TY - CHAP A1 - Kornaropoulos, Evgenios I. A1 - Taylor, William R. A1 - Duda, Georg A1 - Ehrig, Rainald A1 - Matziolis, Georg A1 - Müller, Michael A1 - Wassilew, Georgi A1 - Asbach, Patrick A1 - Perka, Carsten A1 - Heller, Markus O. T1 - An imageless method to quantify the mechanical femoral-tibial angle based on the functional determination of joint centers and axes T2 - Annual meeting of the ESMAC 2009 Y1 - 2009 CY - London ER - TY - JOUR A1 - Kornaropoulos, Evgenios I. A1 - Taylor, William R. A1 - Duda, Georg A1 - Ehrig, Rainald A1 - Matziolis, Georg A1 - Müller, Michael A1 - Wassilew, Georgi A1 - Asbach, Patrick A1 - Perka, Carsten A1 - Heller, Markus O. T1 - Frontal plane alignment: An imageless method to predict the mechanical femoral–tibial angle (mFTA) based on functional determination of joint centres and axes JF - Gait & Posture Y1 - 2010 U6 - https://doi.org/10.1016/j.gaitpost.2009.10.006 VL - 31 IS - 2 SP - 204 EP - 208 ER - TY - JOUR A1 - Deppe, Dominik A1 - Gabriele, Matteo A1 - Mazzoleni, Manuel Giovanni A1 - Ordas-Bayon, Alejandro A1 - Fidanza, Andrea A1 - Rozhko, Yuriy A1 - Şimşek, Ekin Kaya A1 - Keltz, Eran A1 - Osterhoff, Georg A1 - Damm, Philipp A1 - Duda, Georg N. A1 - Leskovar, Marko A1 - Zachow, Stefan A1 - Trepczynski, Adam A1 - Heyland, Mark T1 - Interobserver Reliability of the Modified Radiographic Union Score (mRUST) for Tibial and Femoral Fractures JF - Journal of Orthopaedic Trauma N2 - OBJECTIVES: To evaluate the reliability of the modified Radiographic Union Score for Tibial fractures (mRUST) as a reliable tool for monitoring lower limb fractures (femur, tibia) treated with various modalities (nail, plate). METHODS: Design: Retrospective analysis. Setting: Single center academic hospital in Germany. Patient Selection Criteria: Adult patients (≥18 years) with extra-articular long bone fractures of the lower extremities treated surgically between January 2005 and April 2022, requiring radiographs in two perpendicular planes and at least one follow-up visit, were included. Exclusion criteria were critical clinical conditions, inability to consent, joint articulation fractures, inadequate documentation, or insufficient imaging quality. Outcome Measures and Comparisons: Six international investigators (five orthopedic surgeons, one radiologist) independently assessed fracture line and callus growth per cortex (mRUST) at individualized follow-up time points based on clinical practice. To evaluate interrater reliability, intraclass correlation coefficients were calculated for the overall dataset, and for subsets of rated images, that were defined based on anatomical location (femur/tibia), treatment type (plate/nail fixation), and treatment combinations across locations. RESULTS: A total of 166 patients (63 femur fractures, 103 tibia fractures; 32.5% female, mean age 43.4 (18–84)) with 1136 follow-up time points were analyzed. Overall interrater reliability for mRUST was good (intraclass correlation coefficient 0.77), consistent across fixation methods (nail/plate fixation, 0.79) and anatomical locations (tibia, 0.78; femur, 0.81). Cortex-specific reliability varied, with highest agreement for the medial cortex (0.70–0.74) and lowest for the posterior cortex (0.65–0.74). CONCLUSIONS: The mRUST (radiographic score) demonstrated reliability for monitoring fracture healing in the femur and tibia, irrespective of fixation method, supporting its use as a generalizable tool across lower limb fractures. