Internal Impingement Em Antonogiannakis Orthopaedic surgeon Director Center for shoulder...

Internal ImpingementInternal Impingement

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Em AntonogiannakisOrthopaedic surgeon

DirectorCenter for shoulder arthroscopy

IASO General HospitalAthens

• 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

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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Internal Impingement

Some contact between these structures is physiologic but

repetitive contact with altered shoulder mechanics

may be pathologic

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For undefined reasons this contact in some athletes become pathologic and

produces symptoms

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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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Mechanism of Internal Impingement

Two major theories:

• Andrew

• Burkhart & Morgan

May co-exist

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Mechanism of Internal ImpingementAndrew Theory:

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Repeated ABER

Repeated ABER

Dynamic stabilizers

fatigue

Dynamic stabilizers

fatigue

Increase stress to anterior & IGHL

Increase stress to anterior & IGHL

Anterior capsule laxity

to allow max ABER

Anterior capsule laxity

to allow max ABER

Reduction of posterior & inferior translation of HH

Reduction of posterior & inferior translation of HH

Increased contact of undersurface of RC and posterosuperior glenoid




Mechanism of Internal ImpingementBurkhart & Morgan Theory:

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Repeated ABER

Repeated ABER

Tight posterior capsule

Tight posterior capsule

Superior translation of Humeral Head

Superior translation of Humeral Head

Torsional stress to biceps anchor

Torsional stress to biceps anchor

Peel-off

Mechanism

Peel-off

MechanismSLAP II and Pseudolaxity

SLAP II and Pseudolaxity





Internal impingement

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• 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%


It is essentially an overuse injury associated with

overhead athletes

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• 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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Throwing phases:


Structures involved:

– Humeral head– Anterior capsule– Inferior GHL– Posterior capsule

– Rot cuff muscles

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• Chronicity of pain

• Posterior pain

• Abduction + external rotation aggravates pain

Internal impingement – History

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• 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

Internal impingement – History

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Inspection:

– no rot cuff atrophy

– no abnormality

– Slight hypetrophy of

muscles on dominant side

Internal Impingement – Clinical Examination

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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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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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Provocative tests:

– Neer’s test = negative


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Provocative tests:

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Hawkins test = negative


Provocative tests:

Cross arm adduction test = negative

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Provocative tests:

O’Brien’s test = negative (unless SLAP lesion)

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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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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

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Muscles strength = normal

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Internal Impingement – MRI findings

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• 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).

Internal Impingement – Differential Diagnosis

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Internal Impingement – Bennett’s Lesion

• 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

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Internal Impingement – Differential Diagnosis


Why partial rot cuf tears are usually at the articular side?

• Fewer arteriolars• Greater stiffness• Less favorable stress-

strain curve

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Internal Impingement – Arthroscopic findings

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Internal Impingement – Arthroscopic findings

Internal Impingement –Treatment

• Conservative

• Surgical

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• 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

Internal Impingement – Conservative Treatment

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• 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

Internal Impingement – Conservative Treatment

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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 ?

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• 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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• Arthroscopic Thermal CapsulorraphyAnother method to reduce the anterior capsular laxity At the same time debridement + arthroscopic fixation of labral

tears86% 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

Internal impingement – Surgical Treatments infrequently Used Today

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Subacromial decompression

• 22% of throwing athletes returned to the same level of participation after subacromial decompression

Tibone ,Jobe. CORR 1985


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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

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• Initial treatment:• Complete REST +

PHYSIOTHERAPY

• If symptoms persists:

• Multiple surgical techniques

• Repair all lesions if possible

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Take home messages

Thank you for your attention

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Internal Impingement Em Antonogiannakis Orthopaedic surgeon Director Center for shoulder...

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