@inproceedings{AlMunajjedNolteRasmussenetal., author = {Al-Munajjed, Amir Andreas and Nolte, Daniel and Rasmussen, John and Dendorfer, Sebastian}, title = {Force distribution in the foot during braking - a musculoskeletal approach}, series = {Human Modeling Symposium 2014, Munich, Germany}, booktitle = {Human Modeling Symposium 2014, Munich, Germany}, abstract = {High loads can appear in the individual joints of the human foot while the driver uses the pedals, in particular, during breaking. Measuring these internal forces is very difficult or almost impossible; therefore, advanced models are necessary to perform musculoskeletal simulations. The objective of this investigation was to see what loads are acting in the individual foot joints from the phalanges to calcaneus and talus during different brake scenarios. The Glasgow-Maastricht AnyBody Foot Model with 26 separate segments, connected by joints, ligaments and muscles was used inside the AnyBody Modeling System to compute individual mid foot joint loads. The amount, the direction of the force and additionally also the load insertion point was varied for several simulations. Figure 1: Seated musculoskeletal body model with applied brake force and forces for the lateral, intermediate and medial cuneiform-navicular joint for two different brake forces. The simulation showed that for the different brake scenarios, different muscles will be activated in the human and therefore different loads are apply in the fore-and mid-foot, respectively. The torso of the subject was assumed to be fixed in the seat. Further studies are ongoing to simulate the seat as an elastic element that allows different H-point locations according to the different loadings in the foot from the brake pedal using a new inverse dynamics analysis method called force-dependent kinematics.}, language = {en} } @inproceedings{AndersendeZeeDendorferetal., author = {Andersen, Michael Skipper and de Zee, Mark and Dendorfer, Sebastian and MacWilliams, Bruce and Rasmussen, John}, title = {Validation of a detailed lower extremity model based on the Klein Horsman data set}, series = {Proceedings of the 12th International Symposium on Computer Simulation in Biomechanics (ISB 2009), July 2nd - 4th 2009, Cape Town, South Africa}, booktitle = {Proceedings of the 12th International Symposium on Computer Simulation in Biomechanics (ISB 2009), July 2nd - 4th 2009, Cape Town, South Africa}, pages = {27 -- 28}, language = {en} } @article{AuerKrutschRenkawitzetal., author = {Auer, Simon and Krutsch, Werner and Renkawitz, Tobias and Kubowitsch, Simone and S{\"u}ß, Franz and Dendorfer, Sebastian}, title = {Kognitiver Stress f{\"u}hrt zu unphysiologisch erh{\"o}hten Kniebelastungen im Profifußball}, series = {Sports Orthopaedics and Traumatology}, volume = {36}, journal = {Sports Orthopaedics and Traumatology}, number = {2}, publisher = {Elsevier}, doi = {10.1016/j.orthtr.2020.04.122}, pages = {202 -- 203}, language = {de} } @misc{AuerKrutschRenkawitzetal., author = {Auer, Simon and Krutsch, Werner and Renkawitz, Tobias and Kubowitsch, Simone and S{\"u}ß, Franz and Dendorfer, Sebastian}, title = {Effect of mental demand on leg loading in highly dynamic motion}, series = {AnyBody online Webinar, Oct 2020}, journal = {AnyBody online Webinar, Oct 2020}, abstract = {Football players have a high risk of leg muscle injuries, especially when exposed to mental stress. Injuries to muscles of the thigh are common in amateur and professional football, representing almost a third of all injuries. These injuries occur primarily in non-contact situations and from overuse. They can lead to a range of costs, including financial costs associated with treatment as well as those associated with long-term recovery, and absence from training and/or competition. Further, there is a high risk of injury recurrence and subsequent injury.}, language = {en} } @article{AuerKubowitschDendorfer, author = {Auer, Simon and Kubowitsch, Simone and Dendorfer, Sebastian}, title = {Kombinierter Einfluss von psychologischen und biomechanischen Faktoren auf die muskul{\"a}ren Belastungen beim Fußballspielen}, series = {Die Orthop{\"a}die}, volume = {52}, journal = {Die Orthop{\"a}die}, number = {11}, publisher = {Springer}, doi = {10.1007/s00132-023-04437-8}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-65113}, pages = {1 -- 6}, abstract = {When mental stress and musculoskeletal loading interact, the risk for injury increases due to altered body kinematics and increased muscle tension. These changes can be detected with musculoskeletal models, and mental loading and stress must be analyzed at emotional, cognitive, and behavioral levels. To investigate these kinematic and loading changes under stress, competitive athletes were subjected to mental stress during highly dynamic movements, and musculoskeletal models were used to analyze the biomechanical loading. It was shown that under mental stress, independent of the subjective perception, a strong change in muscle forces can occur. Accordingly, competitive athletes should undergo screenings to assess individual movement patterns and promote general stress resilience.}, language = {de} } @inproceedings{AuerKubowitschKrutschetal., author = {Auer, Simon and Kubowitsch, Simone and Krutsch, Werner and Renkawitz, Tobias and S{\"u}ß, Franz and Dendorfer, Sebastian}, title = {Effect of mental demand on knee forces in professional youth soccer players}, series = {ISBS Proceedings Archive}, volume = {38}, booktitle = {ISBS Proceedings Archive}, number = {1, Art. 28}, abstract = {Soccer is one of the most popular sports all around the world. It is an injurious type of sport with a focus on lower extremities and high psychological pressure during matches. The stressor is linked with injuries and an increased musculoskeletal loading. This study investigates the influence of cognitive stress on the load profile of the knee joint. Twelve professional youth soccer players performed highly dynamic runs with and without additional cognitive stress. The runs were analysed with a musculoskeletal simulation software. The data analysis shows no difference in knee joint reaction loading under additional mental stress compared to the baseline. Yet running times are significantly lower in the baseline. While there is no increase in the joint loads, the running times indicate an altered movement behaviour when the subjects are exposed to additional mental demand.}, subject = {Kniegelenk}, language = {en} } @article{AuerKurbowitschSuessetal., author = {Auer, Simon and Kurbowitsch, Simone and S{\"u}ß, Franz and Renkawitz, Tobias and Krutsch, Werner and Dendorfer, Sebastian}, title = {Mental stress reduces performance and changes musculoskeletal loading in football-related movements}, series = {Science and Medicine in Football}, volume = {5}, journal = {Science and Medicine in Football}, number = {4}, publisher = {Taylor \& Francis}, doi = {10.1080/24733938.2020.1860253}, pages = {323 -- 329}, abstract = {Purpose: Football players have a high risk of leg muscle injuries, especially when exposed to mental stress. Hence, this study investigated the musculoskeletal response of elite youth football players during highly dynamic movements under stress. The hypothesis is that mental stress reduces performance and changes the muscular forces exerted. Materials \& methods: Twelve elite youth football players were subjected to mental stress while performing sports-specific change-of-direction movements. A modified version of the d2 attention test was used as stressor. The kinetics are computed using inverse dynamics. Running times and exerted forces of injury-prone muscles were analysed. Results: The stressor runs were rated more mentally demanding by the players (p = 0.006, rs = 0.37) with unchanged physical demand (p = 0.777, rs = 0.45). This resulted in 10\% longer running times under stress (p < 0.001, d = -1.62). The musculoskeletal analysis revealed higher peak muscle forces under mental stress for some players but not for others. Discussion: The study shows that motion capture combined with musculoskeletal computation is suitable to analyse the effects of stress on athletes in highly dynamic movements. For the first time in football medicine, our data quantifies an association between mental stress with reduced football players' performance and changes in muscle force.