This document discusses multi-directional shoulder instability (MDI). MDI is characterized by subluxations or dislocations in at least two directions, usually anteriorly, posteriorly, or inferiorly. It is commonly seen in overhead athletes and is associated with capsular laxity. Clinical examination reveals laxity and translation in multiple directions. Treatment involves strengthening dynamic stabilizers through physical therapy initially, with surgery such as arthroscopic capsular plication considered if conservative measures fail. Post-operative rehabilitation is important for successful outcomes. Long-term, over half of untreated MDI patients experience pain and instability.

1. MMultiDDirectional Shoulder
IInstability (MDI)
Manos Antonogiannakis
Director 2nd
Orthopedic Dept.
IASO General Hospital
www.shoulder.gr

2. The Shoulder
 Greatest Range of Motion in the Body
 Motion in all 3 planes of movement
 Prone to injuries
 8-20% of all sports injuries

3. Instability
 Biomechanical Dysfunction
 Failure of static and dynamic stabilizers
 Ranges from mild subluxation to
traumatic dislocation

4. Mechanisms of Glenohumeral
Stability
• Static
• Dynamic
• Negative Intra- articular pressure
Labrum (50% of Glenoid depth)
Capsule
Ligaments-
Glenohumeral- Superior, Middle & Inferior
(stability & proprioception)
Rotator cuff tension-scapula stabilizers

5. Classification Schemes
• Mechanism
– Traumatic
– Atraumatic
– Congenital
– Neuromuscular
• Frequency
– Acute
– Chronic
– Recurrent
– Involuntary
– Voluntary
• Direction
– Anterior (and inferior)
– Posterior (and inferior)
– Superior?
– Multidirectional
• Extent
– Subluxation
– Dislocation

6. Types of instability
Not a black or white issue
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7. T.U.B.S.
Traumatic
Unidirectional
Bankart lesion
Surgery
A.M.B.R.I.
Atraumatic
Multidirectional
Bilateral
Rehabilitation
Inferior capsular shift
A.I.O.S.
Acquired
Instability
Overstress
Surgery
Instability Profiles

8. TUBS AIOS AMBRI

9. MDI Definition
The presence of inferior
instability in combination with
anterior and or posterior
instability

10. Definitions
• MDI implies subluxation or dislocations in
at least two directions either anteriorly,
posteriorly, or inferiorly
• Usually, the patient experiences
symptoms in one direction, but the
examination reveals more directions of
instability
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11. MDI History
First described in detail
in 1980 by
Charles S. Neer
and
Craig R. Foster
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12. MDI types
• Anterior-inferior dislocation with posterior
subluxation
• Posterior-inferior dislocation with anterior
subluxation
• Recurrent dislocation posterior and inferior
Neer and Foster

13. MDI Characteristics
• Relatively common
• Generally bilateral
• Atraumatic condition affecting
shoulder function
• Excessive translation in all
directions but with the
predominance of ONE direction,
typically anteroinferior or
posteroinferior.
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14. MDI Characteristics
• Usually in overhead
active sports
• gymnastics, swimming,
throwing, racquet sports
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15. MDI Characteristics
• Repetitive stretch of the
shoulder capsule to extreme
ranges of motion
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16. MDI Characteristics
• NOT associated with severe trauma
Congenital hyperlaxity of the joint capsule
or generalized joint laxity in association
with failure of dynamic stabilizers and minor
trauma
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Ehlers-Danlos Syndrome

17. MDI clinical presentation
• Frank dislocations with minimum violence
often reduced by the patient
• Subluxations and positive apprehension
sign in one or more directions in a loose
joint individual usually teenager
• Pain and functional impairment in a loose
joint individual, the patient mainly
complaining for pain and not for instability

18. Types of dislocation
• Voluntary dislocation
• Involuntary dislocation
should be recognized early

19. Voluntary dislocation
• Patients with good muscle control who can
dislocate and relocate their shoulder at will
from an early age that may lead to gradual
strain of the capsule and loss of control of
the dislocations
• True voluntary dislocators with psychiatric
problems

