The capitellum and trochlear together form the articulating surface (condyles) of the distal humerus.

Above the condyle, in the supracondylar elbow,  the metaphysis narrows into diaphysis, site most prone to fracture (up to 70% of cases) in a child from a fall onto an outstretched hand (FOOSH) or fall onto the point of the elbow itself.

Besides the supracondylar fracture, other elbow injuries to consider in children include:

• epicondylar fracture
• fractures of the condyles (capitellum and trochlear)
• radial head and neck fractures
• olecranon fractures
• osteochondritis dessicans
• elbow dislocation
• radial head subluxation (Nursemaid’s elbow)
• medial epicondylar apophysitis (Little Leaguer’s elbow)

Supracondylar Fracture

More than half of all elbow fractures in children are supracondylar—i.e. generally extra-articular injuries occurring in a relatively fragile region of bone, the junction of humeral diaphysis and metaphysis. In most (> 90%) cases, a fracture following a fall onto an outstretched hand (FOOSH) leaves the distal fragment displaced posteriorly—into extension.

In the 1950s, supracondylar injuries were the “misunderstood fracture,” often resulting in bony deformity and Volkmann’s contracture despite treatment.¹ It is these fractures (the extension injuries in particular) J. J. Gartland classified in 1959 , in an attempt to rationalise their management and improve prognosis.³

Such extension supracondylar fractures may be complicated by anterior interosseous (branch of median nerve) neuropraxia, presenting with:

• weakness of FDP to Index Finger + FPL muscle: unable to perform “OK” sign
• ± weakness wrist and finger extension is seen from a radial neuropraxia

A careful observation, thankfully, will usually show these neuropraxias to resolve spontaneously.

Conversely, a fall directly onto a flexed elbow may cause the opposite fracture disposition, with the distal fragment displaced anteriorly—into flexion. These less common flexion-type supracondylar fractures may be accompanied by an ulnar neuropraxia, presenting with:

• lost sensation along little finger
• clawing from weakness of the intrinsic hand muscles, a later finding

“CRITOE”: Ossification Centres of the Elbow

How to Interpret X-Rays of the Elbow in Children

Knowing the average age of ossification centre disappearance may help with the distinction of an extraneous “fragment” due to an avulsion fracture. Though ages vary slightly, the mnemonic CRITOE‘s sequence is always preserved:

• Capitellum (capitulum) — 1 year
• Radial head — 3 years
• Internal (medial) epicondyle — 5 years
• Trochlear — 7 years
• Olecranon — 9 years
• External (lateral) epicondyle — 11 years

AP and Lateral X-Rays

Two radiographic imaginary lines, both of which run through the capitellum, to recall when looking at Lateral X-Rays of the Elbow:

• Anterior humeral line (AHL) normally runs through the middle third of the capitellum
• Radiocapitellar line (RCL): axis of radius should run through capitellum – particularly helpful when a radial head ossification centre could be misconstrued for a physeal injury (though the RCL may miss the capitellum in up to 16% of normal radiographs)

Other Elbow X-Ray Clues of Fracture

• posterior fat-pad sign (always pathological) and anterior sail sign (a ballooning)
• Baumann’s angle (between physis of the capitellum and a perpendicular to the axis of the humerus) normally > 11°

Gartland Classification and Care of Supracondylar Elbow Fractures

1. Non-displaced → splint/cast elbow 3-4 weeks (not < 90° to avoid vascular compromise/compartment syndrome))
2. Angulation with intact posterior cortex → closed reduction and percutaneous pinning
3. Completely displaced → closed reduction and percutaneous pinning
4. Complete periosteal disruption with instability in flexion and extension → may require open reduction

Type III fracture with pulseless hand, regardless of whether the hand is a normal temperature and colour with normal capillary refill time (CRT), or the hand is blue and cold, necessitates:

• emergent closed reduction and percutaneous pinning, to restore adequate circulation, then
• observe and splint elbow at 45 degrees

Failing this, emergent vascular exploration and repair is necessitated.

