Ipsilateral Clavicle + Glenoid/Scapula Neck | Double Disruption SSSC | Operative if Displaced
SSSC CONCEPT
Critical Must-Knows
- Double disruption of SSSC creates floating shoulder (unstable)
- SSSC ring: clavicle → AC joint → acromion → spine → glenoid neck → CC ligaments → clavicle
- Fix the clavicle first - often restores alignment without direct scapula fixation
- Glenoid medialization over 1cm or angular deformity over 40° indicates instability
- High-energy mechanism - always assess for associated injuries (pulmonary, brachial plexus)
Clinical Pearls
- "True floating shoulder requires TWO disruptions of the SSSC
- "Clavicle fixation alone may restore scapula alignment (indirect reduction)
- "GPA (Glenopolar Angle) under 20° indicates significant deformity
- "Associated with high-energy trauma - 80% have additional injuries
Clinical Imaging
Imaging Gallery
Critical Floating Shoulder Exam Points
Define SSSC Ring
Superior Shoulder Suspensory Complex is a bone-ligament ring: clavicle → AC joint → acromion → scapula spine → glenoid neck → coracoclavicular ligaments → back to clavicle. Two disruptions = floating shoulder.
Clavicle First Strategy
Fixing the clavicle alone often restores scapula alignment indirectly through intact CC ligaments. Assess post-clavicle fixation alignment before deciding on scapula surgery.
Assess Displacement
Key thresholds: clavicle shortening over 25mm, glenoid medialization over 1cm, GPA under 20°, angular deformity over 40°. Displacement indicates instability requiring fixation.
High-Energy Pattern
80% have associated injuries: rib fractures, pneumothorax, brachial plexus injury, head injury. Complete trauma workup mandatory. Often presents in polytrauma setting.
At a Glance - Management Decision
| Pattern | SSSC Disruptions | Stability | Treatment |
|---|---|---|---|
| Isolated clavicle fracture | One | Stable | Nonoperative or selective fixation |
| Isolated scapula neck fracture | One | Stable | Nonoperative (sling, early ROM) |
| Minimally displaced floating shoulder | Two | Borderline | Consider clavicle fixation alone |
| Displaced floating shoulder | Two | Unstable | Clavicle fixation, reassess scapula |
| Severely displaced both bones | Two or more | Grossly unstable | Fix clavicle AND scapula |
CAGESSSSC Ring Components
| C | Clavicle Medial strut of the ring |
| A | AC joint and Acromion Superior linkage |
| G | Glenoid neck Lateral strut supporting humeral head |
| E | Extra-articular scapula spine Posterior connection |
| S | Strong CC ligaments Coracoclavicular ligaments complete the ring |
| C | Clavicle Medial strut of the ring | E | Extra-articular scapula spine Posterior connection |
| A | AC joint and Acromion Superior linkage | S | Strong CC ligaments Coracoclavicular ligaments complete the ring |
| G | Glenoid neck Lateral strut supporting humeral head |
Hook:The shoulder lives in a CAGE - break two bars and it floats free!
FLOATFloating Shoulder Assessment
| F | Fracture pattern Identify both SSSC disruptions |
| L | Look for displacement Shortening, angulation, medialization |
| O | Other injuries Pulmonary, brachial plexus, ribs, head |
| A | Assess GPA Glenopolar angle (normal 30-45°) |
| T | Treatment strategy Clavicle first, then reassess |
| F | Fracture pattern Identify both SSSC disruptions | A | Assess GPA Glenopolar angle (normal 30-45°) |
| L | Look for displacement Shortening, angulation, medialization | T | Treatment strategy Clavicle first, then reassess |
| O | Other injuries Pulmonary, brachial plexus, ribs, head |
Hook:When the shoulder FLOATs, follow this systematic assessment!
DIMSIndications for Scapula Fixation
| D | Displacement over 1cm Glenoid medialization |
| I | Intra-articular extension Glenoid articular involvement |
| M | Malangulation over 40° Angular deformity |
| S | Shortened GPA under 20° Severely altered mechanics |
| D | Displacement over 1cm Glenoid medialization | M | Malangulation over 40° Angular deformity |
| I | Intra-articular extension Glenoid articular involvement | S | Shortened GPA under 20° Severely altered mechanics |
Hook:DIMS your chances if you miss these indications for surgery!
