Rotator Cuff Impingement

Definition

Supraspinatus Syndrome | Tendonosis of the Rotator Cuff

  • Neer
    • Painful impingement of rotator cuff on anterior 1/3rd of acromion, coracoacromial ligament & acromioclavicular ligament without full thickness tear
  • common cause of shoulder pain & dysfunction

Aetiology

Structural Factors vs Dynamic Factors

StructuralDynamic
*Bone
~ Abnormal Acromial Morphology
~ Osteophytes of ACJ
~ Os acromiale
~ Malunion
– greater tuberosity
– distal clavicle
– acromion
*Soft Tissue
~ Rotator Cuff
– Calcific Tendonitis
– thickening of rotator cuff
– Rotator Cuff Tears
– Partial
– Full thickness
~ Ligament
– Hypertrophy of coracoacromial ligament
~ Bursa
– Inflammatory bursitis		* Imbalance of shoulder musculature
* Primary Tendon Overload
* Scapular dysfunction
* Glenohumeral instability
* Repetitive microtrauma
Causes of Subacromial Pathology

Structural Factors

  • Lead to
    • » mechanical obstruction
    • » ↓ space for clearance of rotator cuff
    • » abrades cuff
    • » tears
    • » degeneration
  • Management
    • Relief of abstruction

Dynamic Factors

  • Cause subacromial impingement secondary to superior migration of humeral head due to elevation
  • greater tuberosity abuts against coracoacromial arch leading to tendon injury
  • Management
    • rehabilitation of shoulder musculature
      • centering of humeral head within glenoid fossa
      • may need operative management for glenohumeral instability

Epidemiology

Anatomy

  • Subacromial Space
    • Roof
      • Coracoacromial Arch
      • Acromion
      • Coracoacromial ligament
      • Coracoid Process
      • ACJ is superior & posterior to coracoacromial ligament
    • Floor
      • Greater tuberosity & superior aspect head

Biomechanics

  • Peak forces under anterior-inferior acromion correspond with painful arc range

Pathology

  • Neer’s Impingement Zone } same thing
  • Codman’s “Critical Zone” }
  • Centered on supraspinatus tendon insertion

Classification

Neer’s Pathological

StageDescription
I. Reversible
. & Haemorrhage
. < 25 years
II. Irreversible change
. Fibrosis & Tendonitis
. 25-40 years
IIANo tear
IIBPartial thickness tears
IIC. Chronic
. Partial & Full thickness tears
. > 40 years
Neer’s Pathological Classification of Rotator Cuff Tears (subdivided by Gartsmen)

Neer’s Aetiological

  • Extrinsic/ Extra-tendinous
    • Outlet
    • CA arch impinges on R/C
  • Intrinsic/ Intra-tendinous
    • Non-Outlet
    • Due to bursal or R/C thickening
    • Now thought to be most common

Bigliani’s Acromial Morphology

TypeDescription%Full Thickness Tears (100%)
1Flat203
2Curved4024
3Hooked4073
Bigliani’s Acromial Morphology
  • 33% of cadavers had full thickness tears of which
    • Type 1 3%
    • Type 2 24%
    • Type 3 73%
  • High inter-observer error
  • Morphology does change with age
  • Spur more common > 50 years
  • Is it a Secondary event to cuff process?

History

  • Age
    • mostly over 40 years old
    • If < 40 years look for instability
  • Pain
    • often worse at night, keeps patient awake
    • Chronic vs acute onset
  • Movement
    • Painful arc
  • Weakness
    • overhead
    • suspect rotator cuff tear if weakness a prominent feature

Examination

  • Look
    • Atrophy of supraspinatus, infraspinatus
  • Feel
    • Anterior to acromion
    • Biceps Tendon
  • Move
    • Painful Arc
      • 70-120°
      • > 120° suggests ACJ Osteoarthritis
        • Terminal phase pain
  • Special Tests
    • Neer Impingement Sign
      • Stabilize scapula from behind patient
      • Pass elevate arm in scapula plane
      • Pain between 70-120°
    • Hawkin’s Modification
      • Internally rotate humerus at 90° flexion
    • Neer Impinge Test
      • LA (10mls xylocaine) in subacromial space
      • Abolish pain & test for cuff tear
    • ACJ Abnormality
      • Palpate
      • Compress with cross arm adduction or IR in extension
      • Push on opposite shoulder
    • Speed’s Test
      • Palpate long head biceps with resisted forced flexion in supination
    • Yergason’s Test
      • Resist forearm supination
    • Jobe Relocation Test
      • If after apprehension positive, a relocation force on the head fails to reduce the pain, then secondary impingement is likely
  • Other
    • Cervical Spine
    • Neurovascular Status

