Paediatric Radial Neck, Olecranon and Elbow Dislocation Injuries

These three injuries sit close together, anatomically and clinically. A child presents with a radial neck fracture, an olecranon fracture or an elbow dislocation, and the surgeon has to go looking for the combined pattern. A radial neck fracture can accompany an elbow dislocation or a Monteggia injury, an olecranon fracture can be part of proximal ulna instability, and a reduced dislocation can hide an incarcerated medial epicondyle or an entrapped nerve.

Mechanism points to the pattern. Each mechanism has a likely injury and a check it should trigger:

• Fall on the outstretched hand with valgus load - radial neck fracture. Measure the angulation and check forearm rotation.
• Posterolateral dislocation mechanism - elbow dislocation with medial epicondyle avulsion, capsuloligamentous injury or nerve traction. Find the medial epicondyle and document median, ulnar and posterior interosseous nerve function.
• Direct blow to the posterior elbow - olecranon fracture, often with swelling over the extensor surface. Assess active extension and articular displacement.
• Forceful triceps contraction or avulsion - olecranon apophyseal or proximal ulna avulsion. Displacement and the state of the extensor mechanism are the decision points.
• High-energy fall or sport injury - biepicondylar fracture-dislocation, radial neck fracture with dislocation, proximal ulna fracture, or open injury. Do not call it isolated until the whole elbow and forearm are imaged.

The radial neck. The radial head ossifies during childhood, and the paediatric radial neck behaves differently from the adult radial head. The periosteal sleeve and the physis contribute to remodelling, but severe angulation, translation and a mechanical block to rotation are poorly tolerated. The posterior interosseous nerve passes close to the proximal radius as it enters the supinator, so its function must be documented before and after any manipulation.

The olecranon. It is the triceps insertion and part of the greater sigmoid notch, so treatment turns on whether the articular surface and the extensor mechanism still work. In a child the olecranon apophysis and proximal ulna alignment can make the injury look deceptively small. Any proximal ulna deformity should raise concern for radiocapitellar instability.

The medial epicondyle. In children the medial collateral ligament attaches to the medial epicondylar apophysis, so a dislocation can avulse the medial epicondyle rather than rupture the ligament in its midsubstance. During spontaneous or closed reduction the fragment can become trapped in the ulnohumeral joint. The ulnar nerve runs posterior to the medial epicondyle, and the median nerve can, rarely, be entrapped after dislocation.

The common theme is failure of the paediatric elbow ring, and the visible fracture may be only one part of the instability pattern.

Radial neck. Valgus and axial load compress the radial head against the capitellum. The cartilaginous head and physis make displacement harder to appreciate on plain films, so painful rotation and a mechanical block matter more than the radiographic label alone.

Olecranon. The triceps pulls the proximal fragment, and the olecranon forms the articular notch of the ulnohumeral joint. Displacement therefore threatens both the joint surface and active elbow extension.

Dislocation. The ulna and radius dislocate relative to the distal humerus, often through posterolateral instability.

Monteggia variants. Proximal ulna deformity changes the relationship of the radial head to the capitellum. Restoring only the radial neck, or only the dislocation, misses the driver of the radiocapitellar malalignment.

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What remodelling will not fix. Young children remodel some angulation. Remodelling does not reliably correct severe translation, blocked forearm rotation, joint incongruity, incarcerated fragments or extensor mechanism failure, and these are the findings that move treatment from observation to reduction or fixation.

Classification should help communication and treatment, not replace clinical judgement. The practical groups for each injury, and the treatment each implies, are set out under Treatment Thresholds. For the radial neck, examiners expect a named formal classification as well.

Judet grades the radial neck fracture by angulation. Higher Judet types are progressively harder to reduce closed and more likely to need percutaneous or intramedullary assistance.

• Type I - undisplaced
• Type II - angulation under 30 degrees
• Type III - angulation about 30-60 degrees
• Type IV - angulation over 60 degrees, up to complete displacement, sometimes subdivided IVa and IVb

O'Brien is a simpler angulation tier and a commonly quoted shorthand: Type I under 30 degrees, Type II 30-60 degrees, Type III over 60 degrees. It maps onto the same treatment ladder.

