SCAPULA FRACTURES - HIGH-ENERGY TRAUMA
Associated Injuries Critical | Glenoid Fractures Key | Floating Shoulder Concept
ANATOMICAL CLASSIFICATION
Critical Must-Knows
- High-energy injury - always look for associated thoracic and shoulder girdle injuries
- Floating shoulder = scapula neck + clavicle fracture disrupts superior shoulder suspensory complex
- Glenoid fractures are the most important - articular involvement determines outcome
- Most body fractures heal well conservatively - surgery for articular/neck displacement
- Ideberg classification for glenoid fossa fractures guides surgical decision-making
Examiner's Pearls
- "80-95% have associated injuries - ribs, lung, clavicle, brachial plexus
- "Scapulothoracic dissociation = devastating - high mortality, look for it
- "Glenoid step more than 4mm or fragment more than 25% = surgical indication
- "Lateral border offset more than 20mm or angulation more than 40 degrees = ORIF neck
Clinical Imaging
Imaging Gallery
Critical Scapula Fracture Exam Points
Associated Injuries
80-95% have associated injuries. Prioritize ATLS assessment. Rib fractures (52%), pulmonary contusion (47%), clavicle fractures (23%), brachial plexus injury (12%). High mortality rate (10-15%).
Floating Shoulder
Scapula neck + clavicle fracture = double disruption of superior shoulder suspensory complex. Creates instability. Often requires surgical stabilization of clavicle or both.
Glenoid Articular
Ideberg classification guides treatment. Step off more than 4mm, fragment more than 25% of surface, or instability = surgical indication. These affect long-term shoulder function.
Scapulothoracic Dissociation
Lateral scapula displacement on CXR. Associated with vascular injury, brachial plexus avulsion, massive soft tissue trauma. High mortality - often forequarter amputation needed.
Quick Decision Guide
| Fracture Pattern | Key Finding | Treatment |
|---|---|---|
| Body/spine - minimally displaced | Less than 1cm displacement | Sling, early ROM, physio |
| Glenoid neck - isolated | Less than 1cm medialization, less than 40 degrees angulation | Conservative - sling, early motion |
| Glenoid neck - displaced | More than 2cm medialization OR more than 40 degrees angulation | ORIF via posterior approach |
| Floating shoulder | Clavicle + scapula neck fracture | Clavicle ORIF (minimum) plus or minus scapula |
| Glenoid fossa - displaced | Step more than 4mm, fragment more than 25% | ORIF for articular congruity |
| Scapulothoracic dissociation | Lateral scapula displacement on CXR | Life-threatening - angiography, stabilization |
SCAPULASCAPULA - Associated Injuries
Memory Hook:SCAPULA fractures mean look for all these injuries - high-energy trauma signature
GOSSGOSS - Glenoid Neck Surgery Indications
Memory Hook:GOSS criteria help decide when neck fractures need surgery
SSSCSSSC - Superior Shoulder Suspensory Complex
Memory Hook:The SSSC is a bone-ligament ring - 2 disruptions = floating shoulder = instability
4-25-40-204-25-40-20 Rule
Memory Hook:4mm step, 25% fragment, 40 degrees angulation, 20mm offset - four surgical thresholds
Overview and Epidemiology
Scapula fractures are uncommon injuries that typically result from high-energy trauma. The scapula is protected by thick muscle coverage and significant force is required to fracture it.
Mechanism of injury:
- Motor vehicle accidents - most common (50-70%)
- Falls from height
- Direct blow (crush injuries)
- Sports (uncommon - typically low energy)
Key principle: The scapula fracture itself is often less important than the associated injuries. Always perform a thorough trauma assessment.
High-Energy Trauma Marker
A scapula fracture indicates massive energy transfer. Maintain high suspicion for associated injuries. Mortality rate is 10-15%, primarily from associated thoracic and head injuries rather than the scapula fracture itself.
Historical Perspective
Traditionally, scapula fractures were treated almost universally conservatively with good results. The shift to surgical treatment in selected cases is based on better understanding of outcomes with significantly displaced glenoid neck and articular fractures.
