Inter-operator variability in the measurement of ‘pelvic height’. Preliminary study and comparison between measurement devices

In 45 Italian laboratories out of 60 registered by the Siamoc on its website, the model described in [1] is used to perform gait analysis of patients. A variable used in the regression equations of this model is the measure of the so called pelvis height (pelH). More properly, pelH is the antero-posterior component of the distance between a point approximating the hip centre and the homolateral ASIS. This point is obtained by the operator based on the position of the prominence of the great trocanter with the patient supine and the leg in neutral position.
To the authors’ knowledge, this measurement is carried out in gait laboratories by means of a Martin pelvimeter or of a caliper used in association with a ruler placed horizontally over the two ASIS. No standard procedure is used across laboratories.
The large inter-operator variability in the identification of the anatomical landmarks (AL) used in the measurement of pelH has been described in the literature [2].
After AL identification, a further error, not yet investigated in the literature, could be introduced during the execution of the measurement, which might be difficult during the clinical practice, i.e. with subjects with a prominent abdomen.
In this preliminary work, we present a comparison of the inter-operator variability in the measurement of pelH, when assessed by a standard caliper (SC) and a novel device, purpose-designed and built, referred to as Anatomical Caliper (AC).