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence. Y1 - 2025 U6 - https://doi.org/10.1097/BOT.0000000000003032 SN - 0890-5339 VL - 39 IS - 10 SP - 557 EP - 563 ER - TY - JOUR A1 - Heller, Markus O. A1 - Duda, Georg A1 - Ehrig, Rainald A1 - Schell, H. A1 - Seebeck, P. A1 - Taylor, William R. T1 - Muskuloskeletale Belastungen im Schafshinterlauf JF - Materialwissenschaft und Werkstofftechnik Y1 - 2005 IS - 36 SP - 775 EP - 780 ER - TY - JOUR A1 - Heller, Markus O. A1 - Kratzenstein, Stefan A1 - Ehrig, Rainald A1 - Wassilew, Georgi A1 - Duda, Georg A1 - Taylor, William R. T1 - The weighted optimal common shape technique improves identification of the hip joint centre of rotation in vivo JF - Journal of Orthopedic Research Y1 - 2011 VL - 29 SP - 1470 EP - 5 ER - TY - JOUR A1 - Ehrig, Rainald A1 - Heller, Markus O. A1 - Kratzenstein, Stefan A1 - Duda, Georg A1 - Trepczynski, Adam A1 - Taylor, William R. T1 - The SCoRE residual: A quality index to assess the accuracy of joint estimations JF - Journal of Biomechanics Y1 - 2011 U6 - https://doi.org/10.1016/j.jbiomech.2010.12.009 VL - 44 IS - 7 SP - 1400 EP - 1404 ER - TY - JOUR A1 - Ehrig, Rainald A1 - Taylor, William R. A1 - Duda, Georg A1 - Heller, Markus O. T1 - A Survey for Formal Methods for Determining Functional Joint Axes JF - Journal of Biomechanics Y1 - 2007 SP - 2150 EP - 2157 ER - TY - CHAP A1 - Kratzenstein, Stefan A1 - Ehrig, Rainald A1 - Heller, Markus O. A1 - Duda, Georg A1 - Taylor, William R. T1 - A Quantification of Accuracy in Estimating Joint Centers T2 - 17th Congress of the European Society of Biomechanics Y1 - 2010 CY - Edinburgh ER - TY - CHAP A1 - Kratzenstein, Stefan A1 - Heller, Markus O. A1 - Ehrig, Rainald A1 - Duda, Georg A1 - Schröder, Jörg H. A1 - Taylor, William R. T1 - Die Bestimmung der Genauigkeit nicht-invasiver Techniken zur Ermittlung der Hüftgelenksposition in-vivo T2 - 6th annual meeting of the German Society for Biomechanics (DGfB) Y1 - 2009 CY - Münster ER - TY - CHAP A1 - Kratzenstein, Stefan A1 - Heller, Markus O. A1 - Ehrig, Rainald A1 - Duda, Georg A1 - Schröder, Jörg H. A1 - Taylor, William R. T1 - Der Vergleich von nicht-invasiven Techniken zur Bestimmung der Hüftgelenksposition T2 - Annual meeting of the German Society of Orthopaedics and Trauma Surgery Y1 - 2009 CY - Berlin ER - TY - CHAP A1 - Kratzenstein, Stefan A1 - Heller, Markus O. A1 - Ehrig, Rainald A1 - Duda, Georg A1 - Taylor, William R. T1 - The Residual: A Reliable Measure of Accuracy in the Determination of Joint Centers T2 - Transactions Vol. 35, 2010 Annual Meeting of the Orthopedic Society Y1 - 2010 CY - New Orleans ER - TY - CHAP A1 - Kratzenstein, Stefan A1 - Heller, Markus O. A1 - Ehrig, Rainald A1 - Duda, Georg A1 - Taylor, William R. T1 - The Hip Joint Centre can be determined to within 3 mm T2 - 17th Congress of the European Society of Biomechanics Y1 - 2010 CY - Edinburgh ER - TY - CHAP A1 - Kratzenstein, Stefan A1 - Heller, Markus O. A1 - Ehrig, Rainald A1 - Wassilew, Georgi A1 - Duda, Georg A1 - Taylor, William R. T1 - A new approach for optimally reducing skin marker artifact allows determination of the hip joint center within 3mm T2 - Transactions Vol. 35, 2010 Annual Meeting of the Orthopedic Society Y1 - 2010 CY - New Orleans ER - TY - JOUR A1 - Taylor, William R. A1 - Pöpplau, Berry M. A1 - König, Christian A1 - Ehrig, Rainald A1 - Zachow, Stefan A1 - Duda, Georg A1 - Heller, Markus O. T1 - The medial-lateral force distribution in the ovine stifle joint during walking JF - Journal of Orthopaedic Research Y1 - 2011 U6 - https://doi.org/10.1002/jor.21254 VL - 29 IS - 4 SP - 567 EP - 571 ER - TY - JOUR A1 - Boeth, Heide