Anatomy, Pathogenesis, Natural History and Non-Operative Treatment of

Rotator Cuff Tears

UE RoundsMarch 9, 2012Cai Wadden

Derek Butterwick

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Overview

• Anatomy– tendon footprints

• Function• Etiology of tears• Natural history

– partial thickness– full thickness

• Non-operative management

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Muscle Origin Insertion NerveSubscapularis Subscapularis

fossaLT Upper and

Lower Subscapular

Supraspinatus Supraspinatus fossa

GT (superior facet)

Suprascapular

Infraspinatus Infraspinatus fossa

GT (middle facet)

Suprascapular

Teres Minor Lateral scapula

GT (inferior facet)

Axillary

Tendon Footprints

SS

IS

TM

CA Lig

Biceps Tendon and Groove

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Important Knowledge for repairs

Subscapularis

• Superiorly – on articular margin, very tendinous

• Along medial edge of biceps groove

• Inferiorly – 18 mm from articular surface, musculocapuslar

• Footprint – 4 x 2 cm

Supraspinatus

• Meidal insertion runs from biceps groove anteriorly, along articular margin, to bare area posteriorly

• Footprint - 23 mm x 16mm

• Trapezoidal shape – wider medially

• Note – posterior boarder overlapped by IS, fibers mesh, difficult to seperate tendons

IS

Infraspinatus• Superiorly – overlaps

posterior edge of SS, inserts at edge of articular cartilage, more tendinous

• Inferiorly – moves away from articular margin, 1.6 cm from articular surface, more muscular

• Bare Area – gap btwn articular surface and IS insertion

• Trapezoidal footprint – 29 mm x 19 mm

BARE AREA

IS

IS

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• Cadaveric study investigating humeral insertion– supraspinatus

– infrastinatus

• Difficult to separate tendons secondary to interdigitating fibers

• Overcame this by– removing CH lig. and loose connective tissue

– identify distinct border b/w supra and infra

– separate by following anterior margin of superior tendinous portion of infra

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New Footprints

• Supraspinatus footprint– long tendinous portion in anterior half

– inserts into anteriormost area of highest impression of GT

– inserts into superiomost area of LT 21% of time

– triangular in shape, 6.9mm x 12.6mm

• Infraspinatus footprint– long tendinous portion in superior half

– curves anteriorly to insert into anterolateral area of highest impression of GT

– trapezoidal in shape, 10.2mm x 32.7mm

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• Footprint of supra on GT smaller• Infra actually occupies large part of GT• Clinically: tears previously thought to involve

only supra may have significant infra component

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Cuff Ultrastructure• Layer one - superficial fibers of the

coracohumeralligament (CHL) 

• Layer two - SP and IS CUFF TENDONS – parallel tendon fibers inline with muscle belly

– Bursal sided tendon 

• Layer three - thick tendinous structure, smaller fascials than in layer two, less uniform orientation

– Articular sided tendon 

• Layer four - thick bands of collagen fibers running perpendicular cuff tendons

– deep extension of the coracohumeral ligament

– described as a transverse band, a pericapsular band, or a rotator cable

• Layer five - capsular layer

Cable Crescent Complex

• Arching, cable-like thickening surrounding a thinner crescent of tissue that inserts into the greater tuberosity of the humerus– Thickening of CHL

– Located at the margin of the avascular zone

– Anterior attachment – just posterior to biceps

– Posterior attachment – inferior boarder of IS tendon

Cable Crescent Complex

• Stress transferred to anterior and posterior attachments of the cable

• Shields the avascular zone attachment

• Allows cuff to function despite tear

Function of Rotator Cuff

• Primary dynamic stabilizers to maintain a concentric reduction during rotation of the humeral head on the glenoid

• Does so via...• Force Couple – a system that exerts a

resultant moment, but no resultant force– i.e. Two equal and opposite forces exert a pure

rotational force, no translation occurs

– i.e. Agonist and antagonist muscles

• Coronal Plane Couple– Inferior portion of cuff balances the deltoid moment

– Results in pure abduction w/o superior migration

• Transverse Place Couple– Subscap balances the IS/TM posteriorly

– Results in pure ER/IR, w/o ant/post translation

Loss of force couple

• Burkhart – Tears above the

center of rotation and in the superior half of the infraspin tendon – force couple intact

