[Principles and pathogenesis of post-traumatic axial malalignment in the growth years]

Deviations of the axis or leg-length discrepancies after fractures in children and adolescents can be due to growth disturbances or can be the result of incomplete reduction of the fracture. We distinguish between four types of growth disturbances. In type I, the overall growth activity of the cartilage is increased; growth is then enhanced, which results in the affected bone being too long without deviation; this usually occurs after fractures of the metaphysis or diaphysis. In type II, activity, the epiphyseal cartilage is severely impaired or completely arrested. The direction of growth is unchanged. This results in shortening of the bone, usually due to severe damage to the germination zone of the growth cartilage after destruction of the vessels or infection. In type III, growth of the epiphyseal plate is partially stimulated. The consequence of this disturbance is deviation of the axis with overgrowth (this is in fractures of the proximal tibia). Type IV is characterized by an asymmetric arrest of growth. This results in deviation of the axis and shortening. The cause of such growth arrest can be epiphyseolysis or epiphyseal fracture. The defect in growth cartilage heals with a bone bridge. This is a very serious kind of growth disturbance, and it occurs in only 1% of all fractures before skeletal maturity. Correction after incomplete reduction of fractures during growth can be direct or indirect and specific or nonspecific. Direct corrections occur in combination with fracture healing; indirect corrections occur with physiological changes of the growing skeleton without association with the healing process.(ABSTRACT TRUNCATED AT 250 WORDS)