10.3 Shoulder Instability, Labral Lesions (SLAP/Bankart) & Rotator Cuff Disorders
Key Takeaways
- Anterior glenohumeral dislocation accounts for >95% of traumatic shoulder dislocations and frequently produces a Bankart lesion (avulsion of the anterior-inferior glenoid labrum/IGHL complex) and a reciprocal Hill-Sachs lesion (posterolateral humeral head impaction chondral fracture).
- Superior Labrum Anterior to Posterior (SLAP) tears involve the biceps tendon anchor origin; diagnostic evaluation utilizes the O'Brien active compression test, Speed's test, and Yergason's test.
- Rotator cuff tears most commonly involve the supraspinatus tendon within its hypovascular 'critical zone' 1 cm medial to the greater tuberosity; physical assessment relies on Jobe/Empty Can test, Drop Arm test (massive tears), external rotation lag sign (infraspinatus), and Belly-Press/Lift-Off tests (subscapularis).
- Postoperative rotator cuff repair nursing protocols require strict abduction pillow sling wear (supporting the arm in 15°–30° abduction to offload footprint tension) and absolute prohibition of active shoulder motion for 4–6 weeks, permitting only strictly prescribed passive range of motion.
Shoulder Instability, Labral Lesions (SLAP/Bankart) & Rotator Cuff Disorders
Core Clinical Principle: The glenohumeral joint achieves unmatched multi-axial mobility by sacrificing intrinsic osseous constraint, relying on static labral-capsular restraints and dynamic rotator cuff force couples. Traumatic anterior dislocation compromises the anterior-inferior labrum and posterolateral humeral head, while repetitive overhead microtrauma damages the superior labral-biceps anchor and rotator cuff tendons. Post-surgical nursing mandates strict immobilizer compliance to shield repaired soft-tissue footprints during biological tendon-to-bone integration.
The shoulder complex possesses the greatest range of motion of any diarthrodial joint in the human body. Because the shallow glenoid fossa articulates with less than one-third of the spherical humeral head (analogous to a golf ball sitting on a golf tee), stability depends heavily on static capsulolabral structures and dynamic muscular balance.
1. Stabilizing Architecture of the Glenohumeral Joint
GLENOHUMERAL STABILIZING RESTRAINTS
┌─────────────────────┬────────────────────────────────────────────────────────┐
│ Category │ Anatomical Components & Mechanical Function │
├─────────────────────┼────────────────────────────────────────────────────────┤
│ 1. Static Restraints│ • Glenoid Labrum: Fibrocartilaginous collar deepening │
│ │ the glenoid socket depth by 50%. │
│ │ • Inferior Glenohumeral Ligament Complex (IGHLC): │
│ │ Anterior band is primary restraint to anterior │
│ │ translation at 90° abduction & external rotation. │
│ │ • Joint Capsule & Negative Intra-articular Pressure. │
├─────────────────────┼────────────────────────────────────────────────────────┤
│ 2. Dynamic │ • Rotator Cuff (SITS: Supraspinatus, Infraspinatus, │
│ Restraints │ Teres Minor, Subscapularis): Dynamic concavity- │
│ │ compression centering the humeral head in glenoid. │
│ │ • Long Head of Biceps Tendon (LHBT): Depresses head. │
│ │ • Periscapular Musculature: Serratus anterior, trapezius│
└─────────────────────┴────────────────────────────────────────────────────────┘
2. Traumatic Anterior Instability: Bankart & Hill-Sachs Lesions
Anterior shoulder dislocations account for 95% to 97% of all traumatic glenohumeral dislocations, occurring when the arm is forced into abduction, external rotation, and extension (e.g., an athlete making a tackle or blocking an overhead pass).
ANTERIOR INSTABILITY STRUCTURAL LESION DYNAMICS
[ANTERIOR-INFERIOR LABRUM] [POSTEROLATERAL HUMERAL HEAD]
│ │
▼ ▼
BANKART LESION HILL-SACHS LESION
┌──────────────────────────────────┐ ┌──────────────────────────────────┐
│ Avulsion of the anterior-inferior│ │ Impaction chondral / osseous │
│ labrum from the glenoid rim with │ Reciprocal │ compression fracture on the post-│
│ disruption of the anterior band │ <─────────> │ erolateral humeral head as it │
│ of the IGHL. Bony Bankart = rim │ Trauma │ strikes the hard anterior glenoid│
│ fracture (>20% loss = Latarjet). │ │ rim during dislocation. │
└──────────────────────────────────┘ └──────────────────────────────────┘
Critical Clinical Assessment: Axillary Nerve Surveillance
The axillary nerve (C5–C6) exits the posterior cord of the brachial plexus, traverses the quadrangular space inferior to the humeral head, and wraps around the surgical neck of the humerus. During anterior-inferior humeral head dislocation, the axillary nerve is stretched directly over the displaced bone.
- Mandatory Pre- and Post-Reduction Nursing Assessment:
- Assess cutaneous sensation over the lateral aspect of the proximal arm / deltoid muscle (the 'sergeant's patch' or regimental badge area).
