the

were

seat-

the subacromiab-

imaged position

rotation) rotation,

achieved by holding back. In the dynamic

was the

scans

patients

and

in of the

if the groove was seen on

humerus.

ed during

tendon

Dislocation

was diagnosed and the tendon

proximal

the

(9).

and

with (no also which

the interin was

the hand behind the portion of the study,

arm then

was elevated anteriorly,

attention

was

primarily and at the

paid

to the

bun-

sal system, especially to the gradual distention of the bursa (Fig 1). In 10 cases in which the bursa was distended

with

injection

were

fluid,

aspiration

of corticosteroids

performed

(Fig

of fluid into

2). In five

and

the

bursa

patients,

Oslo), with 240 mg/mL, grams

(Fig

elevations

an iodine concentration was injected. Then 3) were

of the

graphic drome.

diagnosis specific

obtained,

arm,

for

of bursoat different

to verify

of impingement criteria

4-6 AS,

the

sonosynsonograph-

ic diagnosis of impingement syndrome were developed. These were (a) fluid lection in the subacromial-subdeltoid

METHODS

1985

In

(58%) men and 160 (42%) women, a mean age of 45 years (range,

Two

sonography

MD

instead of injection of corticosteroids, mL of iohexol (Omnipaque; Nycomed

ings.

381

Soimakallio,

The

sub-

as edema

or fluid

pingement the reliability Departments

or painful

ligamentous arch without associated rupture of the cuff is a well-established clinical diagnosis. Entrapment of the soft tissues between the great-

The

the

(1-3)

Impingement

tom cuff

scribe the sonogmaphic

From

#{149} Seppo

arch syndrome (4) is a common cause of chronic shoulder pain and

em, it has (7).

1

MD

Syndrome:

evaluating

ology (P.U.F., S. gery (H.J., A.H.), Hospital, P0 Box ceived December January 30, 1990; cepted April 24. P.U.F.

Harju,

Impingement Evaluation’

A method of shoulder sonography in which lateral and anterior elevation of the arm is used during scanning was demonstrated to be effective in cases of suspected impingement syndrome. The value of the method lies in its ability to demonstrate fluid collection in the subacromial-subdeltoid bursal system, with gradual distention of the bursa and lateral pooling of fluid to the subdeltoid portion while the arm is elevated. In 102 of 381 patients studied, surgical diagnosis was available for correlation. Among this group there were seven false-negative and three false-positive sonographic findings. A comparison of sonographic with surgical findings demonstrated a sensitivity of 81% and a specificity of 95% in stages I-Ill, and a sensitivity of 71% and a specificity of 96% in early stages I and II of the impingement syndrome. The results of dynamic shoulder sonographic examination with fluoroscopic

MD

bursa

and

(b) fluid

that gradually pooled laterally while the arm

in

the

bursal

cob-

system

distended the bursa and to the subdebtoid portion was elevated. Nonspecific

845

b.

a. Figure

1.

Subdeltoid-subacromial cuff

muscle

(d) and rotator (c) Gradual distention

bursa. (a) Longitudinal subcutaneous tissue,

(r). s

of bursa

C.

and

lateral

scan

of the

normal

bursa

(arrowheads)

pooling

between

the

deep

surface

of deltoid

of the arm.

b.

a. Figure 3. Bursogram with the arm Note the distention and lateralization

a.

seen

h = humerab head. (b) Fluid-distended bursa (0) in neutral position of the fluid in bursa in impingement syndrome while arm is elevated.

in neutral position (a) and elevated laterally of the bursa as the shoulder is elevated.

90#{176} (b).

b. Figure

2.

