title: Performance of local optimization in single-plane fluoroscopic analysis for total knee arthroplasty.
abstract: Fluoroscopy-derived joint kinematics plays an important role in the evaluation of knee prostheses. Fluoroscopic analysis requires estimation of the 3D prosthesis pose from its 2D silhouette in the fluoroscopic image, by optimizing a dissimilarity measure. Currently, extensive user-interaction is needed, which makes analysis labor-intensive and operator-dependent. The aim of this study was to review five optimization methods for 3D pose estimation and to assess their performance in finding the correct solution. Two derivative-free optimizers (DHSAnn and IIPM) and three gradient-based optimizers (LevMar, DoNLP2 and IpOpt) were evaluated. For the latter three optimizers two different implementations were evaluated: one with a numerically approximated gradient and one with an analytically derived gradient for computational efficiency. On phantom data, all methods were able to find the 3D pose within 1mm and 1° in more than 85% of cases. IpOpt had the highest success-rate: 97%. On clinical data, the success rates were higher than 85% for the in-plane positions, but not for the rotations. IpOpt was the most expensive method and the application of an analytically derived gradients accelerated the gradient-based methods by a factor 3-4 without any differences in success rate. In conclusion, 85% of the frames can be analyzed automatically in clinical data and only 15% of the frames require manual supervision. The optimal success-rate on phantom data (97% with IpOpt) on phantom data indicates that even less supervision may become feasible.
authors.affiliation: Biomechanics and Imaging Group, Department of Orthopaedics, Leiden University Medical Center, The Netherlands.
authors.forename: A H
authors.initials: AH
authors.lastname: Prins
authors.affiliation: Biomechanics and Imaging Group, Department of Orthopaedics, Leiden University Medical Center, The Netherlands. Electronic address: B.L.Kaptein@lumc.nl.
authors.forename: B L
authors.initials: BL
authors.lastname: Kaptein
authors.affiliation: Division of Image Processing, Department of Radiology, Leiden University Medical Center, The Netherlands.
authors.forename: B C
authors.initials: BC
authors.lastname: Stoel
authors.affiliation: Department of Applied Mathematics, Faculty Electrical Engineering, Mathematics and Computer Science, Delft University of Technology, The Netherlands.
authors.forename: D J P
authors.initials: DJ
authors.lastname: Lahaye
authors.affiliation: Biomechanics and Imaging Group, Department of Orthopaedics, Leiden University Medical Center, The Netherlands; Department of Biomechanical Engineering, Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, The Netherlands.
authors.forename: E R
authors.initials: ER
authors.lastname: Valstar
mesh_terms: D019645:Arthroplasty, Replacement, Knee; D001696:Biomechanical Phenomena; D003198:Computer Simulation; D005471:Fluoroscopy / Q000379:methods*; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D007720:Knee Prosthesis; D019047:Phantoms, Imaging
keywords: Fluoroscopic analysis; Optimization; Pose estimation; Shape matching