Overview and Epidemiology
Floating shoulder describes the combination of ipsilateral clavicle and scapula neck (or glenoid) fractures that result in the loss of the bony connection between the axial skeleton and the upper extremity. The term was first coined by Ganz and Noesberger in 1975.
Mechanism of injury:
- High-energy direct trauma to the shoulder (MVA, fall from height, motorcycle accidents)
- Force applied to the lateral aspect of the shoulder
- Axial loading through the humeral head
- Sequential failure of SSSC components
True vs Biomechanical Floating Shoulder
True floating shoulder requires disruption of BOTH superior AND inferior limbs of the SSSC. The biomechanical floating shoulder described by Goss requires disruption at two points creating instability. Not all combined clavicle-scapula fractures are unstable - intact CC ligaments may maintain stability.
Associated injuries (high-energy mechanism):
- Pulmonary: rib fractures (50%), pneumothorax, pulmonary contusion
- Neurological: brachial plexus injury (5-10%), head injury
- Vascular: subclavian/axillary injury (rare but devastating)
- Other: spine injuries, abdominal trauma
Anatomy and Biomechanics
Superior Shoulder Suspensory Complex (SSSC)
The SSSC is a bone-soft tissue ring that suspends the upper extremity from the axial skeleton. Understanding this concept is fundamental to managing floating shoulder injuries.
SSSC Ring Components:
The ring consists of:
- Clavicle - medial strut
- AC joint - connects clavicle to acromion
- Acromion process - superior link
- Scapula spine - posterior connection
- Scapula body/glenoid neck - lateral strut
- Coracoid process - inferior link
- Coracoclavicular ligaments - completes the ring to clavicle
SSSC Superior vs Inferior Struts
| Strut | Components | Function |
|---|---|---|
| Superior strut | Clavicle, AC joint, acromion | Primary link to axial skeleton |
| Inferior strut | Coracoid, CC ligaments, glenoid neck | Secondary support, vertical stability |
Biomechanical principles:
Ring Stability Concept
Like a pelvic ring, the SSSC requires two disruptions to create instability. A single break (isolated clavicle OR isolated scapula neck) typically remains stable. Two breaks create a floating segment that can displace under the pull of attached muscles.
Deforming forces on the scapula:
- Serratus anterior: protracts scapula
- Pectoralis minor: tilts glenoid inferiorly
- Gravity and arm weight: causes medialization
- Trapezius/levator: elevate medial scapula (if intact)
Why the clavicle matters:
- The clavicle is the only bony connection between upper limb and axial skeleton
- Through intact CC ligaments, fixing the clavicle can indirectly reduce the scapula
- Restores the strut function supporting the shoulder
Classification Systems
Goss Classification (1993) - Based on SSSC disruptions
| Type | Description | Stability |
|---|---|---|
| Single disruption | One break in SSSC ring | Stable |
| Double disruption | Two breaks in ring (floating shoulder) | Potentially unstable |
| Triple disruption | Three or more breaks | Unstable |
Key concept: The degree of instability depends on:
- Number of disruptions
- Displacement at each site
- Integrity of remaining structures
Classic Double Disruption Patterns
- Clavicle fracture + scapula neck fracture (most common)
- Clavicle fracture + AC dislocation + glenoid fracture
- AC dislocation + coracoid fracture + scapula neck fracture
Clinical Assessment
History
- Mechanism: High-energy trauma (MVA, fall from height)
- Associated injuries: chest pain, dyspnea, head injury
- Hand dominance
- Occupation and functional demands
- Comorbidities affecting healing
Examination
- Inspection: swelling, deformity, skin tenting
- Palpation: clavicle, acromion, scapula spine
- ROM: usually severely limited by pain
- Neurovascular: brachial plexus exam essential
- Chest: auscultate for pneumothorax
Neurovascular Assessment
Brachial plexus injury occurs in 5-10% of floating shoulder injuries. Test:
- C5: shoulder abduction, biceps
- C6: wrist extension, brachioradialis
- C7: elbow extension, triceps
- C8/T1: finger flexion and intrinsics
- Axillary nerve: regimental badge sensation, deltoid
Physical examination findings:
- Shortened, drooping shoulder appearance
- Visible or palpable clavicle deformity
- Ecchymosis over shoulder girdle
- Scapula body may be palpable posteriorly
- Inability to actively elevate arm