– Tears extendingextending below center of rotation, coronal plane force couple lost impairs function

Rotator Cuff Characteristics• Hypovascular zone – near insertion of

supraspinatus, mostly articular sided– from musculotendinous zone 5 mm from

insertion – Area at risk for tears

• Bursal sided tendon and articular sided tendon different– Bursal side (layer 2) – greater tensile strength,

greater deformation– Articular side (layer 3)– weaker, tears more

common

Tear Etiology

• Traumatic Causes – acute stress tears tendon

• Intrinsic Causes – i.e. Degenerative process– Usually articular sided tears (less strength),

older patients or young over head atheletes

• Extrinsic Causes – i.e. impingment– Usually bursal sided tears– Ozaki – found that all bursal sided tears had

CA lig and acromion lesions

• Both are likely cause

Vicious Cycle (Ozaki)

• Combined Explanation• Primary degenerative process, superior

migration of humerus, causes impingement, tears, more degeneration

Natural History

• Over time fatty infiltration and atrophy of muscle belly occurs– Decreased muscle mass, sarcomere and

strength– Muscle shorten and stiffen– Tendon has

• poor capacity to heal• Poor mechanical properties – progression of

tear, failure of repair, difficult to mobilize intra-op

– Progressive and irreversible• Does not improve with cuff repair

• Rowshan et al. JBJS 2010• Rabbits- sectioned subscap tendon

– Partial tear no retraction• No change at 6 weeks

– Full thickness tear with retraction• Decreased mass, increased fat content

– Denervation (Subscap n. transection)• Similar to full thickness tear

Goutallier Score for Fatty Degeneration based on CT

• Grade 0 - no fatty infiltration• Grade 1 - some fatty streaks• Grade 2 - less fat than muscle• Grade 3 - as much fat as muscle• Grade 4 - more fat than muscle

Goutallier Stage (CT)

Fat (black) Fat (black)

Healthy Muscle-No fat-Not black

MRI for Staging

-Same grading scheme as Goutallier CT staging

- Better inter-observer reliability with MRI

- MRI better at distinguishing muscle from fat

- CT grades usually lower for same patient

-Therefore – don’t compare CT grade at one point, to MRI grade at a different point, will falsely detect progression

Natural History of Partial Tears

• Partial Thickness Tears MOST PROGRESS OVER TIME– Yamanaka – 40 pts partial articular sided tears

– Diagnosed and followed by arthrography

– After 1 year – 53% increased in size, 28% progressed to full thickness, 10% decreased in size, 10% healed

• Histologic studies MOST DON’T HEAL– Show no active repair, granulation tissue at edges

impairs healing

– Tendon stumps - edges rounded, retracted, avascular

• Patients can become asymptomatic – but generally wax and wane

Asymptomatic Rotator Cuff Tears

• Yamaguchi (2001)– 45 patients with asymptomatic tears

– Followed with U/S and fxnal scores for 5 years

– 51% of tears became symptomatic over 2.8 years

– 23 patients had f/u U/S• 9 asymptomatic at f/u – 2 of these patients had tear

progression• 14 symptomatic at f/u - 7 of these patients had tear

progression• No decreases in tear size!

– Large percentage of tears become symptomatic

– Symptoms - can be associated with tear progression

• What factors are associated with asymptomatic tear becoming symptomatic?

• 195 patients asymptomatic rotator cuff tears followed over 5 years

– 23% became symptomatic at 2 years• Symptomatic tears were

– Larger at baseline– Usually in dominant shoulder– Increase in tear size at f/u (i.e partial to full,

enlargement of full)» 23% of symptomatic tears were larger» 4% of asymptomatic tears were larger

– Decreased ROM – Decreased shoulder (ASES) scores

• No association with Ext rotation strength, or fatty infiltration

Natural History of Symptomatic Full Thickness Tears in Pts < 60

yrs

• Safran, Am J Sports Med 2011– Full Thickness tears 5mm or larger– U/S at baseline, F/U at mean of 2 years

