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

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).

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.

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).

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.