A1 - Duda, Georg A1 - Heller, Markus O. A1 - Ehrig, Rainald A1 - Doyscher, Ralf A1 - Jung, Tobias A1 - Moewis, Philippe A1 - Scheffler, Sven A1 - Taylor, William R. T1 - Anterior cruciate ligament-deficient patients with passive knee joint laxity have a decreased range of anterior-posterior motion during active movements JF - The American Journal of Sports Medicine Y1 - 2013 U6 - https://doi.org/10.1177/0363546513480465 VL - 41 IS - 5 SP - 1051 EP - 7 ER - TY - CHAP A1 - Taylor, William R. A1 - Kornaropoulos, Evgenios I. A1 - Ehrig, Rainald A1 - Heller, Markus O. A1 - Duda, Georg T1 - Reproducibility of a functional approach to gait analysis T2 - Annual meeting of the ESMAC 2009 Y1 - 2009 CY - London ER - TY - CHAP A1 - Taylor, William R. A1 - Fröhlich, Annika A1 - Buttgereit, Frank A1 - Ehrig, Rainald A1 - Witaschek, Tom A1 - Duda, Georg ED - Kersting, Uwe ED - Morlock, Michael ED - Jirova-Enzmann, Daniela ED - Dremstrup, Kim T1 - Metacarpophalangeal joint stiffness is reduced in patients affected by rheumatoid arthritis after glucocorticoid medication T2 - Proceedings of the ESM-2012, Aalborg Y1 - 2012 SP - 39 PB - Department of Health Science and Technology, Aalborg University ER - TY - CHAP A1 - Kornaropoulos, Evgenios I. A1 - Taylor, William R. A1 - Duda, Georg A1 - Ehrig, Rainald A1 - Heller, Markus O. T1 - Frontal plane lower limb alignment using functionally determined joint centers and axes T2 - International Conference on Computational Bioengineering Y1 - 2009 ER - TY - CHAP A1 - Kornaropoulos, Evgenios I. A1 - Taylor, William R. A1 - Duda, Georg A1 - Ehrig, Rainald A1 - Heller, Markus O. T1 - An imageless method to quantify the Mechanical Femoral-Tibial Angle (MFTA) using functionally defined joint centers and axes. T2 - 6th Annual meeting of the German Society for Biomechanics (DGfB) Y1 - 2009 ER - TY - CHAP A1 - Krämer, Martin A1 - Maggioni, Marta A1 - Tycowicz, Christoph von A1 - Brisson, Nick A1 - Zachow, Stefan A1 - Duda, Georg A1 - Reichenbach, Jürgen T1 - Ultra-short echo-time (UTE) imaging of the knee with curved surface reconstruction-based extraction of the patellar tendon T2 - ISMRM (International Society for Magnetic Resonance in Medicine), 26th Annual Meeting 2018, Paris, France N2 - Due to very short T2 relaxation times, imaging of tendons is typically performed using ultra-short echo-time (UTE) acquisition techniques. In this work, we combined an echo-train shifted multi-echo 3D UTE imaging sequence with a 3D curved surface reconstruction to virtually extract the patellar tendon from an acquired 3D UTE dataset. Based on the analysis of the acquired multi-echo data, a T2* relaxation time parameter map was calculated and interpolated to the curved surface of the patellar tendon. Y1 - 2018 ER - TY - JOUR A1 - Alves, Sónia A1 - Ehrig, Rainald A1 - Raffalt, Peter C. A1 - Bender, Alwina A1 - Duda, Georg A1 - Agres, Alison N. T1 - Quantifying Asymmetry in Gait: A Weighted Universal Symmetry Index to Evaluate 3D Ground Reaction Forces JF - Frontiers in Bioengineering and Biotechnology N2 - 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. Y1 - 2020 ER - TY - JOUR A1 - Willie, Bettina M. A1 - Pap, Thomas A1 - Perka, Carsten A1 - Schmidt, Carsten Oliver A1 - Eckstein, Felix A1 - Arampatzis, Adamantios A1 - Hege, Hans-Christian A1 - Madry, Henning A1 - Vortkamp, Andrea A1 - Duda, Georg T1 - OVERLOAD of joints and its role in osteoarthritis - Towards understanding and preventing progression of primary osteoarthritis JF - Zeitschrift für Rheumatologie N2 - Intact joints are necessary