Gartland Classification — Supracondylar Humerus (Extension Type)

Overview — The Most Common Paediatric Elbow Fracture

Supracondylar humerus fractures (SCH fractures) are the most common elbow fracture in children, accounting for approximately 60–70% of all paediatric elbow fractures and 3% of all paediatric fractures. They occur predominantly in children aged 5–8 years during the peak period of elbow hypermobility. The extension-type fracture (caused by a fall onto an outstretched hand — FOOSH) accounts for 97–99% of all supracondylar fractures. The Gartland classification of the extension-type SCH fracture is the universal system that guides clinical decision-making, surgical indications, and urgency of intervention. These fractures carry significant risks of neurovascular injury, malunion (cubitus varus — the `gunstock deformity`), and the devastating complication of Volkmann`s ischaemic contracture.

Anatomy: the fracture occurs at the thin, weak metaphyseal region immediately proximal to the condyles — the supracondylar region; in children, this area consists of thin cortical bone with little cancellous support; it is inherently mechanically weak in the AP direction; in extension-type fractures, the distal fragment displaces posteriorly and the periosteum tears anteriorly; the neurovascular structures at risk are in the antecubital fossa — the anterior interosseous nerve (AIN — the branch most commonly injured), the radial nerve (lateral injuries), the brachial artery, and the median nerve
Key vascular anatomy: the brachial artery passes directly anterior to the supracondylar region; in displaced SCH fractures, the proximal fragment spike may tent the brachial artery or the artery may be entrapped, kinked, or lacerated; the brachial artery is at highest risk in Gartland Type III posterolaterally displaced fractures; a pulseless hand after SCH fracture = vascular emergency; the `pink but pulseless` hand is the most important management dilemma in paediatric orthopaedics — pulseless but perfused hand may be managed with reduction and fixation before formal vascular exploration

Gartland Classification (Extension Type)

Type	Description	Radiological Features	Treatment
Type I — Undisplaced	The fracture line is present but there is NO displacement of the distal fragment; the periosteum is intact on both sides; the cortex is disrupted but the fragments remain in anatomical alignment	The fracture line may be subtle on plain X-ray; the anterior humeral line (a line drawn along the anterior surface of the humeral shaft on a true lateral X-ray) should pass through the middle third of the capitellum in a normal elbow — in Type I, this relationship is preserved; the posterior fat pad sign (posterior fat pad visible on the lateral X-ray = haemarthrosis = fracture present, even if the fracture line is not visible); a visible posterior fat pad in a child with elbow pain after trauma = occult supracondylar fracture until proven otherwise	Non-operative — above-elbow posterior slab or collar and cuff for 3 weeks; no reduction required; excellent prognosis; neurovascular status documented and monitored; return to activity at 3–4 weeks
Type II — Displaced with intact posterior cortex	The distal fragment is displaced POSTERIORLY; the posterior cortex remains in contact (intact — the `intact posterior hinge`); the anterior cortex is disrupted; there is angulation (the distal fragment tilts posteriorly) but the posterior periosteum/cortex provides a hinge that partially limits displacement; there may be rotational malalignment (medial or lateral displacement of the distal fragment in addition to the posterior displacement)	The anterior humeral line now passes through the ANTERIOR third (or anterior to) the capitellum — indicating posterior displacement of the distal fragment; the distal fragment is tilted posteriorly; the posterior fat pad is visible; the posterior cortex contact distinguishes Type II from Type III; Type IIA = posterior angulation only; Type IIB = posterior angulation + rotation	Controversial — many centres treat all Type II with closed reduction + percutaneous K-wire fixation (as for Type III) to avoid late loss of reduction; some centres treat undisplaced/minimally displaced Type IIA with above-elbow cast in flexion after gentle reduction; Type IIB (with rotational malalignment) should be treated operatively (closed reduction + K-wire fixation); neurovascular assessment is mandatory
Type III — Completely displaced (no cortical contact)	The distal fragment is COMPLETELY displaced posteriorly; there is NO cortical contact between the proximal and distal fragments; the posterior periosteum is disrupted; the distal fragment may be posterolateral (most common — 70%) or posteromedial (30%); posteromedial displacement is associated with radial nerve injury; posterolateral displacement is associated with anterior interosseous nerve (AIN) injury and brachial artery injury	Complete loss of cortical contact; the anterior humeral line passes ANTERIOR to the capitellum; the distal fragment is completely separated from the proximal humerus; the fracture `bayonet` alignment on AP view; significant soft tissue injury; neurovascular structures at high risk; the proximal fragment spike can be seen medially (posteromedial displacement) or anterolaterally (posterolateral displacement)	SURGICAL — urgent closed reduction + percutaneous K-wire fixation (CRPP) under general anaesthesia; the gold standard treatment for all Gartland Type III and most Type II fractures; reduces within 24 hours for neurovascularly intact fractures; IMMEDIATE if neurovascular compromise; post-operative above-elbow cast for 3–4 weeks; K-wires removed in outpatient clinic at 3–4 weeks

