Etiology of Shoulder Instability

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Etiology of Shoulder Instability

• Noel Goodstadt, MPT, OCS, CSCS
• University of Delaware

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Terminology

• Translation
• Laxity
• Stability
• Instability

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Classification of Instability

• Onset
• Degree
• Direction
• Chronicity

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• Traumatic
• Unilateral
• Bankart Lesion
• Surgery

• Atraumatic
• Multidirectional
• Bilateral
• Rehabilitation
• Inferior Capsular Shift

Matsen
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Spectrum of Instability
TUBS
AMBRI
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Traumatic

• Torn Loose
• FOOSH
• Contact Sports (Football, Wrestling, Boxing)
• Bankart or SLAP Lesion
• Concomitant pathology common

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Incidence of Traumatic Dislocation

• Young Athletes under 50
• Males gt Females
• Older individuals over 50
• Females gt Males
• Trend in the literature
• equal number of dislocations above and below 45
  years of age
• Seitz 2006

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Degree of Instability

• Subluxation - Pops out, but spontaneously
• reduces
• Dislocation - Pops out, Stays out, requires
• manual reduction by MD

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Direction of Instability

• Anterior Dislocation
• Most common
• Subcorocoid
• Subglenoid
• Subclavicular
• Posterior
• Inferior
• Multidirectional

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Associated Complications

• Ligamentous
• Bankart Lesion
• HAGL
• Bone
• Hill-Sachs Lesion
• Glenoid Defect/Bony Bankart
• Greater Tuberosity/Surgical Neck
• Rotator Cuff Tears
• Neurological
• Axilary, Suprascapular, others
• Seitz 2006

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Nerve Injury

• Visser et al. 1999
• Most common nerves injured are the axillary nerve
  and the suprascapular nerve
• EMG gt 3 weeks to detect motor lesion
• NCV gt 7 days to detect a motor lesion
• 85-100 recovery within 6-12 months
• Will effect ER and elevation ROM
• Suspicious
• Older then 40, have hematoma, or associated
  fracture Seitz 2006

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Initial Traumatic Dislocation

• Immobilization
• Best to immobilize 3 weeks for patients under 30
• As needed for patients over 30
• Seitz 2006

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Circle Concept of Stability
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Atraumatic

• Born Loose
• Overhead Athletes (Swimmers, Gymnasts)
• Hyperflexible
• Muscle Imbalances common
• AMBRI tendency to improve with age
• Shaffer 2006

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History

• Chronic
• Easy reduction
• Congenital
• lt/ 20 years of age
• most common for start of history
• traumatic

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Loose capsule

• Repetitive strain
• Rotator interval
• May be a congenital defect
• Histological differences
• More collagen
• Smaller collagen and less stiff
• Shaffer 2006

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Microtraumatic

• Overhead Athletes
• Repetitive Tension Overload

• Stretch out Capsule / Ligaments (IGHL)
• Erosion of Glenoid / Labrum

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(No Transcript)
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Other Causes of Instability

• Poor Scapulohumeral Rhythm
• Scapular Dumping

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Imbalance of Forces
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Neuromuscular Differences

• Rotator Cuff
• Timing Activation
• Pectoralis Major new and not proven
• Hyper-Active
• Passive Tension
• Shaffer 2006

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Objective Exam Considerations

• Fatigue/Endurance
• Control
• Macro-instability
• TUBS do you need to test their laxity/instability?
  
• Micro-instability
• Translation with ER for anterior/inferior and IR
  for posterior
• Does it decrease the translation
• If not treatment success will be limited
• Generalized Ligamentous Laxity

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Chronicity of Instability

• Acute vs. Chronic, Recurrent
• First time vs. Recurrent
• Frequency (Common vs. Rare)
• Voluntary or Involuntary

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Surgery vs. Conservative Treatment 1st time
dislocation

