Pediatric Elbow Anatomy

Definition: Fracture of the distal humerus above the level of the epicondyles

Mechanism

  • Indirect: Fall onto outstretched and hyperextended upper extremity
  • Direct (less common)
    • Direct trauma to the elbow
      • Fall onto a flexed elbow or from object striking the elbow

Epidemiology

  • Comprise of 55-75% of all elbow fractures (Egol 2010)
  • Male predominance
  • Peak incidence between 5-8 years of age after which dislocation is more frequent

S-Shaped Deformity (Brubacher 2008)

Physical Exam

  • Patients will present with a swollen, tender elbow with painful range of motion
  • S-shaped Deformity: Occurs when the fracture is completely displaced at the distal humerus
  • Pucker Sign
    • Puckering, dimpling, or ecchymosis of the skin anterior to the distal humerus
    • Indicates that the proximal fragment has penetrated the brachialis muscle (Brubacher 2008)
  • A thorough neurovascular exam must be performed
    • Neuropraxis is common (Egol 2010)
      • Anterior Interosseous Branch of the Median Nerve Neurapraxia
        • Most Common associated nerve injury
        • Unable to flex the interphalangeal joint of the thumb and the distal interphalangeal joint of the index finger (can’t make an A-OK sign)
      • Radial Nerve Neurapraxia: inability to extend wrist or digits
      • Ulnar Nerve Neurapraxia: inability to abduct or adduct fingers

Anterior Interosseous Syndrome (jcphysiotherapy.com)

  • Vascular Injury
    • Results from direct injury to the brachial artery or secondary to antecubital swelling
    • Can lead to Volkmann’s Contracture: permanent flexion contracture of the hand at the wrist secondary to obstruction of the brachial artery.

Fractures Types

  • Extension type injuries represent 98% of supracondylar humerus fractures
  • Gartland Classification of Supracondylar Fractures
    • Based on the degree and direction of displacement, and the presence of an intact cortex (Alton 2015)
    • Type1: Minimal displacement – fat pad elevation on radiographs
    • Type2: Posterior hinge – anterior humeral line anterior to capitellum
    • Type3: Displaced – no cortices intact
    • Type4: Periosteal disruption with instability in both flexion and extension

Presence of Posterior and Anterior Fat Pad Signs (Case courtesy of Dr Bruno Di Muzio, Radiopaedia.org. From the case rID: 45115)

Diagnostic Imaging

  • Always obtain AP and lateral radiographs
  • Occult Fractures
    • Clear fractures often absent on plain radiographs
    • Look for indirect evidence of fracture
      • Anterior Fat Pad Sign (“Sail Sign”)
        • The presence of a small anterior fat pad can be a normal finding
        • Elevation of the anterior fat pad (abnormal) is secondary to a joint effusion
      • Posterior Fat Pad Sign
        • Presence of a lucent crescent located in the olecranon fossa
        • Presence of posterior fat pad is always pathologic.
      • Anterior Humeral Line
        • In an elbow with normal anatomic alignment, a line drawn down the anterior surface of the humerus should cross the middle third of the capitellum
        • If this line is disrupted, it suggests an occult supracondylar fracture

Normal Anterior Humeral Line (Case courtesy of Dr Benoudina Samir, Radiopaedia.org. From the case rID: 41167)

ED Management

  • Assess for secondary injuries as with any other trauma patient
  • Gartland Type1 Fractures
    • Long arm posterior splint
      • Elbow in 90 degrees of flexion
      • Forearm in neutral position
    • Orthopedic follow-up in one week for likely operative management
  • Gartland Type2/3 Fractures
    • Immediate orthopedic consultation in order to determine appropriate intervention (closed versus open reduction with percutaneous pin placement)
    • Gartland 2/3 fractures have higher likelihoods of occult neurovascular injury and thus residual deformity
    • Closed reduction and percutaneous pinning is the preferred treatment for displaced fractures (Brubacher 2008)
  • Other indications for immediate consultation
    • Open fractures
    • Presence of neuromuscular compromise
    • Evidence of compartment syndrome

Prognosis

  • Long-term outcomes of supracondylar humeral fractures are good; however, there is potential for long-term pain, ulnar nerve sensitivity, and decrease in grip in Type2/3 fractures (Sinikumpu 2016)
  • Most complications from supracondylar humeral fractures are neurapraxias which require no treatment (Egol 2010)

Take Home Points

  • Supracondylar humeral fractures may often present without evidence of fracture lines on diagnostic imaging. Always assess for indirect signs of fractures.
  • Do not forget to conduct a thorough neurovascular exam as supracondylar fractures can be associated with neurapraxias, vascular injuries, and compartment syndrome.
  • Type1 fractures can be splinted and discharged with close orthopedic follow-up; Type2/3 fractures generally require immediate orthopedic consultation.

Read More

Orthobullets: Supracondylar Fracture – Pediatric

References

Egol KA et al. Handbook of Fractures. Lippincott Williams & Wilkins; 2010. Link

Brubacher JW, Dodds SD. Pediatric supracondylar fractures of the distal humerus. Curr Rev Musculoskelet Med. 2008;1(3-4):190-6. PMID: 19468905

Alton TB, Werner SE, Gee AO. Classifications in brief: the Gartland classification of supracondylar humerus fractures. Clin Orthop Relat Res. 2015;473(2):738-41. PMID: 25361847

Sinikumpu JJ et al. The long-term outcome of childhood supracondylar humeral fractures: A population-based follow up study with a minimum follow up of ten years and normal matched comparisons. Bone Joint J. 2016; 98-B(10):1410-1417. PMID: 27694598