Introduction:

Adolescent idiopathic scoliosis (AIS) is the most common and severe spinal deformity, which affects children and adolescents in the stage of neuromotor development and skeletal maturity of the sagittal curvatures of the spine. The literature presents several radiation-free instruments to assess and monitor the progression of scoliotic curvature angles in the AIS. However, the reliability and validity of the inclinometer at different stages of growth in relation to X-ray parameters has not been understood to date.

Objective:

To evaluate the reliability of the inclinometer and its validity with the X-ray exam on the sagittal parameters of the spine in the early and late growth stages of adolescents with AIS.

Methods:

A cross-sectional study was conducted with 39 adolescents with AIS who were divided into two groups: the initial growth phase (10-13 years) and the late growth phase (14-18 years). The evaluated sagittal parameters of the spine were the angle of the thoracic kyphosis and the angle of the lumbar lordosis, both measured by the X-ray image examination and the inclinometer.

Results:

The inclinometer showed excellent inter- and intra-examiner reliability for the different growth phases, early and late, with a strong association with the X-ray (gold standard; r = 0.84; p = 0.308 and r = 0.75; p = 0.517). The angle of lumbar lordosis was different between the inclinometer and X-ray instruments in the early and late stages of growth (p < 0.001), with moderate reliability and a less significant correlation with the gold standard of radiography (r = 0.38; p = 0.001 and r = 0.49; p = 0.024).

Conclusion:

The inclinometer showed excellent reliability and validity for the sagittal parameter of thoracic kyphosis in the early and late stages of growth. The angle of lumbar lordosis measured by inclinometer proved to be of moderate reliability and weak validity when considering the phases of skeletal growth, showing it to be an inefficient instrument for monitoring the lumbar scoliotic curvature for AIS.