Scapula Fractures

Embryology

  • Scapula has 8 ossification centres which appear in the 8th week gestation:
    • Acromion x3
    • Coracoid x2
    • Body x1
    • Vertebral border x1
    • Inferior angle x1

At Birth:

  • Only the blade, body, and spine are ossified at birth.

Failure of fusion results in:

  • Os Acromium
  • Mistaking coracoid for a fracture

Incidence

  • 50% involve scapula body
  • 25% involve neck (10% displaced)
  • 10% involve Glenoid (10% displaced)

Mechanism

  • Scapula is covered in muscle and splinted by the thoracic cage.
  • Fractures tend to be high energy.
  • Fall onto the hand causes scapula spine, glenoid & intra-articular fractures.
  • Direct high energy trauma causes scapula body fractures.
  • Associated with other injuries in 80%:
    • Rib
    • Clavicle
    • Lung contusion
    • Spine (75% Thoracic spine)

Classification

  • Anatomic location:
    • Body
    • Spine
    • Neck
    • Glenoid
    • Coracoid
    • Acromium

Glenoid Fractures (Ideberg – modified by Goss)

Type | Description

  • 1A: Anterior rim
  • 1B: Posterior rim
  • 2: Transverse fracture exiting inferiorly
  • 3: Transverse fracture exiting medial to coracoid
  • 4: Transverse exiting at medial border scapula
  • 5: Combination of 2 and 4
  • 6: Comminuted glenoid

Diagnosis

  • XR:
    • Axillary, AP, Scapula Y, and Stryker notch views (Coracoid)
  • Fine cut CT
  • CXR

Management

  • ABC
  • Rule out and treat other injuries
  • Support chest injuries
  • Check for spinal injury
  • Compartment syndrome:
    • Rare but can occur
    • Comolli sign – haematoma over scapula (triangle-shaped)

Non-Operative Treatment

  • Most can be treated with a broad arm sling
  • Early mobilization of shoulder

Operative Indications

  • Glenoid:
    • Displaced glenoid rim fracture >25% size
    • Incongruent/unstable shoulder joint
    • Articular incongruity >5mm
  • Neck:
    • Medial displacement >1cm
      • Leads to premature OA due to increased contact stresses
      • Main indicator of a poor outcome with extra-articular fractures
    • Angulation >40 degrees
    • Floating Shoulder:
      • Stabilized by fixing clavicle only if scapula parameters are ok

Floating Shoulder

  • Middle 3rd clavicle and scapula neck is the usual pattern
  • Any double disruption of the Superior Shoulder Suspensory Complex

Surgical Tactics

  • Anterior rim fractures:
    • Extensive DP approach
  • Posterior glenoid or neck/spine fractures:
    • Extended Judet approach
    • In-plane between Infraspinatus and Teres minor (SSn & Axillary)
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