}, language = {en} } @misc{AuerNieblerEiglspergeretal., author = {Auer, Simon and Niebler, Michael and Eiglsperger, Josef and Kubowitsch, Simone and Renkawitz, Tobias and Achenbach, Leonard and Krutsch, Werner and Dendorfer, Sebastian}, title = {Cognitive stress increases muscle forces in dynamic football specific movements}, series = {European Society of Biomechanics meeting 2019, Vienna, Austria}, journal = {European Society of Biomechanics meeting 2019, Vienna, Austria}, language = {en} } @misc{AuerReinkerDendorfer, author = {Auer, Simon and Reinker, Lukas and Dendorfer, Sebastian}, title = {Evaluation of muscle recruitment and muscle models in musculoskeletal simulation of dynamic motion}, series = {26th Congress of the European Society of Biomechanics, July 11-14, 2021, Milan, Italy}, journal = {26th Congress of the European Society of Biomechanics, July 11-14, 2021, Milan, Italy}, address = {Milan}, pages = {8}, abstract = {Musculoskeletal simulation plays an increasingly important role in sports biomechanics. In the last years, the field of application widened from orthopaedics and ergonomics to sports [1]. A muscle recruitment algorithm with a quadratic objective function is usually used to calculate muscle activity in dynamic movements. The agreement of calculated and measured thigh muscle activity has already been investigated [2]. They found a strong agreement for sprinting and running, while the correlation decreased for side-cutting manoeuvres. Nevertheless, the influence of different muscle recruitment criteria on muscle activity in dynamic musculoskeletal simulations is currently unknown. Hence, this study aimed to analyse the effect of different muscle recruitment criteria and muscle models on the correlation of numerical and measured muscle activity in highly dynamic movements.}, language = {en} } @misc{AuerReinkerSuessetal., author = {Auer, Simon and Reinker, Lukas and S{\"u}ß, Franz and Dendorfer, Sebastian}, title = {Comparing calculated and measured muscle activity of thigh muscles in dynamic motion.}, series = {27th Congress of the European Society of Biomechanics, 26 - 29 June 2022, Porto, Portugal}, journal = {27th Congress of the European Society of Biomechanics, 26 - 29 June 2022, Porto, Portugal}, pages = {640}, language = {en} } @misc{AuerReinkerSuessetal., author = {Auer, Simon and Reinker, Lukas and S{\"u}ß, Franz and Kubowitsch, Simone and Krutsch, Werner and Weber, Markus and Renkawitz, Tobias and Dendorfer, Sebastian}, title = {Webcast: Effect of mental demand on leg loading in highly dynamic motion}, abstract = {Football players have a high risk of leg muscle injuries, especially when exposed to mental stress. Injuries to muscles of the thigh are common in amateur and professional football, representing almost a third of all injuries. These injuries occur primarily in non-contact situations and from overuse. They can lead to a range of costs, including financial costs associated with treatment as well as those associated with long-term recovery, and absence from training and/or competition. Further, there is a high risk of injury recurrence and subsequent injury.}, language = {en} } @article{AuerSchieblIversenetal., author = {Auer, Simon and Schiebl, Jonas and Iversen, Kristoffer and Subhash Chander, Divyaksh and Damsgaard, Michael and Dendorfer, Sebastian}, title = {Biomechanical assessment of the design and efficiency of occupational exoskeletons with the AnyBody Modeling System}, series = {Zeitschrift f{\"u}r Arbeitswissenschaften}, volume = {76}, journal = {Zeitschrift f{\"u}r Arbeitswissenschaften}, number = {4}, publisher = {Springer Nature}, doi = {10.1007/s41449-022-00336-4}, pages = {440 -- 449}, abstract = {Exoskeletons were invented over 100 years ago but have only become popular in the last two decades, especially in the working industry as they can decrease work-related loads significantly. The most often used exoskeletons are for the lower back and shoulder since these are commonly affected body regions. All devices have in common that their purpose is to reduce internal loads of vulnerable body regions. Nevertheless, there is still little understanding on how biomechanical loading in the human body changes when exoskeletons are used. Therefore, further analyses are needed. A promising candidate for these are musculoskeletal models, which are based on an inverse dynamics approach and can calculate external parameters such as ground reaction forces or other interaction forces as well as internal parameters such as joint reaction forces or muscle activities. The various examples in the literature show that these models are increasingly used for assessing the biomechanical effects of exoskeletons on the human body. Furthermore, musculoskeletal models can calculate biomechanical loadings of humans with and without exoskeletons for all kinds of applications and allow an evaluation of their purpose. Practical Relevance: This article highlights the possibilities of musculoskeletal models for assessing the design and efficiency of occupational exoskeletons. Several practical use cases are described along with distinct descriptions of common implications of musculoskeletal and exoskeleton modeling.}, language = {en} } @inproceedings{AurbachJungtaeublSpickaetal., author = {Aurbach, Maximilian and Jungt{\"a}ubl, Dominik and Spicka, Jan and Dendorfer, Sebastian}, title = {EMG-based validation of musculoskeletal models considering crosstalk}, series = {World Congress Biomechanics, 28-30 June 2018, Dublin}, booktitle = {World Congress Biomechanics, 28-30 June 2018, Dublin}, doi = {10.1109/BIOMDLORE.2018.8467211}, abstract = {BACKGROUND: Validation and verification of multibody musculoskeletal models sEMG is a difficult process because of the reliability of sEMG data and the complex relationship of muscle force and sEMG. OBJECTIVE: This work aims at comparing experimentally recorded and simulated muscle activities considering a numerical model for crosstalk. METHODS: For providing an experimentally derived reference data set, subjects were performing elevations of the arm, where the activities of the contemplated muscle groups were measured by sEMG sensors. Computed muscle activities were further processed and transformed into an artificial electromyographical signal, which includes a numerical crosstalk model. In order to determine whether the crosstalk model provides a better agreement with the measured muscle activities, the Pearson correlation coefficient has been computed as a qualitative way of assessing the curve progression of the data sets. RESULTS: The results show an improvement in the correlation coefficient between the experimental data and the simulated muscle activities when taking crosstalk into account. CONCLUSIONS: Although the correlation coefficient increased when the crosstalk model was utilized, it is questionable if the discretization of both, the crosstalk and the musculoskeletal model, is accurate enough.