• 49% increased in size• 43% unchanged• 8% smaller

– Most Full Thickness tears progress

Massive Rotator Cuff Tear• Risk of tear

progression to massive tear

• Various definitions– Any tear with

diameter > 5 cm (Cofield)

– Complete detachment of 2 or more tendons

• Not all massive tears are inoperable

Massive Cuff Tears• Important since

– Difficult to repair

– Higher failure rate

– May not be repairable

• Signs of irreparability– Static superior

migration of the humeral head

– Narrowed or absent acromiohumeral interval

– Fatty infiltration of > 50% of muscle belly

Rotator Cuff Arthropathy

• Risk of progression to arthropathy• Characterized by:

– Rotator Cuff insufficiency– Degenerative changes in the glenohumeral

joint– Superior migration of the humeral head

• Other features– Humeral head collapse– Subdeltoid effusion (Geyser Sign)– Acetabularization of acromion

Rotator Cuff Arthropathy

Geyser Sign

Etiology

• One school of thought (The Rheumatologists)– Shoulders with Massive rotator cuff tears – get

accumulation of hydroxyapatite crystals within capsule, synovium, cartilage

– Crystals phagocytosed– Release proteolytic enzymes leads to joint

destruction– A chronic inflammatory state

Etiology

• Neer (The Orthopods)– Massive rotator cuff tears + rupture of

long head of biceps superior migration of humeral head and impingment repetitive trauma and leads to joint destruction

– Disuse osteopenia bone erosions

Etiology

• Collins and Harryman– Combination of the two

• Percentage of massive rotator cuff tears that progress to rotator cuff arthropathy– ?? Unsure ??

Non-operative Management

• Options– Anti-inflammatory medication– Physiotherapy – stretching and

strengthening– Injections– Activity modification

• Few studies on non-op treatment– Mostly retrospective

Physio• Goals regain ROM

and strengthen cuff muscles– Strong cuff muscle

resist superior translation of the humeral head less impingement

– Muscles are shock absorbers – protect tendon from stress

– Includes – IR, ER, FF, Abduction and extension

Physiotherapy

• Scapulothoracic Strengthening– Avoid scapular

dyskinesia

– Restores normal scapular motion – allows acromion to clear cuff with forward elevation

– Exercises include• Pull downs, seated

row, push up, bench press, dips and flies

Treatment of Partial Thickness Tears

• Wolff, JAAOS 2006• Non-op measures

– Rest, activity mod, NSAIDs

– PT, goals include• Regain any motion lost from contractures• Begin strengthening after motion regained and

acute inflammation subsides

– +/- corticosteroid injections

• Most patients improve over 6 months• May see continued improvement out to 18

months

Non-op treatment of full thickness tears

• Stedman Hawkins Clinic, CORR 1993– Average Age = 60, with confirmed full

thickness tears by arthroscopy– Treat non-op - NSAIDs, PT, injections – f/u @ 7 years– 74% of patients – slight or no discomfort– 16 patients had pain for > 6 months initially

• 56% rated as satisfactory at f/u– Average forward elevation – 149 degrees– 94% had weakness on physical exam– 56% had visible atrophy

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The Efficacy of Subacromial Corticosteroid Injection in the Treatment of Rotator Cuff Disease: A

systematic Review

• Koester, JAAOS 2007• 9 RCTs identified that compared

subacromial injection to placebo– methylprednisolone, triamcinolone, betamethasone

• Pathologies in included studies ranged from tendinitis to full-thickness tears

• One study showed improvement in pain• Two studies showed improvement in ROM• Overall, little reproducible evidence to

support efficacy of injections42

Anterior Deltoid Retaining in Massive Cuff Tears

• Program– Attempt to maintain

arm in vertical position

– AAROM along forward elevation arc, with progressively increasing amplitude

– Add weight

– Perform in sitting, then standing position without weight, then with

Anterior Deltoid Retraining

• Levy (2008)– f/u at 9 months– Constant score – improved from 26 to

63• **no improvement in strength**

– Forward elevation – improved from 40 degrees to 160 degrees

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Thank You

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MRI Slice, But Example of Anatomy

Supraspin

Subscap

Infraspin

Teres Minor