Rosen & Barkin's 5-Minute Emergency Medicine Consult (28 page)

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Authors: Jeffrey J. Schaider,Adam Z. Barkin,Roger M. Barkin,Philip Shayne,Richard E. Wolfe,Stephen R. Hayden,Peter Rosen

Tags: #Medical, #Emergency Medicine

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ACROMIOCLAVICULAR JOINT INJURY
Aleksandr M. Tichter
•
Wallace A. Carter
BASICS
DESCRIPTION
  • The acromioclavicular (AC) joint is formed by the articulation of the distal clavicle and the scapular acromion
  • It is stabilized by the AC ligament, coracoclavicular (CC) ligament, and attachments from deltoid and trapezius muscles
    • AC ligament is responsible for horizontal stability
    • CC ligament is responsible for vertical stability
  • Rockwood classification (sequential injury pattern):
    • Type I:
      • Sprained AC ligament (AC joint tender)
      • No CC ligament injury
      • No deltoid or trapezius injury
      • No radiographic abnormality (clinical diagnosis)
    • Type II:
      • Ruptured AC ligament (AC joint tender) (distal clavicle horizontally unstable)
      • Sprained CC ligament (CC ligament tender)
      • Minimal deltoid and trapezius injury
      • Radiographs show slight widening of AC joint (normal <5 mm)
      • Normal CC space (11–13 mm)
    • Type III:
      • Ruptured AC ligament (AC joint tender) (distal clavicle horizontally unstable)
      • Ruptured CC ligament (CC ligament tender) (distal clavicle vertically unstable)
      • Detached deltoid and trapezius
      • Radiographs show widening of AC joint.
      • Increased CC space, with distal clavicle above superior aspect of acromion (100% displaced)
    • Types IV, V, and VI:
      • Cause more significant pain than Types I, II, and III.
      • Best visualized on lateral/axillary radiographs
      • All require operative treatment.
      • Greater risk for prolonged disability
    • Type IV:
      • Identical ligamentous/muscular injury pattern to Type III
      • Clavicle is displaced
        posteriorly
        into trapezius muscle
      • Posteriorly displaced clavicle may be palpable on exam
      • May cause tenting of skin posteriorly
    • Type V:
      • Rare
      • Identical ligamentous/muscular injury pattern to Type III
      • Clavicle is displaced
        superiorly
        above the trapezius (100–300% increase in CC space)
      • Shoulder droops severely
      • Clavicle may be palpated subcutaneously
      • May cause tenting, ischemia, or disruption of skin
    • Type VI:
      • Usually associated with severe trauma
      • Identical ligamentous/muscular injury pattern to Type III
      • Clavicle is displaced
        inferiorly
        into subacromial or subcoracoid location.
      • Shoulder appears flattened
      • Associated neurovascular injury is common
ETIOLOGY
  • Injury most commonly seen in young, active males during contact sports
  • Most common mechanism is direct trauma to superior or lateral shoulder while arm is adducted, usually in the setting of a fall
    • acromion is displaced inferomedially
    • clavicle remains stabilized by sternoclavicular ligaments
  • May also occur indirectly via a fall on an outstretched hand or elbow, with transmission of force to the AC joint
DIAGNOSIS
SIGNS AND SYMPTOMS
History
  • Pain to anterior or superior aspect of the shoulder following trauma
  • Pain exacerbated by moving arm across the chest, behind the back, or overhead
  • Mechanism/force will dictate suspicion for and pattern of injury
  • Associated neurovascular symptoms
  • Cervical spine symptoms
Physical-Exam
  • Exam in standing or sitting position, as supine position negates force of gravity which can mask joint instability
  • Inspection: Ecchymosis, abrasion, swelling, symmetry, deformity of AC joint, skin tenting or laceration
    • prominence of clavicle with sagging of the acromion indicates rupture of AC joint (Rockwood Type II injury or greater)
  • Palpation: Sequential exam of sternoclavicular joint, length of clavicle, AC joint, CC ligament, coracoid process, scapular spine, and proximal humerus
    • tenderness over AC joint indicates AC ligament injury (Rockwood Type I injury or greater)