Investigations

  • Neer Test
    • 1st line to differentiate Tear vs Tendonosis

XRay

  • AP of GHJ
    • Internal Rotation View
    • External Rotation View
    • Look for
      • Acromial-Humeral Index
        • Normal 1-1.5cm
        • < 5mm
          • high riding humeral head
          • indicates major rotator cuff tear
      • Sclerosis Greater Tuberosity
      • Acromion Spur & Sclerosis
      • ACJ Osteoarthritis
      • Broken Shenton’s Line of the shoulder
      • Calcific tendinitis
  • Axillary View
    • Os acromion
  • Supraspinatus outlet view
    • for acromion morphology (10° caudal lateral scapular view)
      • curved or beaked anterior acromion
  • ACJ views (10° cephalad view in AP)
  • Subacromial spurring (30° caudal tilt view)

If patient is < 40 years old

Consider Instability

  • therefore add
    • West Point Axillary
    • Stryker Notch Views
      • glenoid rim
      • Hill Sachs Lesions

Ultrasound

  • Useful for larger tears
  • Partial or full thickness
  • Dynamic & better to judge size

MRI

  • Sensitive
  • Difficult to assess small cuff tear from tendonitis & not dynamic
  • Magic angle effect
  • When collagen at 55° to field
  • Increased signal intensity on T1 & proton density
  • Not seen on T2

Differential Diagnosis

  • Bone
    • ACJ arthrosis
    • GH arthrosis
  • Soft tissue
    • Adhesive capsulitis
  • Neurology
    • Bracial plexopathy
    • Cervical radiculitis
    • Thoracic Outlet Syndrome
  • Other
    • Shoulder Tumour
    • Pancoast Tumour
    • Visceral Problems
      • Coronary disease
      • cholecystitis

Treatment

Non-Operative

  • Education
  • Lifestyle Change
    • Rest & avoid provocative activity
  • Medications
    • NSAIDS
    • HCLA usually only 2-3
      • ? accelerate tendon rupture
  • Physiotherapy
    • cuff strengthening/ retraining & posterior capsular stretching
      • Should have 9-12 months of non-op prior to surgery – minimum of 6 months
      • Morrison 1997
        • 616 patients with 67% satisfactory results (28% required decompression)
        • Stretching posterior capsule until ROM restored
        • Then strengthening program begun
        • Start with the cuff muscles & avoid the deltoid as can elevate the humeral head
        • Once painless & fully functional then deltoid begun

Operative Management

  • Acromioplasty
    • Indication
      • primary problem is extrinsic impingement
    • Contraindication
      • Newer evidence suggests that this approach may make the problem worse long term by encouraging superior migration of the head
      • Some now doing only cuff debridement
        • Only < 10% of patients should have decompression, while the majority need cuff debridement
        • 5 years 89% Good/ Excellent results for AS cuff debridement
    • Options
      • Open vs Arthoscopic
      • Arthoscopic
        • Introduced in 1985
        • results similar to open
          • but better
            • cosmesis
            • morbidity
            • early return to function

Open Acromioplasty

  • Open Acromioplasty Surgical Technique
  • Results
    • Neer Open Acromioplasty
      • Described 1972
      • Good/ Excellent ~ 80-90%
      • Anteroinferior Acromioplasty
      • Failure to resect anterior acromion
        • claimed by Rockwood to lead to later failure

Prognosis

Arthroscopic Acromioplasty

  • 80% satisfaction at 10 years

Overhead Athletes

  • Poor results, due to
    • diagnostic error
      • missed instability
      • missed GH OA
    • surgical error
    • rotator cuff pathology