What is the clinical detection threshold for lower limb length inequality? In silico study of reproducibility and optimization using a centimeter graduated support.

Introduction: The threshold of a Leg Length Discrepancy (LLD) by clinical examination on a sheet or centimeter paper (CP) is not known precisely whether or not it concerns limbs equipped with a hip prosthesis. We therefore conducted a prospective in silico study in order to: (1) determine the reproducibility and sensitivity of the clinical measurement of the LLD in different ideal and "degraded" clinical situations, (2) determine the threshold from which the human eye is capable of detecting a length inequality in clinic, (3) to determine whether the use of a graduated support (centimeter paper) improves the clinical measurement threshold.

Hypothesis: Our hypothesis was that clinical measurement on a centimeter support would improve clinical measurement accuracy.