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History. Ask enough to establish the injury pattern and its urgency:

• Mechanism - fall, valgus load, direct posterior blow, dislocation event or high-energy trauma
• Time from injury, and whether the elbow was reduced before you saw it
• Where it hurts - radial head and neck, olecranon, medial epicondyle, or diffusely
• Mechanical block - inability to pronate or supinate suggests radial neck displacement or an intra-articular block
• Neurological symptoms - numbness, paraesthesia, weakness, clawing, inability to extend the fingers or thumb
• Vascular symptoms - cold hand, colour change, severe swelling or an escalating analgesic requirement
• Previous elbow injury, hyperlaxity, sporting demand and hand dominance

Look. Inspect the elbow from the front, the side and behind for swelling, deformity, bruising, skin puckering, wounds and the carrying angle. Gross deformity suggests a dislocation or displaced fracture, and posterior swelling localises to the olecranon. Threatened skin or an open wound escalates urgency.

Feel. Palpate the distal humerus, medial epicondyle, lateral condyle, radial head and neck while gently rotating the forearm, then the olecranon, proximal ulna and wrist. Focal radial neck tenderness with painful rotation supports a radial neck injury, and medial tenderness after a dislocation suggests epicondyle avulsion. Ulna tenderness raises concern for a Monteggia injury.

Move. If it is safe, assess active flexion-extension and pronation-supination, and do not force movement in a displaced injury. Blocked rotation suggests radial neck displacement, an incarcerated fragment or a radiocapitellar problem.

The extensor mechanism. Ask the child to extend the elbow actively against gravity if pain and the fracture pattern allow. Loss of active extension with an olecranon fracture suggests extensor disruption and supports fixation.

Stability after reduction. Reassess congruity clinically and radiographically, and avoid aggressive stress testing in an awake child. Persistent instability or blocked motion suggests a complex dislocation, an incarcerated fragment or an associated fracture.

Nerves and vessels. Test and record each structure before and after reduction.

Differential diagnosis. The painful, swollen paediatric elbow has several overlapping causes, and their management differs sharply. Separate them with a systematic radiograph read rather than a single glance.

What to request. Order imaging that answers the surgeon's questions, not just "elbow X-ray":

• AP and true lateral elbow radiographs - mandatory first-line views
• Radiocapitellar or oblique view - helpful if radial neck alignment or the relationship to the capitellum is unclear
• Forearm AP and lateral including wrist and elbow - when there is ulna pain, deformity, plastic bowing or any concern for a Monteggia variant
• Post-reduction AP and lateral radiographs - mandatory after reduction of an elbow dislocation
• Comparison elbow radiographs - useful when the ossification centres make the medial epicondyle or trochlea difficult to interpret
• CT - complex fracture-dislocation, articular olecranon fracture planning, uncertainty about an incarcerated fragment, or surgical planning
• MRI or ultrasound for nerve entrapment - not routine, but useful when neurological symptoms persist or median nerve entrapment is suspected

The radiocapitellar line. A line drawn down the centre of the radial shaft and neck should pass through the capitellum. Failure suggests a radial head dislocation, a Monteggia pattern or an inadequate reduction. Draw it on both the AP and the lateral: apparent reduction on one projection is insufficient.

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Radial neck angulation and translation. Measure the angle between the radial shaft axis and the radial head and neck axis on the view showing maximum deformity, never from a single suboptimal view. Then assess percentage displacement and head-neck contact. Translation plus angulation predicts reduction difficulty and may require percutaneous or intramedullary assistance.

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The olecranon and the ulna. Inspect the greater sigmoid notch on the true lateral and AP, and get a CT if the joint line is unclear. Look along the ulna for a proximal fracture, plastic deformation or bowing, and image the forearm if uncertain.

The medial epicondyle. After a dislocation, confirm that the medial epicondyle is visible in its normal position for age. An absent or intra-articular fragment suggests entrapment and operative extraction and fixation. A trapped medial epicondyle can mimic another ossification centre and should not be dismissed as normal development.