• Edmonds et al, 2003 - RCT
• Early arthroscopic stabilization no better than
  immobilization in proprioceptive response
  threshold to detection of passive motion (TTDPM)
  or reproduction of passive positioning (RPP)
• Kirkly et al, 2005 RCT
• Significant difference in rate of redislocation
• No significant difference in shoulder function
• Recommended early arthroscopic stabilization in
  young athletes, under 30 high level sports
• Jakobsen et al, 2007
• Concluded primary repair in active patients was
  indicated to reduce the risk of recurrence

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Evaluation of Stability

• A variety of tests that can be performed in
  several positions
• Find a group of tests that you can perform
  consistently and reliably and use them as your
  core tests
• Other tests for the suspected condition can be
  used to confirm the Dx if necessary

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Tests for Inferior Stability

• Sulcus Sign
• Indicates MDI
• SGHL, CHL
• Inferior directed, long axis traction of the
  humerus
• tests will display a sulcus sign

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Tests for Anterior Instability

• Anterior Apprehension Test
• Aka Fulcrum test
• Performed supine or seated
• Maximum passive ER in the 90-90 position
• Anterior band of the IGHL is directly anterior to
  the joint
• Test is apprehension or pain Magee 4th ed.

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Tests for Anterior Instability
Relocation Test Positive in patients with
congenital laxity or functional
instability/microlaxity
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Tests for Anterior Instability
Load Shift in seated Supine
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Load Shift / Drawer Grading
Minimal Translation
Translates to Rim
Perches on the Rim
Dislocates
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Tests for Anterior Instability
Anterior Drawer in Supine
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Tests for Posterior Instability

• Posterior Apprehension
• Horiz. Adduction 10
• Posterior load through the elbow
• Test is apprehension or pain
• Posterior Load Shift
• Posterior Glide
• Test is grade 2 or higher and signs of
  apprehension

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Tests for Posterior Instability
Posterior Drawer Test
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Posterior Instability

• Kim Test
• Patient is seated with uninvolved side against
  the back of a chair or wall
• Examiner holds the test arm at 90 applying an
  axial load through the elbow with simultaneous
  upward elevation of 45 at the distal arm.
• At the proximal arm a inferior and posterior
  force is applied
• Positive test is pain in the posterior shoulder,
  regardless if there is a clunk
• Sensitivity 80
• Specificity 94

Kim et al., AJSM 2005
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Anterior Dislocations

• 85 to 90 of all dislocations
• Typical MOI - combined abduction, extension, and
  external rotation

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Posterior Dislocations

• Relatively uncommon - approximately 2
• More common in impaired populations
• Typical MOI - axial loading of the abducted,
  internally rotated arm

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Inferior Dislocations

• Generally subglenoid with humeral shaft pointing
  overhead
• Very Rare
• MOI - Hyperabduction force causes the neck of the
  humerus to impinge on the acromion driving the
  head inferiorly

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Surgical Procedures

• Over 150 procedures described
• Two Major Categories
• 1) Anatomic
• 2) Non-anatomic

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Decision-Making

• Direction(s) of Instability
• What degree of trauma lead to instability?
• What pathology is responsible / involved?
• Bankart lesion
• Capsule / G-H ligament insufficiency
• Large capsular redundancy
• Bony problems (Hill Sachs or Rim Fx)
• A combination of the above ...

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Decision Making

• Patients Hx (e.g. TUBS vs. AMBRI, recurrent,
  Voluntary Instability)
• Functional goals (overhead athlete vs. general)
• Timing of surgery its impact on patients
  quality of life

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Anatomic Procedures

• Attempt to restore anatomy to Normal
• Bankart Repair
• Capsular Shift
• Tissue Shrinkage
• Capsular Plication

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Non-Anatomic Procedures

• Designed to alter anatomy to limit translation
• Shorten Subscapularis tendon
• Putti-Platt, Magnusum-Stack
• Osteotomy Procedures
• Bristow, glenoid/humeral osteotomies

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Structure Dictates Function

• Capsular extracapsular contractures common
  (often intentional)
• Alters normal mechanics / kinematics
• Increases joint reaction forces
• Rarely used today (last resort)
• Function limited, but instability is too!

