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MR Imaging of Glenohumeral Instability

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Title: MR Imaging of Glenohumeral Instability


1
MR Imaging of Glenohumeral Instability
  • Timothy G. Sanders, M.D.
  • Assistant Professor
  • Uniform Services University
  • Bethesda, MD

2
Glenohumeral Joint
  • Intrinsically Unstable joint
  • Shallow glenoid fossa
  • Large articular surface of the humeral head
  • Static Stabilizers
  • Joint capsule
  • Glenohumeral Ligaments
  • Glenoid labrum
  • Dynamic Stabilizers
  • Rotator cuff
  • Tendon of the long head of the biceps

3
Classification
  • TUBS
  • Traumatic
  • Unidirectional
  • Bankart
  • Surgery
  • AMBRI
  • Atraumatic
  • Multidirectional
  • Bilateral
  • Rehabilitation
  • Inferior Capsular Shift

4
Multidirectional Instability
  • AMBRI Patient
  • Causes of Multidirectional Instability
  • Hypermobility or Laxity
  • Stretching or Overuse of Support Structures
  • MR Imaging not usually Required
  • MR Findings Nonspecific
  • MR Useful if Direction Unknown to Rule Out
    Conventional Causes

5
Anterior Stabilizers
  • Labrum
  • Glenohumeral Ligaments
  • Capsule
  • Subscapularis Muscle
  • Most Important Anterior Stabilizer Inferior
    Glenohumeral Labroligamentous complex
  • Anteroinferior labrum
  • Anterior Band of the Inferior Glenohumeral
    Ligament

6
Normal Labrum
Anterior and Posterior Labrum best seen in the
Axial Plane
LABRUM -Dark on all Pulse Sequences -May be
triangular, rounded, or blunted
7
Normal Superior Labrum
Seen Best in the Coronal Plane
Superior Labrum -Dark on all pulse
sequences -Triangular -Extends off of Superior
Glenoid
8
Glenohumeral Ligaments
Superior GH Ligament
Middle GH Ligament
Anterior Band of the Inferior GH Ligament
9
Superior Glenohumeral Ligament
-Prevents inferior subluxation with arm in 0º
abduction
-Courses from superior glenoid tubercle to lesser
tuberosity -Parallels Coracoid process
10
Middle Glenohumeral Ligament
-Prevents external rotation of humeral head when
arm is between 45º and 60º of abduction
-Originates at superior glenoid tubercle
-Courses obliquely superficial to the anterior
labrum -Blends with the deep fibers of
subscapularis
11
Middle Glenohumeral Ligament
Most Variable of the GH Ligaments
12
Inferior Glenohumeral Ligament
-Most important GHL -Prevents anterior
subluxation with arm in full abduction and
external rotation
-Extends from anterior inferior labrum to humeral
neck
-Lax with arm in neutral position
13
Inferior Glenohumeral Ligament
-Redundant when the Arm is in Neutral Position
14
ABER Positioning
15
Scout Position and Scan Plane for ABER
-Coronal scout with arm in ABER position
-Scan plane along the long axis of the humeral
shaft
16
Inferior Glenohumeral Ligament ABER Imaging
-Provocative position -Stretches the anterior
band of IGHL and places tension on the anterior
labrum -Helps in the identification of subtle
nondisplaced anterior labral tears
17
Normal Anatomic Variants
Cartilage Undermining
-Articular Cartilage Hyaline- Intermediate -Labrum
- Fibrocartilage Dark Signal
-Smooth, tapering -Does not Extend Completely
Beneath Labrum
18
Normal Anatomic Variant
Labral Tear
Cartilage Undermining
19
Normal Anatomic Variants
Sublabral Foramen (Hole)
-Complete detachment of the labrum from the
glenoid -Occurs only in the anterosuperior
quadrant
20
Normal Anatomic Variant
Sublabral Recess
-Smooth, Tapering -Extends Toward the Glenoid
-No Signal Extends into the Black Triangle of the
Superior Labrum -Can Mimic a SLAP Tear
21
Normal Anatomic Variant
Sublabral Recess
-Axial Plane -Smooth Linear collection of
Contrast between Superior Labrum and Osseous
Glenoid
22
Normal Anatomic Variant
-Buford Complex -1.5 of Patients -Can Mimic
Anterior Labral Tear
-Thick Cord-like MGHL
-Absent or Diminutive Anterior-Superior Labrum
23
Buford Complex
1
2
3
24
Anterior Instability
  • 95 of all Dislocations
  • Mechanism
  • Fall on an outstretched arm
  • Abduction and external rotation

