This study compares different lower-limb length measurements using tests of lower-limb upright full-length radiography and anteroposterior radiography of load-bearing hips.
Forty-seven consecutive individuals aged 17 to 61 years (mean ± SD, 31.47 ± 11.42 years) voluntarily took part in the study; 23 (48.9%) were women and 24 (51.1%) were men. All individuals presenting a difference of 5 mm or greater between both lower limbs quantified with a tape measure were included. All of the participants signed an informed consent form to take part in the study. Two anteroposterior load-bearing radiographs were taken: one of the hip and an upright full-length radiograph of the lower limbs. Lower-limb–length discrepancy was quantified by taking different reference points. Interobserver and intraobserver reliability was assessed for each radiographic measurement. Any correlation between the different measurements were also verified.
Interobserver and intraobserver reliability was high for all of the measurements because the intraclass correlation was greater than 0.75 in all of the cases. There was a strong and positive correlation between the different measurements because when performing bivariate correlations with the Pearson correlation coefficient, positive values close to 1 were found.
In this study, the different reference points reported in the upright full-length radiograph in addition to the hip radiographs are useful for assessing lower-limb–length discrepancy. The results showed that there is a correct correlation between the different measurements.