Floating Shoulder

Introduction

• A floating shoulder refers to a double disruption of the superior shoulder suspensory complex (SSSC):
  • Typically includes a fracture of the scapular neck/body
  • And a clavicle fracture, or sometimes acromioclavicular (AC) joint dislocation

Brief history

• 1993 – Dr. Thomas P. Goss introduced the concept that the SSSC functions as a ring, and that two or more breaks in the ring (e.g., clavicle fracture + scapular neck fracture) can lead to an unstable shoulder girdle.
• He termed this injury pattern a “floating shoulder.”

 

Superior Shoulder Suspensory Complex (SSSC)

• SSSC is a ring-like structure
• made up of bones and soft tissue
• Between 2 struts- middle 3^rd clavicle ( superior) and Lateral scapular body and Spine (superior)
• provides suspension and stability to the upper extremity.
• connects the upper limb to the axial skeleton via the clavicle and scapula

 

• Coracoclavicular ligaments (conoid, trapezoid)
• Glenoid fossa
• Coracoid process
• Distal clavicle
• Acromioclavicular joint
• Acromion process

 

Biomechanical Function

• Maintains normal spatial alignment of the scapula, clavicle, and humerus.
• Supports load transmission from the arm to the axial skeleton.
• Provides a stable base for shoulder motion and muscle attachment.
• Protects neurovascular structures (brachial plexus, subclavian vessels).

 

Double Disruption = Instability

• A single break in the SSSC ring (e.g., isolated clavicle fracture) is usually stable.
• A double disruption (e.g., clavicle + scapular neck fracture) makes the ring unstable — this is a floating shoulder.
• Primary disruption is scapular neck fracture
• Secondary can be bony, ligamentous or combined
• Most often- clavicle fracture

Primary disruption

• Scapular neck fracture- 2 parts are created
• Distal part with glenoid and coracoid process
• Proximal part with scapular body, spine and acromion

Instability leads to:

• Inferior displacement of the glenoid
• Medialization of the shoulder
• Rotational malalignment
• Poor shoulder mechanics and function

Mechanism of Injury

• High-energy trauma:
• Motor vehicle collisions
• Falls from height
• Common in polytrauma patients
• Often associated with:
• Rib fractures
• Pulmonary injuries
• Brachial plexus injury

Clinical Presentation

• Severe shoulder pain associated with abnormal contour
• Decreased range of motion
• Obvious deformity (especially if clavicle is displaced)
• Neurovascular exam is critical

Imaging

• Plain radiographs:
• AP, axillary lateral and scapular Y lateral views
• Look for:
  • Clavicle fracture
  • Scapular neck/body fracture.
• CT scan with 3D reconstruction:
• For better assessment of scapular involvement
• Helps plan surgery

 

 Gleno-planar angle

• Measures the rotational alignment of glenoid about an Ap axis perpendicular to scapular plane

It is the angle between:

• A line connecting the superior pole of the glenoid to the inferior angle of the scapula, and
• A line connecting the superior and inferior poles of the glenoid fossa (glenoid vertical axis)
• Normal Glenopolar Angle: 30° to 45°
• The GPA reflects the rotational alignment and displacement of the glenoid and scapula.
• useful in determining the need for surgical fixation.
• GPA < 20°: significant malrotation/medialisation of the glenoid
• Often associated with functional impairment
• Surgical fixation usually recommended
• GPA > 20°: May be considered for non-operative treatment if other criteria are favorable

Treatment

• Follow ATLS protocol
• Stabilise the patient
• Usually high energy injuries and poly trauma patients.

Management

• Non-operative:
• Minimally displaced fractures
• No signs of significant ligamentous instability
• Non-dominant arm, low-demand patient
• Broad arm sling / special shoulder immobliser for 3-4 weeks

Operative method

• When there is significant displacement
• Stepwise approach to convert double disruption of SSSC to single disruption
• Clavicle fixation first
• Assess stability of Glenoid (GPA)
• Fix scapula/ other ligamentous repair if instability is warranted

Indications for Surgery

• >1 cm displacement between fracture fragments
• Glenopolar angle < 20° ( normal 30* – 45*)
• Medialisation of glenoid neck- > 10-20 mm
• Floating shoulder + clavicle displacement
• Open fractures
• Associated neurovascular injury

Operative:

• Fixation of both clavicle and scapula (or sometimes clavicle only)
• ORIF of:
  • Clavicle: plate fixation
  • Scapula: lateral border, neck — usually posterior approach (Judet Approach)- 3.5mm Recon plate.
  • Patient lateral, inverted L incision

Post-Operative Care

• Immobilization in sling for comfort (1–2 weeks)
• Passive ? active-assisted ROM
• Strengthening after 6–8 weeks
• Return to function in ~3–4 months

Outcomes

• Operative management generally shows:
• Improved shoulder function
• Faster return to activity

Risk of complications:

• Mal-union
• Shoulder stiffness
• Drooping of shoulder
• Neurological injury
• Subacromial pain.