Fast 3D reconstruction of the lower limb using a parametric model and statistical inferences and clinical measurements calculation from biplanar X-rays

Abstract

In clinical routine, lower limb analysis relies on conventional X-ray (2D view) or computerised tomography (CT) Scan (lying position). However, these methods do not allow 3D analysis in standing position. The aim of this study is to propose a fast and accurate 3D-reconstruction-method based on parametric models and statistical inferences from biplanar X-rays with clinical measurements' (CM) assessment in standing position for a clinical routine use. For the reproducibility study, the 95% CI was under 2.7° for all lower limbs' angular measurements except for tibial torsion, femoral torsion and tibiofemoral rotation ( < 5°). The 95% CI were under 2.5 mm for lower limbs' lengths and 1.5 to 3° for the pelvis' CM. Comparisons between X-rays and CT-scan based 3D shapes in vitro showed mean differences of 1.0 mm (95% CI = 2.4 mm). Comparisons of 2D lower limbs' and 3D pelvis' CM between standing ‘Shifted-Feet’ and ‘Non-Shifted-Feet’ position showed means differences of 0.0 to 1.4°. Significant differences were found only for pelvic obliquity and rotation. The reconstruction time was about 5 min.

Keywords:

• biplanar X-rays
• lower limb
• 3D modelling
• clinical 3D measurements
• parametric model
• statistical inferences

Acknowledgements

This work was partly financed by the research and development ‘SterEos+’ project of the MEDICEN pole (Ile de France, Paris). The authors would like to thank the Biospace Med Company, all volunteers who have participated in this study and team members of the laboratories, especially B. Godbout, D. Branchaud, L. Humbert, L. Vancura and C. Fedelich, for their technical contributions.

Notes

1. Laboratoire de Biomécanique (UMR CNRS 8005), Arts et Métiers ParisTech, 151, Boulevard de l'hôpital, 75013 Paris, France. Tel: [phone]. Fax: [phone].

Additional information

Notes on contributors

Y. Chaibi

1

W. Skalli

1