RADIAL NECK FRACTURES
Pediatric | O'Brien Classification | Reduction Techniques
O'BRIEN CLASSIFICATION (By Angulation)
Critical Must-Knows
- Less than 30° angulation = no reduction needed in children less than 10 years
- Less than 45° angulation = acceptable in children over 10 years
- Closed reduction techniques: supination and valgus, Israeli technique (thumb pressure)
- Patterson technique: percutaneous K-wire joystick reduction
- Avoid open reduction if possible - high rate of stiffness and AVN
Examiner's Pearls
- "Radial head does not appear until age 3-5, neck fractures more common in children
- "Posterior interosseous nerve (PIN) at risk - assess finger/thumb extension
- "Open reduction associated with higher complication rates
- "Metaizeau technique: ESIN reduction without opening
Critical Exam Concepts
Reduction Threshold
Less than 30° angulation = No reduction needed. Aim for less than 30° in young children, less than 45° in adolescents. The radial head has significant remodeling potential.
Avoid Open Reduction
Open reduction has higher complications. Associated with stiffness, AVN, radioulnar synostosis. Try closed, then percutaneous, then intramedullary (Metaizeau) before opening.
PIN Injury
Posterior interosseous nerve at risk. Assess finger and thumb extension before and after any intervention. Usually neurapraxia. Watch for iatrogenic injury during percutaneous methods.
Mechanism
Valgus force with axial load. Fall on outstretched hand with elbow extended. Associated with Monteggia variants and elbow dislocation in 10% of cases.
Quick Decision Guide by Angulation
| Angulation | Classification | Management |
|---|---|---|
| Less than 30° | O'Brien Type I | Non-operative - cast |
| 30-45° | O'Brien Type II | Closed reduction attempted |
| 45-60° | O'Brien Type II-III | Closed or percutaneous reduction |
| Greater than 60° | O'Brien Type III-IV | Percutaneous/Metaizeau/consider open |
30-45Angulation Thresholds
Memory Hook:30 for young, 45 for old - both end in fives!
CIPOMReduction Escalation
Memory Hook:Escalate systematically - avoid open if possible!
SASAComplications of Open Reduction
Memory Hook:SASA remember why to avoid open!
Overview and Epidemiology
Why Neck Not Head?
In children, the radial head is largely cartilaginous and the neck is weaker. Force transmission causes neck fractures rather than head fractures seen in adults. The radial head ossification center appears at age 3-5 years.
Epidemiology
- 5-10% of pediatric elbow fractures
- Peak age 9-10 years
- Equal male to female ratio
- Usually falls (playground, sports)
- Associated injuries common (50%)
Associations
- Elbow dislocation (10%)
- Olecranon fractures
- Ulna fractures (Monteggia variant)
- Medial epicondyle fractures
- Capitellum injuries
Anatomy and Biomechanics
Critical Anatomy
The posterior interosseous nerve (PIN) runs anteriorly around the radial neck. At risk during injury and during percutaneous/open procedures. Enters supinator at arcade of Frohse. Assess finger and thumb extension.
Radial Head Vascularity
Blood supply: Primarily through periosteal vessels around the neck. Intramedullary flow minimal.
AVN risk: Disruption of periosteal vessels during open reduction can cause AVN. Preserve soft tissues if surgery needed.
Remodeling: Excellent potential in children due to physis contribution to growth and robust blood supply.
Classification Systems
O'Brien Classification (By Angulation)
| Type | Angulation | Treatment |
|---|---|---|
| Type I | Less than 30° | Non-operative |
| Type II | 30-60° | Closed reduction |
| Type III | Greater than 60° | Percutaneous or open reduction |
| Type IV | 90° (complete displacement) | Usually requires open reduction |
Key point: Angulation measured from shaft axis on lateral X-ray.