}, language = {en} } @article{AurbachSpickaSuessetal., author = {Aurbach, Maximilian and Spicka, Jan and S{\"u}ß, Franz and Dendorfer, Sebastian}, title = {Evaluation of musculoskeletal modelling parameters of the shoulder complex during humeral abduction above 90°}, series = {Journal of Biomechanics}, volume = {106}, journal = {Journal of Biomechanics}, number = {June}, publisher = {Elsevier}, doi = {10.1016/j.jbiomech.2020.109817}, abstract = {Based on electromyographic data and force measurements within the shoulder joint, there is an indication that muscle and resulting joint reaction forces keep increasing over an abduction angle of 90°. In inverse dynamics models, no single parameter could be attributed to simulate this force behaviour accordingly. The aim of this work is to implement kinematic, kinetic and muscle model modifications to an existing model of the shoulder (AnyBody™) and assess their single and combined effects during abduction up to 140° humeral elevation. The kinematics and the EMG activity of 10 test subjects were measured during humeral abduction. Six modifications were implemented in the model: alternative wrapping of the virtual deltoid muscle elements, utilization of a three element Hill model, strength scaling, motion capture driven clavicle elevation/protraction, translation of the GH joint in dependency of the acting forces and an alteration of the scapula/clavicle rhythm. From the six modifications, 16 different combinations were considered. Parameter combinations with the Hill model changed the resultant GH joint reaction force and led to an increase in force during abduction of the humerus above 90°. Under the premise of muscle activities and forces within the GH joint rising after 90° of humeral abduction, we propose that the Hill type muscle model is a crucial parameter for accurately modelling the shoulder. Furthermore, the outcome of this study indicates that the Hill model induces the co-contraction of the muscles of the shoulder without the need of an additional stability criterion for an inverse dynamics approach.}, subject = {Schultergelenk}, language = {en} } @misc{AurbachSpickaSuessetal., author = {Aurbach, Maximilian and Spicka, Jan and S{\"u}ß, Franz and Dendorfer, Sebastian}, title = {Musculoskeletal modelling of the shoulder - effects on muscle recruitment and joint reaction force}, series = {European Society of Biomechanics meeting 2019, Vienna, Austria}, journal = {European Society of Biomechanics meeting 2019, Vienna, Austria}, language = {en} } @misc{AurbachSuessDendorfer, author = {Aurbach, Maximilian and S{\"u}ß, Franz and Dendorfer, Sebastian}, title = {The impact of the hill type muscle model on the glenohumeral joint reaction force}, series = {16th International Symposium on Computer Methods in Biomechanics and Biomedical Engineering (CMBBE) 2019, New York City, USA}, journal = {16th International Symposium on Computer Methods in Biomechanics and Biomedical Engineering (CMBBE) 2019, New York City, USA}, language = {en} } @inproceedings{AurbachWagnerSuessetal., author = {Aurbach, Maximilian and Wagner, Kilian and S{\"u}ß, Franz and Dendorfer, Sebastian}, title = {Implementation and Validation of Human Kinematics Measured Using IMUs for Musculoskeletal Simulations by the Evaluation of Joint Reaction Forces}, series = {CMBEBIH 2017, Proceedings of the International Conference on Medical and Biological Engineering 2017, Sarajevo, Bosnia and Herzegovina}, volume = {Vol. 62}, booktitle = {CMBEBIH 2017, Proceedings of the International Conference on Medical and Biological Engineering 2017, Sarajevo, Bosnia and Herzegovina}, editor = {Badnjevic, Almir}, publisher = {Springer}, address = {Singapore}, doi = {10.1007/978-981-10-4166-2_31}, pages = {205 -- 211}, abstract = {The gold standard for the analysis of human kinematics and kinetics is a camera-based motion capture system in combination with force measurement platforms. Alternatively, inertial measurement units can be utilized to obtain human kinematics, while ground reaction forces are computed from full body dynamics. This setup represents a system independent from the spatial confinement of a gait laboratory. The aim of this study is the comparison of the two methods by the investigation of lower limb kinematics and the resulting joint reaction forces within the ankle-, knee- and hip joints. For this purpose, human motion during gait was captured simultaneously by both measurement techniques. 13 trials from 8 different test subjects were evaluated in total. IMU data was processed with a quaternion based Kalman Filter. The data sets were implemented into a musculoskeletal simulation program in order to drive a virtual human body model. Each sensor was aligned to the gravitational and magnetic field vectors of the earth. The angles of flexions, extensions and rotations were analyzed to determine kinematic differences. Joint reaction forces defined kinetic dissimilarities. The overall kinematic differences of both models yielded root mean square errors of 7.62°, 6.02°, 4.95°, 2.79°, 2.38° and 3.56° for ankle flexion, subtalar eversion, knee flexion, hip external rotation, hip abduction and hip flexion, respectively. The proximo-distal differences in force peaks between the models yielded overall for the ankle, 57.33 \%Bodyweight(BW) ± 46.86 \%BW (16.66 \%(Maximum peak to peak) ± 13.62 \%) for the knee 37.09 \%BW ± 29.33 \%BW (17.65 \% ± 15.44 \%) and 32.03 \%BW ± 24.33 \%BW (15.6 \% ± 12.54 \%) for the hip. The overall outcome of this work investigated an approach independent of the common setup of the gait laboratory, thus enabling a cheaper and more flexible technology as an alternative. However, kinematic and thus kinetic differences remain rather large. Future work aims to improve the contact criterion for the calculation of the ground reaction forces and the implementation of a full-body calibration algorithm for the IMU system in order to counteract magnetic field disturbances.}, subject = {Bewegungsapparat}, language = {en} } @article{AurbachŠpičkaSuessetal., author = {Aurbach, Maximilian and Špička, Jan and S{\"u}ß, Franz and Vychytil, J. and Havelkov{\´a}, Leonard and Ryba, T. and Dendorfer, Sebastian}, title = {Torus obstacle method as a wrapping approach of the deltoid muscle group for humeral abduction in musculoskeletal simulation}, series = {Journal of Biomechanics}, volume = {109}, journal = {Journal of Biomechanics}, number = {August}, publisher = {Elsevier}, doi = {10.1016/j.jbiomech.2020.109864}, abstract = {Musculoskeletal models of the shoulder complex are valuable research aids to investigate tears of the supraspinatus and the resulting mechanical impact during abduction of the humerus. One of the major contributors to this motion is the deltoid muscle group and for this, an accurate modeling of the lines of action is indispensable. The aim of this work was to utilize a torus obstacle wrapping approach for the deltoids of an existing shoulder model and assess the feasibility of the approach during humeral abduction. The shoulder model from the AnyBody™ modeling system was used as a platform. The size of the tori is based on a magnetic resonance imaging (MRI) approach and several kinematic couplings are implemented to determine the trajectories of the tori during abduction. To assess the model behavior, the moment arms of the virtual muscle elements and the resultant glenohumeral joint reaction force (GHJF) were compared with reference data from the literature during abduction of the humerus in the range 20°-120°. The root mean square error for the anterior, lateral and posterior part between the simulated muscle elements and reference data from the literature was 3.9, 1.7 and 5.8 mm, respectively. The largest deviation occurred on the outer elements of the muscle groups, with 12.6, 10.4 and 20.5 mm, respectively. During abduction, there is no overlapping of the muscle elements and these are in continuous contact with the torus obstacles, thus enabling a continuous force transmission. This results in a rising trend of the resultant GHJF. The torus obstacle approach as a wrapping method for the deltoid muscles provides a guided muscle pathing by simultaneously approximating the curvature of the deltoid muscle. The results from the comparison of the simulated moment arms and the resultant GHJF are in accordance with those in the literature in the range 20°-120° of abduction. Although this study shows the strength of the torus obstacle as a wrapping approach, the method of fitting the tori according to MRI data was not suitable. A cadaver study is recommended to better validate and mathematically describe the torus approach.