Pathogenesis of posttraumatic deformities of the lower extremities during growth

Posttraumatic deformities after pediatric fractures are either the result o f incomplete or failed remodeling, complete or partial stimulation of the g rowth plates, or complete or partial closure of a growth plate. In contrast to fractures of the upper extremities, spontaneous remodeling should not b e intentionally integrated in the treatment algorithm. Thus, stimulative growth disturbances with subsequent changes of the leg le ngth can be prevented. Therefore, one should strive for anatomical alignmen t and rotation without shortening. The latter provokes remodeling, with act ivation of the adjacent physis. Growth disturbances with partial stimulatio n typically occur after metaphyseal bending fractures of the proximal tibia . If minimal valgization is overlooked,growth disturbances will lead to a p rogressive valgus deformity. Partial closure of a growth plate is still inevitable after epiphyseal frac tures (Salter-Harris type III and IV) as well as after simple epiphysiolysi s (Salter-Harris-type I,II). The resulting deformity depends on the size of the physeal closure, its localization,and on the remaining growth. A "wate rproof reduction and osteosynthesis of type III and IV fractures may well d iminish the risk of a partial physeal closure but will not reliably prevent it. It will occur in about 35% after physeal fractures at the distal femur , in 30% at the proximal and 20% at the distal tibia. Based on this knowled ge patients and parents should be informed correspondingly and follow-up sh ould be continued until skeletal maturity.