Clinical Assessment
History
- Fall on outstretched hand
- Valgus mechanism
- Lateral elbow pain
- Difficulty with rotation
- Associated dislocation
Examination
- Lateral elbow tenderness
- Swelling radiocapitellar region
- Limited pronation/supination
- PIN function (finger/thumb extension)
- Elbow stability
PIN Assessment
Test BEFORE any intervention. Ask child to extend fingers at MCPs and thumb at IP joint. Compare to other side. PIN injury presents as weak or absent extension. Usually neurapraxia with complete recovery.
Associated Injuries
50% have associated elbow injuries. Check for olecranon fracture, medial epicondyle fracture, elbow dislocation. Monteggia variant may have associated radial neck injury.
Investigations
X-ray Protocol
Standard views: AP and lateral elbow.
Measurements: Angulation on lateral view - angle between radial shaft and head/neck line.
Associated injuries: Check for elbow dislocation, ulna fracture, olecranon fracture.
Management
Key Principle
Avoid open reduction if possible. Open reduction has significantly higher rates of stiffness, AVN, and synostosis. Escalate through closed, then percutaneous, then intramedullary techniques before considering open.
Non-Operative Management
Indications: Angulation less than 30° in younger children (under 10 years). Angulation less than 45° in adolescents. Stable elbow.
Protocol: Above-elbow cast or splint for 2-3 weeks. Early ROM exercises after. Full activity at 6 weeks.
Outcomes: Excellent. These fractures remodel well.
Reduction Escalation
Escalate systematically. Closed reduction first (supination-valgus, Israeli). If failed, percutaneous K-wire (Patterson). If failed, Metaizeau ESIN. Open only as last resort due to complications.
Surgical Technique Considerations
Percutaneous K-Wire Reduction
Setup: Patient supine. Fluoroscopy. Sedation or GA.
Approach: Insert 1.5-2mm K-wire from lateral side into fracture site adjacent to tilted radial head.
Reduction: Use wire as joystick. Lever angulated head back into position while applying gentle supination.
Post-reduction: Above-elbow cast. Wire removed at 2-3 weeks.
Complications
Complications of Radial Neck Fractures
| Complication | Incidence | Management |
|---|---|---|
| Loss of ROM | 20-50% | Usually pronation/supination. Most improve with time. |
| PIN injury | 5-10% | Usually neurapraxia. Observe. Most recover. |
| AVN radial head | 5-10% | Related to open reduction. May need excision if symptomatic. |
| Radioulnar synostosis | Rare | Cross-union. May need excision. |
| Malunion | Variable | Accept some angulation. Remodeling helps. |
| Heterotopic ossification | Rare | May limit motion. Excise if mature and symptomatic. |
Open Reduction Complications
Open reduction has 2-3x higher complication rates. Stiffness rates up to 50% with open vs 10-20% with closed. AVN and synostosis almost exclusively with open procedures. This is why escalation through closed techniques is so important.
Postoperative Care
Post-Treatment Protocol
Above-elbow cast or splint. Elbow at 90°. Neutral forearm rotation. Non-weight bearing.
Remove cast. Begin active ROM - focus on pronation/supination. Avoid passive stretching.
Progressive strengthening. Return to light activities. Avoid contact sports.
Full return to sports. Monitor for late stiffness. Some ROM loss may persist but often not functional.
Outcomes and Prognosis
Prognosis by Treatment
Non-operative (less than 30°): Excellent prognosis. Full ROM expected. Complete remodeling.
Successful closed reduction: Good outcomes. Some minor ROM loss common but rarely functional.
Percutaneous/Metaizeau: Intermediate outcomes. Better than open reduction.
Open reduction: Higher complication rates. Significant stiffness in up to 50%. AVN risk.
Special Considerations
Radial Neck with Elbow Dislocation
Frequency: 10% of radial neck fractures associated with dislocation.
Priority: Reduce dislocation first. Assess radial head position after.
Management: May need fixation if radial head unstable after dislocation reduced.
