Paediatric elbow fracture

X-ray

First and second year — the floor first, then every step

Three lines and two fat pads on the lateral and AP radiographs find almost every paediatric elbow fracture: the anterior humeral line, the radiocapitellar line, and the ossification centres in their CRITOE order.

Orient first

A displaced POSTERIOR fat pad on a true lateral view means an effusion, and in a child after trauma that means an occult fracture (usually supracondylar) until proven otherwise.
Ossification centres appear in a predictable order — Capitellum, Radial head, Internal (medial) epicondyle, Trochlea, Olecranon, External (lateral) epicondyle (CRITOE). A trochlear centre seen without a medial epicondyle centre in its place suggests an avulsed medial epicondyle trapped in the joint.
The supracondylar fracture is the commonest; the lateral condyle fracture is the one that looks minor and goes wrong.

Acquire the study

AP and TRUE LATERAL of the elbow (the lateral in 90° flexion, with the humerus and forearm on the cassette); comparison views of the other elbow only for specific ossification questions.

The manoeuvre

True lateral: the posterior fat pad (should be invisible) and the anterior fat pad (should be a thin line, not a "sail").
True lateral: the ANTERIOR HUMERAL LINE drawn along the anterior humeral cortex should pass through the middle third of the capitellum; passing through the anterior third or missing it means posterior displacement (supracondylar extension fracture).
Both views: the RADIOCAPITELLAR LINE along the radial neck axis must pass through the capitellum — if not, the radial head is dislocated (look for a Monteggia ulnar fracture).
AP: the lateral condyle — a thin metaphyseal flake with a fracture line into the capitellar physis; measure displacement at the widest gap in mm.
Count the ossification centres against CRITOE and the child's age; check the medial epicondyle is where it should be.
The ulna along its whole length (Monteggia) and the olecranon.

What confirms it

A fracture line, or a positive fat pad sign with a deviated anterior humeral line.

What licenses you to exclude it

An elbow with a displaced posterior fat pad and no visible fracture is treated as an occult fracture; it is not normal.

The classic misread

Calling a trapped medial epicondyle the trochlear centre.
Missing a radial head dislocation because the ulnar bow fracture is subtle (Monteggia).
Using a non-true lateral view, which makes the fat pads and the anterior humeral line unreliable.

Reporting the injury

Classification to use

Supracondylar: Gartland I (undisplaced), II (displaced, posterior cortex intact — hinged), III (completely displaced); some add IV (multidirectionally unstable). Lateral condyle fractures by displacement (and Milch type). Medial epicondyle: displacement and entrapment. Monteggia: Bado I–IV.

Measurements — and how to take them

Lateral condyle fracture: the maximal gap in mm (≥ 2 mm is commonly used to separate conservative from operative management — verify).
Medial epicondyle displacement in mm, and whether it lies in the joint.

What to report

Fat pads, anterior humeral line and radiocapitellar line findings; the fracture, its type and displacement; ossification centres present and in position; forearm bones.

How to report it

X-ray: "Elevated anterior and posterior fat pads. The anterior humeral line passes anterior to the capitellum. Supracondylar fracture with posterior displacement of the distal fragment and an intact posterior cortex — Gartland II."
X-ray: "Lateral condyle fracture with 3 mm displacement at its widest point on the AP view."

What not to report

Do not report "no fracture" when the posterior fat pad is displaced; report an effusion and a probable occult fracture.

Associated injuries to look for

Brachial artery and median/anterior interosseous nerve injury with Gartland III; forearm (Monteggia) injuries; non-accidental injury in a young child with an unusual pattern or history.

What changes management

Gartland II–III — reduction and pinning; pulseless hand — emergency.
Displaced lateral condyle fracture; medial epicondyle entrapped in the joint — surgery.
Radial head dislocation — look for and treat the Monteggia ulnar injury.

Reference values

Each value carries the caveat that keeps it from being misused. Normal limits and diagnostic criteria are kept apart on purpose: a disease cut-off read as a normal range is the more dangerous mistake.

