Validity of clinical methods in the detection of leg-length discrepancies.

INTRODUCTION: Lower limb-length discrepancy is highly prevalent in the general population. Numerous methods and measurement instruments for its diagnosis appear in the literature, but there has not been an agreement about their validity. The aim of this work is to determine the validity of the Weber-Barstow manoeuvre (WB) of the pelvic measuring device (PMD) and the block method (BM), in comparison with standing anteroposterior telemetry of the lower limbs in subjects with leg-length discrepancy (LLD). METHODS: 71 subjects took part in the study. First, the WB was carried out in the supine position. the LLD was then quantified standing with the PMD and with the BM. Lastly, standing anteroposterior telemetry of the lower limbs was obtained. This was measured with Autocad 2013, using the highest part of the head of the femur and the most distal edge of the bisection of the femur as points of reference. RESULTS: The Kappa index was calculated to check the agreement between the WB manoeuvre and the telemetry. This was 0.52. The relation of the PMD, BM and telemetry difference variables was calculated. A direct relation between the BM and telemetry was shown, with p > 0.05 (0.48 cm and 0.51 cm, respectively). CONCLUSIONS: The WB manoeuvre got acceptable validity results. The PMD was not valid according to the results obtained in this work. The BM achieved a good validity result for the diagnosis of LLD.

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.