Associated injury screening:
- Chest: breath sounds, chest wall tenderness
- Neurology: complete brachial plexus exam
- Vascular: pulses, capillary refill, expanding hematoma
Differential diagnosis - distinguishing the floating shoulder from its mimics:
Differential Diagnosis of the Apparently Unstable Shoulder Girdle
| Pattern | SSSC Disruptions | Key Distinguishing Feature | Stability / Treatment |
|---|---|---|---|
| True floating shoulder | Two (clavicle + scapular neck) | Ipsilateral clavicle AND scapular neck fracture on imaging | May be unstable - decide on displacement / GPA |
| Isolated displaced clavicle fracture | One | Intact scapula on CT; SSSC broken in one place only | Stable - selective fixation by clavicle criteria |
| Isolated scapular neck fracture | One | Intact clavicle and CC ligaments | Usually stable - nonoperative, early ROM |
| Scapulothoracic dissociation | Two or more + soft tissue | Lateral scapular displacement on non-rotated chest film, vascular/plexus injury | Limb-threatening - urgent vascular and neuro assessment |
| High AC dislocation + clavicle fracture | Two | AC widening / CC distance increase rather than scapular neck break | Double disruption variant - assess displacement |
| Type I (basal) coracoid fracture + clavicle/AC injury | Two | Coracoid base fracture on axillary/CT, not scapular neck | Double disruption - fix medial-to-lateral if displaced |
Do Not Miss Scapulothoracic Dissociation
The most dangerous mimic is scapulothoracic dissociation - a closed forequarter amputation equivalent. Look for lateral scapular displacement on a non-rotated chest radiograph, an absent pulse, a flail/anaesthetic limb, and massive swelling. This is a vascular and brachial plexus emergency, not a fixation decision.
Investigations
Imaging Protocol
- AP chest: pulmonary injury, rib fractures
- AP clavicle: assess shortening, displacement
- Scapular Y view: glenoid position, GPA measurement
- Axillary lateral: glenoid articular surface
- AP shoulder: glenohumeral relationship
- 3D reconstruction: fracture pattern, displacement
- Glenoid articular involvement: size, displacement
- Scapula neck displacement: medialization measurement
- Surgical planning: plate contouring, screw trajectories
- CT angiography: if vascular injury suspected
- MRI: brachial plexus injury (subacute)
- EMG/NCS: delayed brachial plexus assessment
Key measurements on imaging:
Radiographic Measurements
| Measurement | Method | Significance |
|---|---|---|
| Glenopolar Angle | Angle between glenoid axis and scapula body on Y view | Under 20° = significant deformity |
| Medialization | Distance glenoid has shifted medially on CT | Over 1cm = operative indication |
| Angular deformity | Angulation of glenoid neck relative to body | Over 40° = instability |
| Clavicle shortening | Compare to contralateral or measure displacement | Over 25mm = consider fixation |
Management Algorithm
Key Decision Points:
Management Algorithm
- Count number of disruptions
- Single disruption: usually stable, nonoperative
- Double disruption: assess displacement
- GPA, medialization, angulation, clavicle shortening
- Minimally displaced: consider nonoperative or clavicle alone
- Significantly displaced: surgical stabilization
- Plate fixation of clavicle
- Intraoperative fluoro of scapula
- Reassess scapula alignment after clavicle fixation
- If alignment restored: stop
- If persistent displacement: proceed to scapula ORIF
Clavicle First Strategy Rationale
Fixing the clavicle restores the strut function of the SSSC. Through intact CC ligaments, this can indirectly reduce the scapula. Studies show clavicle fixation alone achieves acceptable alignment in 60-70% of floating shoulders.
Surgical Technique
Positioning:
- Beach chair or supine with bump
- Entire shoulder girdle in field
- Image intensifier available for scapula assessment
Approach:
- Standard anterior or superior approach to clavicle
- Protect supraclavicular nerves
- Identify fracture pattern
Fixation:
- Superior plating: 3.5mm reconstruction or precontoured plate
- Anteroinferior plating: biomechanically stronger
- 3 screws each side of fracture minimum
- Lag screws for butterfly fragments
Intraoperative Assessment:
- Fluoro scapular Y view after clavicle fixation
- Measure GPA, medialization
- If acceptable → close
- If persistent displacement → proceed to scapula
Why Anteroinferior Plating?