25
Bankart Lesions
  • The Most Common Injury Following Anterior
    Dislocation
  • First-Time Dislocators Under 35 y.o.
  • Anterior Labro-Ligamentous Avulsion with
    Disruption of the Medial Scapular Periosteum

26
Bankart Lesion
1. Anterior labroligamentous avulsion
2. Disruption of the medial scapular periosteum
27
Bankart Lesion
28
Osseous Bankart
-Fracture of Inferior Glenoid -Disruption of the
Cortex of the Anteroinferior Glenoid
29
Hill-Sachs Lesion
-Results from Impaction of Humeral Head against
Anterior-inferior Glenoid -Associated with
Bankart Lesion -Normally Top 3 Images
Round -Hill-Sachs Flattening or Concavity
30
Double Axillary Pouch Sign
-Normal anteroinferior labrum on coronal image
-Double axillary pouch Small collection of
contrast in inferior labrum
31
Double Axillary Pouch Sign
-Normal anteroinferior labrum on coronal image
-Double axillary pouch Small collection of
contrast in inferior labrum
32
Perthes Lesion Nondisplaced Bankart
  • Bankart Variation
  • Labro-Ligamentous Disruption
  • Medial Scapular Periosteum Intact
  • May Resynovialize in Place
  • Best Detected on ABER View

33
Perthes Lesion
1. Anterior labroligamentous avulsion
2. Medial scapular periosteum remains
intact --Nondisplaced Bankart
34
Nondisplaced Tear Anteroinferior Labrum
Cartilage Undermining
Perthes Lesion
35
ABER Positioning
36
Perthes Lesion
Normal Anteroinferior Labrum
Nondisplaced Labral Tear
37
ALPSA Lesion Medialized Bankart
  • Anterior Labroligamentous Periosteal Sleeve
    Avulsion
  • Intact Medial Scapular Periosteum
  • Medialized Bankart Lesion
  • Surgical Repair Technique Differs From Bankart

38
ALPSA Lesion
Medialized Bankart
39
Medialized Bankart Lesion
ALPSA
-Avulsed Labrum Pulled Medially by an intact
Medial Scapular Periosteum -Easily Identified in
the Acute Setting
40
Chronic Medialized Bankart Lesion
-Labrum scars down medially
-Scar tissue mounds up covering medialized labrum
and resynovializes -Treatment complete Bankart
and reconstruction
41
Axillary Nerve Neuropraxy
Axillary Nerve can be stretched at time of
anterior dislocation resulting in denervation
atrophy Deltoid and Infraspinatus muscles
Denervation atropy -Acute edema -Chronic fatty
42
First Time Dislocation Over Age 35
  • Clinical Presentation can be Confusing
  • Tear Supraspinatus Tendon
  • Fracture Greater Tuberosity
  • Avulse Subscapularis and Anterior Capsule from
    the Humerus
  • MRI can Play Pivotal Role in Directing Patient
    Therapy

43
Tear of the Supraspinatus Tendon
First Time Dislocation Over Age 35 Bankart
Lesion is Uncommon
Rotator Cuff becomes the Weak Link
44
First Time Dislocation Over Age 35
Avulsion fracture of the greater tuberosity
45
Greater Tuberosity Fracture
-Avulsion of the Greater Tuberosity is often
Occult Radiographically -Can Mimic RCT
-Treated Conservatively -MRI can Accurately
Distinguish
46
Avulsion of Subscapularis
-Subscapularis Muscle can Avulse off of Lesser
Tuberosity -Associated with Dislocation of the
Biceps Tendon -Seen best in Axial Plane
47
Disruption of Subscapularis
-Disruption of Subscapularis at Musculotendinous
Junction -Requires Surgical Repair
48
HAGL LESION
  • Humeral Avulsion of the Glenohumeral Ligament
  • Results from Dislocation
  • No Age Predilection
  • MR Findings Contrast Extravasation from Joint
    Capsule/ Avulsion of Subscapularis

