This document discusses shoulder instability, including definitions, anatomy, evaluation, and treatment. It defines instability as the inability to maintain the humeral head in the glenoid fossa, ranging from dislocation to laxity. Static stabilizers include the labrum and ligaments, while dynamic stabilizers are the rotator cuff and scapulothoracic muscles. Evaluation involves history, exam, and imaging to classify instability by direction, degree, and etiology. Treatment depends on classification but may include immobilization, rehabilitation, or surgical repair of labral tears or bone defects.

1. Dr. Atif Shahzad PGR
Orthopedic Dept. SHL

2. DEFINITION:
Instability:
• Inability to maintain the humeral head in the glenoid
fossa.
• Includes a spectrum of disorders
Dislocation
Complete loss of glenohumeral articulation
Subluxation
Partial loss of glenohumeral articulation with symptoms
Laxity
Incomplete loss of glenohumeral articulation
unassociated with pain

3. STABILITY
Static Factors
 Articular Congruence
 Articular Version
 Glenoid Labrum
 Capsule and Ligament
Dynamic Factors
 Rotator Cuff
 Biceps Tendon
 Scapulothorasic Motion
 Negative Pressure
 Propioception

4. OSTEOLOGY
 Glenoid fossa
 Pear shaped
 7 deg. of retroversion
 5 deg. of sup tilt
 Glenoid version
 30o anterior
 Humerus
 Neck-shaft – 130o to 140o
 Retrotorsion – 30o

5. GLENOHUMERAL JOINT
 Humeral head 3x larger
than glenoid fossa
 Ball and socket with
translation
 3 degrees of freedom
 Flex/Ext
 Abd/Add
 Int/Ext rot
 Plus
Cricumduction

6. GLENOID LABRUM
 Static stabilizer
 contributes 20% to GH
stability
 Fibro cartilaginous tissue
 Deepens glenoid(50%)
 3purposes:
 Inc. surface contact area
 Buttress
 Attachment site for GH
ligaments

7. CAPSULE AND LIGAMENTS
Capsule
 Attached medially
glenoid fossa
 laterally to anatomical
neck of humerus
 Ant cap thicker than post.
 2-3 mm of distraction
 Little contribution to joint
stability
 Strengthened by GHLs and
RC tendons

8. GLENOHUMERAL LIGAMENTS
(Superior, Middle , Inferior)
SGHL
 O = tubercle on glenoid
just post to long head
biceps
 I = upper end of lesser
tubercle
 Resists inf. subluxation
and contributes to
stability in post and inf.
directions

9. MGHL
 O= sup glenoid and labrum
 I = blends with subscapularis tendon
 Limits ant. instability especially in 45 deg abduction
position
 Limits ext rotation

10. IGHL
 O= ant. glenoid rim and labrum
 I= inf. aspect of humeral articular surface and anatomic
neck
 3 bands, anterior, axillary and posterior
 Acts like a sling ,the most important single ligamentous
stabilizer .
 Primary restraint is at 45-90 deg abduction.

11. Coracoacromial ligament
 secondary stabilizer.
Coracohumeral ligament
 Contribute to restraining inferior subluxation with
arm at side,

12. Dynamic Factors
 Rotator Cuff
 Biceps Tendon
 Negative Pressure
 Scapulothoracic motion
 Proprioception

13. ROTATOR CUFF
 Compression enhances conformity
 Greater than static stabilizers
 Coordinated contractions/steering effect
 Supraspinatus most important
 Dynamization

14. Biceps long head, Deltoid
 secondary stabilizer head depressor
Periscapular Muscles
 help position scapula and orient glenohumeral joint
contributes compressive force across joint

15. SCAPULOTHORACIC MOTION
 2:1 glenohumeral to scapulothoracic motion
 Scapulothoracic muscle (trapezius, serratus anterior,
teres major, levator scapulae)
 less stable platform

16. NEGATIVE INTRA-ARTICULAR
PRESSURE
 -42 cm H2O in cadaver
 Secondary to high osmotic pressure in interstitial
tissues
 Only clinically important in the arm at rest in
adduction
 Lost with lax capsule or defect

19. PATHOANATOMY OF SHOULDER
INSTABILITY
Laberal Lesions
 – Bankart
 – Reverse Bankart
 – SLAP lesions
Capsular Injury
 – Intrasubstance Tear
 – HAGL
 – Capsular Laxity
Bone Loss
 – Glenoid
 – Humeral Head-Hill-Sachs Lesion

