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4/23/19
1
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
12
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