}, language = {en} } @misc{BeimlerLeisslEbneretal., author = {Beimler, Josef and Leißl, Caroline and Ebner, Lena and Elsner, Michael and M{\"u}hlbauer, Gerhard and Kohlert, Dieter and Schubert, Martin J. W. and Weiß, Andreas P. and Sterner, Michael and Raith, Thomas and Afranseder, Martin and Krapf, Tobias and Mottok, J{\"u}rgen and Siemers, Christian and Großmann, Benjamin and H{\"o}cherl, Johannes and Schlegl, Thomas and Schneider, Ralph and Milaev, Johannes and Rampelt, Christina and Roduner, Christian and Glowa, Christoph and Bachl, Christoph and Schliekmann, Claus and Gnan, Alfons and Grill, Martin and Ruhland, Karl and Piehler, Thomas and Friers, Daniel and Wels, Harald and Pflug, Kenny and Kucera, Markus and Waas, Thomas and Schlachetzki, Felix and Boy, Sandra and Pemmerl, Josef and Leis, Alexander and Welsch, Andreas F.X. and Graf, Franz and Zenger, Gerhard and Volbert, Klaus and Waas, Thomas and Scherzinger, Stefanie and Klettke, Meike and St{\"o}rl, Uta and Heyl, C. and Boldenko, A. and Monkman, Gareth J. and Kujat, Richard and Briem, Ulrich and Hierl, Stefan and Talbot, Sebastian and Schmailzl, Anton and Ławrowski, Robert Damian and Prommesberger, Christian and Langer, Christoph and Dams, Florian and Schreiner, Rupert and Valentino, Piergiorgio and Romano, Marco and Ehrlich, Ingo and Furgiuele, Franco and Gebbeken, Norbert and Eisenried, Michael and Jungbauer, Bastian and Hutterer, Albert and Bauhuber, Michael and Mikrievskij, Andreas and Argauer, Monika and Hummel, Helmut and Lechner, Alfred and Liebetruth, Thomas and Schumm, Michael and Joseph, Saskia and Reschke, Michael and Soska, Alexander and Schroll-Decker, Irmgard and Putzer, Michael and Rasmussen, John and Dendorfer, Sebastian and Weber, Tim and Al-Munajjed, Amir Andreas and Verkerke, Gijsbertus Jacob and Renkawitz, Tobias and Haug, Sonja and Rudolph, Clarissa and Zeitler, Annika and Schaubeck, Simon and Steffens, Oliver and Rechenauer, Christian and Schulz-Brize, Thekla and Fleischmann, Florian and Kusterle, Wolfgang and Beer, Anne and Wagner, Bernd and Neidhart, Thomas}, title = {Forschungsbericht 2013}, editor = {Baier, Wolfgang}, address = {Regensburg}, organization = {Ostbayerische Technische Hochschule Regensburg}, doi = {10.35096/othr/pub-799}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-7990}, pages = {80}, language = {de} } @article{BenditzAuerSpoerreretal., author = {Benditz, Achim and Auer, Simon and Sp{\"o}rrer, J.F. and Wolkerstorfer, S. and Grifka, Joachim and S{\"u}ß, Franz and Dendorfer, Sebastian}, title = {Regarding loads after spinal fusion, every level should be seen separately: a musculoskeletal analysis}, series = {European Spine Journal}, volume = {27}, journal = {European Spine Journal}, number = {8}, publisher = {Springer-Verlag}, doi = {10.1007/s00586-018-5476-5}, pages = {1905 -- 1910}, abstract = {The number of spinal fusion surgeries is steadily increasing and biomechanical consequences are still in debate. The aim of this study is to provide biomechanical insights into the sagittal balance of the spine and to compare spinal load before and after spinal fusion. METHOD: The joint reaction forces of 52 patients were analyzed in proximo-distal and antero-posterior direction from the levels T12-L1 to L5-S1 using musculoskeletal simulations. RESULTS: In 104 simulations, pre-surgical forces were equal to post-surgical. The levels L4-L5 and T12-L1, however, showed increased spinal forces compression forces with higher sagittal displacement. Improved restauration of sagittal balance was accompanied by lower spinal load. AP shear stress, interestingly decreased with sagittal imbalance. CONCLUSION: Imbalanced spines have a risk of increased compression forces at Th12-L1. L4-L5 always has increased spinal loads. These slides can be retrieved under Electronic Supplementary Material.}, subject = {Biomechanische Analyse}, language = {en} } @inproceedings{BillingGoetzWeberetal., author = {Billing, A. and G{\"o}tz, J. and Weber, Tim and Dendorfer, Sebastian}, title = {Positionsanalyse von winkelstabilen Plattenosteosynthesesystemen zur Versorgung von Metatarsalfrakturen mit Hilfe von patientenspezifischen biomechanischen Modellen}, series = {Vereinigung S{\"u}ddeutscher Orthop{\"a}den und Unfallchirurgen Jahrestagung 2015, Baden-Baden, Germany}, booktitle = {Vereinigung S{\"u}ddeutscher Orthop{\"a}den und Unfallchirurgen Jahrestagung 2015, Baden-Baden, Germany}, language = {de} } @misc{BroserFalterŁawrowskietal., author = {Broser, Christian and Falter, Thomas and Ławrowski, Robert Damian and Altenbuchner, Amelie and V{\"o}gele, Daniel and Koss, Claus and Schlampp, Matthias and Dunnweber, Jan and Steffens, Oliver and Heckner, Markus and Jaritz, Sabine and Schiegl, Thomas and Corsten, Sabine and Lauer, Norina and Guertler, Katherine and Koenig, Eric and Haug, Sonja and Huber, Dominik and Birkenmaier, Clemens and Krenkel, Lars and Wagner, Thomas and Justus, Xenia and Saßmannshausen, Sean Patrick and Kleine, Nadine and Weber, Karsten and Braun, Carina N. and Giacoppo, Giuliano and Heinrich, Michael and Just, Tobias and Schreck, Thomas and Schnabl, Andreas and Gilmore, Amador T{\´e}ran and Roeslin, Samuel and Schmid, Sandra and Wellnitz, Felix and Malz, Sebastian and Maurial, Andreas and Hauser, Florian and Mottok, J{\"u}rgen and Klettke, Meike and Scherzinger, Stefanie and St{\"o}rl, Uta and Heckner, Markus and Bazo, Alexander and Wolff, Christian and Kopper, Andreas and Westner, Markus and Pongratz, Christian and Ehrlich, Ingo and Briem, Ulrich and Hederer, Sebastian and Wagner, Marcus and Schillinger, Moritz and G{\"o}rlach, Julien and Hierl, Stefan and Siegl, Marco and Langer, Christoph and Hausladen, Matthias and Schreiner, Rupert and Haslbeck, Matthias and Kreuzer, Reinhard and Br{\"u}ckl, Oliver and Dawoud, Belal and Rabl, Hans-Peter and Gamisch, Bernd and Schmidt, Ottfried and Heberl, Michael and G{\"a}nsbauer, Bianca and Bick, Werner and Ellermeier, Andreas and Monkman, Gareth J. and Prem, Nina and Sindersberger, Dirk and Tschurtschenthaler, Karl and Aurbach, Maximilian and Dendorfer, Sebastian and Betz, Michael A. and Szecsey, Tamara and Mauerer, Wolfgang and Murr, Florian}, title = {Forschung 2018}, editor = {Baier, Wolfgang}, address = {Regensburg}, organization = {Ostbayerische Technische Hochschule Regensburg}, isbn = {978-3-9818209-5-9}, doi = {10.35096/othr/pub-1382}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-13826}, pages = {98}, subject = {Forschung}, language = {de} } @article{DePieriAtzoriFergusonetal., author = {De Pieri, Enrico and Atzori, Federica and Ferguson, Stephen J. and Dendorfer, Sebastian and Leunig, Michael and Aepli, Martin}, title = {Contact force path in total hip arthroplasty: effect of cup medialisation in a whole-body simulation}, series = {HIP International}, volume = {31}, journal = {HIP International}, number = {5}, publisher = {Sage}, doi = {10.1177/1120700020917321}, pages = {624 -- 631}, abstract = {Background: Cup medialisation down to the true acetabular floor in total hip arthroplasty with a compensatory femoral offset increase seems to be mechanically advantageous for the abductor muscles due to the relocation of the lever arms (body weight lever arm decreased, abductor lever arm increased). However, limited information is currently available about the effects of this reconstruction type at the head cup interface, compared to an anatomical reconstruction that maintains the natural lever arms. Through a whole-body simulation analysis, we compared medialised versus anatomical reconstruction in THA to analyse the effects on: (1) contact force magnitude at the head cup interface; (2) contact force path in the cup; and (3) abductor activity. Methods: Musculoskeletal simulations were performed to calculate the above-mentioned parameters using inverse dynamics analysis. The differences between the virtually implanted THAs were calculated to compare the medialised versus anatomical reconstruction. Results: Cup medialisation with compensatory femoral offset increase led to: (1) a reduction in contact force magnitude at the head cup interface up to 6.6\%; (2) a similar contact force path in the cup in terms of sliding distance and aspect ratio; and (3) a reduction in abductor activity up to 17.2\% (gluteus medius). Conclusions: In our opinion, these potential biomechanical gains do not generally justify a fully medialised reconstruction, especially in younger patients that are more likely to undergo revision surgery in their lifetime. Cup medialisation should be performed until sufficient press fit and bony coverage of a properly sized and oriented cup can be achieved.