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Andrew J Grainger

MSK Radiology

Leeds, UK

Norwegian MSK Imaging Seminar 25-26.04.2019 Farris Bad in Larvik

� Impingement of the rotator cuff and joint capsule/labrum on the glenoid or

between the glenoid and humerus

� Mechanisms remain controversial

� Descriptions remain confused

� Two types described:

� Posterosuperior

� Anterosuperior (Anterior)

� Both types associated with:

� Undersurface rotator cuff tears

� Labral damage

� Bone changes

� First type of internal impingement described

� Posterosuperior cuff contacts posterosuperior glenoid in ABduction and External

Rotation (ABER) position

Walch G. J Shoulder Elbow Surg. 1992:1;238

� Jobe et al

� Injury to cuff, labrum and bone

� Seen in throwers and overhead

athletes

� Tennis

� Gymnastics

� Swimmers

� Due to increased frequency or force of activity

Jobe. Curr Orthop Prac 1996; 330:98

V o lu n teer p o sitio n ed in 0 .5-T o p en M R im ag er.

© 2 0 0 7 b y R a d io lo g ic a l S o c ie t y o f N o r t h A m e r ic aGold et al. Radiology 2007;244:815

� Contact between cuff and

posterosuperior glenoid is shown

to be a normal phenomenon on the

basis of MRI and arthroscopic

studies

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V o lu n teer p o sitio n ed in 0 .5-T o p en M R im ag er.

Gold G E et al. Radiology 2007;244:815-822

© 2 0 0 7 b y R a d io lo g ic a l S o c ie t y o f N o r t h A m e r ic aGold et al. Radiology 2007;244:815 Gold et al. Radiology 2007;244:815

� Jobe et al

� Injury to cuff, labrum and bone

� Seen in throwers

� Due to increased frequency or force

of activity

Jobe. Curr Orthop Prac 1996; 330:98

� Undersurface rotator cuff tears� Classically posterior supraspinatus and

anterior infraspinatus

� 81% to 100% in those with clinical PSGI

Jobe. Arthroscopy 1995; 11: 530

Tirman et al Radiology 1994; 193: 431

Giaroli et al. AJR 2005; 185: 925

� Undersurface rotator cuff tears� Classically posterior supraspinatus and

anterior infraspinatus

� Posterosuperior labral tear� Classically type II SLAP but posterior in

location (IIB)

Biceps

Anterior

Type II SLAP

Type IIB SLAP Type IIA SLAP

� Undersurface rotator cuff tears� Classically posterior supraspinatus and

anterior infraspinatus

� Posterosuperior labral tear� Classically type II SLAP but posterior in

location (IIB)

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� Undersurface rotator cuff tears� Classically posterior supraspinatus and

anterior infraspinatus

� Posterosuperior labral tear� Classically type II SLAP but posterior in

location (IIB)

� Bone Changes� Superior humeral head

� Posterosuperior glenoid

� Is it simply a case of impingement?

� Peel-back mechanism resulting from

hyper-external rotation

� Hyper-twisting of rotator cuff

� Hyper-twisting of biceps

� Posterior traction on superior

labrum

Morgan et al. Arthroscopy 1998;14:553

Burkhart et al. Arthroscopy 1998;14:637

Posterior

� Initially thought microinstability

important in aetiology

� Recurrent overstretching of anterior

capsule leading to anterior capsular

laxity

� Allows increased ABER

� Increased impingement

� Increased peel back

� Rational behind capsular

reconstruction or plication for

treatment

� Initially thought microinstability

important in aetiology

� Recurrent overstretching of anterior

capsule leading to anterior capsular

laxity

� Allows increased ABER

� Increased impingement

� Increased peel back

� Rational behind capsular

reconstruction or plication for

treatment

� Initially thought microinstability

important in aetiology

� Recurrent overstretching of anterior

capsule leading to anterior capsular

laxity

� Allows increased ABER

� Increased impingement

� Increased peel back

� Rational behind capsular

reconstruction or plication for

treatment

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� Role of microinstability questioned

� No evidence of instability found clinically or at arthroscopy

� Biomechanics would suggest that anterior capsular laxity should lessen

impingement and peel-back by allowing humeral head to sublux

Walch et al. J Shoulder Elbow Surg 1992;1:238

Halbrecht et al. Arthroscopy 1999;15:458

Burkhart et al. Arthroscopy 2003;19:404

� Repetitive strain on posterior capsule and ligaments on follow-through leads

to posterior tightening and contracture

Posterior

� The centre of contact between

the glenoid and humerus moves

posterosuperiorly

Posterior

Posterior

� The centre of contact between

the glenoid and humerus moves

posterosuperiorly

Posterior

� The centre of contact between

the glenoid and humerus moves

posterosuperiorly

� Increases external rotation

� Increases Peel-Back effect

� Reduces allowable internal

rotation

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� The centre of contact between