(a)

Schematic

diagram

of

the

technique used to aspirate fluid and to inject contrast medium into the distended bursa. (b) Note the tip of the needle in the bursa (arrowhead) on this corresponding scan.

but suggestive findings (Fig 4) or thinning (Fig hyperechogenicity

without

bursal

ten nonspecific recognize, but

findings comparison

affected shoulder asymmetry.

rotator

collection.

cuff

These

lat-

were difficult to with the non-

helped

in assessment

RESULTS The

subacromial-subdeltoid

is delineated

846

#{149} Radiology

by

the

boundary

bunsa be-

the

cuff and nography graphically as normal

were thickening 5) and hypoor

of the

fluid

tween

of

thmognaphy

deltoid is poorly

muscle and rotator identified at so-

in its

normal

this

space

in 3i3

and

of 381

state.

was

Sono-

depicted

patients.

sonogmaphy

107 and 92 rotator cuff tears, tively, in these 313 patients. The sonographic appearance

Ar-

revealed respecof the

bursa! system was abnormal in 68 (i8%) of 38i patients. Arthrography showed normal cuffs in 38 of these 68. Thus, 30 patients with arthnographically diagnosed rotator cuff tears had fluid-containing bursal sys-

tems

found

only

Inflamed

and

at sonogmaphy.

thickened

tems

were

documented

i02

patients

who

(Table

bursal

sys-

in 37 of the

underwent

1). In 30 of these

surgery 37,

sonogna-

phy depicted fluid collection in the subacromial-subdeltoid bursa, which distended the bursa and pooled laterally the this

with arm fluid could elevation

en false-negative maphy, findings derwent

elevation. In two cases, be found only with test. In addition to sev-

findings

at sonog-

there were three false-positive in the 102 patients who unsurgery. The association be-

September

1990

C.

D.

Figure 4. (a) Longitudinal genic change (arrowheads)

thickened

and (b) transverse scans of a partial-thickness representing an intratendinous tear. (c) Scan

rotator cuff tear within of a splitlike horizontal

a thickened partial-thickness

cuff that is an almost tear (arrowheads)

anechoin a

cuff.

9i%

(93

of i02).

The

positive

predic-

tiye value of sonography was 83% (15 of 18), and the negative predictive value was 93% (78 of 84) (Table 3). Five

bursognams

were

obtained

to

verify the sonographic diagnosis of impingement syndrome in the early stage. With sonographic guidance, contrast medium was injected into the bunsa after aspiration of fluid. On these bunsograms, acquired at different degrees of arm elevation, the mechanical impingement of the rotator cuff and bursa by the acromion could be detected by distention and gradual lateralization of the bursal fluid

(Fig

3).

DISCUSSION The subacromial bursa is the langest human bursa, situated like a cap over the rotator cuff. It is thin walled and lined by synovial membrane. This bursa is composed of subacromial and subdeltoid portions as well as subcomacoid extension in some mdividuals (6). Normally, the bursal system cannot be visualized on plain ma-

b. Figure

drome

5. (a) Scan of impingement synassociated with rotator cuff tear.

Thinning of the cuff (between curved arrows) shows the tear. Bursal fluid is seen between arrowheads. d = deltoid muscle, r rotator cuff, h humeral head. (b) Fluoroscopically obtained impingement view of the same patient reveals disease progression on the undersurface of the acromion with large osteophytes.

tween a pathologic bursal system and other surgical findings and true-positive sonographic examinations is shown in Table i. In 21 (57%) of 37 cases, bursal abnormalities were not associated with rotator cuff tear, and thus

these

cases

impingement Volume

represent

early-stage

syndrome. 176

#{149} Number

In four 3

cases subacromial spurs were mevealed at impingement radiography and surgery. In the assessment of impingement syndrome

of stages

I-Ill

when

diographs. with fluid,

com-

pared with surgical results, US showed a sensitivity of 8i% (30 of 37), a specificity of 95% (62 of 65), and an accuracy of 90% (92 of 102). The positive predictive value of sonography was 91% (30 of 33), and the negative predictive value was 90% (62 of 69) (Table 2). In the diagnosis of early stage of impingement

(stages

I-Il,

without

tator cuff tear), US showed a sensitivity of 71% (15 of 21), a specificity of 96% (78 of 81), and an accuracy of

no-

However, if distended the subdeltoid bursa

may

be identified as a watery mass (i2). At arthrography the bunsal system is seen only in full-thickness tears when it fills with contrast medium (13). Mechanical impingement of the rotator cuff by the acromion can be demonstrated

with

subacromial

bun-

sognaphy (5,6). The method sive and requires manipulation painful shoulder. False-positive

is invaof the me-

suits

to opa-

may

arise

from

failure

cify the bursal system, and false-negative results may occur if the mange of motion of the arm is restricted. Distally pointing osteophytes, subRadiology