Anteroinferior plate position is biomechanically superior for clavicle shaft fractures - resists bending forces better and has lower profile reducing hardware prominence.
Complications
Complications of Floating Shoulder
| Complication | Incidence | Risk Factors | Management |
|---|---|---|---|
| Malunion | 10-20% | Nonoperative displaced, inadequate fixation | Osteotomy if symptomatic |
| Nonunion | 5-10% | Smoking, comminution, inadequate fixation | Revision ORIF with bone graft |
| Shoulder stiffness | 15-25% | Prolonged immobilization, adhesive capsulitis | Physiotherapy, manipulation, arthroscopy |
| Brachial plexus injury | 5-10% | High-energy mechanism, severe displacement | Observation, exploration if no recovery |
| Hardware prominence (clavicle) | 10-20% | Superior plate position, thin patients | Hardware removal after union |
| Suprascapular nerve injury | Less than 5% | Surgical approach, direct injury | Observation, nerve release if no recovery |
Outcome-related factors:
Good Prognostic Factors
- Anatomic reduction achieved
- Single surgery (clavicle alone)
- Early mobilization
- Younger patient
- Isolated injury (no polytrauma)
Poor Prognostic Factors
- Persistent glenoid malposition
- Intra-articular involvement
- Associated brachial plexus injury
- Delayed treatment
- Polytrauma, ICU admission
Postoperative Care
Rehabilitation Protocol
- Sling immobilization
- Wound care
- Gentle pendulum exercises
- Elbow, wrist, hand ROM
- Passive and active-assisted ROM
- Forward flexion, external rotation in plane of scapula
- Avoid combined abduction/external rotation
- Continue sling when not exercising
- Discontinue sling
- Full active ROM progression
- Begin isometric strengthening
- Scapular stabilization exercises
- Progressive resistance exercises
- Rotator cuff strengthening
- Sport-specific training if applicable
- Return to non-contact activities
- Full strength and ROM
- Contact sports cleared
- Manual labor cleared
- Hardware removal if symptomatic (after 1 year)
Outcomes and Prognosis
Factors affecting outcome:
Outcome by Treatment
| Treatment | Union Rate | Functional Outcome | Complications |
|---|---|---|---|
| Nonoperative (displaced) | 85-90% | Fair to good | Malunion, weakness common |
| Clavicle fixation alone | 95% | Good to excellent | Hardware prominence |
| Combined clavicle + scapula | 95% | Good to excellent | Longer surgery, nerve risk |
Long-term Outcomes
Studies show operatively treated floating shoulder patients achieve Constant scores of 80-90% of contralateral side. Most return to pre-injury activity level. Residual weakness is more common with nonoperative treatment of displaced injuries.
Controversies and Areas of Uncertainty
The floating shoulder is a classic viva topic precisely because the evidence is thin and genuine equipoise exists. Be ready to argue both sides.
Is the injury inherently unstable?
Goss's biomechanical concept predicts instability from any double disruption, yet van Noort's multicentre series found the injury is not inherently unstable and that good function follows conservative care unless the glenoid is caudally dislocated. The modern view: instability depends on displacement, not the count of disruptions.
Operate or not?
Dombrowsky's systematic review found comparable mean Constant scores (≈80% of ideal) for operative and nonoperative groups, but the small RCT (Lin et al.) favoured fixation for GPA and DASH/Constant. Selection - not a blanket rule - drives outcome.
Clavicle alone vs combined?
Clavicle-first with intraoperative reassessment is widely taught, but indirect reduction of the scapula through intact CC ligaments is unreliable. Some surgeons argue a displaced scapular neck should be addressed directly rather than hoping the clavicle plate corrects the GPA.
Which radiographic threshold?
Cited GPA cut-offs vary (under 20° vs under 22°), as do medialisation (over 10mm vs over 20mm) and angulation (over 40° vs over 45°) thresholds. These numbers are expert-derived, not validated prospectively; treat them as guides, not absolutes.