CRITOE. The ossification centres appear in the order Capitellum, Radial head, Internal (medial) epicondyle, Trochlea, Olecranon, External (lateral) epicondyle, at roughly 1, 3, 5, 7, 9 and 11 years (a useful approximation; girls slightly earlier than boys). The order is far more reliable than the exact ages. After a dislocation, run the sequence on the film: an absent medial epicondyle for age, or an extra fragment in the joint line, means search for and extract an incarcerated medial epicondyle, with comparison films or CT if unsure.

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Each injury has practical groups, and the group sets the treatment direction.

Radial neckOlecranonElbow dislocation

Operate for unacceptable angulation or translation, blocked rotation, failed closed reduction or associated instability. The goal is to restore radiocapitellar alignment and forearm rotation while avoiding open reduction if possible.

Acceptable or minimally displaced

Typical Features

Low angulation, minimal translation, painless or acceptable rotation and no associated instability.

Treatment Direction

Above-elbow immobilisation, early review and motion when safe.

Moderately displaced

Typical Features

About 30-60 degrees angulation (around the common reduction threshold), translation, or clinically important loss or block of rotation.

Treatment Direction

Closed reduction first; accept reduction only if motion and alignment are satisfactory.

Severe or failed closed reduction

Typical Features

Marked angulation, major translation, mechanical block or unsuccessful closed manoeuvre.

Treatment Direction

Percutaneous leverage, joystick technique or intramedullary reduction/fixation.

Irreducible fracture

Typical Features

Soft-tissue interposition, complete displacement, delayed presentation or failed minimally invasive methods.

Treatment Direction

Open reduction only when required.

Associated injury pattern

Typical Features

Elbow dislocation, olecranon or proximal ulna injury, or Monteggia variant.

Treatment Direction

Changes the plan: treat the whole pattern.

Radial Neck: Practical Treatment Groups

Pattern	Typical Features	Treatment Direction
Acceptable or minimally displaced	Low angulation, minimal translation, painless or acceptable rotation and no associated instability.	Above-elbow immobilisation, early review and motion when safe.
Moderately displaced	About 30-60 degrees angulation (around the common reduction threshold), translation, or clinically important loss or block of rotation.	Closed reduction first; accept reduction only if motion and alignment are satisfactory.
Severe or failed closed reduction	Marked angulation, major translation, mechanical block or unsuccessful closed manoeuvre.	Percutaneous leverage, joystick technique or intramedullary reduction/fixation.
Irreducible fracture	Soft-tissue interposition, complete displacement, delayed presentation or failed minimally invasive methods.	Open reduction only when required.
Associated injury pattern	Elbow dislocation, olecranon or proximal ulna injury, or Monteggia variant.	Changes the plan: treat the whole pattern.

Operate for a displaced articular fracture, an unstable fracture, extensor mechanism disruption or a Monteggia-associated injury. The goal is to restore the trochlear notch and the triceps lever.

Undisplaced stable fracture

Key Finding

No meaningful articular displacement; extensor mechanism intact and articular surface congruent.

Treatment Direction

Immobilise, repeat radiographs to ensure it stays reduced, then regain motion.

Displaced intra-articular fracture

Key Finding

Step-off, gap, loss of trochlear notch congruity or loss of extensor mechanism.

Treatment Direction

Anatomical open reduction and stable fixation.

Avulsion/apophyseal pattern

Key Finding

Triceps-driven: apophyseal fragment or extension weakness, often judged by displacement and extension strength.

Treatment Direction

Fix if displaced or extensor mechanism compromised.

Proximal ulna instability (Monteggia-associated)

Key Finding

Olecranon or proximal ulna injury plus radiocapitellar malalignment.

Treatment Direction

Restore ulna length/alignment and radiocapitellar joint.

Olecranon: Practical Treatment Groups

Pattern	Key Finding	Treatment Direction
Undisplaced stable fracture	No meaningful articular displacement; extensor mechanism intact and articular surface congruent.	Immobilise, repeat radiographs to ensure it stays reduced, then regain motion.
Displaced intra-articular fracture	Step-off, gap, loss of trochlear notch congruity or loss of extensor mechanism.	Anatomical open reduction and stable fixation.
Avulsion/apophyseal pattern	Triceps-driven: apophyseal fragment or extension weakness, often judged by displacement and extension strength.	Fix if displaced or extensor mechanism compromised.
Proximal ulna instability (Monteggia-associated)	Olecranon or proximal ulna injury plus radiocapitellar malalignment.	Restore ulna length/alignment and radiocapitellar joint.

