HUMERAL HEAD FRACTURES
Articular Surface | Head Split | Impression | High AVN Risk
TYPE & SEVERITY
Critical Must-Knows
- Head Split Definition: A fracture line traversing the articular surface of the humeral head
- Blood Supply: Disruption of the arcuate artery (ascending branch of circumflex) leads to AVN
- Impression Fractures: Often associated with dislocations (Hill-Sachs or Reverse Hill-Sachs)
- Surgical Dilemma: Reconstruct (high failure rate) vs Replace (activity restrictions)
- Examination: Often indistinguishable from other proximal humerus fractures without CT
Examiner's Pearls
- "Head-splitting fractures are non-reconstructable in the elderly
- "Headless compression screws (Herbert) are used for articular fixation
- "Reverse Total Shoulder is preferred for elderly with cuff dysfunction
- "Monitor for post-traumatic arthritis
Clinical Imaging
Imaging Gallery
Critical Exam Points
The 'Head Split'
Definition: A true head-split fracture separates the articular surface into segments. It has a very poor prognosis for AVN and is difficult to fix reliably.
Posterior Dislocation
Impression Association: Impression fractures (Reverse Hill-Sachs) affecting greater than 40% of the head surface are often caused by missed posterior dislocations.
Axillary Nerve
Neurovascular Check: Always assess axillary nerve function. The proximity to the surgical neck puts it at risk.
Imaging
CT is Mandatory: Plain X-rays cannot accurately characterize the percentage of articular involvement or the number of head fragments.
At a Glance - Management Decision
| Pattern | Population | Key factor | Treatment |
|---|---|---|---|
| Head Split | Young (less than 55) | Bone stock good | ORIF (Headless screws) |
| Head Split | Elderly (greater than 65) | Poor bone stock | Hemi or Reverse Arthroplasty |
| Small Impression | Any | Less than 20% | Non-operative |
| Large Impression | Active | Greater than 40% | Allograft / Arthroplasty |
HEADSurgical Goals
Memory Hook:Keep your HEAD in the game: Restore anatomy or Replace it.
LEGOAVN Risk Factors
Memory Hook:If the LEGO pieces are broken (calcar, hinge), AVN risk is high.
SIZEImpression Fracture Sizing
Memory Hook:Use the SIZE of the defect to determine treatment.
Overview
Humeral head fractures involve the articular surface of the proximal humerus. They are distinct from extra-articular tuberosity or surgical neck fractures. These injuries pose significant challenges due to the risk of avascular necrosis (AVN), post-traumatic arthritis, and technical difficulty in reduction.
Pathology
Mechanism:
- High energy trauma (axial load)
- Fall from height
- Seizures (Impression/Dislocation)
- Osteoporotic bone collapse
Prognosis
Outcomes:
- High rate of complications
- AVN is the primary concern
- Stiffness is common
- Arthroplasty reliable for pain relief but variable function
Anatomy and Pathophysiology
Anatomical Considerations
Arcuate Artery:
- Branch of Anterior Humeral Circumflex artery.
- Ascends in bicipital groove.
- Enters head at ligamentous insertion.
- Main supplier to humeral head.
Posterior Circumflex:
- Current evidence suggests this provides significant supply via posterior cuff.
- Medial hinge preservation protects this supply.
Disruption of the medial calcar often compromises perfusion.
Classification
Classification
Articular Segment Involvement:
- Anatomical Neck Fracture: Rare, high AVN risk.
- Impression Fracture:
- Less than 20%
- 20-40%
- Greater than 40%
- Head Splitting: Comminuted articular surface.
Neer focused on displacement and AVN risk.
Classification Prognosis
| Type | AVN Risk | Reconstructability | Treatment Choice |
|---|---|---|---|
| Head Split (Young) | High | Difficult but possible | ORIF (Attempt salvage) |
| Head Split (Elderly) | Very High | Poor | Arthroplasty |
| Impression less than 20% | Low | Good (Ignore) | Non-op |
| Impression greater than 40% | Variable | Poor | Arthroplasty / Allograft |
Exam Pearl
The "Head Split" is the most feared pattern. In an elderly patient, it is an automatic indication for arthroplasty as fixation failure and AVN are almost guaranteed.
