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1. Impingement Syndromes
in Shoulder pathology
Manos Antonogiannakis
Director
2nd Orthopaedic Department
Center for Shoulder Arthroscopy
IASO General Hospital
www.shoulder.gr

2. Introduction
Subacromial Space
a number of soft-tissue structures are
situated between two rigid structures .
 The superior border (the roof) of the
space is the coracoacromial arch,
which consists of the acromion, the
coracoacromial ligament, and the
coracoid process.
 The acromioclavicular joint is directly
superior and posterior to the
coracoacromial ligament.
 The inferior border (the floor) consists
of the greater tuberosity of the
humerus and the superior aspect of
the humeral head.
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3. By definition “shoulder
impingement syndrome” was
considered the Subacromial outlet
obstruction resulting in trauma to
the supraspinatus tendon.
In other words the supraspinatus
tendon was pinched against the
undersurface of the acromion
during elevation of the arm
The History of Impingement Syndrome
The concept was attributed to Charles Neer, MD, in 1972 www.shoulder.gr

4. The History of Impingement Syndrome
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Neer classified and named the
disorder as shoulder
impingement.
More over he classified the
diagnostic process.
Neer, JBJS(A) 1972

5. The History of Impingement Syndrome
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However, the process
itself was first
described but not
named by Meyer as
early as 1931.
Meyer AW JBJS
1931;13:341-360

6. The History of Impingement Syndrome
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The Neer Classification of Impingement Syndrome was an
important step in understanding shoulder pathology for its time,
but it is now outdated.
 Type I: <25 years old, Reversible, swelling,
tendonitis, no tears, conservative treatment
 Type II: 25-40 years old, Permanent scarring,
tendonitis, no tears, SAD
 Type III: >40 years old, Small RTC tear, SAD with
debridement/repair
 Type IV: >40 years old, Large RTC tear, SAD with
repair

7. Current classification of shoulder impingement
syndromes
• Primary and secondary Subacromial Impingement
• Coracohumeral Impingement
• Glenoid (Internal) Impingement
• ASI (AnteroSuperior Impingement)
• PSGI (PosteroSuperior Glenoid Impingement)
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8. Primary Subacromial Impingement
Primary impingement or external-Subacromial
impingement is the closest thing to Neer’s original
description of shoulder impingement syndrome.
The area of the RC that is torn or irritated in primary
impingement is typically the bursal side of the RC.
This means that the source of pathology is confined to the
Subacromial space.
Andrews, 1994
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9. Primary Subacromial Impingement
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 Usually in patients >40 yo
 pain in the anterior or front of the shoulder during
overhead activities.
 pain at night.
 pathologic changes of the coracoacromial arch.
 most common in the industrial population.

10. Primary Subacromial Impingement
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 Subacromial spurring
 DJD AC joint
 Os Acromiale
 Increased thoracic kyphosis

11. www.shoulder.gr
Acromial Morphology
Type I: Flat acromion low incidence of impingement
Type II: Curved acromion higher incidence of impingement
Type III: Beaked acromion very high incidence of impingement
Bigliani, 1986

12. www.shoulder.gr
Radiographic Evaluation
 Plain X-ray
Outlet View
 MRI
 Ultrasound

13. Subacromial external impingement
Impingement
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Neer’s test positive
Hawkins test positive

14. Primary subacromial Impingement
Why partial rot cuf tears
are usually at the
articular side?
 Fewer arteriolars
 Greater stiffness
 Less favorable stress-
strain curve
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15. Secondary Subacromial Impingement
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•Secondary Impingement by definition implies that there is a problem with the
functional ability of the shoulder to keep the humeral head centered in the glenoid
fossa during movement of the arm.
•Generally is caused by weakness in the RC muscles (functional instability)
combined with a glenohumeral joint capsule and ligaments that are to loose
(micro-instability). The combination allows a superior motion of the humeral head
and as a consequence narrowing of the subacromial space
•Tearing of the RC is the primary event due to fatigue and the
subacromial impingement is secondary due to loss of the ability to
center the humeral head worsening the condition .
•Intra-articular partial tearing is seen in these patients.

