@article{EhrigTaylorDudaetal.2007, author = {Ehrig, Rainald and Taylor, William R. and Duda, Georg and Heller, Markus O.}, title = {A Survey for Formal Methods for Determining Functional Joint Axes}, series = {Journal of Biomechanics}, journal = {Journal of Biomechanics}, pages = {2150 -- 2157}, year = {2007}, language = {en} } @inproceedings{KratzensteinHellerEhrigetal.2010, author = {Kratzenstein, Stefan and Heller, Markus O. and Ehrig, Rainald and Wassilew, Georgi and Duda, Georg and Taylor, William R.}, title = {A new approach for optimally reducing skin marker artifact allows determination of the hip joint center within 3mm}, series = {Transactions Vol. 35, 2010 Annual Meeting of the Orthopedic Society}, booktitle = {Transactions Vol. 35, 2010 Annual Meeting of the Orthopedic Society}, address = {New Orleans}, year = {2010}, language = {en} } @inproceedings{KornaropoulosTaylorDudaetal.2009, author = {Kornaropoulos, Evgenios I. and Taylor, William R. and Duda, Georg and Ehrig, Rainald and Matziolis, Georg and M{\"u}ller, Michael and Wassilew, Georgi and Asbach, Patrick and Perka, Carsten and Heller, Markus O.}, title = {An imageless method to quantify the mechanical femoral-tibial angle based on the functional determination of joint centers and axes}, series = {Annual meeting of the ESMAC 2009}, booktitle = {Annual meeting of the ESMAC 2009}, address = {London}, year = {2009}, language = {en} } @article{KornaropoulosTaylorDudaetal.2010, author = {Kornaropoulos, Evgenios I. and Taylor, William R. and Duda, Georg and Ehrig, Rainald and Matziolis, Georg and M{\"u}ller, Michael and Wassilew, Georgi and Asbach, Patrick and Perka, Carsten and Heller, Markus O.}, title = {Frontal plane alignment: An imageless method to predict the mechanical femoral-tibial angle (mFTA) based on functional determination of joint centres and axes}, series = {Gait \& Posture}, volume = {31}, journal = {Gait \& Posture}, number = {2}, doi = {10.1016/j.gaitpost.2009.10.006}, pages = {204 -- 208}, year = {2010}, language = {en} } @article{BoethBiesenHollnageletal.2021, author = {Boeth, Heide and Biesen, Robert and Hollnagel, Jeremias and Herrmann, Sandra and Ehrig, Rainald and Pelli, Lorenzo and Taylor, William R. and Duda, Georg and Buttgereit, Frank}, title = {Quantification of morning stiffness to assess disease activity and treatment effects in rheumatoid arthritis}, series = {Rheumatology}, volume = {60}, journal = {Rheumatology}, number = {11}, doi = {10.1093/rheumatology/keab323}, pages = {5282 -- 5291}, year = {2021}, abstract = {Objectives The clinical parameter "morning stiffness" is widely used to assess the status of rheumatoid arthritis (RA), but its accurate quantitative assessment in a clinical setting has not yet been successful. This lack of individual quantification limits both personalized medication and efficacy evaluation in the treatment of RA. Methods We have developed a novel technology to assess passive resistance of the metacarpophalangeal (MCP) III joint (stiffness) and its Passive Range of Motion (PRoM). Within this pilot study, nineteen female postmenopausal RA patients and nine healthy controls were examined in the evening as well as in the morning of the following day. To verify the specificity of the biomechanical quantification, eleven patients with RA were assessed both prior to and ∼3 h after glucocorticoid therapy. Results While the healthy controls showed only minor changes between afternoon and morning, in RA patients mean±SD PRoM decreased significantly by 18 ± 22\% and stiffness increased significantly by 20 ± 18\% in the morning compared with the previous afternoon. We found a significant positive correlation between RA activity and biomechanical measures. Glucocorticoids significantly increased mean PRoM by 16 ± 11\% and reduced mean stiffness by 23 ± 22\%. Conclusion This technology allowed mechanical stiffness to be quantified in MCP joints, and has demonstrated high sensitivity in respect to disease status as well as medication effect in RA patients. Such non-invasive, low risk, and rapid assessment of biomechanical joint stiffness opens a novel avenue for judging therapy efficacy in patients with RA, and potentially also in other non-RA inflammatory joint diseases.