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 & Interpretation
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 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
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
Admission Criteria
Open injury
Types IV, V, and VI require admission for operative repair
Discharge Criteria
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 space
Conservative management with rest, ice, sling, and ROM/strength exercises
Type III injuries:
100% superior displacement of distal clavicle
Management somewhat controversial
Require early orthopedic follow-up
Type IV-VI injuries:
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)