}, subject = {H{\"u}ftgelenkprothese}, language = {en} } @article{Dendorfer, author = {Dendorfer, Sebastian}, title = {{\"A}lterwerden muss auch mal wehtun!}, series = {Gesunde Hochschule, OTH Regensburg, 4.7.2016}, journal = {Gesunde Hochschule, OTH Regensburg, 4.7.2016}, language = {de} } @inproceedings{Dendorfer, author = {Dendorfer, Sebastian}, title = {The effect of multifidus muscles atrophy following disc herniation on disc loading}, series = {Deutsche Gesellschaft f{\"u}r Biomechanik, Murnau, 2011}, booktitle = {Deutsche Gesellschaft f{\"u}r Biomechanik, Murnau, 2011}, language = {en} } @misc{Dendorfer, author = {Dendorfer, Sebastian}, title = {The influence of modeling parameters in the AnyBody Modeling System on muscle and joint loading in the shoulder}, series = {International Shoulder Group Meeting}, volume = {05}, journal = {International Shoulder Group Meeting}, language = {en} } @misc{Dendorfer, author = {Dendorfer, Sebastian}, title = {Biomechanische Aspekte bei Sportverletzungen}, series = {OT World Leipzig, Internationale Fachmesse und Weltkongress f{\"u}r Orthop{\"a}die und Rehatechnik, 10.-13. Mai 2022}, journal = {OT World Leipzig, Internationale Fachmesse und Weltkongress f{\"u}r Orthop{\"a}die und Rehatechnik, 10.-13. Mai 2022}, language = {de} } @misc{Dendorfer, author = {Dendorfer, Sebastian}, title = {KI-basierte mechanische Modelle f{\"u}r Pr{\"a}vention, Diagnostik und Rehabilitation}, series = {Serien-Webmeeting zu AI - KI-basierte Bildanalyse zur computer-unterst{\"u}tzten Frakturerkennung, 09.11.22}, journal = {Serien-Webmeeting zu AI - KI-basierte Bildanalyse zur computer-unterst{\"u}tzten Frakturerkennung, 09.11.22}, organization = {Deutsche Gesellschaft f{\"u}r Orthop{\"a}die und Orthop{\"a}dische Chirurgie}, language = {de} } @inproceedings{Dendorfer, author = {Dendorfer, Sebastian}, title = {Virtuelle Menschmodelle - von der Bewegung zur Belastung}, series = {Medbo Bezirksklinikum Regensburg, April 2016}, booktitle = {Medbo Bezirksklinikum Regensburg, April 2016}, language = {de} } @inproceedings{Dendorfer, author = {Dendorfer, Sebastian}, title = {Biomechanik des Alterns}, series = {Kolpingfortbildung Lambach, April 2016}, booktitle = {Kolpingfortbildung Lambach, April 2016}, language = {de} } @inproceedings{Dendorfer, author = {Dendorfer, Sebastian}, title = {Einf{\"u}hrung in die Mechanik}, series = {Biomechanik Workshop, Klinikum Bad Abbach, Nov. 2013}, booktitle = {Biomechanik Workshop, Klinikum Bad Abbach, Nov. 2013}, language = {de} } @inproceedings{Dendorfer, author = {Dendorfer, Sebastian}, title = {Innovationen in der Medizintechnik}, series = {Oberpfalztag Weiherhammer, Nov. 2013}, booktitle = {Oberpfalztag Weiherhammer, Nov. 2013}, language = {de} } @misc{Dendorfer, author = {Dendorfer, Sebastian}, title = {Virtuelle Modelle der oberen Extremit{\"a}t}, series = {22. Interdisziplin{\"a}res Symposium Medizin-Physiotherapie-Sportwissenschaften, 22.-23.11.2019, Regensburg, Germany}, journal = {22. Interdisziplin{\"a}res Symposium Medizin-Physiotherapie-Sportwissenschaften, 22.-23.11.2019, Regensburg, Germany}, language = {de} } @misc{Dendorfer, author = {Dendorfer, Sebastian}, title = {The influence of mental stress on the musculoskeletal system}, language = {en} } @inproceedings{Dendorfer, author = {Dendorfer, Sebastian}, title = {Mechanobiology - Impact on regeneration and degradation}, series = {Translations in Regenerative Medicine, TIRM and FIFA Symposium, Regensburg, 2015}, booktitle = {Translations in Regenerative Medicine, TIRM and FIFA Symposium, Regensburg, 2015}, language = {en} } @inproceedings{Dendorfer, author = {Dendorfer, Sebastian}, title = {How much iron to pump? The determination of muscle forces for activities of daily living}, series = {DGU, Berlin, 2008}, booktitle = {DGU, Berlin, 2008}, language = {en} } @inproceedings{Dendorfer, author = {Dendorfer, Sebastian}, title = {Biomechanical evaluation and optimisation of countermeasure exercises}, series = {ESA/ESTEC Bedrest Strategy Workshop, Noordwijk, NL, 2009}, booktitle = {ESA/ESTEC Bedrest Strategy Workshop, Noordwijk, NL, 2009}, language = {en} } @misc{Dendorfer, author = {Dendorfer, Sebastian}, title = {Patientenindividuelle biomechanisch optimierte Rehabilitation}, series = {Prim{\"a}r- und Revisionsendoprothetik des Kniegelenks. Trends und zuk{\"u}nftige Herausforderungen. Regensburg 2023}, journal = {Prim{\"a}r- und Revisionsendoprothetik des Kniegelenks. Trends und zuk{\"u}nftige Herausforderungen. Regensburg 2023}, language = {de} } @misc{Dendorfer, author = {Dendorfer, Sebastian}, title = {Muskuloskelettale Simulation - Implikationen f{\"u}r die H{\"u}ftendoprothetik}, series = {Prim{\"a}r- und Revisionsendoprothetik des H{\"u}ftgelenks Trends und zuk{\"u}nftige Herausforderungen, 11.-12.11.2022, OTH Ostbayerische Technische Hochschule, Regensburg}, journal = {Prim{\"a}r- und Revisionsendoprothetik des H{\"u}ftgelenks Trends und zuk{\"u}nftige Herausforderungen, 11.-12.11.2022, OTH Ostbayerische Technische Hochschule, Regensburg}, language = {de} } @inproceedings{DendorferCarbesRasmussen, author = {Dendorfer, Sebastian and Carbes, S. and Rasmussen, John}, title = {The influence of muscle forces on biomechanical fracture fixation simulations - from in-vivo forces to tissue strains}, series = {World Congress on Medical Physics and Biomedical Engineering, 7 - 12, 2009, Munich}, booktitle = {World Congress on Medical Physics and Biomedical Engineering, 7 - 12, 2009, Munich}, language = {en} } @inproceedings{DendorferEnglert, author = {Dendorfer, Sebastian and Englert, Carsten}, title = {Forces on a clavicles midshaft fracture and influence of fracture type}, series = {AO Symposium, Regensburg, 2009}, booktitle = {AO Symposium, Regensburg, 2009}, language = {en} } @inproceedings{DendorferFeldottoWalchetal., author = {Dendorfer, Sebastian and Feldotto, Benedikt and Walch, Blasius and Koch, Patrick and Knoll, Alois}, title = {Co-Development of an Infant Prototype in Hardware and Simulation based on CT Imaging Data}, series = {IEEE International Conference on Cyborg and Bionic Systems (CBS), 2019, Munich}, booktitle = {IEEE International Conference on Cyborg and Bionic Systems (CBS), 2019, Munich}, pages = {6}, abstract = {The development of biomimetic robots has gained research interest in the last years as it may both help under-standing processes of motion execution in biological systems as well as developping a novel generation of intelligent and energy efficient robots. However, exact model generation that builds up on observations and robot design is very time intensive. In this paper we present a novel pipeline for co-development of biomimetic hardware and simulation models based on biological Computer Tomography (CT) data. For this purpose we exploit State of the Art rapid prototyping technologies such as 3D Printing and the Neurorobotics Platform for musculoskeletal simulations in virtual environments. The co-development integrates both advantages of virtual and physical experimental models and is expected to increase development speed of controllers that can be tested on the simulated counterpart before application to a printed robot model. We demonstrate the pipeline by generating a one year old infant model as a musculoskeletal simulation model and a print-in-place 3D printed skeleton as a single movable part. Even though we hereonly introduce the initial body generation and only a first testsetup for a modular sensory and control framework, we can clearly spot advantages in terms of rapid model generation and highly biological related models. Engineering costs are reducedand models can be provided to a wide research community for controller testing in an early development phase.