title: In vivo application of an optical segment tracking approach for bone loading regimes recording in humans: a reliability study.
abstract: This paper demonstrates an optical segment tracking (OST) approach for assessing the in vivo bone loading regimes in humans. The relative movement between retro-reflective marker clusters affixed to the tibia cortex by bone screws was tracked and expressed as tibia loading regimes in terms of segment deformation. Stable in vivo fixation of bone screws was tested by assessing the resonance frequency of the screw-marker structure and the relative marker position changes after hopping and jumping. Tibia deformation was recorded during squatting exercises to demonstrate the reliability of the OST approach. Results indicated that the resonance frequencies remain unchanged prior to and after all exercises. The changes of Cardan angle between marker clusters induced by the exercises were rather minor, maximally 0.06°. The reproducibility of the deformation angles during squatting remained small (0.04°/m-0.65°/m). Most importantly, all surgical and testing procedures were well tolerated. The OST method promises to bring more insights of the mechanical loading acting on bone than in the past.
authors.affiliation: Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi'an, China; Institute of Aerospace Medicine, German Aerospace Center, Cologne, Germany; Institute of Biomechanics and Orthopaedics, German Sport University Cologne, Germany. Electronic address: yangpf@nwpu.edu.cn.
authors.forename: Peng-Fei
authors.initials: PF
authors.lastname: Yang
authors.affiliation: Institute of Biomechanics and Orthopaedics, German Sport University Cologne, Germany.
authors.forename: Maximilian
authors.initials: M
authors.lastname: Sanno
authors.affiliation: Institute of Aerospace Medicine, German Aerospace Center, Cologne, Germany.
authors.forename: Bergita
authors.initials: B
authors.lastname: Ganse
authors.affiliation: Department of Orthopaedic and Trauma Surgery, University of Cologne, Germany.
authors.forename: Timmo
authors.initials: T
authors.lastname: Koy
authors.affiliation: Institute of Biomechanics and Orthopaedics, German Sport University Cologne, Germany.
authors.forename: Gert-Peter
authors.initials: GP
authors.lastname: Brüggemann
authors.affiliation: Department of Orthopaedic and Trauma Surgery, University of Cologne, Germany.
authors.forename: Lars Peter
authors.initials: LP
authors.lastname: Müller
authors.affiliation: Institute of Aerospace Medicine, German Aerospace Center, Cologne, Germany.
authors.forename: Jörn
authors.initials: J
authors.lastname: Rittweger
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D001863:Bone Screws; D005240:Feasibility Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009038:Motion; D009068:Movement / Q000502:physiology; D061848:Optical Imaging / Q000295:instrumentation / Q000379:methods*; D010147:Pain Measurement; D015203:Reproducibility of Results; D013977:Tibia / Q000502:physiology* / Q000601:surgery
keywords: In vivo; Locomotive activities; Motion capture system; Optical approach; Tibia segment deformation