title: A novel dual fluoroscopic imaging method for determination of THA kinematics: in-vitro and in-vivo study.
abstract: Accurate measurement of six-degrees-of-freedom in-vivo kinematics of the total hip arthroplasty (THA) is essential in gaining insights into in-vivo THA performance. The objective of this study was to validate a novel dual fluoroscopy imaging system (DFIS) for determination of the THA kinematics using both in-vitro and in-vivo approaches. The in-vitro validation utilized cadaveric hip specimens to compare the THA motion using the DFIS technique with those measured by a radiostereometric analysis (RSA). The differences between the DFIS technique and the RSA were within 0.33±0.81 mm (mean±SD) in translation and 0.45±0.65° in rotation during dynamic motion of the hips. In the in-vivo validation, the THA kinematics of two patients during a treadmill gait was assessed for the feasibility/repeatability of the DFIS technique in measurement of THA kinematics. The poses of the THAs during the treadmill gait was measured using the DFIS technique with the maximum standard deviation of 0.35 mm in translation and of 0.55° in rotation. This study demonstrated that the DFIS technique has comparable accuracy of the RSA and is highly repeatable for measurement of dynamic THA motion, suggesting that the DFIS is a promising tool in evaluating the in-vivo THA biomechanics during functional activities.
authors.affiliation: Bioengineering Laboratory, Department of Orthopaedic Surgery, Massachusetts General Hospital, Harvard Medical School, 55 Fruit Street, Boston, MA 02114, USA.
authors.forename: Tsung-Yuan
authors.initials: TY
authors.lastname: Tsai
authors.forename: Jing-Sheng
authors.initials: JS
authors.lastname: Li
authors.forename: Shaobai
authors.initials: S
authors.lastname: Wang
authors.forename: Hao
authors.initials: H
authors.lastname: Lin
authors.forename: Henrik
authors.initials: H
authors.lastname: Malchau
authors.forename: Guoan
authors.initials: G
authors.lastname: Li
authors.forename: Harry
authors.initials: H
authors.lastname: Rubash
authors.forename: Young-Min
authors.initials: YM
authors.lastname: Kwon
mesh_terms: D000368:Aged; D001696:Biomechanical Phenomena; D005471:Fluoroscopy; D005684:Gait / Q000502:physiology*; D006615:Hip / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D016138:Walking / Q000502:physiology*