}, subject = {Biomechanische Analyse}, language = {en} } @article{DendorferGschossman, author = {Dendorfer, Sebastian and Gschoßman, Lukas}, title = {Hightech in der Rehabiliation}, series = {BVOU Infobrief: Hightech in Orthop{\"a}die und Unfallchirurgie}, journal = {BVOU Infobrief: Hightech in Orthop{\"a}die und Unfallchirurgie}, number = {1}, publisher = {BVOU - Berufsverband f{\"u}r Orthop{\"a}die und Unfallchirurgie e.V.}, address = {Berlin}, issn = {2747-5913}, pages = {9 -- 11}, abstract = {Aufgrund der steigenden Lebenserwartung und dem damit einhergehenden demographischen Wandel wird der Bedarf an Rehabilitations-Behandlungen in absehbarer Zukunft stark ansteigen. Ein Beispiel f{\"u}r diesen Trend ist die physiotherapeutische Behandlung nach Erhalt einer Knie-Totalendoprothese (Knie-TEP). So gehen Modellrechnungen basierend auf dem Bev{\"o}lkerungswachstum und der bisherigen Pr{\"a}valenz von Knie-TEPs davon aus, dass die Anzahl an durchgef{\"u}hrten Eingriffen in einkommensstarken L{\"a}ndern wie Deutschland weiter zunehmen wird. Weiterhin stoßen traditionelle Rehabilitationsverfahren, gerade in strukturschwachen Regionen, schon heute an ihre Grenzen. Deutlich zu sehen war das w{\"a}hrend den Hochphasen der aktuellen Covid-19-Pandemie, als der Kontakt zwischen Therapeut*in und Patient*in fl{\"a}chendeckend eingeschr{\"a}nkt war. Eine erh{\"o}hte Nachfrage nach neuartigen Reha-Angeboten ist die logische Konsequenz. Innovative Konzepte sind daher dringend notwendig, um die daraus resultierenden technischen, sozialen und {\"o}konomischen Herausforderungen zu bew{\"a}ltigen.}, language = {de} } @article{DendorferHammerLenich, author = {Dendorfer, Sebastian and Hammer, Joachim and Lenich, Andreas}, title = {Characterisation and testing of biomaterials}, series = {Technology and Health Care}, volume = {19}, journal = {Technology and Health Care}, number = {5}, doi = {10.3233/THC-2011-0644}, pages = {357 -- 371}, subject = {Biomaterial}, language = {en} } @incollection{DendorferHammerLenich, author = {Dendorfer, Sebastian and Hammer, Joachim and Lenich, Andreas}, title = {Characterisation and testing of biomaterials}, series = {Basic Engineering for Medics and Biologists: An ESEM Primer}, booktitle = {Basic Engineering for Medics and Biologists: An ESEM Primer}, number = {Chapter IV.4.}, editor = {Lee, T. Clive and Niederer, Peter F.}, publisher = {Non Basic Stock Line}, isbn = {978-1607505266}, subject = {Biomaterial}, language = {en} } @inproceedings{DendorferKubowitsch, author = {Dendorfer, Sebastian and Kubowitsch, Simone}, title = {The interaction of mental stress and biomechanics}, series = {Health Technology Triangle, Weiden, 2016}, booktitle = {Health Technology Triangle, Weiden, 2016}, language = {en} } @inproceedings{DendorferKubowitschSuess, author = {Dendorfer, Sebastian and Kubowitsch, Simone and S{\"u}ß, Franz}, title = {How to determine the effect of working conditions on the human body}, series = {11th International Scientific Conference on Production Engineering DEVELOPMENT AND MODERNIZATION OF PRODUCTION (RIM 2017), Sarajevo, Bosnia and Herzegovina}, booktitle = {11th International Scientific Conference on Production Engineering DEVELOPMENT AND MODERNIZATION OF PRODUCTION (RIM 2017), Sarajevo, Bosnia and Herzegovina}, abstract = {Work places and conditions strains the human body, both psychologically and biomechanically. In order to analyse working conditions and in the following to improve them, detailed knowledge about the effect of the different stressors on the body is needed. This manuscript discusses methods on how to evaluate biomechanical and mental loading and its effect on the musculoskeletal system. A possible workflow for the analysis is presented.}, subject = {Arbeitsbedingungen}, language = {en} } @article{DendorferMaierHammer, author = {Dendorfer, Sebastian and Maier, Hans J{\"u}rgen and Hammer, Josef}, title = {Fatigue damage in cancellous bone: an experimental approach from continuum to micro scale}, series = {Journal of the Mechanical Behavior of Biomedical Materials}, volume = {2}, journal = {Journal of the Mechanical Behavior of Biomedical Materials}, number = {1}, doi = {10.1016/j.jmbbm.2008.03.003}, pages = {113 -- 119}, abstract = {Repeated loadings may cause fatigue fractures in bony structures. Even if these failure types are known, data for trabecular bone exposed to cyclic loading are still insufficient as the majority of fatigue analyses on bone concentrate on cortical structures. Despite its highly anisotropic and inhomogeneous structure, trabecular bone is treated with continuum approaches in fatigue analyses. The underlying deformation and damage mechanism within trabecular specimens are not yet sufficiently investigated. In the present study different types of trabecular bone were loaded in monotonic and cyclic compression. In addition to the measurement of integral specimen deformations, optical deformation analysis was employed in order to obtain strain distributions at different scale levels, from the specimens' surface to the trabeculae level. These measurements allowed for the possibility of linking the macroscopic and microscopic mechanical behaviour of cancellous bone. Deformations were found to be highly inhomogeneous across the specimen. Furthermore strains were found to already localise at very low load levels and after few load cycles. Microcracks in individual trabeculae were induced in the very early stage of cyclic testing. The results provide evidence of the capability of the method to supply essential data on the failure behaviour of individual trabeculae in future studies.}, subject = {Knochen}, language = {en} } @incollection{DendorferMaierHammer, author = {Dendorfer, Sebastian and Maier, Hans J{\"u}rgen and Hammer, Josef}, title = {How do age and anisotropy affect the fatigue behaviour of cancellous bone?}, series = {Medicine Meets Engineering}, booktitle = {Medicine Meets Engineering}, publisher = {IOS Press}, pages = {68 -- 74}, abstract = {The fatigue behaviour of materials is of particular interest for the failure prediction of materials and structures exposed to cyclic loading. For trabecular bone structures only a few sets of lifetime data have been reported in the literature and structural measures are commonly not considered. The influence of load contributions not aligned with the main physiological axis remains unclear. Furthermore age effects on the fatigue behaviour are not well described. In the present study, different groups of human vertebral cancellous bone were exposed to cyclic compression. The inital modulus and therefore lifetimes were found to be highly dependent on age. The decrease in both with increasing age was much more pronounced in specimens which were not aligned with the main physiological axis. This implies that old bone is much more sensitive to (cyclic) failure loads in general but particularly to loads which are not coincident with the physiological main axis.