Supracondylar Humeral Fracture

Original Editor - Peter Sheehy

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Clinically Relevant Anatomy

The elbow complex consists of the distal humerus and proximal ulna and radius forming the humeroulna, humeroradial, and proximal radioulnar joints. The distal humerus includes the lateral capitellum, the medial trochlea, the posterior olecranon fossa, and anterior coronoid fossa.

Mechanism of Injury / Pathological Process

Pediatric population predisposed, especially during ages when the supracondylar bone is undergoing skeletal maturation and has a thin and weak cortex. Fractures are classified as either an extension- or flexion-type fracture. The majority of supracondylar humeral fractures are extension-type fractures (97-99%) resulting from a fall on outstretched hand with the elbow in full extension. The forced elbow hyperextension stresses the distal humerus with the olecranon acting as a fulcrum while the anterior elbow joint capsule produces an anterior tensile load, resulting in fracture and disruption of anterior periosteum. Posterior periosteum may or may not remain intact. A small number are classified as flexion-type fractures caused by a direct blunt trauma with the elbow in a flexed position.

Clinical Presentation

Typically seen in the skeletally immature pediatric population, with most occurring between the ages of 5 and 7 years old. The incidence rates between boys and girls is comparable. Supracondylar fracture often present with associated forearm fractures, soft tissue damage, neurologic injury, and significant risk for developing compartment syndrome, thus examination of the entire upper extremity should be performing including:

• Soft tissue edema, ecchymosis, and skin puckering
• Bleeding puncture wound (indicates open fracture)
• Vascular status classification:
  • Class I - well perfused (warm and red) with radial pulse
  • Class II – well perfused but radial pulse absent
  • Class III – poorly perfused (cool and blue or blanched) and radial pulse absent
• Neurologic status – especially ulnar nerve
• Compartment syndrome – swelling and/or ecchymosis, anterior skin puckering, and absent pulse

Diagnostic Procedures

Radiographs should include true AP of distal humerus (not elbow) and true lateral elbow views. If signs of osseous injury (fat pad sign) present the following 2 parameters used to assess for supracondylar fracture.

Anterior humeral line to capitellum orientation on lateral view

• Normal elbow - line passes through middle third
• Fracture – capitellum posterior to line

The Baumann angle (Humeral capitellar angle) on AP view

• Angle between line perpendicular to long axis of humeral shaft and lateral condyle physeal line
• Normal range – 9 to 26 degrees
• Decrease in angle – varus angulated fracture with possible medial column comminution
  

Modified Gartland classification of supracondylar fractures (based on lateral radiograph):

Type I

• Nondisplaced or minimally displaced (<2mm) with intact anterior humeral line
• No disruption of periosteum – stable fracture
• Fat pad signs may be only finding

Type II

• Displaced (>2mm) with hinged intact posterior cortex
• Anterior humeral line does not pass through middle third of capitellum on lateral radiographs
• No rotational deformity on AP radiograph

Type III

• Displaced with no meaningful cortical contact, usually sagittal plane extension and frontal/horizontal plane rotation
• Significant periosteum disrupture, soft tissue and neurovascular injuries common
• Medial column comminution and collapse with malrotation in frontal plane

Type IV

• Multidirectional instability
• Incompetent periosteal hinge circumferentially, with instability in flexion and extension
  

Outcome Measures

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Management / Interventions

Closed reduction and pin fixation is the most common treatment and is the indicated initial treatment for nearly all displaced closed fractures. Criteria for successful reduction include Braumann angle >10 degrees, intact medial and lateral columns, and anterior humeral line through middle third of capitellum. Kirschner wires are commonly used to hold reduced fracture and arm is immobilized (between 40-60 degrees flexion). With failed closed reduction, open fractures, and limb vascular compromise open reduction is the indicated treatment method. Anterior or lateral approach may be used, while posterior approach is not recommended due to significant rates of limited motion and osteonecrosis of trochlea. In-hospital traction is no longer a commonly used treatment technique given the outcomes and minimal hospital stay with closed reduction.
Type I

• Immobilization with long cast (60-90 degrees flexion) for ~3weeks
• Radiographic check at 1 and 2 weeks

Types II, III, and IV

• Operative reduction and pin fixation

Differential Diagnosis

Common complications and associated injuries:

• Vascular injury
• Compartment syndrome
• Neurologic injury
• Open or associated forearm fractures
• Medial or lateral column collapse
• Cubitus varus deformity

Key Evidence

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Resources

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Case Studies

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Recent Related Research (from Pubmed)

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References

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