Operate for an irreducible dislocation, an incarcerated medial epicondyle, an open injury, persistent instability or an associated fracture that needs fixation. The goal is to restore congruity, extract incarcerated fragments and stabilise the elbow. An incarcerated fragment is an absolute operative indication; other displaced medial epicondyle fractures need an individual decision on stability, nerve status and functional demand, and remain a genuine controversy.

Simple stable dislocation

What You See

No fixation-requiring fracture, congruent and stable reduction, stable functional arc.

Treatment Direction

Brief immobilisation then early protected motion.

Medial epicondyle entrapment

What You See

Fragment absent from its normal location or visible in the joint after reduction.

Treatment Direction

Open extraction and fixation; protect ulnar nerve.

Unstable dislocation

What You See

Redislocates, opens under stress, gross instability or cannot maintain congruent reduction.

Treatment Direction

Address bony and ligamentous stabilisers; temporary fixation or repair if needed.

Complex fracture-dislocation

What You See

Associated radial neck, olecranon, epicondylar, lateral condyle, coronoid or proximal ulna injury.

Treatment Direction

Treat the reconstructable pattern; do not manage as a simple dislocation.

Elbow Dislocation: Simple vs Complex

Pattern	What You See	Treatment Direction
Simple stable dislocation	No fixation-requiring fracture, congruent and stable reduction, stable functional arc.	Brief immobilisation then early protected motion.
Medial epicondyle entrapment	Fragment absent from its normal location or visible in the joint after reduction.	Open extraction and fixation; protect ulnar nerve.
Unstable dislocation	Redislocates, opens under stress, gross instability or cannot maintain congruent reduction.	Address bony and ligamentous stabilisers; temporary fixation or repair if needed.
Complex fracture-dislocation	Associated radial neck, olecranon, epicondylar, lateral condyle, coronoid or proximal ulna injury.	Treat the reconstructable pattern; do not manage as a simple dislocation.

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Initial care. Pain control and a splint come first, because a calm, supported child is easier and safer to assess. Open injury, threatened skin, vascular compromise or compartment concern override routine fracture pathways and are escalated. Document median, ulnar and posterior interosseous nerve function before any reduction, so that a new deficit after manipulation is recognised.

Reduction. Reduce a dislocated elbow promptly if there is no contraindication; a congruent joint protects the soft tissues and nerves. Then repeat the neurovascular examination and the AP and lateral radiographs.

Non-operative care is appropriate when the joint is congruent, fracture displacement is acceptable, extensor function is preserved where relevant, and there is no nerve, vascular, open or mechanical-block concern.

Immobilisation and early films. An above-elbow splint or cast, with the forearm position chosen for comfort and stability, protects the fracture or the reduced joint while swelling settles. Repeat the films early for fractures at risk of displacement, to detect loss of position before it becomes established.

Motion. The paediatric elbow stiffens quickly after trauma, so avoid prolonged immobilisation once stability allows motion. Encourage hand, wrist and shoulder movement while the elbow is protected, which reduces stiffness and swelling outside the injured elbow.

Safety-net advice. Parents should bring the child back for increasing pain, numbness, cold fingers, swelling, fever, a wound concern or loss of finger extension. These symptoms may signal a nerve, vascular, infective or compartment problem.

Radial neck reduction ladder

The principle is to reduce the radial neck with the least soft-tissue stripping that gives a stable, congruent, mobile elbow.

Closed reduction. Traction, varus or valgus correction as appropriate, forearm rotation and direct pressure over the radial head and neck, under the image intensifier. Do not force the fracture repeatedly; recheck rotation and radiocapitellar alignment.

Percutaneous leverage. A small K-wire or elevator is used as a joystick or lever under fluoroscopy. Stay aware of the posterior interosseous nerve: make controlled passes and avoid multiple blind attempts. In the rotation-prying manoeuvre a prebent wire is advanced to the fragment and rotated to elevate the radial head, with controlled thumb pressure added. Every pass is image-guided to protect the posterior interosseous nerve and the physis.