Clinical Assessment
History and Physical Examination
History
Mechanism:
- High energy fall or MVA (Young).
- Low energy fall (Elderly).
- Seizure (Think posterior dislocation/impression).
Symptoms:
- Severe pain.
- Crepitus with ANY motion.
- global swelling.
Severe crepitus suggests intra-articular comminution.
Examination
Inspection:
- Extensive ecchymosis (Chest wall/Arm).
- Deformity.
Neurovascular:
- Axillary Nerve: Check deltoid tone and patch sensation.
- Distal Pulses: Ensure vascular tree is intact.
Motion:
- Do NOT check ROM: Aggressive motion can displace fragments further.
- Gentle pendulum only if stable.
Protect the soft tissues and neurovascular structures.
Investigations
Imaging Studies
Trauma Series:
- AP (Grashey): Joint space narrowing, fragmentation.
- Scapular Y: Dislocation check.
- Axillary: Key for head shape and tuberosity position.
Limitations:
- Often underestimates articular involvement.
- Overlapping shadows obscure split lines.
Plain films are screening tools only.
Management Algorithm
Treatment Decision Making
Indications:
- Non-displaced fractures.
- Minimally displaced head splits (rarely stay reduced).
- Impression fractures less than 20%.
- Low demand / Medical contraindications.
Protocol:
- Sling 2-4 weeks.
- Early passive motion (prevent stiffness).
- Monitor for displacement (X-ray weekly).
Accepts risk of post-traumatic arthritis.
Surgical Technique
Operative fixation
Indication: Young patient, Head Split.
- Approach: Deltopectoral.
- Reduction: Open book tuberosities to see joint. Clamp head fragments.
- Fixation: 3.0mm or 4.0mm Headless Compression Screws (Herbert).
- Placement: Buried beneath articular cartilage (must be sub-flush).
- Suture: Repair tuberosities/cuff over the construct.
Meticulous technique required to avoid screw cutout.
Complications
Potential Complications
Avascular Necrosis (AVN)
Major Risk: Ischemia leads to head collapse. Rate is greater than 50% for displaced head splits. Leads to screw cutout and joint destruction.
Post-Traumatic Arthritis
Cartilage Damage: Even with healing, the articular damage leads to rapid arthrosis. May require future conversion to arthroplasty.
Non-union
Tuberosity Failure: In both ORIF and Arthroplasty, if tuberosities don't heal, function is poor (loss of active elevation/rotation).
Stiffness
Frozen Shoulder: Scarring and pain limit motion. Early rehab is balanced against fixation stability.
Postoperative Care
Rehabilitation Protocol
- Sling immobilization.
- Pendulums only.
- Elbow/Wrist/Hand ROM.
- Supine passive forward elevation.
- External rotation restricted (protect subscap/tuberosities).
- Pulley exercises.
- Wean sling.
- AAROM (Wand exercises).
- Hydrotherapy.
- X-ray check for AVN/Collapse.
- Cuff strengthening.
- Scapular stabilizers.
- Return to non-contact activity.
Outcomes
Prognosis
- ORIF: High reoperation rate (20-30%) due to hardware removal or AVN conversion. Good function if reduction maintained and AVN avoided.
- RTSA: Reliable pain relief (90%). Active elevation greater than 130 degrees. Rotation depends on tuberosity healing.
- Hemiarthroplasty: variable pain relief (depends on glenoid wear). Good option if glenoid is pristine, but RTSA is surpassing it for reliability.
Evidence Base
Key Studies
Hertel et al. - Predictors of Ischemia
- Identified medial hinge less than 8mm as key predictor
- Anatomical neck fracture has highest risk
- Complex patterns increase ischemia risk
Jobin et al. - Reverse Arthroplasty for Fracture
- RTSA provides reliable outcomes for proximal humerus fractures in elderly
- Better forward elevation than Hemiarthroplasty
- Tuberosity healing improves external rotation
Gerber et al. - Latarjet for Reverse Hill-Sachs
- Described reconstruction of large anterior defects
- Avoids arthroplasty in young patients
- Technical difficulty is high
Solberg et al. - Locked Plating Outcomes
- High complication rate in head-splitting fractures with plates
- Screw penetration and AVN commmon
- Advocated for primary arthroplasty in selected cases
Chesser et al. - Head Split Definition
- Defined head split vs tuberosity fracture
- Poor interobserver reliability on plain film
- CT improves classification accuracy
Viva Scenarios
Practice these scenarios to excel in your viva examination
"You see a 75-year-old female with a comminuted humeral head splitting fracture. The tuberosities are also fractured. What is your management plan?"