the glenoid and humerus moves

posterosuperiorly

� Increases external rotation

� Increases Peel-Back effect

� Reduces allowable internal

rotation Sport Internal Rotation External Rotation

Non-athlete 70o 90o

College swimmers 49o 100o

Pro-Baseball 57o 109o

Tennis 55o 105o

� First described in 1941

� Recognised imaging finding

� Calcification in region of posteroinferior capsule

� Association with GIRD postulated

� Also seen in asymptomatic overarm

athletes

Bennett. J Am Med Assoc 1941;117:510

Nakagawa et al. J Shoulder Elbow Surg 2006; 15: 72

� First described in 1941

� Recognised imaging finding

� Calcification in region of

posteroinferior capsule

� Association with GIRD postulated

� Also seen in asymptomatic overarm

athletes

Bennett. J Am Med Assoc 1941;117:510

Nakagawa et al. J Shoulder Elbow Surg 2006; 15: 72

1) Posterior Cuff

2) Posterosuperior Labrum

3) Bone Changes

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2

3

1) Posterior Cuff

2) Posterosuperior Labrum

3) Bone Changes1

2

� More confusing as terminology varies:

� Anterosuperior impingement

� Anterior impingement

� Refer to impingement on anterior glenoid

� Don’t confuse with subcoracoid impingement

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� Occurs in position of horizontal adduction and internal rotation � Vulnerable structures

� Subscapularis

� Structures of rotator interval

� Anterior edge of supraspinatus

� Anterosuperior labrum

� Normal discontinuity in the cuff

between subscapularis and

supraspinatus

� Contents

� Biceps tendon

� Coracohumeral ligament

� Superior glenohumeral ligament

� Arises from base of coracoid

� Covers rotator interval

� Blends

� Laterally with Supraspinatus

� Medially with Subscapularis

� Forms coalescent sling with

superior glenohumeral

ligament

� Biceps stabiliser

� Painful attrition of biceps pulley and subscapularis

� SGHL & CHL tears è LHB instability

� Associated undersurface partial thickness tears Subscapularis & Supraspinatus

Hebermeyer et al. J Shoulder Elbow Surg 2004; 13:5

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� Initial descriptions described damage to rotator interval and cuff as result of

impingement on anterior glenoid

� Gerber & Sebesta. J Shoulder Elbow Surg 2000;9:483

� Subsequent suggestion that anterior cuff and interval disruption leads to

painful impingement on the glenoid through resulting instability

� Habermeyer et al. J Shoulder Elbow Surg 2004;13:5

� Spectrum of injury

1. Rotator interval disruption

2. Biceps instability

3. Failure to resist anterior translation of humeral head

4. Decentered humeral head è Anterosuperior Impingement

Hebermeyer et al. J Shoulder Elbow Surg 2004; 13:5

� As with posterosuperior internal impingement key for the radiologist is

recognition of pattern of injury

� Evidence of rotator interval

disruption

� Subscapularis partial tear

� Supraspinatus partial tear

� Bone change

� Humeral head in region of interval

� Anterosuperior glenoid

� Superior labral damage

(anterosuperior)

Superior

Labrum

Anterior

Cuff

SLAC

MR arthrography

� Subcoracoid space contrast leakage

� Contrast tracking through rotator interval

� Contrast surrounding CHL

� Fraying /Thickening or disruption of CHL

� Biceps subluxation

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� Rotator interval difficult to evaluate

� Biceps subluxation relatively easy

� Look for associated subscapularis and supraspinatus damage

� Cardinal sign – Medial subluxation of biceps tendon

� Pattern of injury determines whether superficial, within or deep to

subscapularis

� Cardinal sign – Medial subluxation of biceps tendon

� Pattern of injury determines whether superficial, within or deep to

subscapularis

� Cardinal sign – Medial subluxation of biceps tendon

� Pattern of injury determines whether superficial, within or deep to

subscapularis

� Cardinal sign – Medial subluxation of biceps tendon

� Pattern of injury determines whether superficial, within or deep to

subscapularis

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� Recognise the association between

� Rotator interval disruption

� Biceps subluxation

� Partial tears of supraspinatus

� Partial tears of subscapularis

� Bone change in this region

� Superior Labrum

� SLAC Lesion: Superior Labrum,

Anterior Cuff

Posterosuperior Impingement

� Undersurface rotator cuff tears

� Posterior Cuff

� Superior Labrum

� SLAP Lesions

� Bone edema and irregularity

� Bennett lesion

� Anterior cuff tears

� Rotator Interval

� Biceps instability

� PT Subscapularis

� PT Supraspinatus

� Bone irregularity

� SLAP lesions

� (SLAC Lesion)

Anterosuperior Impingement