possible implications of physeal injuries The Salter–Harris (S-H) classification is most commonly applied, as described in Chapter 111 Musculoskeletal Trauma Inversion ankle injuries in preadolescents most commonly cause an S-H type I fracture of the distal fibula (Fig 40.1 ) Clinically, the patient presents with swelling about the lateral malleolus and tenderness at the distal fibular physis Fractures confined to the physes may not be visible on radiographs Consequently, routine radiographs may appear normal despite the presence of a fracture In severe inversion injuries, the distal fibular fracture described previously may be accompanied by a fracture of the tibia (Fig 40.2 ) This additional fracture is usually an S-H type III or IV injury through the medial malleolus that also extends below or across the distal tibial physis These patients will have tenderness at the medial malleolus and the distal fibular physis Fractures resulting from eversion of the ankle are usually a combination of an S-H type II fracture of the lateral tibia and a transverse fracture of the fibula (Fig 40.3 ) The fibular fracture is often relatively high (4 to cm above the fibular physis) Therefore, it is important to examine the full length of the fibula in patients with ankle injuries Direct axial compression of the ankle is uncommon but can cause an S-H type V injury to the distal tibia Given the mechanism, this type of injury may be associated with fractures of the spinal column External rotation injuries are responsible for lesions known as transitional fractures Transitional fractures occur during adolescence when closure of the growth plates is beginning Closure of the distal tibial physis starts centrally and then spreads medially, posteriorly, and finally laterally The distal tibial physis closes before the distal fibular physis As skeletal maturity (and physeal closure) progresses, the relative strengths of various parts of the tibia change As a result, the same mechanism of injury may cause very different fracture patterns, depending on the age of the patient The juvenile Tillaux fracture and the triplane fractures are examples of transitional fractures In the juvenile Tillaux fracture, a fragment of bone is torn off the lateral border of the tibia by the anterior tibiofibular ligament (Fig 40.4 ) It is an S-H type III injury of the distal tibia This fracture is seen almost exclusively in patients between the ages of 12 and 14 years This is because the closure of the medial aspect of the distal tibial physis begins around 12 to 14 years of age, whereas the lateral aspect remains open and therefore less stable for approximately another 18 months The greater the skeletal maturity of the patient, the more lateral the epiphyseal fracture line occurs