We reviewed the cases of 727 patients with idiopathic scoliosis in whom
the initial curve measured from 5 to 29 degrees. The patients were followed
either to the end of skeletal growth or until the curve progressed. One
hundred and sixty-nine patients (23.2 per cent) showed progression of the
curve. The incidence of curve progression was found to be related to the
pattern and magnitude of the curve, the patient's age at presentation, the
Risser sign, and the patient's menarchal status. We found no correlation
between progression of the curve and the patient's sex, Harrington factor,
rotational prominence, family history, or radiographic measurements. A
progression factor was calculated using the three strongest correlations
available at initial examination: the magnitude of the curve, the Risser
sign, and the patient's chronological age. A graph and nomogram are
presented that can serve as a guide for advising patients' families and for
planning continuing care.