Snapshot An 7-year-old girl falls from a jungle gym and lands on her outstretched left hand. She develops immediate-onset left elbow pain and swelling. On exam, her arm is held in 30 degrees of extension and she is unable to move her elbow due to pain. A radiograph is shown and demonstrate a dorsally displaced supracondylar humerus fracture. Introduction Clinical definition fracture of the distal humerus proximal to the medial and lateral condyles Epidemiology Incidence most common pediatric elbow fracture accounts for 41% of all serious pediatric elbow injuries extension type injury most common (95-98%) Demographics children aged 5-7 years of age rare in adults males and females equally likely Etiology Accidental trauma (e.g., fall from moderate height) fall on outstretched hand leads to an extension type injury fall on posterior elbow leads to a flexion type injury Pathoanatomy normal anatomy humerus articulates with the radius and ulna at the elbow joint medial and lateral condyles are located at the distal portion of the humerus condyles represent the medial and lateral columns of the distal expansion of the humerus supracondylar humerus is the part of the humerus just proximal to the medial and lateral condyles fracture mechanics in an extension type injury, the olecranon process is forced against the weaker metaphyseal bone of the supracondylar humerus distal fracture fragment will be angulated and/or displaced posteriorly accounts for 95-98% of supracondylar fractures in a flexion type injury, a direct blow to the posterior elbow forces the distal condylar bone to displace anteriorly distal fracture fragment will be angulated and/or displaced anteriorly accounts for 2-5% of supracondylar fractures Salter Harris classification - if through a growth plate Type I: slipped growth plate Type II: above the physis w/metaphysis fracture Type III: below physis w/epiphysis fracture Type IV: through the physis Type V: crushed growth plate Associated conditions vascular brachial artery can be damaged neurapraxia anterior interosseous nerve (AIN) neurapraxia branch of median nerve innervates flexor pollicis longus, pronator quadratus, and radial half of flexor digitorum profundus most common neurapraxia in extension type fractures radial nerve neurapraxia second most common neurapraxia in extension type fractures ulnar nerve neurapraxia most common neurapraxia in flexion type fractures Presentation Symptoms elbow pain and limited range of motion Physical exam inspection gross deformity only in severe cases swelling ecchymosis palpation tender to palpation motion limited passive and active range of motion neurologic exam important to assess motor and sensory nerve function AIN neurapraxia inability to flex the interphalangeal joint of the thumb and the distal interphalangeal joint of the index finger (can't make A-OK sign) radial nerve neurapraxia inability to extend wrist or digits vascular exam important to assess for vascular insufficiency cold, pale, pulseless hand necessitates immediate reduction and pinning if hand is still dysvascular after reduction and pinning, may require vascular exploration Imaging Radiographs indications anteroposterior (AP) and lateral radiographs always indicated if fracture is suspected findings fracture fragment may or may not be visible positive anterior fat pad sign (sail sign) anterior fat pad is normally visible with supracondylar fracture, anterior fat pad is elevated because of hemarthrosis positive posterior fat pad sign posterior fat pad is normally NOT visible with supracondylar fracture, posterior fat pad may be visible because of hemarthrosis Treatment Conservative long arm posterior splint followed by long arm casting indication non-displaced fractures minimally displaced fractures with no comminution and minimal swelling Operative closed reduction and percutaneous pinning indication displaced fractures flexion-type fractures dysvascular hand Differential Radial head subluxation (Nursemaid's elbow) second most common serious pediatric elbow injury arm held in flexion and pronation commonly occurs due to excessive traction, not a fall Lateral epicondyle fracture third most common serious pediatric elbow injury will be tender on lateral side with minimal tenderness on medial side Complications Malunion cubitus varus (gunstock deformity) malalignment resulting in change from physiologic valgus elbow alignment to varus alignment cosmetic deformity with minimal functional impairment Vascular injury Volkmann ischemic contracture damage to brachial artery leads to volar compartment syndrome and muscle necrosis irreversible muscle contractures in the forearm, wrist, and hand Prognosis Favorable non-displaced or minimally displaced fractures Negative poor anatomic reduction vascular injury