for skeletal function and mobility in daily life. A healthy musculoskeletal system is the basis for a functional cardiovascular system as well as an intact immune system. Locomotion, physiotherapy, and various forms of patient activity are essential clinical therapies used in the treatment of neurodegeneration, stroke, diabetes, and cancer. Mobility is substantially impaired with degeneration of joints and, in advanced stages, nighttime pain and sleep disturbance are particularly cumbersome. Osteoarthritis (OA) is also known as degenerative joint disease. OA involves structural and compositional changes in the articular cartilage, as well as in the calcified cartilage, subchondral cortical bone, subchondral cancellous bone, meniscus, joint capsular tissue, and synovium; which eventually lead to degeneration of these tissues comprising synovial joints. Y1 - 2015 U6 - https://doi.org/10.1007/s00393-014-1561-2 VL - 76 IS - Suppl. 1 SP - 1 EP - 4 ER - TY - JOUR A1 - Krämer, Martin A1 - Maggioni, Marta A1 - Brisson, Nicholas A1 - Zachow, Stefan A1 - Teichgräber, Ulf A1 - Duda, Georg A1 - Reichenbach, Jürgen T1 - T1 and T2* mapping of the human quadriceps and patellar tendons using ultra-short echo-time (UTE) imaging and bivariate relaxation parameter-based volumetric visualization JF - Magnetic Resonance Imaging N2 - Quantification of magnetic resonance (MR)-based relaxation parameters of tendons and ligaments is challenging due to their very short transverse relaxation times, requiring application of ultra-short echo-time (UTE) imaging sequences. We quantify both T1 and T2⁎ in the quadriceps and patellar tendons of healthy volunteers at a field strength of 3 T and visualize the results based on 3D segmentation by using bivariate histogram analysis. We applied a 3D ultra-short echo-time imaging sequence with either variable repetition times (VTR) or variable flip angles (VFA) for T1 quantification in combination with multi-echo acquisition for extracting T2⁎. The values of both relaxation parameters were subsequently binned for bivariate histogram analysis and corresponding cluster identification, which were subsequently visualized. Based on manually-drawn regions of interest in the tendons on the relaxation parameter maps, T1 and T2⁎ boundaries were selected in the bivariate histogram to segment the quadriceps and patellar tendons and visualize the relaxation times by 3D volumetric rendering. Segmentation of bone marrow, fat, muscle and tendons was successfully performed based on the bivariate histogram analysis. Based on the segmentation results mean T2⁎ relaxation times, over the entire tendon volumes averaged over all subjects, were 1.8 ms ± 0.1 ms and 1.4 ms ± 0.2 ms for the patellar and quadriceps tendons, respectively. The mean T1 value of the patellar tendon, averaged over all subjects, was 527 ms ± 42 ms and 476 ms ± 40 ms for the VFA and VTR acquisitions, respectively. The quadriceps tendon had higher mean T1 values of 662 ms ± 97 ms (VFA method) and 637 ms ± 40 ms (VTR method) compared to the patellar tendon. 3D volumetric visualization of the relaxation times revealed that T1 values are not constant over the volume of both tendons, but vary locally. This work provided additional data to build upon the scarce literature available on relaxation times in the quadriceps and patellar tendons. We were able to segment both tendons and to visualize the relaxation parameter distributions over the entire tendon volumes. Y1 - 2019 U6 - https://doi.org/10.1016/j.mri.2019.07.015 VL - 63 IS - 11 SP - 29 EP - 36 ER -