How to Handle This in the Viva
State the controversy explicitly: "There is no high-level consensus. I would individualise based on the degree of glenoid displacement and GPA, the patient's physiological status and demands, and the overall trauma burden - reserving combined fixation for the displaced, physiologically stable patient." This shows judgement rather than dogma.
Evidence Base
Goss: Double Disruptions of the SSSC (concept paper)
- Defined the superior shoulder suspensory complex as a bone-soft tissue ring
- Introduced the 'double disruption' principle - two breaks create instability
- Unified previously isolated injury descriptions under one framework
- Surgical reduction/stabilisation indicated when displacement is unacceptable
Systematic Review: Conservative vs Surgical Floating Shoulder
- 17 studies, 371 shoulders; mean follow-up 49 months
- 58% treated surgically, 42% nonoperatively
- Mean Constant-Murley score 80% of ideal in BOTH operative and nonoperative groups
- Significant scapular neck displacement may benefit from combined fixation
RCT: Combined vs Clavicle-Alone vs Conservative (GPA correlation)
- Prospective randomised study, 39 patients, 3 arms, over 2 year follow-up
- Combined clavicle + scapula fixation gave the best post-union GPA (p=0.015)
- Combined group had best DASH and Constant scores (p=0.008 and 0.002)
- DASH and Constant scores strongly correlated with GPA after consolidation (p under 0.001)
The Floating Shoulder: A Multicentre Study (van Noort)
- 46 patients; 35 followed up, mostly treated conservatively
- Mean Constant 76 (conservative) vs 71 (operative) at 35 months
- Caudal glenoid dislocation was the key driver of poor results (Constant 42 vs 85)
- The injury is NOT inherently unstable
Coracoid (Type I) Fractures as SSSC Double Disruption
- 36 surgically treated type I coracoid fractures; double disruption in 94%
- Reduction proceeded medial-to-lateral, fixing the coracoid last
- Bone union in all fractures with no additional operations
- Mean Constant score ratio 93% of the normal side
Exam Viva Scenarios
Use these scenarios to practise clinical reasoning and management decisions
Scenario 1: Classic Floating Shoulder
"A 35-year-old male motorcyclist presents after high-speed accident. X-rays show a displaced mid-shaft clavicle fracture and an ipsilateral scapula neck fracture. He has no neurovascular deficit. How would you assess and manage this patient?"
Scenario 2: Minimally Displaced Pattern
"A 55-year-old female falls from standing height onto her shoulder. X-rays show a minimally displaced mid-shaft clavicle fracture (10mm shortening) and an ipsilateral scapula neck fracture with GPA of 32°. She is a low-demand patient. How would you manage this?"
Scenario 3: Persistent Displacement After Clavicle
"You have fixed a displaced clavicle fracture as part of a floating shoulder. Intraoperative fluoroscopy shows the GPA is now 15° and there is 15mm glenoid medialization. How do you proceed?"
MCQ Practice Points
MCQ #1: SSSC Components
Q: Which structure is NOT part of the Superior Shoulder Suspensory Complex?
A) Clavicle B) Coracoacromial ligament C) Coracoclavicular ligaments D) Acromion
A: B - The coracoacromial ligament connects coracoid to acromion but is not part of the SSSC ring. The SSSC includes: clavicle, AC joint, acromion, scapula spine, glenoid neck, coracoid, and CC ligaments.
MCQ #2: Surgical Threshold
Q: What glenopolar angle represents a surgical threshold in floating shoulder?
A) Less than 40° B) Less than 30° C) Less than 20° D) Less than 10°
A: C - GPA under 20° indicates significant angular deformity and is a surgical indication. Normal GPA is 30-45°.
MCQ #3: Treatment Strategy
Q: In the management of floating shoulder, the recommended initial surgical strategy is:
A) Fix scapula first, then assess clavicle B) Fix clavicle first, then assess scapula C) Always fix both clavicle and scapula D) Fix whichever has more displacement
A: B - Clavicle-first strategy is recommended. Fixing the clavicle restores the strut function and through intact CC ligaments often reduces the scapula indirectly. Assess scapula position after clavicle fixation.
MCQ #4: At-Risk Structure
Q: Which nerve is at risk during posterior approach to the scapula?
