1. Shoulder Instability
Jeff Johnson

2. The Amazing Human Body

3. Shoulder Most mobile joint in the body
Minimally constrained articulation that must balance mobility with stability
Not always successful, as it is the most likely joint to dislocate

4. Laxity vs. Instability
Laxity: Asymptomatic passive translation of humeral head on the glenoid
Instability: Excessive symptomatic translation of humeral head on glenoid during active motion

5. Definition of Terms Direction: Anterior vs. Posterior vs. MDI
Timing: Acute vs. Chronic
Frequency: Single vs. Recurrent
Etiology: Traumatic vs. Atraumatic
Degree: Subluxate vs. Dislocate
Volition: Voluntary vs. Involuntary

6. The Stable Shoulder Static Restraints Dynamic Restraints Bone
Glenoid
Humerus
Ligaments
Labrum
Capsule
Negative pressure
Adhesion/cohesion
Dynamic Restraints
Rotator Cuff
Concavity compression
Biceps
Deltoid
Scapula Rotators

7. Static: Bone Glenoid Articular Version Bone loss
30° anterior on Chest wall
3° upward tilt
7° retroversion (25% of people of anteversion 2-10°)
Bare spot in the center and more cartilage in periphery (increases the depth)
Bone loss
Fracture
Dysplasia

8. Static: Bone Humerus Version Articular Surface
130° neck shaft angle
30° retroversion
Articular Surface
More of sphere in the center and elliptical in the periphery
In any position, there is only 25-30% of the humeral head in contact with the glenoid
Importance of soft tissue for stability
Congruity
Almost a perfect match with glenoid (<3mm)
Behaves like a ball and socket joint with < 2mm translation
Congruity less important than total surface area
Hill-Sachs
Reverse
Engaging

9. Static Restraints Labrum Anchor for capsule & ligaments
Deepens the concavity of the socket
Increases depth of socket by 50% (5-9mm)
Increases surface area
Load bearing?
Bumper or “Chock Block”
Resection decreases resistance to translation by 20%

10. Static Restraints Capsuloligaments
Coracohumeral ligament
Primary restraint to inferior translation of the ADDucted arm and to ER
SGHL
Primary restraint to ER in ADDucted or slightly abducted arm
Primary restraint to inferior translation in the ADDucted arm
MGHL (absent in 30-40%)
Primary stabilizer to anterior translation with the arm abducted to 45 (45-90)
IGHLC- A&P bands, hammock
Primary stabilzer for anterior and inferior instability in abduction
Posterior band in flexion/adduction to posterior instability

11. Static Restraints Adhesion/cohesion Suction Cup
Attraction of joint fluid to itself and to the articular surface
Suction Cup
The glenoid and labrum act as a suction cup
Negative joint pressure
Analogous to pulling on the plunger of a plugged syringe
Venting the joint allows 55% increase in anterior translation

12. Dynamic Restraints Rotator Cuff Concavity-Compression
Enhances the conformity of the joint and increases the force required to translate
Could be more important than ligament restraints
RC blend into ligaments and could provide dynamic restraints through them
Importance of RC strengthening in Rehab
Anterior-superior escape in CTA

13. Dynamic Restraints Biceps Deltoid
Difficult to determine its actual contribution
Many studies with differing results
Most likely is a humeral head depressor
Must be flexing or supinating forearm for any shoulder contribution
Deltoid
Increase activation in unstable shoulder

14. Dynamic Stability Scapular Rotators Proprioception
Trapezius, Rhomboids, Lat, Serratus, Levator
2:1 ratio of GH motion to Scapulothroacic motion
Provide stable platform beneath humeral head
Importance rehab to include scapular rotators
Proprioception
Mechanoreceptors send message in reflex arc to control shoulder
Increased hand position error in pts with MDI
Surgery improves GH proprioception

15. Breakdown of Stability
Minimal loads:
Negative intraarticular pressure
Adhesion/Cohesion
Suction Cup
Moderate loads, Mid-range:
Concavity-compression
Labrum
Scapulothoracic Rhythm & Proprioception
Large loads, End-range:
IGHL

