1. Center for shoulder arthroscopy
Internal Impingement
Em Antonogiannakis
Orthopaedic surgeon
Director
Center for shoulder arthroscopy
IASO General Hospital
Athens

2. Overhead athletes subject their shoulder to tremendous forces during competition
During the late cocking phase of throwing the arm may achive 170 to 180 degrees of ext. rotation to generate the torque required

3. 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

4. Internal Impingement
Some contact between these structures is physiologic but repetitive contact with altered shoulder mechanics may be pathologic

5. Internal Impingement
For undefined reasons this contact in some athletes become pathologic and produces symptoms

6. Internal Impingement 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

7. Internal Impingement

8. Mechanism of Internal Impingement
Two major theories:
Andrew
Burkhart & Morgan
May co-exist

9. Mechanism of Internal Impingement Andrew Theory:
Dynamic stabilizers fatigue
Increase stress to anterior & IGHL
Repeated ABER
Anterior capsule laxity
to allow max ABER
Internal Impingement
Increased contact of undersurface of RC and posterosuperior glenoid
Reduction of posterior & inferior translation of HH

10. Mechanism of Internal Impingement Burkhart & Morgan Theory:
Superior translation of Humeral Head
Repeated ABER
Tight posterior capsule
Internal Impingement
Torsional stress to biceps anchor
Increased contact of undersurface of RC and posterosuperior glenoid
Peel-off
Mechanism
SLAP II and Pseudolaxity

11. Internal impingement
SLAP lesions are not caused by internal impingement, they are rather the result of excessive torsional stress to the biceps anchor
Once produced SLAP lesions may increase the anterior translation of the humeral head up to 6 mm and the strain to the inferior glenohumeral ligament up to 100%

12. It is essentially an overuse injury associated with overhead athletes
Internal Impingement
It is essentially an overuse injury associated with overhead athletes

13. Internal Impingement 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

14. Internal impingement

15. Internal impingement
Throwing phases:

16. Internal impingement
Throwing phases:

17. Internal Impingement Structures involved: Humeral head
Anterior capsule
Inferior GHL
Posterior capsule
Rot cuff muscles

18. Internal impingement – History
Chronicity of pain
Posterior pain
Abduction + external rotation aggravates pain

19. Internal impingement – 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

20. Internal Impingement – Clinical Examination
Inspection:
no rot cuff atrophy
no abnormality
Slight hypetrophy of muscles on dominant side

21. Internal Impingement – 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.

22. Internal Impingement – 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

23. Internal Impingement – Clinical Examination
Provocative tests:
Neer’s test = negative

24. Internal Impingement – Clinical Examination
Provocative tests:
Hawkins test = negative

25. Internal Impingement – Clinical Examination
Provocative tests:
Cross arm adduction test = negative

26. Internal Impingement – Clinical Examination
Provocative tests:
O’Brien’s test = negative (unless SLAP lesion)

27. Internal Impingement – 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)

28. Internal Impingement – Clinical Examination
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

29. Internal Impingement – Clinical Examination
Muscles strength = normal

30. Internal Impingement – MRI findings

31. Internal Impingement – Differential Diagnosis
Rot cuff tendonitis or bursitis
Pain usually worse the day AFTER activity than DURING the actual event.
Typically deep soreness.
Unlikely internal impingement pain is more diffuse and not localized to the posterior aspect of the shoulder.
Difficulty in lifting the arm, pain at the GT, that improves with rest and NSAID after a short period.
Throwers’ exostosis (Bennett’s lesion).
Pain at the posterior part of the shoulder (more toward the inferior than the superior aspect of the shoulder).
Ceases with rest.
Radiographs can help (stryker notch view= calcification at the posteroinferior glenoid rim consistent with an exostosis).

32. Internal Impingement – Bennett’s Lesion

33. Internal Impingement – Differential Diagnosis
SLAP lesions
Pain more anterior than Internal Impingement.
Positive O’Brien test and SLAPrehension test. These tests are negative for internal impingement.
Coronal oblique MRI can help
Isolated posterior labrum tear
The most difficult to differentiate from internal imp.
Both posterior pain in the abducted and ext rotated position.
Arthroscopy can help

34. Internal Impingement
Why partial rot cuf tears are usually at the articular side?
Fewer arteriolars
Greater stiffness
Less favorable stress-strain curve

35. Internal Impingement – Arthroscopic findings

36. Internal Impingement – Arthroscopic findings

37. Internal Impingement – Arthroscopic findings

38. Internal Impingement – Treatment
Conservative
Surgical

39. Internal 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

40. Internal 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

41. Internal 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 ?

42. Internal 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
( % pre-injury level)

43. Internal Impingement – Surgical Treatment

44. Internal Impingement – Surgical Treatment

45. Internal Impingement – Surgical Treatment

46. 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

47. Internal Impingement – Surgical Treatment
Subacromial decompression
22% of throwing athletes returned to the same level of participation after subacromial decompression
Tibone ,Jobe. CORR 1985

48. 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

49. Take home messages Initial treatment: If symptoms persists:
Complete REST + PHYSIOTHERAPY
If symptoms persists:
Multiple surgical techniques
Repair all lesions if possible

50. Thank you for your attention