summary Triplane Fractures are traumatic ankle fractures seen in children 10-17 years of age characterized by a complex salter harris IV fracture pattern in multiple planes. Diagnosis can be made with plain radiographs of the ankle. CT scan may be required to further characterize the fracture pattern and for surgical planning. Treatment is closed reduction and casting or surgical fixation depending on the patient age and degree of fracture displacement. Epidemiology Incidence accounts for 5-15% of pediatric ankle fractures Demographics more common in males occurs in children during physeal closure (average age is 13 years old) juvenile ankle physis ossifies in specific order, which leads to transitional fractures such as triplane and tillaux fractures younger than tillaux fracture age group Etiology Pathophysiology mechanism of injury lateral triplane fractures results from supination-external rotation injury similar to tillaux fractures medial triplane fractures results from adduction injury pathoanatomy a complex SH IV fracture pattern with components in all three planes may be 2, 3, or 4 part fractures sagittal plane - epiphysis is often fractured on the lateral aspect in the sagittal plane (same as tillaux fracture) and is seen on the AP radiograph axial plane - physis is separated coronal plane - metaphysis is fractured on the posterior aspect in the coronal plane and is seen on the lateral radiograph Associated conditions fibular fractures occurs in 50% typically spiral fracture located proximal to the physis in children nearing skeletal maturity remains unstable after fixation of tibia, so fixation of fibula is usually necessary ipsilateral tibial shaft fractures Anatomy Physeal considerations distal tibial physis accounts for 35-40% of overall tibial growth and 15-20% of overall lower extremity growth rate of growth is 3-4 mm/year growth continues until 14 years in girls and 16 years in boys closure occurs during an 18 month transitional period occurs in a predictable pattern: central > anteromedial > posteromedial > lateral Classification Parts Classification by Parts 2-part Part 1 - anterolateral and posterior epiphysis is connected to the posterior metaphyseal fragment Part 2 - anteromedial epiphysis is connected to the remainder of the distal tibia 3-part Part 1 - anteriolateral epiphysis Part 2 - posterior epiphysis is connected to the posterior metaphyseal fragment Part 3 - anteromedial epiphysis is connected to the remainder of the distal tibia 4-part Comminuted variant Can only be distinguished from 3-part fractures via CT Pattern Classification by Pattern Lateral triplane fracture Most common Epiphyseal fracture occurs in the sagittal plane Physeal fracture occurs in the axial plane Metaphyseal fracture occurs in the coronal plane Similar to tillaux fractures on AP radiographs (distinguish from tillaux fractures by SH II or I fracture on lateral radiograph) Medial triplane fracture Epiphyseal fracture occurs in the coronal plane Physeal fracture occurs in the axial plane Metaphyseal fracture occurs in the sagittal plane Intramalleolar triplane fracture Type I - intraarticular intramalleolar fracture involving the weight-bearing surface Type II - intraarticular intramalleolar fracture outside of the weight-bearing surface Type III - extraarticular intramalleolar fracture Presentation Symptoms pain inability to bear weight Physical exam inspection swelling focal tenderness deformity Imaging Radiographs recommended views AP lateral mortise best view to assess the amount of displacement findings consists of 3 parts anterolateral quadrant of distal tibial epiphysis medial and posterior portions of epiphysis with posterior metaphyseal spike tibial metaphysis AP radiograph shows SH III fracture lateral radiograph shows SH II fracture CT scan indications usually required to delineate fracture pattern and assess articular congruity if closed reduction planned, consider CT after reduction to assess quality of reduction findings fracture involvement seen in all 3 planes Mercedes-Benz sign Treatment Nonoperative closed reduction and casting indications < 2mm displacement techniques ideal for 2-part fractures (difficult to achieve reduction of 3-part or 4-part fractures) reduction maneuvers reduce fibula fracture prior to attempting reduction of tibial fracture for lateral triplane fractures, reduce with internal rotation for medial triplane fractures, reduce with eversion obtain post-reduction CT to assess reduction long leg cast initially for 3-4 weeks to control rotational component of injury follow early with radiographs to assess for displacement immobilize an additional 2-4 weeks in a short leg cast or walking boot (to initiate ankle ROM) Operative CRPP vs. ORIF indications > 2mm displacement Techniques CRPP vs. ORIF approach anterolateral approach for lateral triplane fractures anteromedial approach for medial triplane fractures reduction for lateral triplane fractures, reduce with internal rotation for medial triplane fractures, reduce with external rotation arthroscopically-assisted reduction has been described instrumentation K wires or cannulated screws epiphyseal screws placed parallel to physis metaphyseal fixation if component is large enough post-op long leg cast for 3-4 weeks then short leg walking cast for 2 weeks complications specific to this treatment hardware irritation transient neuropathy Complications Growth arrest occurs in 7-21% risk factors increased risk with pronation-abduction injuries compared to supination-external rotation injuries increased risk with residual fracture displacement following reduction usually insignificant but should closely follow patients with > 2 years of growth remaining Ankle pain and degeneration increased risk with articular step-off > 2mm