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Floating Shoulder

Definition

  • scapular fracture combined with an upper humerus fracture or a clavicular injury
  • true floating shoulder does not occur unless, in addition to a clavicular shaft fracture:
    • scapular spine/acromial fracture
    • or disruption of the acromioclavicular (AC) & coracoacromial (CC) ligaments

Floating Shoulder

Anatomy

  • coracoacromial (CA) ligament
    • is an important stabilizer of glenoid neck fractures because it is the only direct ligamentous connection between proximal & distal

Superior Shoulder Suspensory Complex (SSSC)

  • bony/soft tissue ring composed of
    • glenoid
    • coracoid
    • acromion
    • distal clavicle
    • connecting ligaments
  • Maintains the stable relationship between the upper extremity & the axial skeleton
  • Isolated, single traumatic disruptions are common (e.g., grade II acromioclavicular separation) & do not significantly change the stability of the ring
  • Double disruption is failure of the ring in two or more places & results in delayed healing, ↓ strength, & other long-term problems
  • Single soft tissue disruption + clavicle fracture or the body/spine of scapula
    • may produce the same result as double disruption
  • Glenoid neck fracture + either an AC separation or a clavicle fracture
    • double disruption of the SSSC, creating a need for surgical restoration of stability

Superior Shoulder Suspensory Complex (SSSC)

Pathology

  • ipsilateral clavicular & scapular neck fractures:
    • weight of the arm & the muscle pull allow the glenoid to move anteromedially, leading to ptosis of the shoulder

Treatment

  • Such complex injury patterns could lead the clinician to consider stabilizing one or both fractures
  • For displaced fractures, operative intervention should be considered for
    • medial glenoid displacement of greater than 3.0 cm
    • clavicle displacement that meets indications for open reduction
    • multiple trauma with the need for upper extremity weight bearing as soon as possible
    • greater than 40° of abnormal glenoid version
  • Patients can do well with clavicular fixation alone

Complications

  • delayed union/nonunion
  • malunion
  • impingement
  • ↓ function (strength, mobility)
  • early degenerative changes
  • NV compromise

Prognosis

  • Herscovici, D., et al, JBJS-B, 1992
    • 9 Patients with ipsilateral midshaft clavicle/ scapular neck fracture ("floating shoulder")
    • 7 ORIF clavicle, 2 nonoperative
    • 4 year avg follow-up
    • 7 operative excellent
    • 2 nonoperative fair or poor with pain, deformity, ↓ ROM
    • all fractures united
  • Leung & Lam, JBJS-A, 1993
    • 15 patients with "floating shoulder"
    • all fractures treated with ORIF
    • 25 month avg. follow-up
    • 14/15 good or excellent (1 activity-related moderate pain
    • all fractures healed at 8 weeks avg
  • Ramos, L., et al, J Trauma, 1997
    • 13 patients with "floating shoulder"
    • managed nonoperatively
    • all fractures healed
    • 7.5 year avg. follow-up
    • 92% good or excellent
    • 3 patients had shoulder asymmetry