49
HAGL Variants
50
HAGL Lesion
Disrupted IGHL at humeral attachment site
51
HAGL Lesion
-Inferior GHL can Disrupt Anywhere Along
Course -Humeral Attachment/ Mid Substance
-Difficult to Detect with Scope -Cause of Failed
Repairs
52
HAGL Lesion
-Can Present on MRI as Avulsion of Subscapularis
Muscle
53
Posterior Instability
  • 2 - 4 of all traumatic dislocations
  • 20 - 25 of shoulder instability cases in active
    duty military population
  • Adduction with internal rotation
  • Seizure, electrocution, weight lifting, swimming,
    lineman blocking
  • Reverse Hill Sachs, Bankart

54
Posterior Instability
Reverse Bankart
Reverse Hill Sachs
55
Posterior Instability
-Repetitive Microtrauma Nondisplaced posterior
labral tear
56
GLAD Lesion
  • Glenolabral Articular Disruption
  • Forced adduction injury (humeral head impacts the
    glenoid fossa)
  • Clinically a Stable Lesion
  • Partial Tear Anteroinferior Labrum / Articular
    Cartilage Injury

57
GLAD Lesion
-Non displaced tear anteroinferior labrum
-Articular Cartilage Injury
58
GLAD Lesion
-Non displaced tear anteroinferior labrum -Best
seen on ABER
-Articular Cartilage Injury -Best seen on axial
or coronal
59
Posterior Superior Glenoid Impingement
  • Also known as Internal Impingement
  • Undersurface tearing of posterior rotator cuff
    (posterior SST or IST)
  • Impingement between posterior labrum and greater
    tuberosity
  • Throwing athletes- posterior shoulder pain
  • Associated with anterior instability

60
Posterior Superior Glenoid Impingement
-Undersurface of posterior rotator cuff impinged
between the greater tuberosity and the
posterosuperior labrum -Seen best on ABER view
61
Posterior Superior Glenoid Impingement
1) undersurface tear of posterior rotator cuff
2) degenerative changes of posterosuperior labrum
3) cystic change in greater tuberosity
4) internal impingement seen on ABER view
62
Glenohumeral Internal Rotation Deficit (GIRD)
-Scarring and thickening of the posterior capsule
and has recently been described as a source of
potential pain in throwing athletes - MR imaging
demonstrates thickening of the posterior capsule
63
SLAP Tears
  • The Superior labrum, anterior-to-posterior
    lesion, can include biceps tendon
  • Mechanism
  • Fall on outstretched arm
  • Repetitive overhead activity (throwing, swimming)
  • Symptoms pain with overhead activity, catching,
    popping sensation

64
SLAP Tear Type I
Fraying of the undersurface of the superior labrum
65
SLAP Tear Type II
Avulsion of the labrum from the osseous glenoid
66
SLAP Tear Type III
Bucket handle tear of the superior labrum
67
SLAP Tear Type IV
Extension of the SLAP tear to involve the biceps
anchor
68
Important factors to observe
  • Abnormal signal in superior labrum
  • Extent of lesion
  • Posterior labrum
  • Anteroinferior quadrant
  • Biceps involvement
  • Type of SLAP tear

69
SLAP Lesion
-Normal Superior Labrum -No internal Signal
-TYPE 1 -Fraying and degeneration but labrum
firmly attached
70
SLAP Lesions
-TYPE 2 -Fraying of labrum and superior labrum
avulsed from glenoid
-Signal extends into the triangle of the superior
labrum
71
SLAP Lesions
-TYPE 3 -Bucket-handle tear of the superior
labrum Biceps tendon remains intact
-On MR imaging Fragment seen displaced into
superior joint space
72
SLAP Lesions
-TYPE 4 -Bucket-handle tear of superior labrum
involves biceps anchor
-Biceps involvement best seen on axial/coronal
images
73
Pitfalls SLAP Tears
-SLAP tear -Any signal extending into black
triangle
-Sublabral recess -Smooth, tapering -No signal in
sup labrum
74
Pitfalls SLAP Tears
-SLAP on axial images -Irregular contrast
collection
-Sublabral recess axial images -Smooth linear
collection of contrast
75
Pitfalls SLAP Tears
-Sublabral recess -No displacement of sup labrum
-Type 2 SLAP tear -Labrum pulled away from glenoid
76
Paralabral Cyst
  • High association with labral tears and GH joint
    instability
  • Superior labral cyst SLAP tears
  • Posterior labral cyst Posterior labral tears
  • Labral tear may resynovialize
  • Can result in shoulder pain and adjacent nerve
    entrapment