20. BANKART LESION.
 The traumatic detachment
of the glenoid labrum has
been called the Bankart
lesion. 85%

21. HILL-SACHS
LESION
This is a defect in the
posterolateral aspect of the
humeral head.

22. INSTABILITY
Classification:
 Frequency
 Etiology
 Direction
 Degree

23. Frequency
 Acute
 Recurrent
 Fixed (chronic)
Etiology
 Traumatic event (macrotrauma)
 Atraumatic event (voluntary, involuntary)
 Microtrauma
 Congenital condition
 Neuromuscular condition (epilepsy, seizures)

24. Directions of instability
 Anterior
 Posterior
 Inferior
 Superior
 Multidirectional
Degree
 Subluxation
 Dislocation

25. SPECTRUM
Traumatic Microtrauma Atraumatic
Less laxity More laxity
Unidirectional Multidirectional

26. EVALUATION OF INSTABILITY
History
 Age
 Trauma-Duration
 Associated Pain
 Sports, throwing or overhead activities
 Voluntary subluxation
 “Clunk” or knock
 Fear-Limitation of Movements
 Hx dislocationsand energy associated
 Hx 1st dislocation or injury
 Subsequent dislocations/ subluxations

27. Physical Examination
 Inspection
 Palpation
 ROM
 Winging
 Neurovascular testing
 Generalized ligamentous laxity
 Instability tests

28.  Sulcus sign
 Drawer tests
 Load & Shift test

29.  Apprehension test
 Jobe’s Relocation
 Jerk test
 Fulcrum
Grade = 1 - 4

30. DIAGNOSIS
 X-rays
 CT Scan
 MRI
 Arthroscopy

31. RADIOLOGY
 X-Rays
 Identify Bankart or Hill-Sachs Lesion

32. AP VIEW

33. Axillary View

34. Scapular Y-View

35. Stryker view Humeral Head Defect

36. Apical Oblique view Glenoid rim lesion

37. West Point Axillary view Anteroinferior glenoid rim

38. ANTERIOR DISLOCATION
97% of recurrent dislocation
 abduction, extension and
external rotation
 subcoracoid
 subglenoid
 subclavicular
Associated Injuries:
Fractures
 Head & Neck
Rotator Cuff Tears
 > 40 y/o = 30 %
 > 60 y/o = 80%

39. Neurologic Injury
 Axillary nerve
 10-25% incidence 1st time.
 2-5% in recurrent dislocators
 Tx: “watchful expectancy”
 Poor prognosis if no recovery
by 10 wks
Vascular Injury
 Axillary artery
 2nd part thoracoacromial
trunk

40. TREATMENT
NONOPERATIVE
 Closed Reduction
 Immobilization-Sling
 Analgesics
 Rehabilitation
 ROM
 Strengthening exercises

41. Treatment of 1st time dislocators :
2 groups
 Immobilize x 4wks
80% recurrence
 Surgical repair
14% recurrence

42. TREATMENT OF RECURRENT ANT.
DISLOCATION
Non-operative Tx:
 Only 16% traumatic respond
 80% atraumatic respond
 Poor response to non operative Tx
Surgical stabilization
 Open or arthroscopic

43. MATSEN'S CLASSIFICATION
TUBS:
 Traumatic
 Unidirectional
 Bankart lesion
 Surgery is often necessary.
AMBRI:
 Atraumatic
 Multidirectional
 Bilateral
 Rehabilitation is the primary mode of treatment.
 Inferior capsular shift & internal closure often performed.

44. OPERATIVE TREATMENT:
Capsulolabral Repair
 Bankart
 Modified Bankart
Subscapularis Procedures
 Putti-Platt
 Magnuson-Stack
Coracoid Transfer
Procedures
 Bristow
 Latarjet

45. POSTERIOR DISLOCATION
 Incidence: < 5% all
shoulder dislocations
 3% of recurrent

46. Mechanism:
 Axial load
 Flexed/Adduction
 Bench press-“lock out”
 Swimming- pull thru
 Rowing
 Football Offensive
Lineman

47. Examination
 Shift & load test
 Post. Apprehension test
 Jerk test
 Kim test
Imaging studies
 X-ray
 CT
 MRI

48. TREATMENT
Non Operative
 Immobilization
 Protection
 Rehabilitation
 70-90% improve
 Functional disability
improved
 Instability not eliminated

49. Operative Management
 Overall 50-95 % success
 Higher recurrence vs ant.
instability procedures
Soft Tissue Procedures
 Posterior Capsulorrhaphy
 Reverse Putti-Platt
(IS Capsular Tenodesis)
 McLaughlin
Bone Procedures
 Posterior Glenoid
Osteotomy
 Posterior Bone Block

50. REHABILITATION
1. Immobilization in first 4 weeks
No ext rotation
Abduction less than 45°
Isometric resistance exercises
2. Graduated in 4 – 8 weeks
↑ ROM
Graduated weight training
3. Return to sport
Non contact = 6 weeks
contact = 12 weeks

51. THANKS