ABSTRACT ID NO: 50

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 SPECTRUM OF MRI FINDINGS IN GLENOHUMERAL
INSTABILITY 

• ABSTRACT ID NO 50

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INTRODUCTION

• The shoulder joint is a ball and socket type of
  joint that has two main stabilizers
• the rotator cuff
  muscles (dynamic)
• the labral-ligamentous
  complex (static).
• The primary function of the rotator cuff muscles
  is to centralize the humeral head, limiting
  superior translation during abduction.
• The glenohumeral joint is the most commonly
  dislocated joint. The normal glenoid labrum
  height and width are 3 mm and 4 mm.
• The glenoid labrum is the ring of fibrocartilage
  that provides attachment to the glenohumeral
  ligaments and the capsule at the glenoid rim and
  deepens the glenoid fossa. The attachments of the
  glenohumeral ligaments and the long head biceps
  anchor to the labrum are stronger than the
  attachment of the labrum to the glenoid rim.
  Therefore, the glenoid labrum is commonly torn or
  avulsed when excessive force is applied to a
  glenohumeral ligament or the long head biceps

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ANATOMY

• LATERAL VIEW OF THE GLENOID FOSSA WITH ITS
  LIGAMENTS

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The glenohumeral ligaments (inferior, middle, and
superior) are thickened bands of the joint
capsule that extend from the inferior and
anterior glenoid and glenoid labrum, to the
anatomic neck region of the humerus.

• The inferior glenohumeral ligament (IGHL) is a
  hammock-like structure that attaches to the
  inferior glenoid, glenoid labrum, and the humeral
  neck. Thickened portions of the IGHL anteriorly
  and posteriorly are referred to as the anterior
  and posterior bands.

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• The middle glenohumeral ligament (MGHL) varies in
  thickness, shares a common origin with the SGHL
  helps stabilize the shoulder anteriorly from 0-45
  degrees of abduction and external rotation.
• The superior glenohumeral ligament (SGHL) is the
  smallest ligament and acts with the coracohumeral
  ligament to stabilize the glenohumeral joint It
  prevents posterior and inferior translation of
  the humeral head.

MGHL
CHL
SGHL
LH BICEPS TENDON
GL
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On MRI the normal labrum demonstrates low signal
intensity on all pulse sequences, due to the lack
of mobile protons in this dense fibrocartilage.
On cross sectional imaging, the normal labrum is
most commonly triangular, but can also be round,
cleaved, notched, flat, or absent
DISCUSSION

• For localization purposes, the labrum is divided
  into six zones includes superior,
  anterosuperior, anteroinferior, inferior,
  posteroinferior, and posterosuperior.

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• MRI diagnosis of labral tears is based on
  abnormalities in the signal intensity,
  morphology, and location (displacement) of the
  labrum. The labrum may be frayed, crushed,
  avulsed, or torn.
• Tears are classified by morphology, displaced or
  nondisplaced, and by location. Labral tears can
  extend into the biceps anchor as well as the
  glenohumeral ligaments.
• MRI criteria for diagnosing labral tears include
  
• Surface irregularity,
• Increased signal within the substance of the
  labrum that extends to the labral surface ,
• Fluid or contrast imbibed into the substance of
  the labrum ,
• Labral avulsions.
• Secondary signs of labral tears include
  paralabral cysts , periosteal stripping and
  tearing, labral associated bone injuries .

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• Anterior Instability

• Posterior Instability

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• A Bankart lesion is a tear of the
  anterioinferior glenoid labrum with an associated
  tear of the anterior scapular periosteum, with or
  without associated fracture of the anterior
  inferior glenoid rim

Classic Bankart lesion
Bony Bankart lesion
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• A Perthes lesion is a variant of the Bankart,
  where the anterioinferior labrum is avulsed from
  the glenoid and the scapular periosteum remains
  intact but is stripped medially.

