Prognosis in infantile idiopathic scoliosis.

A review was performed of 86 cases of infantile idiopathic scoliosis treated between 1962 and 1979. The single primary curves were classified as resolving, stable, progressive with a low rib--vertebra angle difference (RVAD) and progressive with a high RVAD. Two single primary curves subsequently developed a second curve and 17 were double when first diagnosed. Prognosis was difficult to establish before the age of five years. Only 18 per cent of curves showing progression beyond 50 degrees reached that point before the age of four. Conversely, if a scoliosis of 50 degrees or more was present before the age of four it always progressed. A more favourable outcome was indicated by male sex, a left-sided curve, a low initial curve measurement, an RVAD of less than 20 degrees in the initial radiograph, and the onset of scoliosis in the first year of life.