Anatomy and Biomechanics
Bony anatomy:
- Body - flat triangular bone, thin (2-7mm)
- Spine - posterior ridge, divides supraspinatus from infraspinatus
- Acromion - lateral extension of spine, articulates with clavicle
- Coracoid process - anterior projection, muscle and ligament attachments
- Glenoid fossa - articular surface for humeral head
- Glenoid neck - transition between glenoid and body
Superior Shoulder Suspensory Complex (SSSC):
SSSC Concept
The Superior Shoulder Suspensory Complex is a bone-ligament ring that suspends the upper extremity from the axial skeleton. Components: glenoid process, coracoid, CC ligaments, clavicle (distal), AC joint, acromion. Single disruption = stable. Double disruption = floating shoulder = unstable.
Muscular attachments (17 muscles):
- Rotator cuff: supraspinatus, infraspinatus, teres minor, subscapularis
- Scapulohumeral: deltoid (partial), coracobrachialis, biceps (long head)
- Axioscapular: trapezius, levator scapulae, rhomboids, serratus anterior
- Scapulothoracic: pectoralis minor, omohyoid
Neurovascular relationships:
- Suprascapular nerve (in suprascapular notch - injury in coracoid fractures)
- Axillary nerve (quadrangular space)
- Subscapular nerves and vessels
- Brachial plexus runs anterior to scapula
Classification Systems
Anatomic Classification (most practical)
| Location | Frequency | Typical Management |
|---|---|---|
| Body/Spine | 50-60% | Conservative (thick muscle coverage aids healing) |
| Glenoid neck | 25% | Conservative vs ORIF depending on displacement |
| Glenoid fossa | 10% | ORIF if displaced more than 4mm or more than 25% involvement |
| Acromion | 8% | Conservative unless significantly displaced |
| Coracoid | 3-7% | ORIF if displaced more than 1cm or associated AC dislocation |
| Scapular spine | Rare | Usually with body fractures |
Clinical Significance
Glenoid fractures are most important prognostically - they affect glenohumeral joint function. Glenoid neck fractures matter when significantly displaced or combined with clavicle injury (floating shoulder).
Clinical Presentation and Assessment
Primary Survey: Scapula fractures are high-energy injuries. ATLS protocol is mandatory.
ATLS First
Complete the primary survey before focusing on the scapula fracture. Life-threatening chest injuries, hemorrhage, and neurological injuries take priority.
History:
- Mechanism (MVA, fall from height, direct blow)
- Associated symptoms (chest pain, dyspnea, neurological symptoms)
- Pre-injury function
- Hand dominance
Physical examination:
Physical Examination Findings
| Finding | Significance | Associated Condition |
|---|---|---|
| Posterior shoulder swelling | Local hematoma | Body/neck fracture |
| Flattened shoulder contour | Significant displacement | Displaced glenoid neck |
| Lateral scapula on CXR | Scapulothoracic dissociation | Life-threatening injury |
| Subcutaneous emphysema | Pneumothorax | Rib fractures, lung injury |
| Absent pulses/expanding hematoma | Vascular injury | Subclavian/axillary injury |
| Sensory/motor deficit | Brachial plexus injury | High-energy trauma |
Associated injuries to look for:
- Rib fractures (52%)
- Pulmonary contusion (47%)
- Pneumothorax (38%)
- Clavicle fractures (23%)
- Brachial plexus injury (12%)
- Humeral fractures (11%)
- Spine fractures (8%)
- Subclavian artery injury (rare but serious)
Scapulothoracic Dissociation
Look at the chest X-ray for lateral displacement of the scapula compared to the contralateral side. This indicates massive soft tissue disruption, likely vascular injury, and brachial plexus avulsion. High mortality. May require forequarter amputation.
Investigations
Standard imaging:
Trauma series (AP pelvis/chest/lateral C-spine):
- Chest X-ray often first to show scapula fracture
- Look for lateral scapula displacement (scapulothoracic dissociation)
- Associated rib fractures, pneumothorax
Dedicated scapula views:
- True AP scapula (Grashey view) - 30-40 degree posterior oblique
- Scapula Y-view (lateral) - shows glenoid neck and body
- Axillary lateral - glenoid rim fractures
Glenopolar Angle
The glenopolar angle is measured on the true AP or Y-view. Draw a line through the most superior and inferior glenoid points. Draw a second line from the inferior glenoid to the most superomedial angle of the scapula. Normal = 30-45 degrees. Less than 20 degrees suggests significant displacement requiring surgery.
