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British Medical Books Health Issues Computerized Tomography

Anatomy

  • joint between lateral end of clavicle & medial margin of acromion
  • hyaline cartilage initially -> fibrocartilage by age of 25 yrs
  • intra-articular disc -> meniscus
    • degeneration -> 40 yrs
  • nerve supply - axillary, suprascapular & lat. pectoral nn.

Stabilisers

  • dynamic stabilizers
    • deltoid & trapezius mm. -> cross the joint
  • AC ligaments
    • reinforce capsule (anterior, posterior, inferior, superior)
  • coraco-clavicular ligaments
    • very strong - strengthen AC joint
    • two components - conoid & trapezoid
    • distance between clavicle & coracoid ~ 1,5 cm
  • coraco-clavicular articulation
    • rare ~ 1%
    • X-ray bony outgrowth from the undersurface of clavicle
  • motion of AC joint ~ 5-8°

Mechanism Of Injury

  • direct force - pt. falling onto point of shoulder
    • force drives acromion downwards & medially
    • sprain AC lig.->tear AC lig.->sprain CC lig.->tear deltoid & trapezius
    • tear CC lig.->displacment of clavicle(superior, posterior,inferior)
  • indirect force - in line of humeral shaft
    • rare
    • tear AC ligaments, but CC ligaments intact

Classification (Rockwood)

  • Type I
    • sprain AC lig.
    • others intact
  • Type II
    • AC lig. torn, AC joint wider
    • CC sprain
  • Type III
    • AC lig. torn
    • CC lig. torn -> shoulder displaced inferiorly
    • CC distance 25-100% increased
    • deltoid & trapezius detached from distal clavicle
    • variants: physeal injury in kids coracoid process #
  • Type IV
    • as III
    • clavicle posteriorly displaced
  • Type V
    • as III
    • gross superior displacement of clavicle (2-300%)
  • Type VI
    • as III
    • clavicle inferiorly displaced
    • under coracoid process & biceps SH/ coracobrachialis tendons

Incidence

  • common injury (rugby & hockey players)
  • more in males
  • more often incomplete (type I-II)

Signs & Symptoms

  • Type I
    • moderate tenderness & swelling over ACJ
    • no palpable displacement
    • no tenderness at CC interspace
  • Type II
    • severe pain
    • outer end of clavicle slightly superior to acromion
  • Type III-IV-V
    • severe pain
    • complete disruption of AC joint with displaced clavicle (superior or posterior)
    • tenderness at CC interspace
    • palpate for clavicle #s
  • Type VI
    • clavicle displaced inferior
    • high energy->associated injuries (# ribs, clavicle, brachial plexus or vessels)

Imaging

Plain X-rays

  • AP view
    • both joints should be shown - compare
    • 10-15° cephalic tilt of beam gives clear view of ACJ
  • Lateral view (axillary)
    • small #s or posterior displacement of clavicle
  • Stress views (AP)
    • 5-7 kgs strapped to wrist
    • downward displacement of the shoulder & arm >>>
  • Ultrasound
    • visible joint disruption, ligament tears, haematoma

CT, MRI

Radiographic evaluation

  • Normal joint
    • ACJ width on AP 1-3mm
    • CC interspace 1,1-1,3mm
  • Type I
    • normal x-ray
    • soft tissue swelling
  • Type II
    • lateral end of clavicle elevated
    • AC widened
    • stress film normal - no CC ligament tear
  • Type III
    • ACJ totally displaced
    • CC interspace >>>
  • Type IV
    • clavicle posterior on axillary lateral view
  • Type V
    • clavicle superiorly displaced (2-3x interspace)
  • Type VI
    • clavicle inferior - subacromial or subcoracoid

Treatment

Type I (all ligaments intact)

  • always non-operative
  • ice pack, sling for 5-7 days
  • early mobilization
  • avoid lifting, contact sports for 2-3 weeks
  • Type II (AC lig. torn)
  • non-operative
    • sling for 1-2 weeks
    • gradual mobilization
    • avoid stress {lifting, sports) 6 weeks
  • Operative
    • if chr. pain develops 2nd to traumatic arthritis
    • excision of distal clavicle (2cm)
    • conoid lig. must remain intact to anchor clavicle down
    • return to activities after 8 weeks
  • Type III (AC & CC lig. torn)
    • controversial - good results with both Rx
    • non-operative
      • “skillful neglect”
      • in inactive, non-laboring pts. or athletes with contact sports
      • icepack, analgesics, sling for 2 weeks
      • early mobilization when pain <
  • operative
    • heavy laborers, daily stress on shoulder etc.
    • ACJ exposed, debrided -> AC & CC lig. approximated, repaired -> extra-articular screw fixation to hold clavicle in position -> deltoid & trapezius repaired
    • other methods:
      • primary ACJ fixation with pins, screws, wires with or without lig. repair
      • primary CC ligament fixation with screw, wire fascia with ? AC lig.repair
      • excision of distal clavicle
  • always repair CC lig.
  • sub-periosteally < 3 cm excised
  • dynamic muscle transfer - coracoid process with short head of biceps to clavicle
  • Type IV-V-VI
    • usually surgical
    • can try closed reduction

Chronic ACJ problems

  • try non-operative Rx first
    • physio, exercise etc.
  • Type II - traumatic arthritis -> excision of distal clavicle
  • Type III-VI -> CC lig. reconstruction with coracoacromial lig & lag screw

Prognosis

  • Type I-II - good with non-operative Rx
  • Type III-VI - good results with both methods

Complications

  • Associated
    • clavicle, coracoid process, sterno-clavicular joint
  • Coraco-clavicular ossification
    • with both non & operative Rx
    • bony bridge from clavicle to coracoid
    • no functional deficit
  • Osteolysis of distal clavicle
    • if repeated stress on ACJ after injury -> osteoporosis, lysis, tapering
    • if bilateral -> RA, hyperparathyroidism, scleroderma
    • DD: gout, myeloma
    • Rx: excision of distal clavicle
  • Non union of coracoid process
    • rare
    • ORIF & BG
  • Complications of surgery
    • wound infection
    • AC arthritis
    • pin migration -> always bend
    • recurrent deformity