Rotator Cuff Tears — Repair Principles

Rotator cuff tears are among the most common musculoskeletal conditions, with prevalence increasing significantly with age. The four rotator cuff muscles — supraspinatus, infraspinatus, teres minor, and subscapularis — function together to provide dynamic glenohumeral stability and generate shoulder motion. Supraspinatus tears at the critical zone (the avascular region near the greater tuberosity insertion) account for the vast majority of clinically significant tears. Understanding tear classification, the factors determining reparability, surgical technique principles, and the evidence base for repair is central to shoulder surgery practice.

• Prevalence: asymptomatic full-thickness tears present in approximately 20–30% of adults over 60 years and 50% of those over 80; symptomatic tears account for a significant proportion of surgical referrals; incidence increases sharply after the fifth decade
• The critical zone of the supraspinatus: a hypovascular area approximately 1 cm proximal to the greater tuberosity insertion; the watershed area between the osseous vessels from the greater tuberosity and the musculotendinous vessels from the muscle; this zone is the most common site for degenerative tear initiation; the poor vascularity in this zone impairs intrinsic healing capacity
• Aetiology: degenerative (most common — intrinsic tendon degeneration + extrinsic outlet impingement); traumatic (acute tear, usually on a background of degeneration); acute-on-chronic (minor trauma completing a partial tear)
• Tear progression: full-thickness tears generally progress over time — approximately 50% of untreated full-thickness tears increase in size over 2–3 years; tear progression is associated with functional deterioration and fatty infiltration of the muscle belly

• Goutallier classification of fatty infiltration (CT or MRI): Grade 0 — normal muscle; Grade 1 — some fat streaks; Grade 2 — less fat than muscle; Grade 3 — equal fat and muscle; Grade 4 — more fat than muscle; Grades 3 and 4 = advanced fatty infiltration = poor prognosis for functional recovery after repair; fatty infiltration is irreversible and the primary determinant of biological reparability

• History: pain at the deltoid insertion (C5 referral); nocturnal pain (characteristic — patients wake unable to find a comfortable position); weakness with overhead activities; acute event in traumatic tears; insidious onset in degenerative tears
• Clinical tests:

• Plain radiographs: AP (true AP in the scapular plane), outlet view, axillary lateral; supraspinatus outlet view: shows the acromion shape (Bigliani Type I — flat, Type II — curved, Type III — hooked; Type III associated with impingement and rotator cuff tears); superior migration of the humeral head (<7 mm acromiohumeral interval = massive cuff tear with superior migration)
• MRI shoulder: gold standard for rotator cuff assessment; full-thickness tear (complete fluid signal through tendon on fat-suppressed sequences); partial tear; tear size (AP dimension, ML dimension, number of tendons); tendon retraction (graded); fatty infiltration of muscle bellies (Goutallier); tendon quality; osseous changes at the greater tuberosity
• Ultrasound: high sensitivity and specificity for full-thickness tears (>90% each) in experienced hands; dynamic assessment; identifies partial tears; cheap and accessible; limited by operator dependency; cannot assess fatty infiltration as comprehensively as MRI
• Acromiohumeral interval (AHI): measured on AP X-ray as the distance between the inferior acromion and the superior humeral head; normal >7 mm; <7 mm = significant superior migration suggesting massive cuff tear and cuff tear arthropathy; key pre-operative assessment parameter

• First-line for most rotator cuff tears: physiotherapy (rotator cuff strengthening, deltoid strengthening, scapular stabilisation), NSAIDs, activity modification
• Subacromial corticosteroid injection: USS-guided; provides short-term (6–12 weeks) pain relief; facilitates physiotherapy participation; not more than 3 injections; does not alter the natural history of the tear
• Non-operative treatment is appropriate for: older patients, low-demand patients, partial thickness tears, small full-thickness tears in the elderly, patients with significant comorbidities, patients who improve with rehabilitation; approximately 50–60% of small to medium tears achieve satisfactory outcome with non-operative management
• Indications to consider earlier surgery: acute traumatic full-thickness tear in a young active patient; significant functional deficit (inability to raise arm); progressive tear enlargement; young age; failure of 3–6 months structured physiotherapy

