Radiographic Assessment of Lower-Limb Discrepancy

Background: This study compares different lower-limb length measurements using tests of lower-limb upright full-length radiography and anteroposterior radiography of load-bearing hips. Methods: 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. Results: 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. Conclusions: 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.