16. Pathoanatomy of Instability: Bankart Lesion
“Essential lesion”
Separation of inferior capsulolabral complex from glenoid neck
Broca and Hartmann 1890
Perthes 1906
Bankart 1923, 1939

17. Bankart Lesion: 1. Disrupts the conacavity compression
2. Eliminates the chock-block
3. Decreases depth by 50%
4. Detaches capsuloligamentous structures
5. May eliminate the negative intraarticular pressure

18. Pathoanatomy of Instability: Capsular injury
Bankart Less often considered the all-or-none “Essential lesion” but still the most common lesion: 62-97% Incidence
Simulation of Bankart results in only minimal increase in translation
Plastic deformity of the capsule is required
ALPSA: anterior labral periosteal sleeve avulsion
HAGL/BHAGL: humeral avulsion of the glenohumeral ligaments
GLAD: glenolabral articular disruption

19. Pathoanatomy of Instability:
ALPSA Lesion

20. Pathoanatomy of Instability:
HAGL Lesion

21. Pathoanatomy of Instability: Bone Loss
Humerus
Hill-Sachs or Reverse Hilll-Sachs
80-100% of anterior dislocations
25% of subluxations
Larger defects
Longer dislocations
Recurrent
Inferior
>30% defect may lead to recurrent instability
Tendon
Allograft
Replacement

22. Pathoanatomy of Instability: Bone Loss
Glenoid
Bony Bankart
Erosion from Recurrent dislocation
Defects < 20% repair labrum/capsule
Bigliani – loss of > 25% warrants bony reconstruction
Burkart – inverted pear glenoid requires bony reconstruction
61% recurrence w/ inverted pear or engaging Hill Sachs
4% recurrence without
Measure bare spot to anterior rim.
Reconstruction
Iliac crest
Coracoid (Latarjet)

24. Glenoid
Greis – Glenoid defect of 30% of the diameter at the anterior inferior quadrant
Contact area across entire glenoid decreased 41%
Contact pressure increased by almost 100%

25. Pathoanatomy of Instability: Associated Injuries
Rotator cuff tear
Under 30 rare
Over 40
85%
Nerve injuries
Axillary: up to 33%
Musculocutaneous

26. Clinical Evaluation Etiology: Traumatic vs. Atraumatic
Direction: Ant vs. post vs. MDI
Timing: Acute vs. chronic
Frequency: Single vs. recurrent
Degree: Sublux vs. Dislocate
Volition: Voluntary vs. involuntary

27. Clinical Evaluation History PE EUA Arthroscopy Radiographs
Acute vs. Chronic
Isolated vs. recurrent
Dislocation vs. subluxation
Direction
Past treatment PE
ROM
Atrophy
Winging
Sulcus
Load and Shift
Apprehension
Relocation
Release test
EUA
Arthroscopy
Radiographs

28. Hill Sachs Evaluation Stryker notch view CT preferred over MRI
Hand to head, elbow up
Beam angle up 10 degrees
Centered over coracoid
CT preferred over MRI
MRI underestimates bone defect

29. West Point view Prone, 25 degree from midline, directed through axilla
Itoi – correlated West Point view with CT for glenoid bone loss
Axillary view underestimates

30. Anterior Dislocation 85-95% of dislocations Treatment
Prompt atraumatic reduction
Immobilization
Risk of Recurrence
Age (<30)
Activity level
Compliance with rehab
Contralateral shoulder instability
Bony defects

31. Emergent Management Closed reduction
Adequate sedation and analgesia needed
Analgesic techniques
Intravenous
Intra-articular lidocaine (Kosnik et al., 1999; Miller et al., 2002)
Reduced time and resources
Equivalent success

32. Emergent Management
Hippocratic
Counter traction
Stimson
Milch

34. Emergent Management Immobilization (duration)
No change in outcome ? (Hovelius et al., 1983; Rowe et al. 1961)
One week (Kazar et al., 1969)
Three weeks (Kiviluoto et al., 1980; Stromsoe et al 1980)
Dependent on age ?
>40 1 week
<40 3 weeks

35. Emergent Management Immobilization (position)
Internal rotation and adduction (sling)
Labrum anatomically better position in ER (Itoi et al, 2001)

