summary Traumatic Hip Dislocations in the pediatric population are usually posterior and may occur due to low energy sports injuries in children less than 10 years of age and high energy trauma in children greater than 10. Diagnosis is made with plain radiographs. CT or MRI studies are indicated post-reduction to assess for joint congruity and articular injuries. Treatment is urgent closed reduction under general anesthesia or sedation. Open reduction may be required if there is an intraarticular fragment following reduction. Epidemiology Anatomic location 80% are traumatic posterior dislocations more common than hip fracture in pediatric patients Etiology Pathophysiology mechanism of injury age <10 may have low energy sports injury, or trip and fall age >10 mostly high energy (e.g. MVA) Associated conditions fractures acetabular fractures lower incidence of acetabular fractures compared with adults due to cartilaginous acetabulum and ligamentous laxity posterior wall fractures are most common femoral head fracture femoral neck fracture proximal femoral physis avascular necrosis of femoral head increased rate if not reduced within 6 hours Presentation Symptoms pain, inability to bear weight Physical exam posterior dislocation (most common) slight flexion, adduction, and internal rotation of the limb clinical limb length discrepancy if large posterior wall acetabular fracture, can appear shortened without malalignment anterior dislocation slight flexion, abduction, and external rotation inferior dislocation External rotation and extension neurovascular exam check for sciatic or gluteal nerve palsy (rare) Imaging Radiographs recommended views AP most can be diagnosed on AP pelvis films lateral used to differentiate between anterior vs. posterior dislocation scrutinize femoral neck to rule out fracture prior to attempting closed reduction post reduction films necessary to inspect for joint incongruity or nonconcentric reduction findings loss of congruence of femoral head with acetabulum CT indications second choice behind MRI for any abnormal findings on post-reduction radiographs such as joint widening radiation exposure should be considered findings inspect for joint incongruity or nonconcentric reduction osteochondral fragments can be seen in older children and are easily detected by CT interposed soft-tissue can be difficult to appreciate on CT scan MRI indications study of choice for any abnormal findings on post-reduction radiographs such as joint widening decreased radiation exposure than a CT scan findings inspect for joint incongruity or nonconcentric reduction osteochondral fragments can be seen in older children and are easily detected by CT interposed soft-tissue is best evaluated with MRI entrapped labrum or capsule is best evaluated via MRI Treatment Nonoperative closed reduction under general anesthesia or sedation within 6 hours indications urgent attempt at closed reduction is first line treatment most are successful reduced with closed means (85%) outcomes increased risk of AVN if not performed within 6 hours Operative open reduction indications nonconcentric reduction intra-articular fragment unstable acetabular rim fracture, associated femoral head or neck fracture irreducible by closed means technique surgical approach is typically performed in direction of dislocation (most commonly posterior) Techniques Closed reduction technique reduction adequate anesthesia or sedation during reduction is mandatory in order to decrease the risk of displacing an unrecognized fracture of the proximal femoral epiphysis reduction under fluoroscopy has been recommended to decrease risk of displacement due to possibility of epiphyseolysis mainly traction in flexion with gentle rotation maneuver post-reduction test hip stability before weaning sedation obtain post-reduction imaging some advocate spica cast or bed rest with abduction splint for 4 weeks in patients < 10 years old or bracing in older children with 6-12 weeks protected weight-bearing on crutches Complications Osteonecrosis reported in 3-15% decreased incidence under age 5 less frequent than in adults if there is an absence of an associated femoral neck fracture if present, thought to be related to delayed reduction Coxa magna common radiographic finding (20%) not associated with functional limitation Redislocation rare sequela treatment prolonged immobilization if recurrent and recalcitrant to immobilization: address with capsulorrhaphy Nerve injury sciatic or gluteal nerve injury can occur, usually resolves after reduction Prognosis Typically associated with good long-term outcomes when treated promptly most have mild or no pain most return to high-demand activities