#{149} 847

acnomial

spurs,

or spurs

mioclavicular

joint

pression and they common

acmo-

cause

com-

and wear of the cuff (13), are claimed to be the most cause of the impingement

syndrome

(14).

however, spurs This

of the

may

In the

present

osteophytes

were seen is probably

of the

acmomion

with

impingement ated with

seven

is thought an abnormally which

was

found

cases. patients

respect

to

dislocation, Normally

and the

ally

is poorly

ed state

(21).

however, confidently

In the

nondistend-

present

surgical

In nearly

study,

group,

fluid

be in 30

half

of the

collection

was

found to be associated with rotator cuff tear. In the other half, the condition was diagnosed with US as impingement syndrome without team of the rotator cuff. We think that these cases Neem

represent (18) and

lesions defined Neem and Welsh

by (22)

as

stage I or stage I! impingement. Stage I consists of edema and hemorrhage in the

bumsa

and

rotator

cuff.

Stage

I!

the distal clavicle (17). However, MR imaging is time-consuming, of limited availability, and much more expensive than sonognaphy. The prevalence of the impingement syndrome is high, and it affects people of all ages from young adults to the elderly. The syndrome fre-

implies fibrosis and thickening of the subacromial soft tissues and sometimes a partial rupture of the rotator cuff. There were no criteria to sono-

quently

occurs

dens,

pecially repetitive,

in young frequent

tions

(eg,

ton,

javelin,

before

age

25 (2,3),

es-

athletes engaged throwing mo-

in

volleyball,

tennis,

and

badmin-

swimming).

patients,

symptoms

taneously sporting

or in association on occupational

may

In older appear

spon-

with stresses

drome

have

proved

nonspecific. ten

has

Thus, been

the

delayed

diogmaphic occur only disease

to be

In a typical

case

on

the

nomion. ever,

inferior

may

tous 848

the

arch

even

also

comacoacromial

and

#{149} Radiology

the

portion

hypo-

ac-

how-

at stage

III,

be-

ligamen-

of the

cmomial ligament, which could not be found at sonognaphic examination in any case. Sonographic equipment with a 7.5-MHz transducer seems to provide inadequate resolution for visualization of this thin ligament. We found that thinning of the cuff

mostly

of the

occur

coracoa-

penechogenic

on sclerosis of the may be a normal can

tight

of-

of ad-

changes,

be absent

and irregularity greaten tuberosity variant (15,19). Impingement tween

surface

Radiographic

and

ma-

vanced-stage impingement, radiographs may show bone changes associated with rotator cuff team and an acromiohumeral distance of less than 7 mm (20), superior migration of the humeral head, and concave depression

a thickened

tears of the cuff. The in these cases changed

changes may be absent or late in the course of the

(1,2).

stages.

degenerative echogenicity

somewhat Plain

these

impingement, cases represented

desyn-

diagnosis (18).

differentiate

Surgical results in these cases mevealed an inflamed and scarred bumsa containing fluid and, in many shoul-

was seen with most of these

(1,4).

Several clinical tests (1,18,19) vised to detect the impingement

graphically

ten-

to the

of the

rather

direction.

cuff

could

but large

than

hy-

Thickening

also

be found

with

impingement, but we noted that this finding was also seen with partialthickness team, which at surgery proved to be an onionskin tear. There are some pitfalls that must be remembered

before

impingement

making

diagnosis

the

on the

basis

of US findings. First, primary bursitis, which is claimed to be seen only in rheumatoid arthritis, tuberculosis,

gout,

and

must

be

pyogenic ruled

tive

findings.

may

occur

infections to avoid

(23), false-posi-

False-negative if the

are restricted sive and not addition,

out

motions

or if the distended

bumsal

fluid

findings of the

bursa with collections

that

some

of the

sonographic

arm

is adhefluid. In may

the

to avoid

In our

fluid collection could observed with US

of 37 patients.

