summary Humeral Shaft Fractures in the pediatric population are usually traumatic in nature, although nonaccidental trauma and pathologic lesions can not be overlooked. Diagnosis is made with plain radiographs. Treatment is almost always immobilization due to the high remodeling potential of the pediatric humerus. Epidemiology Incidence represent <10% of humerus fractures in children Etiology Pathophysiology mechanism of injury typically associated with trauma pathomechanics neonates hyper-extension or rotational injury during birth adolescents usually direct trauma pathophysiology consider a pathologic process if fracture is a result of a low energy mechanism may be associated with child abuse if age <3 and fracture pattern is spiral Associated conditions radial nerve palsy associated with up to 5% of humeral shaft fractures Presentation History history of traumatic event Symptoms pain arm deformity Physical exam inspection mid-arm swelling and deformity open fractures are rare palpation tenderness to palpation motion weakness or absence of wrist and digit extension if radial nerve palsy is present pseudoparalysis irritability or refusal to move upper limb in neonates reflexes remain intact Imaging Radiographs recommended views full length AP and lateral views of humerus optional views orthogonal views of shoulder and elbow required to rule out associated injuries findings typical fracture patterns are transverse and oblique examine closely for pathologic lesions Treatment Nonoperative immobilization in splint or brace indications utilized for almost all pediatric humeral shaft fractures (if not pathologic) due to remodeling potential acceptable alignment younger children < 35-45 deg angulation older children < 20 deg varus/valgus < 20 deg procurvatum <15 deg rotation malalignment < 2cm shortening techniques sling and swathe or cuff and collar in young children Coaptation splint or hanging arm cast Sarmiento functional brace in older children/adolescents ROM exercises can be initiated in 2-3 weeks once pain is controlled Operative open reduction internal fixation indications open fractures multiply injured patient ipsilateral forearm fractures "floating elbow" associated shoulder injury unacceptable alignment techniques flexible intramedullary nail fixation anterior, anterolateral or posterior approach with 3.5mm or 4.5mm plate fixation Complications Radial nerve palsy occurs in <5% most commonly associated with middle and distal 1/3 fractures typically due to a neuropraxia spontaneous resolution is expected exploration is rarely needed if function has not returned in 3-4 months, EMGs are performed and exploration considered Malunion rarely produces functional deficits, due to the wide range of motion at the shoulder up to 20-30° of angulation is associated with excellent outcomes Delayed union rare may consider ultrasound bone stimulation Limb length discrepancy commonly occurs, but rarely causes functional deficits Physeal growth arrest proximal and distal humerus growth plates contributes 80:20 percent to overall humeral length Prognosis Excellent associated with enormous remodeling potential and rarely requires surgical intervention up to 20° of angulation is associated with excellent outcomes due to the large range of motion of the shoulder