• Arthroscopic vs open repair: arthroscopic repair is now the standard approach for most tears — smaller incisions, faster recovery, equivalent or superior outcomes compared to mini-open or open repair; mini-open repair (lateral deltoid-splitting approach after arthroscopic subacromial work) is still used in some centres for larger tears
• Footprint repair: the goal of rotator cuff repair is restoration of the anatomical footprint of the tendon on the greater tuberosity; the supraspinatus footprint is approximately 25 mm wide (AP) and 12 mm mediolateral; single-row repair (anchors medially only); double-row repair (medial row + lateral row of anchors) provides greater footprint contact area and better biomechanical fixation; suture bridge (transosseous-equivalent) technique is the most commonly used double-row method — evidence for improved healing rates in larger tears
• Suture anchors: titanium, bioabsorbable, or PEEK anchors placed in the greater tuberosity; sutures passed through the tendon and tied to achieve tendon-to-bone apposition; anchor placement angle should be approximately 45° to the bone surface (deadman angle) for optimal pull-out strength
• Acromioplasty: performed at the time of repair if a Type III (hooked) acromion or significant subacromial spurs are present; resection of the anterior inferior acromion; controversial whether it improves outcomes in arthroscopic repair — some surgeons routinely perform it, others selectively
• Biological augmentation: platelet-rich plasma (PRP), bioinductive collagen scaffold (REGENETEN), and other biological augments are used in larger and revision repairs to attempt to improve healing biology; evidence for PRP is mixed; REGENETEN patch (collagen scaffold) placed on the bursal surface of the repair promotes bioinduction of new tissue; growing evidence in massive and partial thickness tears
• Partial thickness tears: articular surface tears >50% tendon thickness (Ellman Grade III) generally benefit from repair — either transtendinous repair or tear completion and standard repair; bursal surface tears >50% thickness similarly repaired

• Reparability assessment: the key factors determining whether a massive tear is repairable are: tendon quality and mobility (can it be brought to the footprint without excessive tension?), fatty infiltration (Goutallier Grade 3–4 = poor prognosis for biological healing even if repair is technically possible), and muscle atrophy (Thomazeau classification — severe atrophy → poor functional recovery)
• Superior capsule reconstruction (SCR): for irreparable massive superior cuff tears (supraspinatus and infraspinatus) without pseudoparalysis in young patients; a fascia lata autograft or dermal allograft is used to reconstruct the superior capsule between the glenoid and the greater tuberosity; restores the superior fulcrum for the deltoid; evidence for improvement in pain and function in appropriately selected patients
• Tendon transfers for irreparable tears: latissimus dorsi transfer for irreparable posterosuperior cuff tears (restores external rotation); pectoralis major transfer for irreparable subscapularis tears
• Reverse total shoulder arthroplasty (rTSA): the definitive salvage for massive irreparable rotator cuff tears with cuff tear arthropathy (CTA) — the Hamada classification grades CTA (Grade 1–5); rTSA eliminates the need for the rotator cuff by using the deltoid as the primary motor; provides reliable pain relief and functional restoration; discussed in the reverse shoulder arthroplasty article

• Re-tear rate after rotator cuff repair: a significant challenge — re-tear rates vary from 10–40% for small/medium tears to over 50% for massive tears; healing is influenced by: tear size, fatty infiltration, patient age, tissue quality, and surgical technique; re-tears are often asymptomatic — functional outcomes can be satisfactory even with a structurally failed repair; the biological environment for healing (vascularity, growth factors) is as important as the mechanical repair construct
• Deltoid management in open vs arthroscopic repair: open rotator cuff repair historically required deltoid detachment and reattachment from the acromion — the most common cause of poor outcome in open repair is deltoid dehiscence; arthroscopic repair avoids this entirely; if a deltoid-splitting approach (mini-open) is used, the split should not extend beyond 5 cm distal to the acromion (risk of axillary nerve injury)
• Speed of progression and fatty infiltration: once advanced fatty infiltration (Goutallier Grade 3–4) develops, it does not reverse after repair; the functional result of repair depends on the muscle quality at the time of surgery, not the integrity of the repair construct; this is the strongest argument for earlier repair in younger, active patients with larger tears before fatty infiltration progresses
• Subscapularis tears — recognition and repair: subscapularis tears are commonly missed (approximately 25–30% of rotator cuff tears involve the subscapularis); the upper subscapularis fibres tear first (comma sign — a comma-shaped condensation of the superior glenohumeral and coracohumeral ligaments identifies the torn upper subscapularis arthroscopically); lift-off and bear hug tests are the key clinical tests; repair restores internal rotation strength and prevents anterior instability

• Critical zone: hypovascular area 1 cm proximal to greater tuberosity insertion; most common site of degenerative tear initiation
• Goutallier Grade 3–4: equal or more fat than muscle — poor prognosis for repair; fatty infiltration is IRREVERSIBLE; repair before this stage
• AHI <7 mm on AP X-ray = massive cuff tear with superior humeral migration = cuff tear arthropathy; consider rTSA
• External rotation lag sign: highly specific for full-thickness infraspinatus tear; larger lag = larger posterior cuff tear
• Lift-off test (Gerber): subscapularis; bear hug test: upper subscapularis; both test internal rotation against resistance
• Double-row (suture bridge) repair: better footprint coverage and biomechanical fixation; improved healing rates for larger tears vs single-row; supraspinatus footprint 25 mm × 12 mm
• Acromioplasty: Type III (hooked) acromion associated with impingement and tears; performed selectively at time of repair
• Re-tear rate: 10–40% small/medium; >50% massive; re-tear often asymptomatic; function can remain good with structurally failed repair
• SCR (superior capsule reconstruction): for irreparable massive posterosuperior tears in young patients; fascia lata or dermal allograft; restores superior fulcrum
• Subscapularis: commonly missed (25–30% of tears); comma sign arthroscopically; repair restores internal rotation and prevents anterior instability