it with

help

2 mm at uland usu-

in its

suspect

false-negative

paring

tendinitis. subacromial-subdel-

seen

We

which could of bumsal fluid

findings were due to this phenomenon. However, changing the gain settings, elevating the arm, and com-

in the

toid bursa is thinner than trasound (US) examination

internal echoes, the recognition

difficult.

to be associshallow

present study in five cases with simultaneous rotator cuff tear, bicipital

or subacromial

who underwent surgery were young (mean age, 42 years). Our findings melate to shoulder impingement in the younger age group and are in concordance with the results obtained by Cone et al in i984 (15). Although based on a relatively small number of patients, previous studies have suggested that MR imaging is capable of demonstrating notaton cuff abnormalities in patients with impingement syndrome (16). Unlike our findings here with sonognaphy, MR imaging can also show the causes for impingement syndrome to be subacromial spurs, capsular hypertrophy of the acromioclaviculam joint, and inferior displacement

have make

groove,

study,

only in four because the

don of the long head of the biceps brachii muscle situated in the intertubercular groove (3). This type of

found

other

this

series

shoulder

primary

in only

can

pitfall.

two

bursitis

patients

was

with

rheumatoid arthritis, which comdance with other studies For one false-positive result, was no reasonable explanation.

is in con(23,24). there Like

Middleton

we

et al (25)

in

1986,

have

also found many restrictions to reliable shoulder sonography (26). Theme is evidence that timely acromioplasty can retard the progress of rotator cuff weakening and possible rupture (6,27). US seems to have own place in assessing early-stage

its

impingement syndrome, which facilitate more timely treatment; however,

unlike

MR

imaging,

it can-

not demonstrate the causes disability. As the diagnosis acromial

osteophyte

can

for this of a sub-

is important

in

altering the treatment from conservative to surgical management (15), we advocate obtaining fluoroscopic impingement-view madiographs (28) for all

patients

with

especially

bursitis

when

MR

found

at US,

imaging

equip-

ment is not available. Good results from using US to help diagnose rotator cuff tears have been reported by others (9-1 1) and by our-

selves (26,29). The negative predictive value of sonography (83%) was less

than

the

positive

predictive

ue (93%). This means cases with false-negative

that

val-

some of the findings

should be reexamined with another modality (26). On the other hand, the findings of bunsal fluid or thickening may increase one’s confidence that

the shoulder is pathologic. Therefore, if an effusion of the bursal system is found with sonography, a careful sonographic search for other abnormalities should be performed. If a team

the

is not

rotator

a dynamic nogmaphy

agnose drome. The

observed

cuff

elevation should

early-stage treatment

with

US

is otherwise

and

normal,

test during be performed

soto di-

impingement

syn-

of impingement

syndrome depends on the patient’s age and degree of discomfort, chronicity of the disorder, and associated abnormalities. Dynamic sonognaphic

examination, is elevated only and

in which both attention

subacromial-subdeltoid

the

humerus

laterally and is focused

antenion the

bunsal September

sys1990

tem,

seems

to give

valuable

and

able information mial soft tissue acromion and

about the encroached coracoacromial

mentous

arch.

Although

nography

can

fluid

only

distention,

laterally

to the

results

subacmoon by the liga-

dynamic

display

and

meli-

of fluid bursa,

are comparable

with

the

those

lution useful

equipment as an initial

in patients impingement

with

by experts imaging

suspected syndrome.

9.

ob-

tamed at subacromial bursognaphy. (Bursography is, however, invasive, uncomfortable, and little used.) We believe that dynamic sonognaphic examination with real-time high-reso-

may be modality early-stage U

10.

1 1.

12.

2.

Neer CS II. Anterior acromioplasty for the chronic impingement syndrome in the shoulder. J Bone Joint Sung [Am]

3.

Penny

JN,

Welsh

ment syndrome gical management. 9:11-15.

4.

Kessel

L, Watson

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#{149} 849