CT imaging:
Essential for:
- All glenoid fractures (articular surface assessment)
- Surgical planning for displaced neck fractures
- Complex/comminuted patterns
- Assessment of lateral border offset
3D CT reconstruction:
- Excellent for visualizing fracture pattern
- Helps plan surgical approach and fixation strategy
CT angiography:
Indications:
- Scapulothoracic dissociation
- Expanding hematoma
- Absent or diminished pulses
- Suspected subclavian/axillary injury
Management
Conservative management:
The majority of scapula fractures (80-90%) are treated conservatively with good outcomes.
- Sling immobilization for comfort
- Ice, analgesia
- Address associated injuries first
- Gentle pendulum exercises as pain allows
- Wean from sling
- Active assisted ROM
- Progress as pain allows
- Avoid extremes of motion
- Once radiographic callus visible
- Progressive resistance exercises
- Rotator cuff strengthening
- Full ROM and strength expected
- Sport-specific rehabilitation
- Most return to pre-injury function
Surgical indications:
Surgical Indications by Fracture Type
| Fracture Type | Indication for Surgery |
|---|---|
| Glenoid fossa | Step more than 4mm, fragment more than 25% of surface, subluxation |
| Glenoid neck | Angulation more than 40 degrees, medialization more than 20mm, glenopolar angle less than 20 degrees |
| Floating shoulder | Double SSSC disruption - stabilize at minimum the clavicle |
| Acromion | Displaced fractures impinging on rotator cuff, reducing subacromial space |
| Coracoid | Displacement more than 1cm, associated with AC joint disruption |
| Body/spine | Rarely surgical - consider if lateral border more than 20mm displaced |
Surgical approaches:
Modified Judet Approach (most common)
- Patient lateral or prone
- Incision along scapular spine, curves distally along lateral border
- Develop interval between infraspinatus and teres minor
- Excellent exposure of glenoid neck, body, spine
- Can extend for glenoid fossa
Key structures:
- Suprascapular nerve (protected by staying below spine)
- Infraspinatus and teres minor (preserve vascularity)
- Axillary nerve (inferior limit)
The Judet approach provides excellent access to the scapula body and neck.
Fixation methods:
- 3.5mm reconstruction plates (can be contoured)
- Lag screws for simple patterns
- Locking plates for osteoporotic bone
- Suture anchors for small rim fragments
Floating Shoulder Management
For floating shoulder, the traditional approach is to fix the clavicle first. This is technically easier and often provides sufficient stability. If residual scapula displacement persists after clavicle fixation, address the scapula neck. Some advocate fixing both primarily.
Surgical Technique
Patient Positioning
Modified Lateral Decubitus (Most Common):
- Beanbag support at 30-45 degrees
- Arm supported in traction or on mayo stand
- Allows anterior and posterior access
- C-arm from cephalad direction
Prone:
- Alternative for posterior-only approach
- Better visualization of medial border
- Limited anterior access
Positioning depends on approach requirements and associated injuries.
Complications
Complications
| Complication | Incidence | Prevention/Management |
|---|---|---|
| Shoulder stiffness | 5-15% | Early motion protocols, physiotherapy |
| Malunion | Variable | Rarely symptomatic for body; affects glenoid function |
| Nonunion | Rare (less than 1%) | Rich blood supply protects; treat with bone graft if symptomatic |
| Suprascapular nerve injury | 5-10% surgical | Careful retraction, identify nerve |
| Glenohumeral arthritis | 10-20% glenoid fx | Related to articular step-off; minimize displacement |
| Infection | 1-2% | Standard precautions, prophylactic antibiotics |
Stiffness:
- Most common complication
- Related to prolonged immobilization and associated injuries
- Prevention: early motion when safe
Post-traumatic arthritis:
- Primarily in glenoid fossa fractures
- Related to residual step-off
- Emphasizes importance of anatomic reduction for articular fractures
Suprascapular Nerve
The suprascapular nerve passes through the suprascapular notch and supplies supraspinatus and infraspinatus. Injury causes external rotation and abduction weakness. Protect during posterior approaches by staying inferior to the scapular spine.