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• A HAGL lesion is humeral avulsion of the
  glenohumeral ligament that occurs from shoulder
  dislocation, with avulsion of the inferior
  glenohumeral ligament from the anatomic neck of
  the humerus.
• A BHAGL is a bony HAGL, that involves a bone
  fragment.
• Reverse HAGL lesion In posterior instability
  there is complete avulsion of the posterior
  attachment of the shoulder capsule and the
  glenohumeral ligament from the posterior humeral
  neck

HAGL
Reverse HAGL lesion
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• The GLAD lesion refers to glenolabral articular
  disruption, which involves a tear of the anterior
  inferior labrum with an associated glenoid
  chondral defect
• Glenoid avulsion of the glenohumeral ligaments
  (GAGL) implies an avulsion of the IGHL from the
  inferior pole of the glenoid, without an
  associated inferior labral disruption

GLAD
GAGL
AVUL OF IGHL
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• The ALPSA lesion is characterized by a torn
  anteroinferior labrum with an intact but
  stripped periosteum and medial displacement of
  the labrum and inferior glenohumeral ligament
• Inferior ALPSA or cul-de-sac lesion is medial
  displacement of both the anterior-inferior labrum
  and the IGHL under the inferior neck of the
  glenoid

ALPSA
TORN ANTR INF LABRUM
IGHL
Inferior ALPSA
AIL
IGHL
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• Hill-Sachs lesion consists of bony injury to the
  posterosuperior humeral head as a result of
  inferior displacement (which occurred when the
  humeral head struck the anterior inferior glenoid
  during anterior dislocation).
• Reverse Hill-Sachs lesion consists of an
  anteromedial superior humeral head impaction
  fracture
• Bennett lesion is an extra-articular crescentic
  posterior ossification associated with posterior
  labral injury and capsular avulsion

Hill-Sachs lesion
Reverse Hill-Sachs lesion
Bennett lesion
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• Rotator cuff interval tear do not appear as
  complete disruption of the fibers of its
  components but as thinning, irregularity, or
  focal discontinuity of the rotator interval
  capsule.
• Posterosuperior labral tear in association with a
  paralabral cyst may be seen in patients with
  posterior instability

Rotator cuff interval tear
Paralabral cyst
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The SLAP lesion is an injury involving the
superior aspect of the glenoid labrum, which
includes the biceps tendon anchor.
SLAP CLASSIFICATION
Type II
Type IV
BHL with extension into biceps tendon
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TYPE VII
SLAP CLASSIFICATION
TYPE V
SLAP lesion with anteroinferior extension
Superior labral tear with MGHL extension
TYPE IX
Fraying of MGHL
global labral abnormality
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CONCLUSION

• Anterior instability is the most common type of
  shoulder instability.
• It is associated with a Bankart lesion and its
  variants and abnormalities of the anterior band
  of the inferior glenohumeral ligament, whereas
  posterior instability is associated with reverse
  Bankart and reverse Hill-Sachs lesions.
• REFERENCES
• Neviaser TJ. The anterior labroligamentous
  periosteal sleeve avulsion lesion a cause of
  anterior instability of the shoulder. Arthroscopy
  1993 917-21.
• Lynne S, Steinbach, Tirman Philip FJ, Peterfy
  Charles G, Feller John F. Philadelphia
  Lippincott Raven 1998. Shoulder magnetic
  resonance imaging.
• Waldt S. Burkart A, Imhoff AB, Bruegel M, Rummeny
  EJ, Woertler K. Anterior shoulder instability
  accuracy of MR arthrography in the Classification
  of Anteroinferior labroligamentous injuries.
  Radiology 2005 237578-583.
• Bottoni CR, Franjs BR, Moore JH, DeBerardino TM,
  Taylor DC, Arciero RA. Operative stabilization of
  the posterior shoulder instability. Am J Sports
  Med. 2005339961002. PubMed 15890637
• Vidal LB, Bradley JP. Management of posterior
  shoulder instability in the athlete. Curr Opin
  Orthop. 20061716471.

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