title: HiL simulation in biomechanics: a new approach for testing total joint replacements.
abstract: Instability of artificial joints is still one of the most prevalent reasons for revision surgery caused by various influencing factors. In order to investigate instability mechanisms such as dislocation under reproducible, physiologically realistic boundary conditions, a novel test approach is introduced by means of a hardware-in-the-loop (HiL) simulation involving a highly flexible mechatronic test system. In this work, the underlying concept and implementation of all required units is presented enabling comparable investigations of different total hip and knee replacements, respectively. The HiL joint simulator consists of two units: a physical setup composed of a six-axes industrial robot and a numerical multibody model running in real-time. Within the multibody model, the anatomical environment of the considered joint is represented such that the soft tissue response is accounted for during an instability event. Hence, the robot loads and moves the real implant components according to the information provided by the multibody model while transferring back the position and resisting moment recorded. Functionality of the simulator is proved by testing the underlying control principles, and verified by reproducing the dislocation process of a standard total hip replacement. HiL simulations provide a new biomechanical testing tool for analyzing different joint replacement systems with respect to their instability behavior under realistic movements and physiological load conditions.
authors.affiliation: Department of Orthopaedics, University of Rostock, Germany. sven.herrmann@med.uni-rostock.de
authors.forename: Sven
authors.initials: S
authors.lastname: Herrmann
authors.forename: Michael
authors.initials: M
authors.lastname: Kaehler
authors.forename: Robert
authors.initials: R
authors.lastname: Souffrant
authors.forename: Roman
authors.initials: R
authors.lastname: Rachholz
authors.forename: János
authors.initials: J
authors.lastname: Zierath
authors.forename: Daniel
authors.initials: D
authors.lastname: Kluess
authors.forename: Wolfram
authors.initials: W
authors.lastname: Mittelmeier
authors.forename: Christoph
authors.initials: C
authors.lastname: Woernle
authors.forename: Rainer
authors.initials: R
authors.lastname: Bader
mesh_terms: D001696:Biomechanical Phenomena; D003198:Computer Simulation; D019544:Equipment Failure Analysis / Q000706:statistics & numerical data; D006801:Humans; D007593:Joint Instability / Q000209:etiology / Q000503:physiopathology; D007595:Joint Prosthesis / Q000009:adverse effects; D011474:Prosthesis Design; D016059:Range of Motion, Articular; D012086:Reoperation