impingement syndromes

Impingement Syndromesin Shoulder pathology

Manos AntonogiannakisDirector

2nd Orthopaedic Department

Center for Shoulder Arthroscopy

IASO General Hospital

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Introduction

Subacromial Spacea 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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By definition “shoulder

impingement syndrome” was considered the Subacromial outlet obstruction resulting in trauma to the supraspinatus tendon.

In other words the supraspinatustendon 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


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Neer classified and named the disorder as shoulder impingement.

More over he classified the diagnostic process.

Neer, JBJS(A) 1972


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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


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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of Impingement Syndrome was an important step in understanding shoulder pathology for its time,but it is now outdated.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

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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Primary Subacromial Impingement

Primary impingement or external-Subacromialimpingement 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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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.


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Subacromial spurring

DJD AC joint

Os Acromiale

Increased thoracic kyphosis

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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

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Radiographic Evaluation

Plain X-ray

Outlet View

MRI

Ultrasound

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Subacromial external impingement Impingement

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Neer’s test positive

Hawkins test positive

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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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.

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

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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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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Conservative Treatment

Duration up to 6 months depending on patients demands

Modification of activity

NSAIDs

Steroid Injections

Physiotherapy

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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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Surgical Treatment

Acromioplasty

Detachment of CA ligament

Soft tissue removal

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Surgical Treatment

Acromioplasty

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Surgical Treatment

Distal Clavicle Excision

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Subcoracoid impingement

Impingement of the coracoid process against the humerus (usually the lesser tuberosity) in a coracoidimpingement position (humerus is flexed, adducted and internally rotated)

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Subcoracoid Impingement

Subcoracoid space: Interval between the tip of the coracoid and the humeral head (the coracohumeralinterval).

Normal coracohumeral interval: 8.4-11.0mm

Subcoracoid stenosis: Narrowing of the Subcoracoid space with a coracohumeral interval of less than 6mm.

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Bigliani, JBJS 1997 Current Concepts Review -

Subacromial Impingement Syndrome

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.

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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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Types:

I. Anterior Superior Impingement (ASI)

II. Posterior Superior GlenoidImpingement (PSGI)

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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 defindconcept

Gerber and Sebesta first described ASI as a form of intra-articularimpingement responsible for unexplained anterior shoulder pain and managed to reproduce the impingement mechanism during arthroscopy

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J Shoulder Elbow Surg

(2000) 9:483–490


While the articular side of the posterior-superior rotator cuff is involved in PSGI, the articularside 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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ASI–HISTORY

MORE COMMON IN SWIMMERS

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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 subscapularistendon

Habermeyer (2004)J Shoulder Elbow Surg 13:5–12


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Hawkins with forward elevation >90 positive

Internal Impingement –Clinical Examination

O’Brien’s test = positive 66.7%

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Imaging

•Ultrasound•MRI•MRI Arthro

No specific findingsLHB tendon instability in u/s

Clinical tests and imaging are not specific for ASI.

ASI is best determined by dynamic evaluation in arthroscopy


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Treatment•there are no published guidelines or treatment protocols forthe 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

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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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

For undefined reasons this contact in some athletes become pathologic and

produces symptoms

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Posterior Superior Glenoid Internal Impingement

Normally

in abduction and external rotation (ABER) there is

obligate posterior & inferiortranslation

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

Mechanism of PSGI

Two major theories:

Andrew

Burkhart & Morgan

May co-exist

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Mechanism of PSGIAndrew 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


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Mechanism of PSGIBurkhart & Morgan Theory:

Repeated ABER

Tight posterior capsule

Superior translation of Humeral Head

Torsional stress to biceps anchor

Peel-off

MechanismSLAP II and

Pseudolaxity

Increased contact of undersurface of RC and posterosuperior glenoid Internal

Impingement

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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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Internal impingement

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Structures involved:

Humeral head

Anterior capsule

Inferior GHL

Posterior capsule

Rot cuff muscles

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PSGIHistory

Chronicity of pain

Posterior pain

Abduction + externalrotation aggravates pain

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PSGIHistory

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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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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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:

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

Internal Impingement –


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PSGIMRI findings

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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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PSG Internal Impingement –Arthroscopic findings

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PSG Impingement –Treatment

Conservative

Surgical

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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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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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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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Open/Arthroscopic CapsulolabralReconstruction

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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Internal impingement –Surgical Treatments

Infrequently Used Today

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 OsteotomyDerotation osteotomy of humerous

=> increase of retroversion + shortening of subscapularis=> less impingement

55% return to pre-injury level

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Subacromialdecompression

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 persist: Multiple surgical techniques

Repair all lesions if possible

Take home messages

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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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Secondary subacromialimpingement 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

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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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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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Thank you for your attention

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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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Case-1

MRI

Partial RC tear

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Case-1

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Case-1

6 months post OP

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Throwing phases:

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Internal impingement

Throwing phases:

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PSG Impingement –Arthroscopic findings

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impingement syndromes

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