Normal limits

Elbow · Carrying angle
approximately 5–15°, greater in women
AP radiograph with the elbow extended and the forearm fully supinated. The angle between the long axis of the humerus and the long axis of the ulna.
Reduced or reversed (cubitus varus, "gunstock" deformity) after a malunited supracondylar fracture. ⚠️ SUPINATION AND FULL EXTENSION ARE REQUIRED — any flexion or pronation changes the angle materially. Compare with the uninjured side.
X-ray
Elbow ossification centres · CRITOE / CRITOL order
a named order: Capitellum, Radial head, Internal (medial) epicondyle, Trochlea, Olecranon, External (lateral) epicondyle — ages are approximate and the ORDER is the test
⚠️ Do not quote remembered ages as if they were laboratory values — the appearance ORDER catches the missing medial epicondyle that has been mistaken for a "trochlea". The contralateral film is the reference.
X-ray
Distal humerus · Baumann angle
approximately 70–75°, and within about 5° of the uninjured side
AP elbow radiograph with the beam along the humeral shaft. The angle between the humeral shaft axis and a line along the lateral condylar physis.
⚠️ THE CONTRALATERAL SIDE IS THE REFERENCE, not the absolute figure — normal varies between children, and the reason to measure at all is to detect coronal malalignment after a supracondylar fracture. Rotation of the film changes the angle. This entry was NOT confirmed against a named source in this session; treat the absolute range as unverified.
X-ray
Radiocapitellar joint · Radiocapitellar joint-space concentricity
a congruent radiocapitellar space on every projection (the radiocapitellar-line entry is the alignment companion); isolated space loss is uncommon and usually technical
A dropped radiocapitellar line is Monteggia / dislocation, not “joint-space narrowing”. True lateral first.
X-ray

Diagnostic criteria

Elbow · Anterior humeral line
passes through the middle third of the capitellum
TRUE lateral elbow radiograph. A line drawn along the anterior cortex of the humeral shaft, extended distally across the capitellum.
A line passing anterior to the middle third indicates posterior displacement of the distal fragment — the classic sign of an extension-type supracondylar fracture. ⚠️ REQUIRES A TRUE LATERAL; obliquity invalidates it entirely, and in children under about 4 the capitellum may be too poorly ossified to judge.
X-ray
Elbow · Radiocapitellar line
passes through the capitellum on EVERY projection
A line along the central axis of the radial neck, extended proximally. Assessed on AP, lateral and oblique views.
⚠️ "EVERY PROJECTION" IS THE RULE, and it is the one most often broken — a radial head can look located on the AP and be dislocated on the lateral. A missed Monteggia is a classic and consequential paediatric miss; check the ulna for a fracture or plastic bowing whenever this line is abnormal.
X-ray
Elbow · Fat pad signs
a thin anterior fat pad may be normal; a posterior fat pad is always abnormal
True lateral elbow radiograph in 90° flexion.
A visible POSTERIOR fat pad indicates a joint effusion and, in the right clinical setting, an occult fracture — radial head in adults, supracondylar in children. An elevated anterior ("sail") fat pad is the same message. ⚠️ Only valid on a true lateral in flexion; a poorly positioned film both hides and fabricates it.
X-ray
Lateral condyle (paediatric) · Milch type of lateral-condyle fracture
a named I–II pattern by whether the fracture enters the trochlear groove (II, unstable) or stays lateral to it (I); Jakob / Song displacement grades are the companion conversation
Internal-oblique views show displacement that the AP hides. A “hairline” lateral condyle is not a soft-tissue injury.
X-ray · paediatric
Forearm (Monteggia) · Bado I–IV (direction of the radial head)
ulnar fracture plus radiocapitellar dislocation. I = anterior radial-head displacement (commonest). II = posterior. III = lateral. IV = both-bone forearm fracture plus radial-head dislocation. The radiocapitellar-line entry is the alignment test
The radiocapitellar-line entry is the measurement. An “isolated” ulnar shaft fracture in a child is a Monteggia until the radial head is proven reduced on every view.
X-ray
Capitellum · Panner disease versus capitellar osteochondritis dissecans
a named age-split: Panner is the younger, whole-capitellum osteochondrosis that usually heals; OCD is the older, focal articular lesion whose stability is an MRI conversation
Do not invent a fragment-size cut-off. Unstable OCD is a fluid-cleft / cyst / displaced-fragment report, not a millimetre.
X-ray · MRI

See it on real cases

Direct links to Radiopaedia — the reference article and worked cases with their images. Each opens on Radiopaedia.

Key papers

Reviews and guidelines from RSNA, ESR and related journals. Each opens at its DOI.

Pediatric elbow fractures: a new angle on an old topic ↗Emery KH, Zingula SN, Anton CG, et al. · Pediatric Radiology 2016SPR · ESPR · PubMed
Pediatric bone imaging: imaging elbow trauma in children--a review of acute and chronic injuries ↗Iyer RS, Thapa MM, Khanna PC, et al. · AJR 2012ARRS · PubMed
Monteggia fracture: an easy fracture to miss ↗Mathur N, Lau KK · Emergency Radiology 2020ASER · PubMed
Gartland classification concordance of supracondylar fractures among pediatric emergency medicine physicians, radiologists, and orthopedic surgeons ↗Schultz RJ, Amaral JZ, Bridges CS, et al. · Pediatric Radiology 2024SPR · ESPR · PubMed