Evidence Base and Key Studies
O'Brien Classification Study
- Developed angulation-based classification
- Established 30° as threshold for reduction
- Identified relationship between angulation and outcomes
- Described remodeling potential in children
Closed vs Open Reduction Outcomes
- Open reduction had higher complication rates
- Stiffness more common with open treatment
- Closed reduction preferred when possible
- Long-term follow-up showed satisfactory outcomes
Patterson Percutaneous Technique
- Described K-wire joystick technique
- Allows reduction without open surgery
- Lower morbidity than open reduction
- Still widely used today
Metaizeau Intramedullary Technique
- Described ESIN technique for radial neck
- Avoids open reduction entirely
- Good reduction achieved in most cases
- Lower complication rate than open
Long-term Outcomes Study
- Followed radial neck fractures long-term
- Most had good functional outcomes
- Some ROM loss common but rarely limiting
- Remodeling significant in younger children
Exam Viva Scenarios
Practice these scenarios to excel in your viva examination
Scenario 1: Moderately Angulated Radial Neck
"A 9-year-old girl falls on an outstretched hand. X-ray shows a radial neck fracture with 40° angulation. Finger and thumb extension are normal. How would you manage this?"
Scenario 2: Severely Angulated Radial Neck
"An 8-year-old boy has a radial neck fracture with 70° angulation and moderate translation. Closed reduction under sedation failed to improve angulation beyond 50°. What are your next steps?"
Scenario 3: PIN Injury After Reduction
"You perform closed reduction of a radial neck fracture. Post-reduction, the child cannot extend their fingers at the MCPs or their thumb at the IP joint. What is your assessment and management?"
MCQ Practice Points
Angulation Threshold Question
Q: What angulation threshold is acceptable for non-operative management in a 7-year-old? A: Less than 30°. Younger children have greater remodeling potential. Older children (over 10) = 45° threshold.
Nerve at Risk Question
Q: Which nerve is at risk in radial neck fractures? A: Posterior interosseous nerve (PIN). Motor branch of radial nerve. Test finger and thumb extension.
Reduction Technique Question
Q: What technique uses a K-wire as a joystick for radial neck reduction? A: Patterson technique. Percutaneous K-wire inserted adjacent to radial head, used to lever head into position.
Complication Question
Q: Why should open reduction be avoided in radial neck fractures? A: Higher complication rates. Stiffness (up to 50%), AVN, and radioulnar synostosis all more common with open reduction.
Classification Question
Q: What is O'Brien Type III radial neck fracture? A: Greater than 60° angulation. Usually requires percutaneous or open reduction.
Metaizeau Question
Q: What is the Metaizeau technique? A: ESIN reduction. Flexible nail inserted through distal radius, used to lever radial head from below without opening.
Australian Context
Epidemiology
- Common presentation in Australian pediatric EDs
- Falls in playgrounds, trampolines common
- Sports injuries (gymnastics, cricket)
- Often managed at pediatric tertiary centers
Practice
- Conservative management preferred
- Metaizeau technique widely used for severe angulation
- Open reduction avoided when possible
- Good access to pediatric orthopedic services
RADIAL NECK FRACTURES
High-Yield Exam Summary
Angulation Thresholds
- •Less than 30° = non-operative (under 10 years)
- •Less than 45° = non-operative (over 10 years)
- •Greater than 30-45° = reduction indicated
- •Greater than 60° = percutaneous or ESIN/open
O'Brien Classification
- •Type I: less than 30° (non-operative)
- •Type II: 30-60° (closed reduction)
- •Type III: greater than 60° (perc/open)
- •Type IV: 90°/complete (usually open)
Reduction Escalation
- •Closed first (Patterson supination-valgus)
- •Then percutaneous K-wire joystick
- •Then Metaizeau ESIN
- •Open reduction LAST resort
Avoid Open Because
- •Stiffness up to 50%
- •AVN of radial head
- •Radioulnar synostosis
- •Higher overall complication rate
PIN Injury
- •5-10% incidence
- •Test finger/thumb extension
- •Usually neurapraxia
- •Recovery expected 3-6 months