Rotator Cuff Tears: Anatomy, Classification, and Rehabilitation

The Rotator Cuff: Structure and Function

The rotator cuff is a group of four muscles — supraspinatus, infraspinatus, teres minor, and subscapularis — that originate from the scapula and insert as a continuous musculotendinous cuff onto the humeral head. Their primary function is not power generation, but dynamic joint centring: compressing the humeral head into the glenoid fossa throughout shoulder movement, counteracting the superior translation force of the deltoid during arm elevation, and providing fine motor control of glenohumeral arthrokinematics. Supraspinatus initiates and assists abduction; infraspinatus and teres minor externally rotate and posteriorly depress the humeral head; subscapularis internally rotates and anteriorly stabilises. This coordinated compression mechanism is what allows the relatively shallow glenohumeral joint — only 25–30% of the humeral head is covered by the glenoid — to remain stable through the enormous range of motion the shoulder demands.

Types of Rotator Cuff Tears

Rotator cuff tears are classified by depth, size, and location. Partial-thickness tears involve only a portion of the tendon thickness — articular-side partial tears (more common, typically affecting the supraspinatus deep surface), bursal-side partial tears, or intratendinous tears. Full-thickness tears penetrate the entire thickness of the tendon, creating a communication between the glenohumeral joint and the subacromial bursa. Full-thickness tears range from small (<1 cm) through medium (1–3 cm), large (3–5 cm), to massive (>5 cm or involving two or more tendons). Supraspinatus is by far the most commonly torn tendon, followed by infraspinatus. Tears arise through two mechanisms: acute traumatic tears from a single high-force event (falling on an outstretched arm, shoulder dislocation, heavy lifting) and degenerative tears accumulating from repetitive microtrauma, impingement, and age-related tendon degeneration.

Clinical Presentation

Rotator cuff tears typically present with a combination of lateral shoulder pain (often radiating into the upper arm), weakness with arm elevation and rotation, and a painful arc of movement (pain between approximately 60–120 degrees of abduction as the torn tendon passes beneath the coracoacromial arch). Night pain — woken by rolling onto the affected shoulder — is a consistent and often dominant complaint. Functional limitations include difficulty reaching overhead, behind the back, or lifting objects away from the body. A positive Jobe (empty can) test, drop arm sign, or Hornblower's sign — depending on which tendon is involved — supports the clinical diagnosis. Infraspinatus and teres minor tears produce disproportionate external rotation weakness that may not correlate with pain severity.

Conservative Management

The majority of rotator cuff tears — including many full-thickness tears — respond well to structured conservative management. Evidence supports a minimum 12-week trial of rehabilitation before surgical consideration in most cases, with outcomes comparable to early surgery at one to two year follow-up for medium tears in patients without massive deficits. Rehabilitation progresses through: pain and inflammation management (activity modification, targeted manual therapy to the periscapular musculature, and subacromial corticosteroid injection if indicated); rotator cuff activation in non-provocative ranges (side-lying external rotation, internal rotation, prone Y and T exercises); scapular stabilisation (serratus anterior, lower trapezius); and progressive loading of the repaired or compensatory tissue through functional range. Dry needling and myofascial release to the hypertonic upper trapezius, levator scapulae, and pectoralis minor that develop secondary to pain-altered movement patterns significantly improves rehabilitation quality.

Surgical Repair and Rehabilitation

Arthroscopic rotator cuff repair is indicated for large and massive tears, acute traumatic tears in younger patients, and cases where conservative management has failed to achieve acceptable function. Repair involves re-anchoring the torn tendon edge to the humeral footprint using suture anchors. Post-operative rehabilitation follows a structured protocol: an initial protective phase (typically six weeks in a sling) allowing early passive range only; an intermediate phase gradually introducing active-assisted and then active movement; and a progressive loading phase building tendon strength and functional integration. Full recovery typically takes nine to twelve months. Compliance with the rehabilitation programme — not the surgery itself — largely determines the functional outcome.