}, language = {en} } @article{AlvesEhrigRaffaltetal., author = {Alves, S{\´o}nia and Ehrig, Rainald and Raffalt, Peter C. and Bender, Alwina and Duda, Georg and Agres, Alison N.}, title = {Quantifying Asymmetry in Gait: A Weighted Universal Symmetry Index to Evaluate 3D Ground Reaction Forces}, series = {Frontiers in Bioengineering and Biotechnology}, journal = {Frontiers in Bioengineering and Biotechnology}, abstract = {Though gait asymmetry is used as a metric of functional recovery in clinical rehabilitation, there is no consensus on an ideal method for its evaluation. Various methods have been proposed but are limited in scope, as they can often use only positive signals or discrete values extracted from time-scale data as input. By defining five symmetry axioms, a framework for benchmarking existing methods was established and a new method was described here for the first time: the weighted universal symmetry index (wUSI), which overcomes limitations of other methods. Both existing methods and the wUSI were mathematically compared to each other and in respect to their ability to fulfill the proposed symmetry axioms. Eligible methods that fulfilled these axioms were then applied using both discrete and continuous approaches to ground reaction force (GRF) data collected from healthy gait, both with and without artificially induced asymmetry using a single instrumented elbow crutch. The wUSI with a continuous approach was the only symmetry method capable of determining GRF asymmetries in different walking conditions in all three planes of motion. When used with a continuous approach, the wUSI method was able to detect asymmetries while avoiding artificial inflation, a common problem reported in other methods. In conclusion, the wUSI is proposed as a universal method to quantify three-dimensional GRF asymmetries, which may also be expanded to other biomechanical signals.}, language = {en} } @inproceedings{KraemerHerrmannBoethetal., author = {Kr{\"a}mer, Martin and Herrmann, Karl-Heinz and Boeth, Heide and Tycowicz, Christoph von and K{\"o}nig, Christian and Zachow, Stefan and Ehrig, Rainald and Hege, Hans-Christian and Duda, Georg and Reichenbach, J{\"u}rgen}, title = {Measuring 3D knee dynamics using center out radial ultra-short echo time trajectories with a low cost experimental setup}, series = {ISMRM (International Society for Magnetic Resonance in Medicine), 23rd Annual Meeting 2015, Toronto, Canada}, booktitle = {ISMRM (International Society for Magnetic Resonance in Medicine), 23rd Annual Meeting 2015, Toronto, Canada}, language = {en} } @inproceedings{BoethDudaHinzmannetal., author = {Boeth, Heide and Duda, Georg and Hinzmann, Daniel and Taylor, William R. and Ehrig, Rainald and Witaschek, Tom and Buttgereit, Frank}, title = {Objektive Quantifizierung der Morgensteifigkeit als Parameter f{\"u}r rheumatoide Arthritis im Metacarpophalangealgelenk}, series = {9. Jahrestagung der Deutschen Gesellschaft f{\"u}r Biomechanik (DGfB), Bonn}, booktitle = {9. Jahrestagung der Deutschen Gesellschaft f{\"u}r Biomechanik (DGfB), Bonn}, language = {de} } @article{BoethDudaHinzmannetal., author = {Boeth, Heide and Duda, Georg and Hinzmann, Daniel and Hermann, Sandra and Taylor, William R. and Ehrig, Rainald and Witaschek, Tom and Buttgereit, Frank}, title = {A Novel Approach to Quantify Morning Stiffness in Patients with Rheumatoid Arthritis}, series = {Annual European Congress of Rheumatology, EULAR 2015, Rome}, journal = {Annual European Congress of Rheumatology, EULAR 2015, Rome}, language = {en} } @inproceedings{KornaropoulosTaylorDudaetal., author = {Kornaropoulos, Evgenios I. and Taylor, William R. and Duda, Georg and Ehrig, Rainald and Heller, Markus O.}, title = {Frontal plane lower limb alignment using functionally determined joint centers and axes}, series = {International Conference on Computational Bioengineering}, booktitle = {International Conference on Computational Bioengineering}, language = {en} }