Complications

• nerve injury
• cubitus varus (cosmetic) deformity
• vascular injury e.g. compartment syndrome
  • Volkmann’s ischaemic contracture when elbow splinted in hyperflexion

Supracondylar Fracture – Summary

• FOOSH in child 3-11 years old
  • was elbow in hyperextension or flexion at time of impact?
• very painful → may require analgesia for full assessment
  • Can they do “ok” sign?
  • Can they extend wrist and fingers?
  • Can they feel (light touch / pin prick) over little finger?
  • Check brachial and radial (and ulnar) pulses and CRT
• Obtain AP & lateral films looking at lines, angles, fat-pads, and ossification centres
• consider emergent closed reduction if neurovascular signs
• Avoid splinting in hyperflexion

Epicondylar Fracture

• 10% of all elbow fractures in children
• medial > lateral
• ossification centre medial epicondyle appears 5-7 years old – fuses to distal humerus at 20 years of age
• palpable avulsion in fractures associated with posterolateral dislocation of elbow, usually 7-15 years old (rare > 20 years old)
  • occasional stress fracture from repeat valgus stress on epicondylar ossification centre: “Little League Elbow“
  • direct blow in adults

Condylar Fracture

Medial: may be difficult to diagnose radiographically before trochlea ossifies

• watch for bleeding / swelling closed fascial space ⇒ compartment syndrome
• > 2 mm displacement ⇒ ORIF

Lateral: usually transphyseal and intra-articular ⇒ ∴ ORIF

• non-displaced: < 2 mm
• minimally displaced: 2-4 mm ⇒ casting / percutaneous fixation / ORIF
• displaced: > 4 mm ⇒ ORIF and pinning
  • cubitus vulgus
  • lateral transposition of the forearm
  • arthritis: capsule / articular disruption
  • ulnar nerve palsy
  • overgrowth and subsequent cubitus varus deformity

Radial Head or Neck Fracture

Epiphyseal fractures of radial neck classified on basis of degree of angulation. In an epiphysis not yet closed, the radiocapitellar line is helpful: it should pass through the centre of the bones as seen on a lateral X-Ray of the elbow.

• angulation < 15°: immobilisation 2 weeks (long-arm posterior splint) + active exercises with sling for support (remodelling will fix angulation)
• angulation > 15°: immobilisation in posterior splint and admit for reduction under GA
• angulation > 60°: i.e. complete displacement ⇒ ORIF

Osteochondritis Dessicans

Following overload in hyperextension, a mechanism commonly suffered by the elbows of gymnasts, the individual will present with the history of a locking joint and one that paradoxically also gives way, along with crepitus on examination. Manage by splinting the elbow for 3-4 days, give NSAIDs, and apply topical heat for comfort. Arthroscopy if/when persistent symptoms or loose bodies.

Subluxation of the Radial Head: Nursemaid’s Elbow

Common in Toddler’s, Nursemaid’s Elbow can be seen at any age after 1 year old up to and including adulthood. The partially dislocated joint is generally readily reduced using a hyperpronation technique 9alternatively, supination and flexion technique), as the radial head clicks into its place under its previously delimiting ligament. X-ray of the joint is only necessary if evidence or history of direct elbow trauma or suspect infection or fracture. The child will begin to use the arm normally within 10-15 minutes. there remains a 25% risk of recurrence, in which case orthopaedic review should be arranged.

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References

1. Alton TB, Werner SE, Gee AO. “Classifications in brief: the Gartland classification of supracondylar humerus fractures.” Clin Orthop Relat Res. 2015 Feb; 473(2): 738-41. doi: 10.1007/s11999-014-4033-8. Epub 2014 Nov 1. PMID: 25361847; PMCID: PMC4294919.
2. “Closed Reduction and Percutaneous Pinning of Supracondylar Fracture of the Humerus.” OrthopaedicsOne Articles. In: OrthopaedicsOne – The Orthopaedic Knowledge Network. Created Jun 05, 2010 05:35. Last modified Jul 25, 2012 04:19 ver.8. Retrieved
3. Gartland J. J. “Management of supracondylar fractures of the humerus in children.” Surg Gynecol Obstet. 1959 Aug;109(2):145-54. PMID: 13675986.
4. Simon’s Emergency Orthopaedics: 7th Edition, Scott Sherman. McGraw Hill, 2015 (New York)
5. Supracondylar Fractures Of The Humerus In Children – YouTube Video, Dr Nabil Ebraheim
6. Paediatric Pearls: Minor Injuries Part 2, Dr Julia Thomson

Further Reading

• CRITOE Makes Me Cry, Cameron Gettel, Brown Emergency Medicine, September 29, 2016.
• CRITOE Quick Quiz, Don’t Forget the Bubbles
• Supracondylar Fracture – Pediatric, Orthobullets