Leitch modification of Gartland: some centres use a modified classification that adds Type IV — a completely displaced fracture with multidirectional instability (the distal fragment can be displaced in any direction due to complete periosteal disruption); these fractures are particularly unstable and may require open reduction if closed reduction is unsuccessful or if there is significant soft tissue interposition

Radiological Assessment — Key Lines & Angles

Line / Angle	How to Assess	Normal	Abnormal
Anterior humeral line	On true lateral X-ray: a line drawn along the ANTERIOR surface of the humeral shaft; the line is extended distally to the capitellum	Should intersect the MIDDLE THIRD of the capitellum	Passes through the ANTERIOR third or anterior to the capitellum = posterior displacement of the distal fragment = Type II or III SCH fracture; even subtle posterior displacement shifts the capitellum posterior to this line
Baumann`s angle	On AP X-ray: the angle between the growth plate of the lateral condyle and the axis of the humeral shaft; the angle between the long axis of the humerus (shaft) and a line drawn along the physis of the lateral condyle	Normal: 70–75° (some texts cite 64–81°); comparison with the contralateral side is essential as there is normal variation between individuals	Decreased Baumann`s angle (<70°) = increased carrying angle = cubitus valgus; increased Baumann`s angle (>75°) = decreased carrying angle = cubitus varus; Baumann`s angle is the best intraoperative guide to achieving anatomical reduction of the carrying angle — each 5° change in Baumann`s angle ≈ 2° change in the carrying angle
Carrying angle (clinical)	Measured with the elbow in full extension and forearm in full supination; the angle of valgus between the long axis of the humerus and the long axis of the forearm	Normal: 11–16° valgus (slightly greater in girls)	Cubitus varus (`gunstock deformity`): the most common malunion after SCH fracture; the medial cortex collapses giving progressive varus; the carrying angle is reduced or reversed (varus); appears as a `gunstock` deformity on profile; causes cosmetic deformity and increased risk of lateral condyle fracture (from increased lateral force transmission); corrected by lateral closing-wedge supracondylar osteotomy when established
Posterior fat pad sign	On lateral X-ray: the posterior fat pad is normally not visible (it lies within the olecranon fossa); a haemarthrosis (from ANY intra-articular fracture) displaces the fat pad posteriorly out of the olecranon fossa → it becomes visible	Posterior fat pad NOT visible = normal	VISIBLE posterior fat pad = haemarthrosis = intra-articular fracture (most commonly occult SCH fracture in a child); treat as SCH fracture (collar and cuff for 3 weeks) even if no fracture line is visible; a visible anterior fat pad alone (anterior sail sign) can be normal or indicate a small effusion; the POSTERIOR fat pad is the more specific sign

Neurovascular Assessment & Complications

Anterior interosseous nerve (AIN) palsy: the most common nerve injury in SCH fractures (~7–16%); the AIN is the deep motor branch of the median nerve; it innervates: flexor pollicis longus (FPL), flexor digitorum profundus to the index and middle fingers (FDP 2&3), and pronator quadratus; AIN palsy produces: inability to flex the interphalangeal joint of the thumb (FPL) and the DIP joint of the index finger (FDP) — the patient cannot make an `OK sign` (pinch); no sensory deficit (AIN is pure motor); associated with posterolaterally displaced Gartland Type III SCH fractures; typically a neuropraxia — most recover within 3–6 months; surgical exploration at 3–4 months if no recovery
Brachial artery injury: occurs in approximately 10–20% of Gartland Type III fractures; the `pink pulseless hand` is the most challenging management problem; (1) Pulseless hand with adequate perfusion (pink, warm, capillary refill <2 seconds, good oxygen saturation) = `pink pulseless hand` = the brachial artery is in spasm or kinked but the collateral circulation (via the anterior and posterior recurrent radial and ulnar arteries) is maintaining perfusion; management: closed reduction + K-wire fixation FIRST — reduction alone restores the pulse in 60–80% of cases; if pulse returns after reduction → observe; if pulse does not return after reduction → Doppler assessment; if adequate perfusion on Doppler despite absent palpable pulse → observe (collateral flow sufficient); if inadequate perfusion → vascular surgical exploration; (2) Pulseless hand with poor perfusion (pale, cold, prolonged capillary refill, SpO2 drop) = VASCULAR EMERGENCY → immediate OR; K-wire fixation first (stabilises the fracture and may restore flow), then vascular exploration and repair
Volkmann`s ischaemic contracture: the most devastating complication; results from unrecognised forearm compartment syndrome (from tight dressings, delayed reduction, or vascular injury); leads to fibrosis and contracture of the forearm flexor muscles; results in a fixed wrist flexion + intrinsic-minus hand deformity; PREVENTED by: (1) urgent reduction of displaced fractures; (2) avoiding tight bandaging or plaster (posterior slab ONLY — not circumferential cast in the acute phase); (3) frequent neurovascular monitoring; (4) low threshold for fasciotomy; the BOAST 11 guideline (British Orthopaedic Association) mandates that all Gartland Type III fractures undergo reduction within 8 hours