- Palpate for isometric contraction of the anterior and lateral deltoid heads (avoid active abduction until reduction is radiographically verified).
3. Superior Labrum Anterior to Posterior (SLAP) Lesions
SLAP tears involve disruption of the superior fibrocartilaginous labrum originating at the anchor site of the Long Head of the Biceps Tendon (LHBT) and extending anteriorly and posteriorly.
SNYDER SLAP TEAR CLASSIFICATION
┌───────────────┬──────────────────────────────────┬─────────────────────────────┐
│ Classification│ Anatomical Pathology │ Treatment Approach │
├───────────────┼──────────────────────────────────┼─────────────────────────────┤
│ Type I │ Fraying/degeneration of superior │ Arthroscopic debridement; │
│ │ labrum; intact biceps anchor. │ LHBT anchor remains stable. │
├───────────────┼──────────────────────────────────┼─────────────────────────────┤
│ Type II │ Pathologic detachment of superior│ Suture anchor repair back │
│ (Most Common) │ labrum AND biceps anchor from rim│ to superior glenoid bone. │
├───────────────┼──────────────────────────────────┼─────────────────────────────┤
│ Type III │ Bucket-handle tear of superior │ Resection of bucket fragment│
│ │ labrum; biceps anchor intact. │ if biceps anchor stable. │
├───────────────┼──────────────────────────────────┼─────────────────────────────┤
│ Type IV │ Bucket-handle tear extending │ Repair/tenodesis of biceps │
│ │ directly into biceps tendon. │ tendon + labral repair. │
└───────────────┴──────────────────────────────────┴─────────────────────────────┘
- Mechanism of Injury: Repetitive overhead throwing creates extreme torsional traction on the posterosuperior labrum ('peel-back' mechanism during late cocking phase) or acute compression from a fall onto an outstretched hand (FOOSH) with the shoulder flexed and abducted.
- Clinical Presentation: Deep, vague, ill-localized shoulder pain exacerbated by overhead activity, clicking/popping, and loss of throwing velocity ('dead arm syndrome').
4. Rotator Cuff Pathology: Tendinopathy, Impingement & Tears
ROTATOR CUFF MUSCLE PROFILES
┌───────────────┬──────────────┬──────────────────┬──────────────────────────────┐
│ Muscle │ Innervation │ Primary Action │ High-Yield Physical Test │
├───────────────┼──────────────┼──────────────────┼──────────────────────────────┤
│ Supraspinatus │ Suprascapular│ Initiates first │ Jobe / Empty Can Test; │
│ (Most torn) │ nerve (C5-C6)│ 15° abduction; │ Drop Arm Test (massive tear) │
│ │ │ head depressor │ │
├───────────────┼──────────────┼──────────────────┼──────────────────────────────┤
│ Infraspinatus │ Suprascapular│ External rotation│ External Rotation Lag Sign; │
│ │ nerve (C5-C6)│ at side (0° abd) │ Resisted ER at 0° abduction │
├───────────────┼──────────────┼──────────────────┼──────────────────────────────┤
│ Teres Minor │ Axillary │ External rotation│ Hornblower's Sign / Patte's │
│ │ nerve (C5-C6)│ at 90° abduction │ test (ER at 90° abduction) │
├───────────────┼──────────────┼──────────────────┼──────────────────────────────┤
│ Subscapularis │ Upper/Lower │ Internal rotation│ Lift-Off Test (Gerber); │
│ │ Subscapular │ & dynamic ant. │ Belly-Press (Napoleon) Test; │
│ │ (C5-C6) │ stabilizer │ Bear-Hug Test │
└───────────────┴──────────────┴──────────────────┴──────────────────────────────┘
The 'Critical Zone' of Codman
The supraspinatus tendon inserts onto the superior facet of the greater tuberosity. Approximately 1 cm proximal to this insertion lies an anatomical hypovascular watershed zone (Codman's critical zone). Repetitive mechanical compression under the rigid coracoacromial arch during overhead abduction combined with intrinsic hypoperfusion makes this zone the primary site for degenerative tendinopathy and full-thickness tears.