Long-term outcomes:
- Body fractures: generally excellent outcomes regardless of treatment
- Neck fractures: good outcomes if displacement parameters respected
- Glenoid fractures: outcomes correlate with reduction quality
Postoperative Care and Rehabilitation
Post-ORIF protocol:
- Sling for comfort and protection
- Gentle pendulum exercises
- No active elevation or external rotation
- Wound management
- Wean sling as comfort allows
- Active assisted ROM
- Progress to active ROM
- Avoid loaded activities
- Full active ROM expected
- Progressive strengthening
- Rotator cuff rehabilitation
- Light functional activities
- Confirm radiographic healing
- Sport-specific training
- Return to full activities typically 4-6 months
- High-impact activities may take longer
Key rehabilitation principles:
- Balance protection of repair with early motion
- Rotator cuff function critical for outcome
- Address associated injuries (rib, clavicle) in rehab plan
- Patient education about expected timeline
Outcomes and Prognosis
Outcomes by fracture type:
| Fracture Type | Outcome | Notes |
|---|---|---|
| Body/spine | Excellent | Conservative treatment adequate |
| Glenoid neck (isolated) | Good | Conservative if meets displacement criteria |
| Glenoid neck (floating) | Good | With surgical stabilization |
| Glenoid fossa (reduced) | Good-Excellent | Key is anatomic reduction |
| Glenoid fossa (malreduced) | Fair-Poor | Develops arthritis |
Prognostic factors:
- Associated injuries (head, chest) - major determinant of mortality
- Articular reduction quality - major determinant of shoulder function
- Patient age and bone quality
- Rehabilitation compliance
Long-term Function
Most patients with scapula body fractures return to full function. Glenoid fossa fractures have variable outcomes depending on reduction quality. The presence of glenohumeral subluxation at presentation is a poor prognostic factor.
Evidence Base
- Surgical treatment of displaced glenoid neck fractures resulted in better functional outcomes compared to conservative treatment when displacement thresholds were exceeded.
- Scapula fractures have 80-95% associated injury rate. Conservative treatment appropriate for most body fractures. Surgical indications include articular step more than 4mm and displaced glenoid neck.
- Clavicle fixation alone often sufficient for floating shoulder. Scapula fixation added if persistent displacement after clavicle repair.
- Surgical fixation of scapula fractures is safe and effective. Complication rate is low (6% wound, 3% neurological). Good functional outcomes with proper indications.
- Glenoid fracture classification system correlating fracture pattern with mechanism and treatment. Types I-VI with increasing complexity.
Exam Viva Scenarios
Practice these scenarios to excel in your viva examination
Scenario 1: Isolated Glenoid Neck Fracture
"A 35-year-old motorcyclist is brought to ED after high-speed accident. GCS 15, hemodynamically stable. Chest X-ray shows multiple left rib fractures and a scapula fracture. CT shows a glenoid neck fracture with 15mm medialization. How do you manage this patient?"
Scenario 2: Floating Shoulder
"A 42-year-old presents after falling from scaffolding. X-rays show a displaced midshaft clavicle fracture and CT reveals a glenoid neck fracture with 25mm medialization and glenopolar angle of 15 degrees. How do you approach this 'floating shoulder' injury?"
Scenario 3: Scapulothoracic Dissociation
"A 28-year-old is brought in after a motorcycle vs truck collision. There is massive left shoulder swelling, the arm is flail, and there is no radial pulse. Chest X-ray shows the left scapula displaced 4cm lateral to the chest wall. What is your diagnosis and immediate management?"
MCQ Practice Points
Epidemiology Question
Q: What percentage of patients with scapula fractures have associated injuries? A: 80-95%. Scapula fractures are high-energy injuries. Rib fractures are most common (52%), followed by pulmonary contusion (47%) and clavicle fractures (23%).
Anatomy Question
Q: What is the superior shoulder suspensory complex (SSSC)? A: A bone-ligament ring connecting the upper extremity to the axial skeleton. Components: glenoid, coracoid, CC ligaments, clavicle, AC ligaments, acromion. Two disruptions = floating shoulder = unstable.
Classification Question
Q: What Ideberg type is an anterior glenoid rim fracture? A: Type Ia. Type Ib is posterior rim. These rim fractures are often associated with shoulder instability and may require treatment directed at the instability rather than just the fracture.
Surgical Indication Question
Q: What glenoid articular step-off is an indication for ORIF? A: More than 4mm step-off or more than 25% articular surface involvement. These thresholds are based on data showing increased rates of post-traumatic arthritis with larger incongruities.
