Physiologic bowling of toddlers
Femur and tibia are mildly bowed.
Predilection for the first 2 y of life. Corrected within 6 mo of walking. Reaches adult pattern of mild valgus by 6–7 y.
Bowing of radius or ulna are the most common sites.
If the radius is fractured, the accompanying bone (ulna) may be fractured (and vice versa).
(see Table 5.42 )
Widening of the medial aspect of the growth plate in older children with an ossified distal femoral epiphysis. The weight-bearing part is always the widest.
Recurrent fracture with malposition
Bowing of fragile bones after repeated fractures.
Occurs in all bone disorders with increased bone fragility (e.g., osteogenesis imperfecta and other intrinsic sclerotic bone dysplasias).
Fig. 5.91a, b, p. 558
Expansile and lucent lesion with a ground-glass matrix.
Typically restricted to the polyostotic variety. Medial bowing of the proximal femur (Shepherd crook deformity).
Intrauterine malposition/congenital bowing of the tibia
Unilateral bowing, mostly involving the tibial diaphysis. Lateral and posterior bowing. Fibula is also bowed.
Believed to result from an abnormal intrauterine position. Usually heals in the neonatal period.
Fig. 5.92a, b, p. 558
Ten percent of patients with neurofibromatosis will have pseudarthrosis of the tibia.
Tibia vara (Blount disease)
Fig. 5.43, p. 524
Varus angulation of the proximal tibia.
Changes in the posteromedial proximal tibial epiphysis that lead to growth suppression. Any varus angulation at the knee in children > 2 y is considered abnormal.
Pseudarthrosis of the tibia
Almost always unilateral. Associated with neurofibromatosis (40%–50% of pseudarthroses of the tibia).
Other syndromes and dysplasias
Fig. 5.93, p. 559
Fig. 5.94, p. 559
Fig. 5.95a, b, p. 559
Osteogenesis imperfecta, achondroplasia, and camp-omelic dysplasia, for example.