}, subject = {Knochenbruch}, language = {en} } @article{DendorferMaierTayloretal., author = {Dendorfer, Sebastian and Maier, Hans J{\"u}rgen and Taylor, David and Hammer, Joachim}, title = {Anisotropy of the fatigue behaviour of cancellous bone}, series = {Journal of Biomechanics}, volume = {41}, journal = {Journal of Biomechanics}, number = {3}, doi = {10.1016/j.jbiomech.2007.09.037}, pages = {636 -- 641}, abstract = {The fatigue behaviour of materials is of particular interest for the failure prediction of materials and structures exposed to cyclic loading. For trabecular bone structures only a few sets of lifetime data have been reported in the literature and structural measures are commonly not considered. The influence of load contributions which are not aligned with the main physiological axis remains unclear. Furthermore site and species dependent relationships are not well described. In this study five different groups of trabecular bone, defined in terms of orientation, species and site were exposed to cyclic compression. In total, 108 fatigue tests were analysed. The lifetimes were found to decrease drastically when off-axis loads were applied. Additionally, species and site strongly affect fatigue lifetimes. Strains at failure were also found to be a function of orientation.}, subject = {Erm{\"u}dung}, language = {en} } @article{DendorferMelzner, author = {Dendorfer, Sebastian and Melzner, Maximilian}, title = {R{\"u}ckenschmerzen bei Geburtshelfer:innen. Die Haltung macht's.}, series = {Deutsche Hebammen-Zeitschrift}, volume = {74}, journal = {Deutsche Hebammen-Zeitschrift}, number = {11}, publisher = {Staude}, address = {Hannover}, issn = {0012-026X}, pages = {60 -- 62}, abstract = {F{\"u}r Mutter und Kind konnte das Risiko der Geburt durch die Weiterentwicklung der Medizin drastisch reduziert werden. Doch wie ist es um das Wohl derer bestellt, die die Geb{\"a}rende unterst{\"u}tzen? Eine Studie der Ostbayerischen Technischen Hochschule Regensburg hat sich mit den muskuloskelettalen Beschwerden von Geburtshelfer:innen auseinandergesetzt}, language = {de} } @inproceedings{DendorferPenzkofer, author = {Dendorfer, Sebastian and Penzkofer, Rainer}, title = {Experimentelle Untersuchung der Belastungen im Kopf beim Treten}, series = {Fachsymposium "Treten gegen den Kopf", April 2013, N{\"u}rnberg}, booktitle = {Fachsymposium "Treten gegen den Kopf", April 2013, N{\"u}rnberg}, language = {de} } @inproceedings{DendorferRasmussen, author = {Dendorfer, Sebastian and Rasmussen, John}, title = {The influence of in-vivo muscle forces on the stress distribution in a vertebral body during activities of daily living}, series = {Eurospine Warsaw, Poland 2009}, booktitle = {Eurospine Warsaw, Poland 2009}, language = {en} } @inproceedings{DendorferRasmussenChristensenetal., author = {Dendorfer, Sebastian and Rasmussen, John and Christensen, Soeren Toerholm and Robie, Bruce}, title = {The Effect of Spinal Disc Herniation on Multifidus Muscles}, series = {56th Orthopaedic Research Society Meeting, New Orleans, USA, 2010}, booktitle = {56th Orthopaedic Research Society Meeting, New Orleans, USA, 2010}, language = {en} } @article{DendorferWeberKennedy, author = {Dendorfer, Sebastian and Weber, Tim and Kennedy, O.}, title = {Musculoskeletal modeling for hip replacement outcome analyses and other applications}, series = {The Journal of the American Academy of Orthopaedic Surgeons}, volume = {22}, journal = {The Journal of the American Academy of Orthopaedic Surgeons}, number = {4}, doi = {10.5435/JAAOS-22-04-268}, pages = {268 -- 269}, subject = {H{\"u}ftgelenkprothese}, language = {en} } @misc{EgerBergstraesserDendorferetal., author = {Eger, Maximilian and Bergstraesser, Marcel and Dendorfer, Sebastian and Lenich, Andreas and Pfeifer, Christian}, title = {Influence of radial head prosthetic design on humeroradial stability: Validation of a test rig therefore}, series = {DOKU2022, Deutscher Kongress f{\"u}r Orthop{\"a}die und Unfallchirurgie, 25.-28. 10.2022, Berlin}, journal = {DOKU2022, Deutscher Kongress f{\"u}r Orthop{\"a}die und Unfallchirurgie, 25.-28. 10.2022, Berlin}, publisher = {German Medical Science GMS Publishing House}, address = {D{\"u}sseldorf}, doi = {10.3205/22dkou611}, url = {http://nbn-resolving.de/urn:nbn:de:0183-22dkou6115}, language = {en} } @article{EngelhardtMelznerHavelkovaetal., author = {Engelhardt, Lucas and Melzner, Maximilian and Havelkova, Linda and Fiala, Pavel and Christen, Patrik and Dendorfer, Sebastian and Simon, Ulrich}, title = {A new musculoskeletal AnyBodyTM detailed hand model}, series = {Computer Methods in Biomechanics and Biomedical Engineering}, volume = {24}, journal = {Computer Methods in Biomechanics and Biomedical Engineering}, number = {7}, publisher = {Taylor \& Francis}, doi = {10.1080/10255842.2020.1851367}, pages = {777 -- 787}, abstract = {Musculoskeletal research questions regarding the prevention or rehabilitation of the hand can be addressed using inverse dynamics simulations when experiments are not possible. To date, no complete human hand model implemented in a holistic human body model has been fully developed. The aim of this work was to develop, implement, and validate a fully detailed hand model using the AnyBody Modelling System (AMS) (AnyBody, Aalborg, Denmark). To achieve this, a consistent multiple cadaver dataset, including all extrinsic and intrinsic muscles, served as a basis. Various obstacle methods were implemented to obtain with the correct alignment of the muscle paths together with the full range of motion of the fingers. These included tori, cylinders, and spherical ellipsoids. The origin points of the lumbrical muscles within the tendon of the flexor digitorum profundus added a unique feature to the model. Furthermore, the possibility of an entire patient-specific scaling based on the hand length and width were implemented in the model. For model validation, experimental datasets from the literature were used, which included the comparison of numerically calculated moment arms of the wrist, thumb, and index finger muscles. In general, the results displayed good comparability of the model and experimental data. However, the extrinsic muscles showed higher accordance than the intrinsic ones. Nevertheless, the results showed, that the proposed developed inverse dynamics hand model offers opportunities in a broad field of applications, where the muscles and joint forces of the forearm play a crucial role.}, language = {en} } @misc{EngelhardtMelznerHavelkovaetal., author = {Engelhardt, Lucas and Melzner, Maximilian and Havelkova, Linda and Fiala, Pavel and Rybarova, Martina and Christen, Patrik and Dendorfer, Sebastian and Simon, Ulrich}, title = {A new musculoskeletal AnyBody detailed hand model}, series = {European Society of Biomechanics meeting 2019, Vienna, Austria}, journal = {European Society of Biomechanics meeting 2019, Vienna, Austria}, abstract = {The AnyBody™ Modeling System (AMS) [1], is an universally used musculoskeletal simulation software using inverse dynamics. Until now, no complete human hand model is known in the AMS. Also considering other musculoskeletal software platforms, just one detailed entire hand model is recently published [2] but is only based on one subject. The aim of this work is to implement a full detailed hand model for the AMS including all extrinsic and intrinsic muscles using data by the UWB gained through an anatomical study of ten cadaver hands.