Surgical Technique — CRPP (Closed Reduction + Percutaneous K-Wire Fixation)

Reduction technique (Swenson technique): the patient is supine under general anaesthesia; fluoroscopy available; the surgeon applies traction in the line of the humerus with the elbow in slight flexion (to unlock the fracture fragments from the muscle mass); traction + disimpaction; then the forearm is pronated (for posterolateral displacement — pronation brings the medial spike medially, avoiding the ulnar nerve); the elbow is then flexed acutely (90–120°) while maintaining longitudinal pressure on the olecranon (Dunlop`s manoeuvre); the position is checked on both AP and lateral fluoroscopy views; the reduction is confirmed by: (1) anterior humeral line passing through the middle third of the capitellum on the lateral view; (2) Baumann`s angle within normal limits (comparison with contralateral side); (3) medial cortex interlocking (the medial column is reduced with the slight pronation)
K-wire configuration — lateral vs crossed: (1) Two or three lateral K-wires (all inserted from the lateral side): this is the SAFEST technique for the ulnar nerve — the ulnar nerve lies medially in the cubital tunnel and is at risk of direct injury if a medial K-wire is inserted without an incision; two lateral wires provide good stability but slightly less rotational control than crossed wires; (2) Crossed K-wires (one lateral + one medial): provides maximum rotational stability but the medial wire risks the ulnar nerve; if a medial wire is used, it must be placed through a small stab incision with the elbow in extension (the ulnar nerve subluxes anteriorly in flexion — the common position for wire insertion — and is directly in the path of a medially inserted wire in elbow flexion); Level I evidence (Kocher et al.) suggests that lateral-only configuration is as mechanically stable as crossed wires and avoids the ulnar nerve risk

Exam Pearls

Gartland classification: Type I = undisplaced (cast); Type II = displaced with intact posterior cortex (consider CRPP for Type IIB); Type III = completely displaced (CRPP); extension type is 97–99% of all SCH fractures; ages 5–8 years peak
Anterior humeral line: on lateral X-ray → should pass through MIDDLE third of capitellum; through anterior third = Type II; anterior to capitellum = Type III; the single most useful radiological line for SCH fractures
Baumann`s angle: AP X-ray; humeral shaft axis vs lateral condyle physis; normal 70–75°; each 5° change ≈ 2° change in carrying angle; intraoperative guide to correct reduction; compare with contralateral side
AIN palsy: most common nerve injury (7–16%); pure motor (no sensory loss); inability to flex thumb IP joint + index DIP (no OK sign); posterolateral displacement; mostly neuropraxia, recovers 3–6 months
Pink pulseless hand: reduce + K-wire fix first → pulse returns 60–80%; if pulse does not return after reduction → Doppler; if perfused → observe; if ischaemic → vascular exploration; NEVER send a pink pulseless hand to angiography — immediate OR
Cubitus varus (gunstock deformity): most common malunion; medial cortex collapse in varus; cosmetic deformity + increased risk of lateral condyle fracture; prevents cubitus valgus (not the same as cubitus valgus OA); treat with lateral closing-wedge osteotomy when established
K-wire safety: lateral-only wires (2–3) are as stable as crossed wires AND avoid ulnar nerve risk; if medial wire used → small stab incision + elbow in EXTENSION (not flexion) to avoid ulnar nerve subluxation into the path of the wire; BOAST 11 mandates reduction of Gartland III within 8 hours
Posterior fat pad sign: pathognomonic of haemarthrosis = fracture present; treat as occult Type I SCH fracture even if no fracture line visible; above-elbow collar and cuff for 3 weeks; anterior fat pad alone is less specific

Gartland Classification — Supracondylar Humerus (Extension Type)

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