16. Secondary Subacromial Impingement
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•Patients are typically younger and the pain is located in the anterior or
anterolateral aspect of the shoulder. The symptoms are usually activity specific
and involve overhead activities.
•It is important to search for and treat the underlying “micro-instability” in
patients with secondary impingement if it exists.
Arroyo et al, Orth Cl North Am 1997

17. Jobe’s Instability Continuum
RC
weakness
generally
occurs
first
Functional
instability
follows
prolonged
RTC
weakness
Capsular laxity, develops
(acquired) or becomes
prominent (preexisting
congenital laxity).
Subluxation
(inability of the
humeral head to
center in the
glenoid during
motion).
RC/Labral tearing (late stage
disease of secondary
impingement).
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18. Clinical Examination
 Rule out neck pathology
(cervical radiculitis / DJD)
 Test Rc muscle strength
 Test active – passive ROM
 Neer’s test
 Hawkins Test
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19. Conservative Treatment
 Duration up to 6 months depending on patients
demands
 Modification of activity
 NSAIDs
 Steroid Injections
 Physiotherapy
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20. Surgical Treatment
 Acromioplasty (primary impingement)
 DCE (primary impingement)
 Cuff debridement/repair (primary or secondary)
 Repair of anterior instability if present (secondary
impingement)
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21. Surgical Treatment
Acromioplasty
 Detachment of CA ligament
 Soft tissue removal
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22. Surgical Treatment
Acromioplasty
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23. Surgical Treatment
Distal Clavicle Excision
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24. Subcoracoid impingement
Impingement of the coracoid process against the
humerus (usually the lesser tuberosity) in a coracoid
impingement position (humerus is flexed, adducted
and internally rotated)
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25. Subcoracoid Impingement
 Subcoracoid space: Interval
between the tip of the coracoid and
the humeral head (the coracohumeral
interval).
 Normal coracohumeral interval: 8.4-
11.0mm
 Subcoracoid stenosis: Narrowing
of the Subcoracoid space with a
coracohumeral interval of less than
6mm.
www.shoulder.gr
Bigliani, JBJS 1997 Current Concepts Review -
Subacromial Impingement Syndrome

26. Coracohumeral Impingement
 Usually resistant to conservative
 Surgical treatment is usually warranted.
 Surgical treatment involves a coracoplasty
(removing a portion of the coracoid process)
with debridement or repair of the
subscapularis tear.

 Lo and Burkhart, Arthroscopy,
19;2003:1142-1150.
www.shoulder.gr

27. Internal Impingement
Backround Knowledge
 Overhead athletes subject their
shoulder to tremendous forces
during competition
 During the late cocking phase of
throwing the arm may achieve
170 to 180 degrees of ext.
rotation to generate the torque
required
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28. Internal Impingement
Types:
I. Anterior Superior
Impingement (ASI)
II. Posterior Superior Glenoid
Impingement (PSGI)
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29. Anterior Superior Internal
Impingement
 Pain is generated during the
followthrough movement, with the
arm in position of internal
rotation, flexion and adduction
 Exact etiology unknown ill defind
concept
 Gerber and Sebesta first described
ASI as a form of intra-articular
impingement responsible for
unexplained anterior shoulder
pain and managed to reproduce
the impingement mechanism
during arthroscopy
www.shoulder.gr
J Shoulder Elbow Surg
(2000) 9:483–490

30. Anterior Superior Internal
Impingement
 While the articular side of the
posterior-superior rotator cuff is
involved in PSGI, the articular
side of the subscapularis tendon
and the pulley system of the long
head of the bicepts are affected in
ASI
 LHB instability combined with
macrotrauma or repetitive
microtrauma are involved in the
acquisition of ASI
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31. ASI–
HISTORY
MORE COMMON IN
SWIMMERS
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32. Anterior Superior Internal
Impingement
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Classification of Pulley Lesions
 type I with an isolated lesion of the SGHL
 type II with a lesion of the SGHL associated with a
partial articular side supraspinatus tendon tear
 type III with a lesion of the SGHL associated with a
partial subscapularis tendon tear
 type IV with a lesion of the SGHL associated with a
partial tear of the supraspinatus and subscapularis
tendon
Habermeyer (2004)J Shoulder Elbow Surg 13:5–12

33. Anterior Superior Internal
Impingement
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Clinical Examination
 Hawkins with forward
elevation >90 positive

34. Internal Impingement –
Clinical Examination
O’Brien’s test = positive 66.7%
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35. Anterior Superior Internal
Impingement
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Imaging
•Ultrasound
•MRI
•MRI Arthro
No specific findings
LHB tendon instability in u/s
Clinical tests and imaging are not
specific for ASI.
ASI is best determined by dynamic
evaluation in arthroscopy

