Classification of tibial hemimelia. In type 1A, fibula is dislocated proximally, tibia is not radiographically evident, and distal femoral epiphysis is smaller than on normal side. In type 1B, fibula is dislocated proximally, and proximal tibial anlage may be visible at birth on ultrasound or magnetic resonance imaging, but not on plain radiographs. Type 2 deformity has proximal dislocation of fibula and radiographically visible proximal tibia with normal-appearing knee joint. In type 3 deformity, fibula is dislocated proximally, distal tibia is radiographically visible, but proximal tibia is not seen. In rare type 4 deformity, fibula has migrated proximally, with diastasis of distal tibiofibular joint. Type 5 Birch modification of Jones classification to include global shortening of the tibia relative to the fibula.