Residency · Residency · Orthopedic Surgery
Rotator Cuff Tears: Pathology, Repair, and Rehabilitation
Overview
The rotator cuff comprises four muscles: supraspinatus, infraspinatus, teres minor, and subscapularis. Its primary functions include dynamic stabilization of the glenohumeral joint, compression of the humeral head into the glenoid (concavity-compression), and initiation and facilitation of shoulder motion. Tears represent a spectrum from tendinopathy to partial-thickness tears to full-thickness tears to massive tears with arthropathy.
Anatomy and Biomechanics
Rotator Cuff Footprint
The supraspinatus inserts on the superior facet of the greater tuberosity, the infraspinatus on the middle facet, and the teres minor on the inferior facet. The subscapularis inserts on the lesser tuberosity. The "rotator cable" and "rotator crescent" concept (Burkhart) describes a thickened band of tissue (the cable) forming a stress-shielding arc, with thinner tissue (the crescent) between the cable and the tuberosity insertion representing the area most susceptible to tears.
Force Couples
In the coronal plane, the deltoid (superior) is balanced against the inferior cuff (infraspinatus, teres minor, subscapularis). In the transverse plane, the subscapularis (anterior) balances the infraspinatus and teres minor (posterior). Disruption of these force couples leads to superior migration of the humeral head and loss of the fulcrum for deltoid function.
Pathophysiology
Etiology Theories
The extrinsic compression theory (Neer) proposes that acromial morphology (Type III hooked acromion) causes impingement and mechanical wear. The intrinsic degeneration theory attributes tears to hypovascularity of the "critical zone" near the supraspinatus insertion combined with age-related tendon degeneration. The combined theory is most likely correct: tears result from multifactorial processes involving intrinsic degeneration with superimposed extrinsic factors and overuse.
Risk Factors
Risk factors include age (prevalence increases markedly after age 60), smoking, diabetes mellitus, hypercholesterolemia, genetic predisposition, and overhead repetitive activities.
Classification
Tear Thickness
Partial-thickness tears may be articular-sided (more common), bursal-sided, or intratendinous. The Ellman classification grades them as Grade I (less than 3 mm), Grade II (3-6 mm), or Grade III (greater than 6 mm). Full-thickness tears are classified as small (less than 1 cm), medium (1-3 cm), large (3-5 cm), or massive (greater than 5 cm or involving 2 or more tendons).
Fatty Infiltration (Goutallier Classification)
| Stage | Description | Clinical Implication |
|---|---|---|
| 0 | Normal muscle, no fat | Excellent repair candidate |
| 1 | Some fatty streaks | Good repair candidate |
| 2 | Less fat than muscle | Acceptable repair candidate |
| 3 | Equal fat and muscle | Poor outcomes after repair; higher re-tear |
| 4 | More fat than muscle | Likely irreparable; consider other options |
Fatty infiltration is assessed on CT or MRI and graded from Stage 0 (normal muscle) through Stage 1 (some fatty streaks), Stage 2 (less fat than muscle), Stage 3 (equal fat and muscle), to Stage 4 (more fat than muscle). Goutallier stage 3 or higher correlates with poor outcomes after repair and higher re-tear rates.
Tendon Retraction (Patte Classification)
The Patte classification grades retraction as Stage 1 (proximal stump near bony insertion), Stage 2 (retracted to the humeral head), or Stage 3 (retracted to the glenoid level). Stage 3 retraction with advanced fatty infiltration suggests irreparability.
<image>MRI of a full-thickness supraspinatus tear showing retraction and fatty infiltration grading</image>
Clinical Evaluation
History and Examination
Night pain is a hallmark symptom. Weakness in external rotation indicates infraspinatus involvement, while weakness in forward elevation suggests supraspinatus pathology. Special tests include the Jobe test (empty can) for supraspinatus, the external rotation lag sign for infraspinatus, the hornblower sign for teres minor, the belly-press and bear-hug tests for subscapularis, and the lift-off test (Gerber) for subscapularis.
Imaging
Radiographs may show superior migration of the humeral head (acromiohumeral interval less than 7 mm suggests a massive tear), acromial morphology, and glenohumeral arthritis. MRI is the gold standard for tear characterization, fatty infiltration, and retraction assessment. Ultrasound is operator-dependent but increasingly used, with comparable sensitivity and specificity to MRI in experienced hands.
Treatment
Nonoperative Management
Nonoperative treatment is indicated for chronic tears in low-demand patients, partial-thickness tears, and patients with advanced fatty infiltration (poor surgical prognosis). It includes NSAIDs, activity modification, and physical therapy focusing on periscapular strengthening and the remaining rotator cuff. Subacromial corticosteroid injections may be used with limited frequency due to potential deleterious effects on tendon quality.