36. Anterior Superior Internal
Impingement
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Treatment
•there are no published guidelines or treatment protocols for
the conservative management of ASI
•surgical treatment guidelinesare are not well established
• It is usually treated as part of other associated injuries
in patients with a pulley lesion, there is some
evidence that early surgical management, when
minor soft injury lesions are present, produces
better clinical outcomes

37. Posterior Superior Glenoid Internal
Impingement - Definition
Injury and dysfunction due to
repeated contact
between the undersurface of the
rot cuff tendons and the
posterosuperior glenoid
Walch JSES 1992
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38. Some contact between these
structures is physiologic,
but repetitive contact with
altered shoulder mechanics
may be pathologic
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Posterior Superior Glenoid Internal
Impingement - Definition

39. For undefined reasons this
contact in some athletes
become pathologic and
produces symptoms
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Posterior Superior Glenoid Internal
Impingement

40. Normally
in abduction and external rotation
(ABER) there is
obligate posterior & inferior
translation
of the humerus that allows for
more motion and less contact
between the greater tuberosity and
the posterosuperior glenoid rim
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Posterior Superior Glenoid Impingement

41. Mechanism of PSGI
Two major theories:
 Andrew
 Burkhart & Morgan
May co-exist
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42. Mechanism of PSGI
Andrew Theory:
Repeated
ABER
Dynamic
stabilizers
fatigue
Increase stress to
anterior & IGHL
Anterior
capsule laxity
to allow max
ABER
Reduction of posterior &
inferior translation of HH
Increased contact of
undersurface of RC and
posterosuperior glenoid
Internal
Impingement
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43. Mechanism of PSGI
Burkhart & Morgan Theory:
Repeated
ABER
Tight posterior
capsule
Superior
translation of
Humeral Head
Torsional
stress to
biceps
anchor
Peel-off
Mechanism
SLAP II and
Pseudolaxity
Increased contact of
undersurface of RC and
posterosuperior glenoid Internal
Impingement
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44. It is essentially an
overuse injury associated
with overhead athletes
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Posterior Superior Glenoid Impingement

45.  Typically symptoms are present only while playing
 No symptoms with activities of daily living
 Represents about 80% of the problems seen in the
overhead athletes
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Posterior Superior Glenoid Impingement

46. Internal impingement
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47. Structures involved:
 Humeral head
 Anterior capsule
 Inferior GHL
 Posterior capsule
 Rot cuff muscles
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Posterior Superior Glenoid Impingement

