summary Distal Humerus Physeal Seperations are traumatic fractures usually seen in children under the age of three and are often associated with child abuse. Diagnosis can be made with plain radiographs of the elbow. Treatment is usually operative closed reduction and percutaneous pinning Epidemiology Demographics typically seen in children under the age of 3 although variations can be seen in older children (see below) Etiology Mechanism vaginal delivery (birth fracture) from force of labor or obstetric maneuvers login to view 1 more bullet cesarean section from excessive traction nonaccidental trauma rotational force / twisting fall on outstretched hand with elbow extended Pathoanatomy physis is biomechanically the weakest location in distal humerus it is also referred to as a transphyseal distal humerus fracture Associated conditions abuse or battered child syndrome (up to 50%) Classification Salter-Harris classification older children (>3y) have Salter-Harris II injuries metaphyseal fragment attached to distal fragment younger children (<3y) have Salter-Harris I injuries pure physeal injury rare cases have intra-articular extension (Salter-Harris III or IV) can be difficult to differentiate from a lateral condyle fracture Displacement of the distal fragment most commonly posteromedial rarely can be anterior Presentation History birthing process (see above) fall from height (bed, chair, down stairs) typically onto extended elbow another child jumps/falls on a child's elbow nonaccidental trauma unwitnessed injuries inconsistent explanations history of multiple injuries, burns, bites, bruising skin lesions are most common findings in nonaccidental trauma Physical exam inspection pseudoparalysis / diminished spontaneous movement swelling or ecchymosis neurovascular rarely neurovascular compromise Imaging Radiographs recommended views AP and lateral centered on the elbow "baby gram" login to view 1 more bullet stress radiographs login to view 1 more bullet skeletal survey login to view 1 more bullet findings posteromedial displacement of the radial and ulnar shafts relative to the distal humerus login to view 1 more bullet forearm not aligned with humeral shaft soft tissue swelling, joint effusion (posterior fat pad) login to view 1 more bullet if capitellar ossification center is present, it will be aligned with radius shaft, making diagnosis definitive Ultrasound indications uncertain diagnosis advantage no need for sedation disadvantage needs experienced technician findings static exam login to view 1 more bullet dynamic exam login to view 1 more bullet MRI not routinely used disadvantage requires sedation in young children Elbow arthrography indications uncertain diagnosis often combined with CRPP in OR findings visualization of entire distal articular surface and proximal radius technique posterolateral approach or direct posterior approach login to view 1 more bullet inject equal parts saline:contrast bring elbow through range of motion if pinning is needed, arthrogram aids visualization of pin starting points on capitellum aids assessment of quality of reduction by seeing anterior humeral line intersecting capitellum advantage if performed under anesthesia in OR, can perform reduction and stabilization simultaneously if needed Differential Elbow dislocation almost never happens in <3 yrs because distal humerus physis is weaker than bone-ligament interface, predisposing to physeal fracture rather than ligament disruption/dislocation typically distal fragment is displaced posterolaterally with elbow dislocations Other fractures often misdiagnosed (or delayed diagnosis up to 1 week) as supracondylar, condyle, epicondyle fractures Treatment Nonoperative posterior long arm splint then long arm casting x 2-3 weeks indications login to view 5 more bullets Operative closed reduction and pinning indications login to view 2 more bullets technique login to view 1 more bullet Technique Closed Reduction and Pinning approach general anesthesia use elbow arthrogram to determine direction of displacement reduction maneuver login to view 4 more bullets acceptable parameters (similar to supracondylar humerus fractures) login to view 3 more bullets pinning 2 or 3 x 0.062inch K wires login to view 1 more bullet from lateral side, retrograde fashion divergent engage both cortices good spread at fracture site then perform live fluoroscopy through range of motion and slight varus/valgus stress to ensure no loss of reduction immobilization bend / cut pins splint the arm postoperative care admit overnight to observe for compartment syndrome (may not be necessary in all cases) see 1 week postoperatively with radiographs to ensure no loss of reduction see 3 weeks postoperatively with radiographs and remove pins in office login to view 2 more bullets typically follow patients for 2-4 years after injury to ensure there is no growth arrest, deformity, or osteonecrosis (see below) Complications Cubitus varus up to 70% have this complication more common than with supracondylar fractures cause AVN of medial condyle malunion (common because of missed diagnosis, or loss of reduction) growth arrest treatment lateral closing wedge osteotomy Medial or lateral condyle AVN may lead to fishtail deformity seen in all distal humerus fractures Loss of motion usually no functional limitation Growth disturbance progressive cubitus varus joint irregularities angular deformity limb-length discrepancy treatment observe initially, undertake surgery when > 5 years old login to view 3 more bullets Prognosis Often missed diagnosis as very difficult to diagnose up to 50% missed by radiologist In patients with early recognition and prompt treatment, outcomes are very good