5. Provocative Physical Examination Tests Matrix
SPECIAL TESTS FOR SHOULDER PATHOLOGY
┌─────────────────────┬────────────────────────────────────────────────────────┐
│ Diagnostic Test │ Technique, Execution & Positive Diagnostic Meaning │
├─────────────────────┼────────────────────────────────────────────────────────┤
│ 1. Anterior │ Arm abducted to 90° and fully externally rotated. │
│ Apprehension Test │ POSITIVE: Patient exhibits facial fear/resistance │
│ │ due to sensation of impending anterior dislocation. │
├─────────────────────┼────────────────────────────────────────────────────────┤
│ 2. Jobe Relocation │ Examiner applies posterior force to anterior humeral │
│ Test │ head during apprehension test. POSITIVE: Immediate │
│ │ reduction of apprehension and pain. │
├─────────────────────┼────────────────────────────────────────────────────────┤
│ 3. Surprise / │ Examiner abruptly releases posterior relocation force. │
│ Release Test │ POSITIVE: Sudden acute recurrence of apprehension. │
├─────────────────────┼────────────────────────────────────────────────────────┤
│ 4. O'Brien Active │ Arm flexed 90°, adducted 10°. Downward force resisted: │
│ Compression (SLAP) │ • Part 1 (Thumb down/pronated): Deep pain elicited. │
│ │ • Part 2 (Thumb up/supinated): Pain relieved/diminished│
├─────────────────────┼────────────────────────────────────────────────────────┤
│ 5. Speed's & │ • Speed: Resisted forward flexion with elbow extended &│
│ Yergason's Tests │ forearm supinated. Pain in bicipital groove = LHBT. │
│ │ • Yergason: Resisted supination/ER with elbow at 90°. │
├─────────────────────┼────────────────────────────────────────────────────────┤
│ 6. Neer & Hawkins- │ • Neer: Passive full forward flexion with scapula locked│
│ Kennedy Impingement │ • Hawkins: Passive 90° flexion with forced int. rot. │
│ │ POSITIVE: Subacromial impingement pain. │
├─────────────────────┼────────────────────────────────────────────────────────┤
│ 7. Drop Arm Test │ Arm passively abducted to 90° and released; patient is │
│ │ asked to lower it slowly. POSITIVE: Arm drops suddenly │
│ │ from 90° (indicates massive full-thickness tear). │
├─────────────────────┼────────────────────────────────────────────────────────┤
│ 8. Gerber Lift-Off │ Dorsum of hand placed on lumbar spine; patient attempts│
│ & Belly-Press │ to lift hand off back. Inability = Subscapularis tear. │
└─────────────────────┴────────────────────────────────────────────────────────┘
6. Postoperative Nursing Care: Rotator Cuff & Labral Repairs
┌────────────────────────────────────────────────────────────────────────────┐
│ ROTATOR CUFF REPAIR POSTOPERATIVE PROTOCOL │
├────────────────────────────────────────────────────────────────────────────┤
│ 1. ABDUCTION PILLOW SLING IMMOBILIZATION (WEEKS 0 – 6) │
│ • Sling with contoured foam abduction pillow maintains 15°–30° abduction. │
│ • Offloads tension across repaired tendon-to-bone footprint at tuberosity. │
│ • Must be worn CONTINUOUSLY (including during sleep); removed ONLY for │
│ pendulum exercises, elbow/wrist active motion, and supervised hygiene. │
├────────────────────────────────────────────────────────────────────────────┤
│ 2. STRICT PROHIBITION OF ACTIVE MOTION (WEEKS 0 – 6) │
│ • NO ACTIVE OR ACTIVE-ASSISTED SHOULDER MOTION PERMITTED. │
│ • Active deltoid/rotator cuff contraction creates tensile distraction that │
│ pulls suture anchors out of soft cancellous bone before scar integration.│
│ • Only surgeon-prescribed PASSIVE Range of Motion (PROM) allowed. │
├────────────────────────────────────────────────────────────────────────────┤
│ 3. PHASED REHABILITATION PROGRESSION │
│ • Phase 1 (Weeks 0–6): PROM only; pendulum/Codman exercises; hand/elbow AROM│
│ • Phase 2 (Weeks 6–12): Wean sling; initiate Active-Assisted (AAROM) and │
│ gentle Active (AROM); scapular stabilizing drills. │
│ • Phase 3 (Weeks 12+): Progressive isotonic resistive strengthening. │
│ • Phase 4 (Months 6–9+): Return to full unrestricted overhead sports. │
└────────────────────────────────────────────────────────────────────────────┘
Clinical Alert: Cryotherapy & Neurovascular Monitoring
Postoperative shoulder patients frequently receive continuous interscalene brachial plexus nerve blocks. The nurse must instruct the patient to protect the insensate limb from thermal injury (never apply ice packs directly to bare skin without a cloth barrier) and monitor for systemic local anesthetic toxicity (LAST) and transient Horner's syndrome (ptosis, miosis, anhidrosis) or phrenic nerve blockade causing mild dyspnea.
A 21-year-old college wide receiver suffers an acute anterior shoulder dislocation during a tackle. Following closed reduction, the orthopaedic nurse performs a neurovascular examination. Which assessment finding is most indicative of an injury to the axillary nerve?
A baseball pitcher presents with deep shoulder pain and clicking during the late cocking phase of throwing. The examiner places the patient's arm in 90 degrees of forward flexion and 10 degrees of adduction, with the thumb pointed down in internal rotation. Downward resistance elicits deep shoulder pain. When the arm is fully supinated (thumb pointed up), the pain is completely relieved. What is the name of this test, and what pathology does it indicate?
An orthopaedic nurse evaluates a 58-year-old painter with chronic shoulder pain. The nurse passively abducts the patient's arm to 90 degrees and asks the patient to slowly lower the arm to the side. The arm suddenly drops uncontrollably to the patient's hip accompanied by sharp pain. Which rotator cuff tendon is severely compromised?
A patient is being discharged following an arthroscopic repair of a full-thickness supraspinatus tendon tear. The orthopaedic nurse provides education regarding sling wear and mobility. Which directive is critical for the patient to follow during the first 6 weeks postoperatively?