One hundred and thirty-three curves in 102 patients who were followed
for an average of 40.5 years were evaluated to quantitate curve progression
after skeletal maturity and for prognostic factors leading to curve
progression. Sixty-eight per cent of the curves progressed after skeletal
maturity. In general, curves that were less than 30 degrees at skeletal
maturity tended not to progress regardless of curve pattern. In thoracic
curves the Cobb angle, apical vertebral rotation, and the Mehta angle were
important prognostic factors. In lumbar curves the degree of apical
vertebral rotation, the Cobb angle, the direction of the curve, and the
relationship of the fifth lumbar vertebra to the intercrest line were of
prognostic value. Translatory shifts played an important role in curve
progression. Curves that measured between 50 and 75 degrees at skeletal
maturity, particularly thoracic curves, progressed the most.