Etiology

Peak age: 6 years


17% of all pediatric distal humerus fractures


2nd most common elbow fracture in children


Mechanism of Injury

Varus stress on a supinated forearm: supination puts supinator muscle on stretch causing avulsion mechanism


"Push vs. Pull": the former is an axial load transmitted through forearm / radial head / into capitellum and lateral condyle, "pushing" fragment off distal humerus


Milch Classification

Type I: fracture line extends from lateral condyle through capitulotrochlear groove


Stable elbow: trochlea intact


Salter-Harris IV


Less common type


Milch Classification

Type II: fracture line extends from lateral condyle through apex of trochlea


Unstable elbow


Salter-Harris II


More common type


Jakob Classification

Stage I: nondisplaced (<2mm), articular surface intact


Stage II: 2-4mm "hinged" displacement of metaphyseal fragment, articular surface intact


Stage III: completely displaced, distal fragment rotated; unstable elbow joint


Horn et al JPO 2002: "integrity of the cartilage hinge at the distal humeral epiphysis determines stability". Only metaphyseal component of lateral condyle fractures visualized on x-ray

Nonoperative Treatment


Jakob Stage I

Long arm cast with 90° elbow flexion, neutral forearm


Follow up with x-rays 2-3 times in first 3 weeks


D/C cast in 4 weeks


Finnobogason et al JPO 1995 followed 112 stage I lateral condyle fractures and found that fractures which did not extend into the elbow joint were stable and not at risk for displacement.

Jakob Stage II or III:


OR, Flouroscopy and/or arthrography to determine nature of fracture

Stage II: CRPP


Stage III: ORPP


CRPP Technique:

Two smooth 0.062 K-wires inserted into lateral condyle


Pins diverge in metaphysis


Range elbow, varus and valgus stress


Open technique:

Incision: anterior to lateral condylar ridge


Traumatic "rent" in extensor mass: enlarge traumatic opening to visualize fragment


DO NOT strip posterior aspect of fragment


Pin as mentioned above


Complications:

Overgrowth: 40% of lateral condyle fractures


Lateral spur: 28% of lateral condyle fractures


coronal rotation of distal fragment laterally displaces a periosteal flap on distal fragment


long-standing varus deformity associated with posterolateral instability of the elbow


Cubitus Valgus


Lateral physeal growth arrest

Delayed (>12 weeks) or Nonunion


More common in non operative treatment

Fishtail Deformity: persistent gap between lateral condyle and trochlea physes


Osteonecrosis:


Late ORIF (>3 weeks)


Iatrogenic

Tardy Ulnar nerve palsy: seen in valgus malunions