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Acromioclavicular Joint Injury, Emergency Medicine

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Acromioclavicular Joint Injury, Emergency Medicine

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 musclesAC ligament is responsible for horizontal stabilityCC ligament is responsible for vertical stability
  • Rockwood classification (sequential injury pattern):Type I:Sprained AC ligament (AC joint tender)No CC ligament injuryNo deltoid or trapezius injuryNo 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 injuryRadiographs 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 trapeziusRadiographs 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 radiographsAll require operative treatment.Greater risk for prolonged disabilityType IV:Identical ligamentous/muscular injury pattern to Type IIIClavicle is displaced posteriorly into trapezius musclePosteriorly displaced clavicle may be palpable on examMay cause tenting of skin posteriorlyType V:RareIdentical ligamentous/muscular injury pattern to Type IIIClavicle is displaced superiorly above the trapezius (100-300% increase in CC space)Shoulder droops severelyClavicle may be palpated subcutaneouslyMay cause tenting, ischemia, or disruption of skinType VI:Usually associated with severe traumaIdentical ligamentous/muscular injury pattern to Type IIIClavicle is displaced inferiorly into subacromial or subcoracoid location.Shoulder appears flattenedAssociated neurovascular injury is common
  • AC ligament is responsible for horizontal stability
  • CC ligament is responsible for vertical stability
  • Type I:Sprained AC ligament (AC joint tender)No CC ligament injuryNo deltoid or trapezius injuryNo 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 injuryRadiographs 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 trapeziusRadiographs 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 radiographsAll require operative treatment.Greater risk for prolonged disability
  • Type IV:Identical ligamentous/muscular injury pattern to Type IIIClavicle is displaced posteriorly into trapezius musclePosteriorly displaced clavicle may be palpable on examMay cause tenting of skin posteriorly
  • Type V:RareIdentical ligamentous/muscular injury pattern to Type IIIClavicle is displaced superiorly above the trapezius (100-300% increase in CC space)Shoulder droops severelyClavicle may be palpated subcutaneouslyMay cause tenting, ischemia, or disruption of skin
  • Type VI:Usually associated with severe traumaIdentical ligamentous/muscular injury pattern to Type IIIClavicle is displaced inferiorly into subacromial or subcoracoid location.Shoulder appears flattenedAssociated neurovascular injury is common
  • Sprained AC ligament (AC joint tender)
  • No CC ligament injury
  • No deltoid or trapezius injury
  • No radiographic abnormality (clinical diagnosis)
  • 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)
  • 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)
  • 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
  • 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
  • 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
  • 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 fallacromion is displaced inferomediallyclavicle 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
  • acromion is displaced inferomedially
  • clavicle remains stabilized by sternoclavicular ligaments

Diagnosis

Signs and Symptoms

  • 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
  • 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 lacerationprominence 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 humerustenderness 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 testsCross-body adduction test:Arm elevated to 90 ° with elbow flexed at 90 °, and adducted across chestPain confirms AC injury by specifically compressing the jointSensitivity 77%, specificity 79%O'Brien testArm elevated to 90 ° with elbow in extension, adduction of 10-15 ° and maximum forearm pronationExaminer applies downward force against resistancePain over top of shoulder confirms AC injurySensitivity 16-93%, specificity 90-95%
  • Complete distal neurovascular exam, including brachial plexus
  • Careful cervical spine exam
  • prominence of clavicle with sagging of the acromion indicates rupture of AC joint (Rockwood Type II injury or greater)
  • 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)
  • Cross-body adduction test:Arm elevated to 90 ° with elbow flexed at 90 °, and adducted across chestPain confirms AC injury by specifically compressing the jointSensitivity 77%, specificity 79%
  • O'Brien testArm elevated to 90 ° with elbow in extension, adduction of 10-15 ° and maximum forearm pronationExaminer applies downward force against resistancePain over top of shoulder confirms AC injurySensitivity 16-93%, specificity 90-95%
  • 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%
  • 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%

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 & Interpretation

  • Specific AC joint radiographRecommended if AC injury suspectedShould include bilateral AC joints (for comparison)Standard shoulder views will over penetrate AC joint and may obscure subtle injuriesStress 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 injuriesUS if CT/MRI is not available
  • 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
  • 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 clavicle encased in periosteal tube:CC ligament within tubeAC 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
  • CC ligament within tube
  • AC ligament external to tube (more vulnerable)