48. PSGI
History
 Chronicity of pain
 Posterior pain
 Abduction + external
rotation aggravates pain
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49. PSGI
History
 Insidious onset
 Increases as the season progresses
 Dull posterior pain
 Worse at late cocking phase
 Rarely can remember any traumatic episode
 Loss of control and velocity
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50. PSGI
Clinical Examination
Palpation:
 pain can be elicited over the infraspinatous
 pain worse posteriorly than on GT, (vice versa on rot cuff
tendonitis)
 Anterior part of the shoulder, biceps groove and tendon
are not painful.
 No bony abnormalities.
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51. PSGI
Clinical Examination
ROM:
 usually full range of motion
 dominant arm tends to have
 10-15 deg more ext rotation and
 10-15 deg less internal rotation at 90 deg abduction
 The most common for an overhead athlete is:
 2+ anterior laxity,
 up to 1+ posterior laxity,
 some inferior laxity,
 but a firm endpoint
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52. PSGI
Clinical Examination
Provocative tests:
 Neer’s test = negative
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53. PSGI
Clinical Examination
Provocative tests:
O’Brien’s test = negative (unless SLAP lesion)
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54. PSGI
Clinical Examination
Provocative tests:
 Internal Impingement test = positive
(patient supine, 90 deg abduction and max external rotation. If
pain experienced at the posterior part of the joint = positive, 90%
sensitive)
 Relocation test = positive,
(different from relocation test for anterior translation)
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55. Relocation test of
Jobe:
Pain in the posterior joint line
when the arm is brought in
abduction external rotation
with the patient supine that is
relieved when a posterior
directed force is applied to the
shoulder
Internal Impingement –
Clinical Examination
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56. PSGI
MRI findings
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57. Internal Impingement –
Differential Diagnosis
 SLAP lesions ASI
 Pain more anterior than Internal Impingement.
 Positive O’Brien test and SLAPrehension test. These tests are
negative for internal impingement.
 Isolated posterior labrum tear
 The most difficult to differentiate from internal imp.
 Both posterior pain in the abducted and ext rotated position
 Posterior instability.
 Arthroscopy can help
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58. PSG Internal Impingement –
Arthroscopic findings
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59. PSG Impingement –
Treatment
 Conservative
 Surgical
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60. PSG Impingement –
Conservative Treatment
 Two main requirements for a good throw:
 Large arc of motion
 Adequate stability
 Thrower’s paradox
some laxity to static restrains
=> some degree of instability
=> muscles compensate
 Fine balance is needed
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61. PSG Impingement –
Conservative Treatment
 Rest (complete stop of throwing is critical)
 Rehabilitation (physical therapy as soon as possible) to
 improve posterior flexibility
 improve dynamic stabilization
 increase strength of rot cuff muscles
 Then gradual return to throwing
 Improvement of throwing technique
 +/- NSAID
 Most athletes return to sport
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62. PSG Impingement –
Surgical Treatment
 Diagnostic arthroscopy
(other pathology
found…SLAP, biceps
tendonitis, rot cuff tears
etc)
 Arthroscopic
Debridement
25-85% return to pre-injury
activity => effective ?
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63. PSG Impingement –
Surgical Treatment
 Open/Arthroscopic Capsulolabral
Reconstruction
 Arthrolysis of posterior capsule tightness
 Repair of SLAP lesions
 Repair of the rot cuff
 Address anterior capsule laxity
(50 - 81% pre-injury level)
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64. PSG Impingement –
Surgical Treatment
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65. PSG Impingement –
Surgical Treatment
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66. PSG Impingement –
Surgical Treatment
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67. Internal impingement –
Surgical Treatments
Infrequently Used Today
 Arthroscopic Thermal Capsulorraphy
Another method to reduce the anterior capsular laxity
At the same time debridement + arthroscopic fixation of labral tears
86% return to pre-injury level
 Rotational Osteotomy
Derotation osteotomy of humerous
=> increase of retroversion + shortening of subscapularis
=> less impingement
55% return to pre-injury level
www.shoulder.gr

68. Subacromial
decompression
 22% of throwing athletes returned
to the same level of participation
after subacromial decompression
Tibone ,Jobe. CORR 1985
PSG Impingement –
Surgical Treatment
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69. Take home messages
 Internal Impingement is a relatively common
problem in overhead athletes
 Difficult to treat
 Caused by repetitive contact between the
undersurface of the rot cuff and
posterosuperior glenoid
www.shoulder.gr

70.  Initial treatment:
 Complete REST + PHYSIOTHERAPY
 If symptoms persist:
 Multiple surgical techniques
 Repair all lesions if possible
Take home messages
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71.  Subacromial impingement was
the first concept developed
 Valid especially in older non-
athletic popullation but partiall
 Subacromial decompression very
effective
Take home messages
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72.  Secondary subacromial
impingement the next concept to
explain RC tears especially in
younger more athletically
oriented patients
 Repair of the cuff very effective
 Search and repair anterior
instability if pressent
 Acromioplasty +/-
Take home messages
www.shoulder.gr

73.  Posterior internal impingement the
concept to explain posterior
shoulder pain and RC tears in
throwers
 Anterior internal impingement
explaining more anterior pain in
young athletes (especially
swimmers)
 Repair the cuff and co existing
pathology
Take home messages
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74.  Subcoracoid impingement an
other cause to keep in mind and
repair when treating
anterosuperior RC tears
(subscapularis LHB anterior
supraspinatus
Take home messages
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75. Thank you for your attention
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76. Case-1
 Female, 23years
 Gym Academy, Volley player
 Loose joints
 4 months Pain at ABD+EXT ROT
 Suprasipatus test +, Relocation Test +
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77. Case-1
MRI
Partial RC tear
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78. Case-1
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79. Case-1
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80. Case-1
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81. Case-1
6 months post OP
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82. Internal Impingement
Throwing phases:
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83. Internal impingement
Throwing phases:
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84. PSG Impingement –
Arthroscopic findings
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85. PSG Impingement –
Arthroscopic findings
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