    • horizontal instability of distal clavicle indicates AC ligament rupture (Rockwood Type II injury or greater)
    • tenderness over CC ligament indicates CC ligament injury (Rockwood Type II injury or greater)
    • vertical instability of distal clavicle indicates CC ligament rupture (Rockwood Type III injury or greater)
  • Special tests
    • Cross-body adduction test:
      • Arm elevated to 90° with elbow flexed at 90°, and adducted across chest
      • Pain confirms AC injury by specifically compressing the joint
      • Sensitivity 77%, specificity 79%
    • O’Brien test
      • Arm elevated to 90° with elbow in extension, adduction of 10–15° and maximum forearm pronation
      • Examiner applies downward force against resistance
      • Pain over top of shoulder confirms AC injury
      • Sensitivity 16–93%, specificity 90–95%
  • Complete distal neurovascular exam, including brachial plexus
  • Careful cervical spine exam
ESSENTIAL WORKUP
  • History to seek mechanisms that commonly cause AC joint injury and associated force
  • Physical exam to evaluate for injury pattern, neurovascular compromise and exclude other causes of pain
  • Radiographic evaluation as outlined below
DIAGNOSIS TESTS & NTERPRETATION
Imaging
  • Specific AC joint radiograph
    • Recommended if AC injury suspected
    • Should include bilateral AC joints (for comparison)
    • Standard shoulder views will over penetrate AC joint and may obscure subtle injuries
    • Stress views no longer recommended
  • Zanca view (10–15° cephalic tilt) for limited initial views
  • Axillary view for Type III–VI injuries to determine position of distal clavicle
  • CT or MRI for further evaluation of surgical cases (Rockwood Types IV–VI)
    • Angiography may be used to evaluate associated neurovascular injuries
    • US if CT/MRI is not available
DIFFERENTIAL DIAGNOSIS
  • Shoulder dislocation
  • Fractures of acromion or clavicle
  • Rotator cuff injury
  • Tendinitis
  • Capsulitis
  • Cervical radiculopathy
  • Osteoarthritis
  • Osteomyelitis
Pediatric Considerations
  • Pediatric clavicle encased in periosteal tube:
    • CC ligament within tube
    • AC ligament external to tube (more vulnerable)
  • AC joint injury rarely occurs in isolation in the pediatric population
  • When injury does occur, it is more often Type I or II
  • Distal clavicular fractures through physis are more common than Type III AC joint dislocations
TREATMENT
PRE HOSPITAL
  • Ice packs
  • Sling immobilization
  • Cervical spine immobilization if indicated
INITIAL STABILIZATION/THERAPY
  • Ice packs
  • Sling immobilization
  • Cervical spine immobilization if indicated
  • Analgesia (NSAIDs, other analgesics)
ED TREATMENT/PROCEDURES
  • Types I and II:
    • Rest, ice, analgesics
    • Brief sling immobilization (typically 3–7 days)
    • Range of motion (ROM) and strengthening exercises as soon as can be tolerated
    • Resume normal activities once painless ROM and strength have returned (2–4 wk)
  • Type III:
    • Rest, ice, analgesics
    • Sling immobilization and early (within 72 hr) orthopedic referral
    • Treatment plan is controversial
    • Insufficient evidence exists to favor one management strategy over the other (conservative vs. surgical)
    • Which approach is chosen may depend on general health of patient, level of activity, occupation, hand dominance, and risk for reinjury
  • Types IV, V, and VI:
    • Rest, ice, analgesics
    • Sling immobilization and immediate orthopedic referral
    • Require early surgical intervention
  • Special circumstance: Potential future complication of AC joint injury is arthritis of the joint
Pediatric Considerations
  • Types I and II:
    • Conservative management (rest, ice, analgesics, sling)
    • Should heal without major sequelae
  • Type III:
    • Age <15 yr, conservative management
    • Age ≥15 yr may require more aggressive treatment.
  • Types IV, V, and VI:
    • Operative repair
MEDICATION
  • Ibuprofen: 600 mg (peds: 4–10 mg/kg) PO QID
  • Ketorolac: 30 mg (peds: 0.5 mg/kg up to 30 mg if >6 mo) IM/IV q6h (15 mg IM/IV q6h if >65 yr or <50 kg)
FOLLOW-UP

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