Rotator Cuff Pathology

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Anatomy & Biomechanics - Shoulder's Stability Crew

  • Rotator Cuff (SITS Muscles) 📌: Four muscles crucial for dynamic glenohumeral joint stability and movement.
    MusclePrimary ActionInnervation
    SupraspinatusAbduction (initial 0-15°)Suprascapular n. (C5,C6)
    InfraspinatusExternal RotationSuprascapular n. (C5,C6)
    Teres MinorExternal RotationAxillary n. (C5,C6)
    SubscapularisInternal RotationUpper/Lower Subscapular nn. (C5,C6)
  • Key Blood Supply: Suprascapular artery, anterior & posterior circumflex humeral arteries, thoracoacromial artery.
  • Essential Biomechanics:
    • Glenohumeral joint compression & centering (concavity compression).
    • Force couples (e.g., deltoid-cuff) for efficient, coordinated motion.
    • Humeral head depression during elevation, preventing superior escape & impingement.

⭐ Supraspinatus initiates abduction (first 0-15°) and is the most frequently injured rotator cuff muscle.

Rotator Cuff Muscles and Shoulder Anatomy

Etiology & Types - Tears & Tantrums

Etiology:

  • Intrinsic Factors: Ageing, hypovascularity ("critical zone" - supraspinatus), tendinosis.
  • Extrinsic Factors:
    • Subacromial Impingement:
      • Primary: Acromial morphology (Bigliani type II/III), AC joint osteophytes, coracoacromial (CA) ligament hypertrophy.
      • Secondary: Glenohumeral (GH) instability, scapular dyskinesis, muscle imbalance.
    • Internal (Posterosuperior) Impingement: Common in overhead athletes, associated with GIRD (Glenohumeral Internal Rotation Deficit).
    • Acute Trauma (e.g., FOOSH - Fall On Outstretched Hand).

Risk Factors:

  • Age >40 years
  • Repetitive overhead activities
  • Smoking
  • Diabetes Mellitus (DM)
  • Trauma history

Spectrum of Pathologies:

  • Subacromial Impingement Syndrome
  • Rotator Cuff (RC) Tendinopathy
  • Subacromial-Subdeltoid (SASD) Bursitis
  • Calcific Tendinitis
  • RC Tears

Rotator cuff tear classification diagram

Rotator Cuff Tear Classification:

FeatureTypes
ThicknessPartial (articular/bursal/intratendinous), Full
EtiologyDegenerative (Chronic), Traumatic (Acute)
Size (Full)Small (<1cm), Medium (1-3cm), Large (3-5cm), Massive (>5cm)

Diagnosis & Tests - Spotting the Strain

  • Symptoms:

    • Anterolateral shoulder pain, aggravated by overhead activities.
    • Night pain, disturbing sleep.
    • Weakness, difficulty lifting arm.
    • Crepitus or clicking sounds.
  • Signs:

    • Tenderness: Greater tuberosity, subacromial space.
    • Painful arc: Typically between 60°-120° of abduction.
    • Atrophy: Supraspinatus/Infraspinatus (chronic tears).

⭐ Night pain is a highly suggestive symptom of rotator cuff pathology.

  • Special Tests:
Test NameTarget Structure(s)Positive Sign
📌 Empty Can (Jobe's)SupraspinatusPain/weakness with resisted abduction (thumb down)
📌 External Rotation LagInfraspinatus/Teres MinorInability to maintain external rotation
📌 Lift-off TestSubscapularisInability to lift hand off back
Hawkins-KennedyImpingementPain with internal rotation at 90° flexion
Neer's SignImpingementPain with passive forward flexion
  • Imaging:

    • X-ray (AP, Outlet, Axillary): May show calcification, acromial spur, ↓acromiohumeral distance (<7mm).
    • USG: Dynamic, good for detecting tears; operator-dependent.
    • MRI: Gold standard for tear characterization (size, retraction, fatty infiltration - Goutallier stages 0-4).
  • Diagnostic Pathway:

Treatment Approaches - Fixing the Fray

  • Conservative (First-line for most):
    • Physiotherapy: Range of Motion (ROM), periscapular & rotator cuff strengthening.
    • NSAIDs: For pain & inflammation.
    • Injections: Corticosteroid (subacromial) for persistent pain (max 2-3/year).
  • Surgical Indications:
    • Failed conservative management >3-6 months.
    • Acute full-thickness tears in young, active individuals.
    • Significant weakness, tear size >1-1.5 cm or >50% thickness.

Arthroscopic Rotator Cuff Repair Technique

  • Surgical Techniques: Arthroscopic repair is common; types include single-row, double-row.
  • Post-op Rehab: Phased approach: sling protection (4-6 weeks), then progressive ROM & strengthening. Return to activity in 4-6+ months.

⭐ Early motion is often emphasized post-operatively for smaller tears, while larger repairs might require more protection and a slower rehabilitation progression to ensure adequate tendon healing to bone.

High‑Yield Points - ⚡ Biggest Takeaways

  • Supraspinatus is the most frequently torn rotator cuff muscle.
  • Painful arc syndrome (pain 60-120° abduction) is a classic sign.
  • Drop arm test and Empty can test assess Supraspinatus integrity.
  • MRI is gold standard for full-thickness tears and surgical planning.
  • Subacromial impingement is a common precursor to rotator cuff tears.
  • Surgical repair for acute full-thickness tears in active individuals.
  • Key symptoms: shoulder pain (especially at night) and weakness.

Practice Questions: Rotator Cuff Pathology

Test your understanding with these related questions

In painful arc syndrome, which movement is painful?

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Flashcards: Rotator Cuff Pathology

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Prepatellar bursitis can be caused by _____ or pressure from excessive kneeling

TAP TO REVEAL ANSWER

Prepatellar bursitis can be caused by _____ or pressure from excessive kneeling

repeated trauma

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