36. Emergent Management Immobilization (position)
Clinical follow-up for 15 months (Itoi et al., 2003)
No recurrent dislocation with ER immobilization
30% dislocation with IR immobilization
0% vs. 45% for patients younger than 30

37. Goals of Rehabilitation
Return dynamic stabilizers to functional state
Protect healing of static stabilizers
Minimal immobilization
Early ROM, avoid ER
Strengthening in plane of scapula
Bracing/harnessing for return to sports

38. Success of Rehabilitation
Aronen 1984: 75% in 20 athletes
Arciero 1994: 20% in 15 athletes
Higher patient expectations
Patients are less willing to alter activities

40. Anterior dislocation Surgery Early vs. Late Open vs. Arthroscopic
<30 y/o surgery may be first line?
Open vs. Arthroscopic
Open still “gold standard”
Reader beware
Some open techniques not anatomic (high OA)
Early scopic studies with poor techniques and implants

41. Scope vs. Open Arthroscopic Open Minimizes dissection
Decreased damage to soft tissues
Subscap
Earlier Rehab
Better ROM
Hard to over tighten
Better visulaization
Treat other pathology
Learning Curve
Outpatient
Open
Gold standard
Initially lower recurrence
Possibly over constrained
Still required for
Large bony defects
HAGL?
Capsular insufficiency
Revision
Cosmesis
OR time
Inpatient

42. Scopic vs. Open Open (recurrence) Scopic Anchors Bacilla 7% Gartsman 8
Putti-Platt %
Mag-Stack
Eden-Hybbinette
Gallie 2.9
DuTolt & Roux
Bristow 1.7
Bankart 3.3
Capsulorrhaphy
Classic Bankart
Rowe and Bankart
96% success
Scopic Anchors
Bacilla 7%
Gartsman
Cole 0
Kim 4
Kim 10
Abrams 6.6
Mazzocca
Fabbriciani 0
Recent scopic anchor technique also with 96% success

43. Open Capsular Subscap Bony Bankart repair Putti-plat Magnuson-Stack
Bristow
Latarjet

44. Arthroscopic Lateral decubitus Bump in axilla or Arthrex Star Sleeve
2-3 portals
Anchors
Knotless?
Bioabsorbable?
Fiberwire?

45. Arthroscopic Bankart EUA Portals Address posterior first
Posterior- more superior and lateral
Anterior- leave room for 2 if needed
Address posterior first
Labrum/capsule
Back anteriorly
Mobilize labrum
Debride surface
Place anchor
Pass suture through capsule shifting north/south and east/wet
Tie- horizontal mattress?
Rotator interval if needed

49. Posterior Acute posterior Chronic Volitional Recurrent
<5%
Unrecognized in 50-80% of patients initially
Chronic
> 6weeks locked out the back
Volitional Recurrent
Habitual dislocator (psych issues)
Voluntary (can selectively fire muscles)
May become involuntary
Dysplastic Recurrent
Hypoplasia, glenoid or humeral retroversion

50. Posterior Treatment Nonop Surgery Results
Rehab focusing on infraspinatus/teres minor/posterior deltoid/scapula
63-68% success
Surgery
OPEN vs. Scopic
Capsulorrhaphy/shift
Reverse bankart
Bone block
Glenoid osteotomy
Infraspinatous Capsular tenodesis
Results
85-91% success

52. MDI
Subluxate or dislocate in multiple directions, with concurrent reproduction of symptoms in at least 2 directions, one being inferior
Symptoms usually in mid-range of motion (ADL’s)
Positive Sulcus with symptoms
Pathology
Widened Rotator Interval
Redundant inferior capsule
Collagen abnormality?
Mechanoreceptor
Abnormal muscle control

53. MDI Nonop – Rehab Surgery Results Rockwood 88% success rate
Must prove that they will be compliant
Surgery
Open or scopic inferior shift
Scopic
Posterior capsule
Anterior capsule
Rotator Interval
Post-op Cast or brace
Results
Pollack %
Brems 85%
Hawkins 60%
Savoie 88%
Gartsman 94%
McIntyre 95%

54. Conclusion