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Perthes - Bankart Lesion

• Detachment of the capsulolabral complex from the
  glenoid neck
• May include a bony avulsion
• Associated stretching of the capsule
• Perthes, 1906 Bankart, 1938

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Bankart Lesion

• Increased laxity of the IGHL complex
• Plastic deformation of the IGHL Bigliani, 1998
• Positive Clunk test indicative of Bankart Lesion
• Most common anterior inferior (3-7 PM)

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Bony Bankart

• With bony lesion the benefit of glenoid
  retroversion and the articular surface is reduced
• Large defect - not repaired
• significant increase in recurrence of instability
• lose available ER ROM

Seitz, 2006
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Procedure- Open Bankart Repair

• Visualization
• subscapularis is violated
• Fixation
• suture anchors (2 or 3) along the glenoid rim
• reattach the soft tissue to glenoid

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Open Bankart Repair

• Methods of gaining exposure to capsule
• 1) Subscapularis taken-down
• 2) Proximal 2/3 of Subscapularis tendon
  divided vertically
• 3) Subscapularis split and retracted

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TAKEN
DOWN
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SPLIT
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Anterior-Inferior Capsular Shift

• Indications
• Chronic, recurrent instability
• Multidirectional
• Hx of voluntary instability
• Unidirectional w/ clear capsular component
• Revisions

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Capsular Shift

• Advantages
• Addresses capsular laxity directly (MDI)
• Get a good idea of your repair in OR
• Effective

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Capsular Shift

• Disadvantages
• Invasive (Increased pain inflammation)
• Poorer cosmesis
• More prone to motion loss (scarring)
• Greater risk of complications
• Subscapularis compromise

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Capsular Shift

• Visualization
• Same as Open Bankart Repair
• Fixation
• Same as Open Bankart Repair

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Hill-Sachs Lesion

• Re-occurrence of dislocation is greater with a
  Hill-Sachs Lesion then without
• Size of lesion increases risk with increased size

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SLAP Lesions

• Superior
• Labrum
• Anterior
• Posterior

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1000
Posterior
Anterior
200
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SLAP Lesions

• 4 Types
• MOI
• Repetitive biceps contraction
• Compressed loading of the shoulder in flexion /
  abduction
• Traction injury
• Snyder et al, Arthroscopy, 1990
• Peel Back
• Tight Posterior Capsule/Muscle tightness
• Shaffer, 2006

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Type I SLAP

• Marked fraying of the superior labrum, but rim
  is firmly attached (11)

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Type II SLAP

• Superior Labrum and attached Biceps tendon
  stripped off underlying glenoid (41)

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Type III SLAP

• Bucket-handle tear of the superior labrum
• with displacement of central portion into joint
  (33)

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Type IV SLAP

• Bucket-handle tear of the superior labrum with
  extension into the biceps tendon (15)
• -tendon splits

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Tests for SLAP Lesions

• OBriens Test
• Differential Diagnosis
• AC joint pathology
• Rotator Cuff Pathology
• SLAP lesion
• Biceps Load Test II
• Speeds Test
• Differential Diagnosis
• Biceps Tendonitis
• Slap Lesion

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OBriens Test

• Part 1
• Flexed 90 with elbow extended and horizontal
  adduction 10, maximum medial rotation
• Examiner applies a downward force
• Part 2
• Same position with the forearm fully supinated
• Positive if pain elicited in part 1 and reduced
  in part 2

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Biceps Load Test II

• Patient is supine
• Arm elevated 120, maximal ER, elbow to 90
  flex., and forearm supinated
• Perform resisted elbow flexion
• for increased pain
• Kim et al., 2001
• On 127 patients, double blind
• Confirmed arthroscopically
• Sensitivity of 89.7
• Specificity of 96.9

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HAGL Lesion

• Humeral
• Attachment
• Glenohumeral
• Ligament

Midsubstance GHL tears are rare, but do occur
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Rehabilitation post surgery

• Judicious joint mobilization and PROM
• Normal ROM?
• Total Motion Concept
• Pitchers shift in ROM
• Greater ER and less IR than their other arm
• Total arc from ER to IR is symmetrical
• GIRD
• Loss of 20 IR at risk of painful shoulder

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