A) Axillary nerve B) Long thoracic nerve C) Suprascapular nerve D) Musculocutaneous nerve
A: C - The suprascapular nerve is at risk at the spinoglenoid notch during posterior scapula approaches. Injury causes infraspinatus weakness.
MCQ #5: Associated Injuries
Q: What percentage of floating shoulder injuries have associated injuries due to high-energy mechanism?
A) 40% B) 60% C) 80% D) 95%
A: C - Approximately 80% of floating shoulder injuries have associated injuries including rib fractures, pneumothorax, brachial plexus injury, or head trauma due to the high-energy mechanism.
MCQ #6: Displacement Threshold
Q: What degree of glenoid medialization is considered a surgical indication in floating shoulder?
A) Greater than 5mm B) Greater than 1cm C) Greater than 2cm D) Greater than 3cm
A: B - Glenoid medialization greater than 1cm is a surgical indication. Other thresholds include GPA under 20° and angular deformity over 40°.
Guidelines, Registries & Global Practice
Global epidemiology
- Scapular fractures account for under 1% of all fractures; the floating shoulder (ipsilateral clavicle + scapular neck) is a small subset, reported in roughly 0.1% of fractures.
- Around 10-15% of scapular neck/body fractures have an associated ipsilateral clavicle fracture.
- Predominantly young men (mean age late 30s) injured in motor vehicle and motorcycle crashes and falls from height; the high-energy mechanism explains the high rate of associated thoracic and neurovascular injury worldwide.
Where Guidance Differs (No Single-Country Frame)
| Body / Source | Position on the Floating Shoulder | Practical Emphasis |
|---|---|---|
| AO Foundation / OTA | Operate the displaced double disruption; clavicle-first then reassess | Glenopolar angle, lateral border displacement, angulation as operative triggers |
| BOA / UK practice | Selective surgery; many isolated-looking patterns do well nonoperatively | Polytrauma-led care, early mobilisation, individualised decision |
| North American shoulder/trauma literature (Cole criteria) | Surgery for medialisation over 20mm, angulation over 45°, GPA under 22°, intra-articular step | Reproducible radiographic thresholds drive the decision |
| EFORT / European consensus | No mandatory fixation; restore glenoid position and GPA | Function tracks glenoid position more than the number of disruptions |
Registry note: There is no dedicated implant registry for the floating shoulder (it is a fracture-fixation, not an arthroplasty, problem), so evidence rests on small series and a single small RCT rather than registry data - a key reason equipoise persists.
High- vs limited-resource practice variation
- High-resource: routine CT with 3D reconstruction for planning, precontoured clavicle and scapular plates, intraoperative fluoroscopy to confirm GPA, single-stage combined fixation when needed.
- Limited-resource: reliance on plain films (scapular Y plus axillary), conservative management for all but grossly displaced injuries, and clavicle-only fixation favoured to minimise theatre time and the morbidity of the posterior Judet approach.
- Across settings the converging principle is the same: reduce the glenoid/restore GPA and treat the patient's overall trauma burden first.
FLOATING SHOULDER
Clinical summary
Definition & SSSC
- •Double disruption of SSSC = floating shoulder
- •SSSC ring: clavicle → AC joint → acromion → spine → glenoid → CC ligaments
- •Single disruption = stable, double = potentially unstable
- •15% of scapula fractures have ipsilateral clavicle fracture
Key Measurements
- •GPA normal 30-45°, surgical threshold under 20°
- •Medialization surgical threshold over 1cm
- •Angular deformity surgical threshold over 40°
- •Clavicle shortening threshold over 25mm
Management Algorithm
- •Step 1: Assess SSSC disruptions and displacement
- •Step 2: Fix clavicle first (plate fixation)
- •Step 3: Intraop fluoro to reassess scapula
- •Step 4: If persistent displacement → scapula ORIF
- •Clavicle alone restores alignment in 60-70%
Surgical Approaches
- •Clavicle: anterior/superior approach, plate fixation
- •Scapula: Judet posterior approach
- •Judet: between deltoid and infraspinatus
- •Protect suprascapular nerve at spinoglenoid notch
Complications
- •Malunion 10-20% (especially nonoperative)
- •Stiffness 15-25%
- •Brachial plexus injury 5-10%
- •Hardware prominence with clavicle plate
- •Suprascapular nerve injury with scapula surgery