Surgical Repair
Partial-Thickness Tears
Tears involving less than 50% of tendon thickness are managed with debridement with or without acromioplasty. Tears involving greater than 50% of thickness may be completed and repaired (converted to a full-thickness tear then repaired) or managed with transtendon repair.
Full-Thickness Tears -- Repair Techniques
Single-row repair uses suture anchors placed at the lateral footprint and is adequate for many tears with a simpler technique. Double-row repair uses medial and lateral row anchors to restore footprint coverage and is biomechanically stronger with greater footprint contact area. The suture bridge (transosseous-equivalent) is the most commonly used double-row configuration. Clinical superiority of double-row over single-row remains debated; meta-analyses show lower re-tear rates with double-row but equivalent clinical outcomes in most studies.
Margin Convergence
Margin convergence involves side-to-side repair of the free edge of the torn tendon to reduce the dimensions of the tear before anchor fixation. It is particularly useful for U-shaped and L-shaped tear patterns.
<image>Arthroscopic double-row suture bridge rotator cuff repair technique illustration</image>
Irreparable Tears and Massive Cuff Deficiency
Definition of Irreparability
A tear is considered irreparable when there is Patte stage 3 retraction combined with Goutallier stage 3-4 fatty infiltration, when the tendon cannot be reduced to the footprint without excessive tension, or when a positive shrug sign or hornblower sign indicates functional irreparability.
Treatment Options
Partial repair addresses what is repairable to restore force couples. Superior capsular reconstruction (SCR) uses fascia lata autograft or dermal allograft bridging from the superior glenoid to the greater tuberosity to restore the superior restraint. Tendon transfers include latissimus dorsi transfer for posterosuperior cuff deficiency, lower trapezius transfer (gaining popularity for external rotation deficiency), and pectoralis major transfer for irreparable subscapularis. The subacromial balloon spacer (InSpace) is a biodegradable spacer providing a cushion effect with promising short-term data. Reverse total shoulder arthroplasty (RSA) is indicated for cuff tear arthropathy (Hamada grade 3 or higher) with pseudoparalysis.
Cuff Tear Arthropathy
Cuff tear arthropathy represents end-stage massive rotator cuff tear combined with glenohumeral arthritis and superior migration. The Hamada classification grades this condition from Grade 1 (acromiohumeral interval 6 mm or greater) through Grade 2 (5 mm or less), Grade 3 (acetabularization of the acromion), Grade 4a (glenohumeral narrowing without acetabularization), Grade 4b (glenohumeral narrowing with acetabularization), to Grade 5 (humeral head collapse from necrosis). Treatment is reverse total shoulder arthroplasty.
<image>Hamada classification of cuff tear arthropathy on AP radiographs</image>
Rehabilitation After Repair
Phases
Phase 1 (0-6 weeks) involves sling immobilization, pendulum exercises, and passive ROM only. Phase 2 (6-12 weeks) progresses to active-assisted ROM and then active ROM. Phase 3 (12-16 weeks) introduces strengthening. Phase 4 (4-6 months) involves progressive resistance and sport-specific or functional training. Return to full activity is typically at 6-9 months.
Factors Affecting Healing
Tear size is a primary factor, with larger tears having higher re-tear rates (massive tears show 40-94% re-tear). Other factors include fatty infiltration and atrophy, patient age, bone quality (anchor purchase), smoking status, and compliance with rehabilitation restrictions.
Clinical Pearls
Acute traumatic tears in young patients should be repaired early because delay leads to retraction, fatty infiltration, and worse outcomes. Subscapularis integrity should always be evaluated during arthroscopy, with the "comma sign" (superior glenohumeral ligament) helping identify the superior border of the subscapularis. Acromioplasty during cuff repair remains controversial; many surgeons perform it routinely, but isolated acromioplasty for impingement without cuff tear has diminishing support. The external rotation lag sign has the highest specificity for full-thickness posterosuperior cuff tears. Biologic augmentation (PRP, stem cells, scaffolds) for cuff repair remains investigational with inconsistent evidence. In patients over 70 with chronic massive tears and good function, a trial of conservative management is reasonable because many compensate with the remaining cuff and deltoid.
References
- Neer CS. Impingement lesions. Clin Orthop Relat Res. 1983;(173):70-77.
- Goutallier D, et al. Fatty muscle degeneration in cuff ruptures. Clin Orthop Relat Res. 1994;(304):78-83.
- Burkhart SS. Reconciling the paradox of rotator cuff repair versus debridement: a unified biomechanical rationale. Arthroscopy. 1994;10(1):4-19.
- Mihata T, et al. Superior capsule reconstruction for irreparable rotator cuff tears. Am J Sports Med. 2013;41(7):1669-1676.
- Galatz LM, et al. The outcome and repair integrity of completely arthroscopically repaired large and massive rotator cuff tears. JBJS Am. 2004;86(2):219-224.
- Patte D. Classification of rotator cuff lesions. Clin Orthop Relat Res. 1990;(254):81-86.