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, analgesicsBrief sling immobilization (typically 3-7 days)Range of motion (ROM) and strengthening exercises as soon as can be toleratedResume normal activities once painless ROM and strength have returned (2-4 wk)
  • Type III:Rest, ice, analgesicsSling immobilization and early (within 72 hr) orthopedic referralTreatment plan is controversialInsufficient 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, analgesicsSling immobilization and immediate orthopedic referralRequire early surgical intervention
  • Special circumstance: Potential future complication of AC joint injury is arthritis of the joint
  • 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)
  • 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
  • Rest, ice, analgesics
  • Sling immobilization and immediate orthopedic referral
  • Require early surgical intervention
  • Types I and II:Conservative management (rest, ice, analgesics, sling)Should heal without major sequelae
  • Type III:Age <15 yr, conservative managementAge ≥15 yr may require more aggressive treatment.
  • Types IV, V, and VI:Operative repair
  • Conservative management (rest, ice, analgesics, sling)
  • Should heal without major sequelae
  • Age <15 yr, conservative management
  • Age ≥15 yr may require more aggressive treatment.
  • 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

Disposition

  • Open injury
  • Types IV, V, and VI require admission for operative repair
  • Types I and II can be discharged with orthopedic referral
  • Type III should have urgent orthopedic referral

Follow-Up Recommendations

  • Type I and II: Orthopedic follow-up within 2-4 wk
  • Type III: Early (within 72 hr) orthopedic follow-up
  • Type IV-VI: Immediate orthopedic referral
  • All pediatric injuries should have prompt orthopedic follow-up, with Type IV-VI injuries requiring immediate referral

Pearls and Pitfalls

  • Type I and II AC injuries:No increase in CC spaceConservative management with rest, ice, sling, and ROM/strength exercises
  • Type III injuries:100% superior displacement of distal clavicleManagement somewhat controversialRequire early orthopedic follow-up
  • Type IV-VI injuries:Identical ligamentous and muscular injuries to Type IIIDifference according to position of distal clavicleOperative management is standard of care
  • No increase in CC space
  • Conservative management with rest, ice, sling, and ROM/strength exercises
  • 100% superior displacement of distal clavicle
  • Management somewhat controversial
  • Require early orthopedic follow-up
  • Identical ligamentous and muscular injuries to Type III
  • Difference according to position of distal clavicle
  • Operative management is standard of care

Additional Reading

  • Bossart PJ, Joyce SM, Manaster BJ, et al. Lack of efficacy of weighted radiographs in diagnosing acute acromioclavicular separation. Ann Emerg Med. 1988;17:47-51.
  • Bussieres AE, Peterson C, Taylor JA. Diagnostic imaging guideline for musculoskeletal complaints in adults - an evidence-based approach-part 2: upper extremity disorders. J Manipulative Physiol Ther. 2008;31(1):2-32.
  • Hegedus EJ, Goode A, Campbell S, et al. Physical examination tests of the shoulder: a systematic review with meta-analysis of individual tests. Br J Sports Med. 2008;42:80-92.
  • Mazzocca AD, Arciero RA, Bicos J. Evaluation and treatment of acromioclavicular joint injuries. Am J Sports Med. 2007;35(2):316-329.
  • Simovitch R, Sanders B, Ozbaydar M, et al. Acromioclavicular joint injuries: Diagnosis and Management. J Am Acad Ortho Surg. 2009;17:207-219.
  • Tamaoki MJS, Belloti JC, Lenza M, et al. Surgical versus conservative interventions for treating acromioclavicular dislocation of the shoulder in adults. Cochrane Database of Sys Rev. 2010;(8):CD007429.

See Also (Topic, Algorithm, Electronic Media Element)

  • Clavicle Fracture
  • Shoulder Dislocation
  • Sternoclavicular Joint Injury

Codes

ICD9

  • 831.04 Closed dislocation of acromioclavicular (joint)
  • 840.0 Acromioclavicular (joint) (ligament) sprain
  • 840.8 Sprains and strains of other specified sites of shoulder and upper arm
  • 831.09 Closed dislocation of shoulder, other
  • 831.14 Open dislocation of acromioclavicular (joint)
  • 831.19 Open dislocation of shoulder, other

ICD10

  • S43.50XA Sprain of unspecified acromioclavicular joint, initial encounter
  • S43.80XA Sprain of other specified parts of unspecified shoulder girdle, initial encounter
  • S43.109A Unsp dislocation of unsp acromioclavicular joint, init
  • S43.119A Subluxation of unsp acromioclavicular joint, init encntr
  • S43.129A Disloc of unsp acromioclav jt, 100%-200% displacmnt, init
  • S43.139A Dislocation of unsp acromioclav jt, > 200% displacmnt, init
  • S43.149A Inferior dislocation of unsp acromioclavicular joint, init
  • S43.159A Posterior dislocation of unsp acromioclavicular joint, init

SNOMED

  • 27182002 sprain of acromioclavicular ligament (disorder)
  • 209412004 Sprain, coracoclavicular ligament (disorder)
  • 209576007 Rupture of acromioclavicular ligament (disorder)
  • 269142003 Rupture of coracoacromial ligament (disorder)
  • 263019000 Dislocation of acromioclavicular joint (disorder)