Critical Diagnosis Question
Q: On chest X-ray, what finding suggests scapulothoracic dissociation? A: Lateral displacement of the scapula compared to the contralateral side. This indicates complete disruption of the scapulothoracic connection with likely vascular injury and brachial plexus avulsion.
Australian Context
Epidemiology:
- Motor vehicle accidents remain the primary cause
- Increasing motorcycle trauma in urban areas
- Rural trauma with delayed transfer considerations
Management considerations:
- Complex cases may require transfer to major trauma center
- Coordination with thoracic surgery for associated injuries
Transfer and retrieval:
- Consider early transfer for:
- Floating shoulder injuries
- Displaced glenoid fractures requiring surgery
- Scapulothoracic dissociation
- Vascular injury
- Aeromedical retrieval services available in most states
Exam Context
Be prepared to discuss management in a rural setting with delayed access to specialist care. Know when to transfer and how to temporize. Understand the role of the Royal Australian College of Surgeons in trauma system development.
SCAPULA FRACTURES
High-Yield Exam Summary
KEY FACTS
- •1% of all fractures - high-energy mechanism required
- •80-95% have associated injuries - ATLS protocol mandatory
- •10-15% mortality (from associated chest/head injuries)
- •Most body fractures (50-60%) treated conservatively
- •Peak age 25-40, M:F ratio 2:1
- •MVA most common mechanism (50-70%)
CLASSIFICATION
- •Anatomic: Body (50-60%), Neck (25%), Glenoid fossa (10%), Processes (8%)
- •Ideberg (glenoid): I (rim), II (transverse), III (oblique), IV (horizontal), V (combined), VI (comminuted)
- •SSSC: double disruption = floating shoulder = unstable
- •Ada-Miller (neck): Type I (anatomic neck), Type II (through body)
- •Body fractures: usually heal well with conservative treatment
SURGICAL THRESHOLDS (4-25-40-20 Rule)
- •Glenoid fossa: step more than 4mm OR fragment more than 25% of surface
- •Glenoid neck: angulation more than 40 degrees OR medialization more than 20mm
- •Glenopolar angle less than 20 degrees (normal 30-45 degrees)
- •Floating shoulder: fix clavicle minimum, consider scapula if residual displacement
- •Humeral head subluxation = surgical indication
- •GH instability with rim fracture = consider Bankart repair
FLOATING SHOULDER
- •Double SSSC disruption (usually clavicle + scapula neck fracture)
- •Creates unstable glenoid segment - weight causes medialization
- •Treatment: stabilize clavicle FIRST (easier, restores length)
- •Reassess scapula after clavicle fixation under fluoroscopy
- •Add scapula ORIF if persistent displacement more than 20mm
- •Some advocate fixing both primarily - evidence mixed
SCAPULOTHORACIC DISSOCIATION
- •Lateral scapula displacement on CXR (compare to contralateral)
- •Complete soft tissue disruption - massive energy transfer
- •Associated vascular injury (subclavian/axillary), brachial plexus avulsion
- •High mortality (10-20%) and amputation rate (20%)
- •Immediate CT angiography, vascular surgery consultation
- •May need forequarter amputation if limb non-salvageable
ASSOCIATED INJURIES (Remember SCAPULA)
- •Spine fractures (cervical/thoracic) - 8%
- •Clavicle fractures - 23% (creates floating shoulder)
- •Arterial injury (subclavian) - rare but serious
- •Pulmonary contusion - 47% (most common thoracic)
- •Upper extremity nerve (brachial plexus) - 12%
- •Lateral rib fractures - 52% (most common association)
SURGICAL APPROACHES
- •Modified Judet (posterior): along spine/lateral border
- •Interval: infraspinatus-teres minor (preserves cuff)
- •Protect suprascapular nerve (stay below spine)
- •Deltopectoral (anterior): for isolated anterior rim
- •Positioning: lateral decubitus 30-45° or prone
- •Fixation: 3.5mm recon plates, lag screws, locking plates
TRAPS AND PEARLS
- •Always complete ATLS trauma assessment first
- •Look for associated chest injuries - ribs, pneumothorax
- •Glenoid fractures affect long-term function most
- •Body fractures heal well conservatively
- •Modified Judet = standard posterior approach
- •Glenopolar angle less than 20° = surgical indication