This is a follow-up study to skeletal maturity
on a cohort of students screened for a 1-year prospective epidemiological prevalence study for scoliosis.
This study aims to identify the prognostic factors for curve progression
to a magnitude of 30° at skeletal maturity
in skeletally immature patients with adolescent idiopathic scoliosis
Summary of Background Data.
The natural history
of idiopathic scoliosis is not well understood. Previous reports have focused on the characteristics of curve progression
where progression has been predefined at specific angles of 5° to 6°. However, the absolute curve magnitude at skeletal maturity
is more predictive of long-term curve behavior rather than curve progression
of a defined magnitude over shorter periods of skeletal growth. It is generally agreed that curves less than 30° are highly unlikely to progress after skeletal maturity
. Hence, defining the factors that influence curve progression
to an absolute magnitude of more than 30° at skeletal maturity
would more significantly aid clinical practice.
One hundred eighty-six patients who fulfilled the study criteria were selected from an initial 279 patients with idiopathic scoliosis detected by school screening, and who were followed-up till skeletal maturity
. The initial age, gender, pubertal status, and initial curve magnitude were used as risk factors to predict the probability of curve progression
to more than 30° at skeletal maturity
Curve magnitude at first presentation was the most important predictive factor for curve progression
to a magnitude of more than 30° at skeletal maturity
. An initial Cobb angle
of 25° had the best receiver-operating characteristic of 0.80 with a positive predictive value of 68.4% and a negative predictive value of 91.9% for curve progression
to 30° or more at skeletal maturity
Initial Cobb angle
magnitude is the most important predictor of long-term curve progression
and behavior past skeletal maturity
. We suggest an initial Cobb angle
of 25° as an important threshold magnitude for long-term curve progression
. Initial age, gender, and pubertal status were less important prognostic factors in our study.