77
Paralabral Cysts
-Suprascapular nerve entrapment -Denervation
edema
-SLAP tear with superior paralabral
cyst -Suprascapular notch
78
Paralabral Cysts
-Posterior paralabral cysts -Extend into
spinoglenoid notch -Entrapment of suprascapular
nerve
79
Paralabral Cysts
-Persistent shoulder pain for 3 years -Small
anterior labral tear with small adjacent
paralabral cyst
80
Paralabral cysts
-3 years later persistent pain -Paralabral cyst
larger -Axillary nerve entrapment -Atrophy Teres
Minor
-Small inferior labral cyst -Teres Minor normal
81
Labral Repair Surgical Approach
  • Direct repair of labral and capsular lesions
  • Indirect repairs
  • Staple capsulorapphy (Du Toit Roux)
  • Subscapularis manipulation to tighten anterior
    capsule (Putti Platt/ Magnuson Stack)
  • Movement of the coracoid process (Bristow
    procedure)

82
Direct Repairs
  • Arthroscopic/ open (deltopectoral interval)
  • Suture anchors 3-,4-,5-, oclock position
  • Capsulorapphy (open/ arthroscopic)
  • Staple redundant capsule
  • Done in conjunction with direct repair
  • High failure rate if done as isolated procedure
  • Osseous Bankart
  • Screw fixation

83
MR Findings of Bankart Repair
  • Suture anchor artifact from repair may obscure
    visualization

84
MR Findings of Failed Bankart Repair
  • Recurrent displaced anterior labrum

85
Failed Bankart Repair
  • Missed HAGL lesion
  • In one series up to 30 of failed repairs

86
Subscapularis Tendon Transfer (Magnuson-Stack)
  • Repositioned subscapularis tendon
  • Labral pathology still evident (indirect)

87
Putti - Platt
MR Findings -Thick anterior capsule -OA -Original
instability lesion still present
  • Subscapularis tendon split lateral portion
    attached to glenoid medial portion is imbricated
    over it
  • Dec ROM poor pt satisfaction recurrence 2-10

88
Bristow Repair
  • Move coracoid process to cause bone block to
    prevent ant dislocation
  • Attached to anterior inferior glenoid

89
Recurrent SLAP Following Repair
  • Displaced fragment anterosuperior labrum
  • Osteochondral defect anterosuperior glenoid

90
5 Months Following SLAP Repair Recurrent Pain
  • Fraying and irregularity of superior labrum no
    displaced fragment
  • Partial thickness articular surface tear rotator
    cuff

91
Multidirectional Instability
  • Treated first with rehabilitation
  • Surgery
  • Inferior capsular shift/plication
  • Decrease volume of GHJ anteriorly, inferiorly,
    posteriorly
  • MR capsular thickening

92
Multidirectional Instability
  • Treated first with rehabilitation
  • Surgery
  • Inferior capsular shift/plication
  • Decrease volume of GHJ anteriorly, inferiorly,
    posteriorly
  • MR capsular thickening

93
Hardware Failure
Displaced tack
94
Hardware Complication
Proud suture anchor
95
Synovitis Prior SA Decompression and Rotator Cuff
Debridement Recurrent Pain
  • Synovitis 4 mm adhesive capsulitis
  • Normal postop capsule
  • 2-4 mm after surgical procedure
  • Thickened and nodular capsule

96
Postop Infection
  • Infectious versus reactive synovitis difficult to
    differentiate with imaging
  • Thickened enhancing capsule effusion/ joint
    destruction/ cartilage loss/ cysts, erosions
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