"A 30-year-old male has a 40% impression fracture of the anterior humeral head (Reverse Hill-Sachs) after a seizure. It engages. Options?"
"Explain the Hertel Criteria for predicting AVN."
MCQ Practice
Self-Assessment Questions
Q1: Blood Supply
Q: Which artery provides the primary blood supply to the humeral head and is most at risk in anatomical neck fractures?
- A) Posterior Humeral Circumflex artery
- B) Anterior Humeral Circumflex artery (Arcuate branch)
- C) Suprascapular artery
- D) Thoracoacromial artery
- E) Subscapular artery
A: B - The arcuate branch of the Anterior Humeral Circumflex Artery ascends in the bicipital groove and enters the head intra-articularly. It is most commonly disrupted in anatomical neck fractures.
Q2: Prognostic Factors
Q: According to Hertel, which factor is the strongest predictor of humeral head ischemia?
- A) Age greater than 60
- B) Medial hinge less than 8mm
- C) 4-part fracture pattern
- D) Head split component
- E) Tuberosity displacement greater than 1cm
A: B - A medial metaphyseal head extension (medial hinge) of less than 8mm is the strongest predictor of ischemia due to disruption of the posterior circumflex contribution.
Q3: Management
Q: What is the preferred treatment for a displaced head-splitting fracture in a 75-year-old active patient?
- A) Non-operative treatment
- B) ORIF with locking plate
- C) Hemiarthroplasty
- D) Reverse Total Shoulder Arthroplasty
- E) Resection Arthroplasty
A: D - RTSA is preferred in the elderly with head-splitting fractures due to the high failure rate of ORIF (AVN/Cutout) and the unreliability of Hemiarthroplasty (tuberosity healing/cuff function).
Q4: Impression Fractures
Q: A 'Reverse Hill-Sachs' lesion is associated with which direction of shoulder instability?
- A) Anterior
- B) Posterior
- C) Inferior (Luxatio Erecta)
- D) Multidirectional
- E) Superior
A: B - A Reverse Hill-Sachs lesion is an impression fracture on the anteromedial aspect of the humeral head, caused by impaction against the posterior glenoid rim during a Posterior dislocation.
Q5: Fixation
Q: When fixing a head-split fracture in a young patient, which implant minimizes articular damage?
- A) 4.5mm Cortical Screws
- B) 3.5mm Locking Screws
- C) Headless Compression Screws (Herbert)
- D) K-wires
- E) Suture Buttons
A: C - Buried Headless Compression Screws are designed to be sunk below the cartilage surface, providing compression across the split without prominence that would damage the glenoid.
Australian Context
Australian Context
- Implants: Wide availability of RTSA systems (Arthrex, Stryker, Zimmer).
- Registry Data: AOANJRR shows increasing use of RTSA for trauma in patients greater than 65 with good survivorship.
- Referral: Complex head splits in young patients are often referred to tertiary upper limb units.
- Follow-up: Long-term surveillance for AVN is standard (up to 2 years).
Humeral Head Fractures - Exam Quick Reference
High-Yield Exam Summary
Key Facts
- •Def: Articular involvement (Split/Impression)
- •Risk: AVN (Arcuate artery)
- •Predictor: Hertel less than 8mm hinge
- •Assoc: Posterior dislocation (Impression)
- •Salvage: RTSA in elderly
Surgical Steps (ORIF)
- •Deltopectoral approach
- •Open book tuberosities
- •Reduce head fragments (Clamps)
- •Buried Headless Screws
- •Reattach Tuberosities
Common Pitfalls
- •Missing the head split on X-ray (Get CT)
- •Prominent hardware in joint
- •Using Hemi in cuff-deficient elderly
- •Ignoring posterior instability
Examiner Favorites
- •Hertel criteria for AVN
- •Blood supply to head
- •Reverse vs Hemi decision
- •Management of missed posterior dislocation