Acromioclavicular Joint Dislocation

Incidence

• peak in 3rd decade
• Review 520 cases

Type	Number
I	185
II	119
III	204
IV	4
V	7
VI	1

Anatomy

• has fibrocartilage intraarticular disc
• Usually degenerative by 4th decade
• Clavicle may lie superior normally

Stability of ACJ

• Coracoacromial ligs
  • Primary restraint to sup translation
  • Primary suspensory ligament of upper limb
  • Trapezoid Ligament
    • Arises anterolateral on coracoid
    • Inserts trapezoid ridge anterolateral to conoid
    • Almost horizontal in sagittal plane
    • PRIMARY restraint to AXIAL compression
  • Conoid Ligament
    • Arises posteromedial to trapezoid
    • Inverted cone
    • Inserts conoid tubercle
    • Lies vertically
    • PRIMARY restraint to SUPERIOR & ANTERIOR translation
• ACJ Capsule
  • Strongest superiorly
  • As reinforced by acromioclavicular ligament
  • Has incomplete fibrocartilage intra-articular disc arising from it
  • Usually degenerates by 4th decade
• Deltotrapezial Fascia
  • Dynamic stabiliser

Motion at ACJ

• Only small 58 degrees
• 40 degrees at sternocla jt
• Motion is at scapulothoracic rather than ACJ

Classification

• Allman grades I-III 1967Rockwood modified 1989Classification of Acromioclavicular Joint DislocationTypeDescriptionLigament InjuryIACJ SprainIncomplete AC ligament injuryIIACJ Disrupted & CCL Intact/sprainedComplete AC, Incomplete CCIIIRupture ACJ & CCL
  (25-100% subluxation)Complete AC, Complete CCIVInto trapeziusComplete AC, Complete CCVHigh dislocation > 1 x Clavicle Width
  • Disrupted Trapezius & Deltoid
  • End of clavicle subcutaneous
  (100-300% subluxation)Complete AC, Complete CCVISubcoracoid DislocationComplete AC, Complete CC

Aetiology

• Direct trauma
  • Usually direct fall onto adducted shoulder
    • Clavicle remains in Normal position
    • Arm falls down
    • magnitude of force determines injury severity
• Indirect trauma
  • fall on flexed elbow or outstretched arm

Pathology

History

• History of Traumatic Event
• Age of patient
  • ? physeal injury
• Previous treatment
  • nonoperative
    • at least 3 months before considering surgey
  • previous surgical procedures
• Symptoms
  • Pain
    • with forward elevation
  • Instability
  • Posterior headache (nuchae)
• Associated injuries
  • distal clavicular fracture
• Functional diasabilities

Examination

• Look
• Feel
  • tenderness
• Move
  • ROM
    • inability to lift arm
      • pain with forward elevation and wing out
  • Strength
• Special Tests
  • Stability
    • AP translation
    • Superior – inferior translation
  • Shoulder shrug
    • reduction of the distal clavicle with shoulder shrug differentiates between Type III from type V (distal clavicle buttonhole through deltotrapezial fascia)

Investigations

Xrays

Normal AC Joints

• 51% overiding clavicle
• 2% underiding
• 29% incongruent
• joint width 0.5-7 mm

Technique

• Zanca Views
  • AP shoulder with 10° cephalad tilt
• 1/3 Penetration of shoulder x-ray
• Axillary, outlet adn AP views of shoulder in scapular plane
• Cross arm adduction view
  • AP shoulder
  • measure clavicel override
• Stress views occasionally used (10lb weight)

MRI

• labral injury masquerading as ACJ pain

CT Scan

• nondisplaced lateral clavicel or acromion fracture

Differential Diagnosis

• Cervical spine disease: trapezial spasm
• Thoracic outlet syndrome
• Scapular dyskinesis
• Hyperlaxity
• Coracoid fracture

Treatment

Type I

• Nonoperative
  • RICE
  • Broad arm sling
• Avoid heavy stress & contact sport till Free Range of Movement & no pain to palpation

Type II

• Nonoperative
  • RICE
  • Broad Arm Sling 2/52
• Avoid heavy lifting, contact sports 810/52 to allow ligament healing

Type III

• Controversial
  • Only 2 RCT OT vs NonOp
    • Pt outcome 88% satisfaction Op or NonOp
    • Further surgery 59% vs 6%
    • Deformity 3% vs 37%
    • ROM 86% vs 95%
• no indication for Operative reconstruction in literature to date
• Perhaps consider repair in
  • Heavy labourer
  • <25 yr undecided on career

Type IV, V, VI

• Operative
  • Open Reduction and Internal Fixation

Chronic Symptomatic Grade III

• Poor results excision distal clavicle
• Convert long high riding clavicle to short high riding clavicle
• Must reconstruct lig as well

Specific Procedures

• Weaver Dunn Reconstruction

Complications

• Joint stiffness
• Deformity
• CC ligament and soft tissue calcification
• AC OA
• Associated fractures
• Distal clavicle osteolysis

Prognosis

• Weaver Dunn Reconstruction

Complications

• Joint stiffness
• Deformity
• CC ligament and soft tissue calcification
• AC OA
• Associated fractures
• Distal clavicle osteolysis

Prognosis