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Intramedullary reduction and fixation. A prebent elastic nail is passed from the distal radius region and rotated to elevate and reduce the radial head fragment. The nail reduces and supports the fragment while limiting direct disruption of the radial head blood supply. It is useful for displaced fractures when closed reduction is inadequate: avoid physeal injury, and confirm head-neck alignment and free forearm rotation before accepting the construct.

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Open reduction. A lateral approach, only when closed and percutaneous methods fail or the fracture is irreducible. Preserve the periosteum and soft tissue, and warn about stiffness, avascular necrosis and synostosis.

Olecranon fixation

A posterior approach centred on the olecranon, with the operation directed by the fracture pattern:

• Simple transverse displaced fracture - reduce the articular surface anatomically. Fixation may be a suture tension band, wire tension band, intramedullary screw or combined construct, depending on size and maturity.
• Comminuted or oblique pattern - a plate may give better control than a tension band alone.
• Skeletally immature child - minimise physeal and apophyseal injury, and choose fixation that avoids unnecessary hardware prominence.
• Associated instability - confirm radiocapitellar congruity and ulna alignment after fixation.

The steps:

1. Position supine or lateral with image intensifier access.
2. Mark the olecranon, proximal ulna, medial epicondyle and the course of the ulnar nerve.
3. Posterior incision; protect the skin flaps and avoid unnecessary ulnar nerve handling unless the approach extends medially.
4. Clear the fracture haematoma without stripping soft tissue unnecessarily.
5. Reduce the articular surface and confirm on AP and lateral fluoroscopy.
6. Fix according to the pattern above, whether tension band, screw, plate or hybrid.
7. Test elbow motion and radiocapitellar alignment before closure.
8. Immobilise initially, then start motion when fixation and soft tissues allow.

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Elbow dislocation with incarcerated medial epicondyle

This is a surgical problem because the fragment blocks restoration of the joint and carries the medial collateral ligament attachment.

1. Position supine with the arm on a hand table.
2. Mark the medial epicondyle, olecranon and ulnar nerve.
3. Use a medial approach centred over the medial epicondyle.
4. Identify and protect the ulnar nerve; transpose only if needed for exposure, instability or nerve symptoms.
5. Open the joint enough to extract the incarcerated fragment.
6. Reduce the medial epicondyle to its origin and fix with a screw, K-wire or suture construct according to fragment size and skeletal maturity.
7. Confirm ulnohumeral and radiocapitellar congruity on AP and lateral images.
8. Check elbow stability through a safe arc.
9. Repeat and document median, ulnar and posterior interosseous nerve function post-operatively.

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Implant migration. An elastic intramedullary nail used for a radial neck fracture can migrate into the joint. New pain, loss of motion or an altered implant position requires urgent imaging and timely removal or revision.

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Unstable fixation or an unrecognised associated injury is worse than a short period of protection, so rehabilitation depends on the stability achieved.

What recovery means. Parents should understand that bone healing is only part of it. The child also needs a congruent elbow, recovering motion, intact nerve function and no missed associated injury.

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Paediatric elbow trauma is managed worldwide, and the broad principles are consistent across societies even though the supporting evidence is mostly low level. There is no implant registry for paediatric elbow fractures comparable to adult arthroplasty registries, so practice is guided by society statements, trauma networks and large series.

Global epidemiology

• Elbow fractures are among the most common paediatric fractures, with supracondylar fractures the largest group; radial neck fractures comprise roughly 5-10% of paediatric elbow fractures and about 1% of all paediatric fractures.
• Medial epicondyle fractures have an estimated incidence near 40-60 per 100,000 per year and are associated with elbow dislocation in about 60% of cases.
• Median nerve injury complicates approximately 3% of paediatric elbow dislocations, linked to medial epicondyle avulsion.

Side-by-side guidance

High- versus limited-resource practice

Much of paediatric elbow trauma rests on retrospective series rather than randomised trials. Examiners reward the candidate who can say where the evidence is genuinely unsettled.