20. MDI Diagnostic Tools
Highly clinical diagnosis
• History
• Clinical examination
• Marginal help of imaging studies
(plain radiographs, MRI, MRI-arthrography)
• Highly supportive:
– Examination under anesthesia (EUA)
– Arthroscopic findings
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21. MDI Clinical Examination
• Bilateral physical findings
• Usually, rotator cuff (dynamic stabilizers) weakness
• Drawer and load-shift tests (anterior and posterior)
reveal displacement with an elastic feeling
• Pathognomonic “sulcus sign”
• Apprehension test may be positive, usually in the
direction of the chief component of instability
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22. Clinical examination
• Usually vague symptoms with activity
• Associated conditions: collagen disorders
• Look for generalized hyper-elasticity
(thumbs can be hyperextended to the distal radius, elbow
hyperextended ,knee recurvatum)
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23. Clinical examination
SULCUS sign with the arm in adduction that
persists in external rotation or abduction is a
major clinical sign
Anterior and posterior load and sift tests

24. Examination Under Anesthesia
• To demonstrate increased
glenohumeral anterior,
posterior and inferior
translation
• Usually, symmetrical
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25. MDI
Examination Under Anesthesia

26. Treatment Options
• Conservative
• Intensive RC strengthening (dynamic stabilizers)
• Scapular Stabilizers strengthening
• Dynamic Upper Limb Propioception
• Surgical
• Open Surgery
– Inferior Capsular Shift
• Arthroscopy
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27. Treatment: Address all factors
• Dynamic stabilizers: rotator cuff and
scapula muscles
• Static stabilizers: plication of
capsuloligamentus stactures

28. treatment
• Open treatment first described by Neer as
the glenoid inferior capsular sift based
laterally on the humeral head
• Arthroscopic management was pioneered
by Gaspari using a transglenoid technique

29. Contraindications
for Surgical Treatment
• Voluntary shoulder instability
• Collagen disorders
(eg, Ehlers-Danlos syndrome, Marfan syndrome)
• Noncompliance with a supervised
rehabilitation program
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30. MDI Arthroscopic Findings
• Usually, no true Bankart lesion
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31. Loose Shoulder

32. MDI Arthroscopic Findings
Capacious axillary pouch
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33. MDI Arthroscopic Findings
• “Drive-through" sign:
• Subluxation without much traction
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34. MDI Arthroscopic Findings

35. MDI Surgical Treatment
The goal is "addressing the capsular
laxity and redundancy to restore
anatomic capsuloligamentous tension
without overconstraining the shoulder."
[Caprise and Sekiya, 2006]
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36. Arthroscopic Treatment Options
• Thermical Shrinkage
• Capsular plication
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38. MDI Arthroscopic Treatment

39. Possible problems
• Axillary nerve injury
• Loose repair
• Healing problems
(collagen diseases: Ehlers-Danlos, Marfan)
• Postoperative noncompliance
• Overtensioning
is not a common problem
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40. Rehabilitation Program
• 0-3 weeks Relaxing phase
• 3-6 weeks Passive movements to ROM
• 6w – 3 m Assisted Active movement to ROM
• 3-6 m Active movement to ROM
• >4m Propioception improvements
• >4m Strengthening exercises
• >9 Return to sports
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41. What to expect
• Painless shoulder
• Full ROM
• No atrophies
• Return to the same sport level
Rowe scores:
78% excellent / good [Snyder, 2001]
75% excellent / good [Wolf, 1999]
88% excellent / good [Treacy, 2002]
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42. What to expect 2 years post op.

43. What to expect 2 years post op.

44. Conclusions
• Most patients present in their late teens
• Complaints of pain during athletic activities
or ADL
• Uncountable dislocations and subluxations
even at sleep reduced by the patient in a
tall thin loose joint individual
• Excessive ROM in more joints
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45. Conclusions
• Excesive translation of the joint anterior
posterior and inferior at clinical
examination with aprehension in one or
more directions
• At arthroscopy a patulous thin capsule
with few other findings.

46. Conclusion
• Treatment should address all factors of
instability mainly the dynamic stabilizers
with an aggressive rehabilitation program
and if this fails arthoscopic or open
capsulorraphy in order to reduce the
volume of the capsule

47. Thank you

48. Posterior Instability

49. Posterior Instability

50. Natural History Of MDI
After 8 years:
• 48.7% pain 46.1% instability
• Mod. Rowe/Zarris:
• 13.8% excellent
• 33% good
• 52.7% poor
[Misamore, JSES 2005]
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