}, language = {en} } @article{EnglertAngeleFierlbecketal., author = {Englert, Carsten and Angele, Peter and Fierlbeck, J. and Dendorfer, Sebastian and Schubert, T. and M{\"u}ller, R. and Lienhard, S. and Zellner, J. and Nerlich, Michael and Neumann, Carsten}, title = {Conductive bone substitute material with variable antibiotic delivery}, series = {Der Unfallchirurg}, volume = {110}, journal = {Der Unfallchirurg}, number = {5}, publisher = {Springer}, doi = {10.1007/s00113-007-1229-3}, pages = {408 -- 413}, abstract = {A new bone substitute, consisting of hydroxylapatite and calcium sulphate, was prepared in two formulations and analysed for its mechanical strength and antibiotic elution.The bone substitute PerOssal has osteoconductive and degradable properties. The material has a built-in capillary structure, which results in an immediate fluid uptake. Antibiotics absorbed to the bone substitute resulted in a prolonged release rate. Mechanical strength was investigated by an unconfined compression test up to failure under both wet and dry conditions for both formulations of the bone substitute. Antibiotic release was analysed microbiologically for two antibiotics, vancomycin and gentamicin, over an elution period of 10 days using the agar diffusion method.The drug release analysis resulted in a prolonged release rate of both antibiotics over 10 days. In vitro the amount of gentamicin and vancomycin eluted at day 10. From one pellet still exceeded the minimal inhibitory concentration of most aetiologically important pathogens. Formulation two of the present bone substitute is significantly harder in both wet and dry conditions when compared to formulation one. Both formulations lose strength in the wet condition relative to their performance in the dry condition. However, formulation two is as hard under wet conditions as formulation one is when dry.PerOssal is a suitable new degradable osteoconductive bone substitute that can be loaded with antibiotic solutions, which are released in effective doses over 10 days. The mechanical strength of PerOssal is sufficient to support cancellous bone defects in non-weight-bearing areas or in combination with osteosynthesis.}, subject = {Knochenersatz}, language = {en} } @misc{EnglertDendorfer, author = {Englert, Carsten and Dendorfer, Sebastian}, title = {Einfluss der Rotatorenmanschette auf die glenohumerale Stabilit{\"a}t}, series = {20. Intensivkurs Schulterendoprothetik Marburg}, journal = {20. Intensivkurs Schulterendoprothetik Marburg}, address = {Marburg}, language = {de} } @inproceedings{EnglertMuellerDendorfer, author = {Englert, Carsten and M{\"u}ller, F. and Dendorfer, Sebastian}, title = {Einfluss der Muskelkr{\"a}fte, des Bewegungsausmaßes und der Bruchform auf die Kraft{\"u}bertragung des Implantat-Knochenverbundes am Beispiel der Claviculafraktur im mittleren Drittel}, series = {17. Jahreskongress der Deutschen Vereinigung f{\"u}r Schulter- und Ellenbogenchirurgie (DVSE), Rosenheim 2010}, booktitle = {17. Jahreskongress der Deutschen Vereinigung f{\"u}r Schulter- und Ellenbogenchirurgie (DVSE), Rosenheim 2010}, abstract = {Fragestellung Es soll in dieser Computersimulationsstudie untersucht werden, wie der Osteosyntheseverbund Platte mit Schrauben im Verbund mit einer im mittleren Drittel gebrochenen Clavicula durch das Bewegungsausmaß in vivo belastet ist. Was sind die grundlegenden Kr{\"a}fte die auf Clavicula und Implantat wirken und welchen Einfl uss hat die Bruchform. Methodik Die Muskel- und Gelenkkr{\"a}fte sowie die Belastung des Implantatverbundes wurden mit einer muskuloskelletalen Simulationssoftware (AnyBody Technology, V.4) berechnet. Hierf{\"u}r wurden mit einem komplexen Model des menschlichen K{\"o}rpers folgende Bewegungen analysiert: eine Flexion von 160° und Abduktion 160° mit einem Gewicht von 2 kg in der Hand. Aus CT-Patientendaten wurden zwei dreidimensionale Modelle des Clavicula-Implantat Verbundes gebildet, die sich in der Frakturform unterscheiden (Querfraktur und vertikale Fraktur). In beiden Modellen wurde eine Claviculaosteosynthese in superiorer Position mit einer 6 Loch LCP mit 2 Schrauben pro Hauptfragment verwendet. Die Materialeigenschaften wurden aus der Dichte des Materials sowie aus Literaturdaten verwendet. Die Muskel- und Gelenkkr{\"a}fte aus der muskuloskelletalen Berechnung wurden auf das Finite Elemente Modell {\"u}bertragen und die Spannungen und Dehnungen des Implantat-Knochenverbundes wurden berechnet. Ergebnisse Es zeigte sich, dass die simulierte in vivo Belastung stark abh{\"a}ngig vom Flexionswinkel ist. Das Implantat ist in der superioren Lage auf Biegung belastet, welche maximale Werte im {\"U}berschulterniveau erreicht. Die Bruchform mit anatomischer Reposition und Kontakt der Hauptfragmente zueinander f{\"u}hrt zu einer deutlichen Entlastung des Osteosyntheseverbundes im Vergleich zu einer Bruchform mit vertikaler Fraktur. Schlussfolgerung Aus den Analysen ist eine Positionierung der Plattenosteosynthese f{\"u}r die im mittleren Drittel frakturierte Clavicula in anterior-superiorer Lage w{\"u}nschenswert. Die anatomische Reposition entlastet den Osteosyntheseverbund und sollte m{\"o}glichst erreicht werden. Die Nachbehandlung sollte ein Bewegungsausmaß f{\"u}r den Arm f{\"u}r 4 Wochen f{\"u}r einfache Bruchformen auf 70° Flexion und Abduktion limitieren und f{\"u}r komplexe Bruchformen diese Limitierung ausgedehnt werden.}, language = {de} } @article{FoerstlSuessEnglertetal., author = {F{\"o}rstl, Nikolas and S{\"u}ß, Franz and Englert, Carsten and Dendorfer, Sebastian}, title = {Design of a reverse shoulder implant to measure shoulder stiffness during implant component positioning}, series = {Medical Engineering \& Physics}, volume = {121}, journal = {Medical Engineering \& Physics}, edition = {Journal Pre-proof}, publisher = {Elsevier}, doi = {10.1016/j.medengphy.2023.104059}, pages = {22}, abstract = {To avoid dislocation of the shoulder joint after reverse total shoulder arthroplasty, it is important to achieve sufficient shoulder stability when placing the implant components during surgery. One parameter for assessing shoulder stability can be shoulder stiffness. The aim of this research was to develop a temporary reverse shoulder implant prototype that would allow intraoperative measurement of shoulder stiffness while varying the position of the implant components. Joint angle and torque measurement techniques were developed to determine shoulder stiffness. Hall sensors were used to measure the joint angles by converting the magnetic flux densities into angles. The accuracy of the joint angle measurements was tested using a test bench. Torques were determined by using thin-film pressure sensors. Various mechanical mechanisms for variable positioning of the implant components were integrated into the prototype. The results of the joint angle measurements showed measurement errors of less than 5° in a deflection range of ±15° adduction/abduction combined with ±45° flexion/extension. The proposed design provides a first approach for intra-operative assessment of shoulder stiffness. The findings can be used as a technological basis for further developments.}, language = {en} } @inproceedings{GalibarovAlMunajjedDendorferetal., author = {Galibarov, Pavel E. and Al-Munajjed, Amir Andreas and Dendorfer, Sebastian and Christensen, Soeren Toerholm and Rasmussen, John}, title = {The effect of varying the stiffness of spinal fusion devices on the adjacent levels using multibody dynamics simulation}, series = {Orthopaedic Proceedings}, volume = {94-B}, booktitle = {Orthopaedic Proceedings}, number = {SUPP_XL01 Sep 2012}, pages = {2}, abstract = {INTRODUCTION Several clinical studies demonstrated long-term adjacent-level effects after implantation of spinal fusion devices[1]. These effects have been reported as adjacent joint degeneration and the development of new symptoms correlating with adjacent segment degeneration[2] and the trend has therefore gone to motion preservation devices; however, these effects have not been understood very well and have not been investigated thoroughly[3]. The aim of this study is to investigate the effect of varying the stiffness of spinal fusion devices on the adjacent vertebral levels. Disc forces, moments and facet joint forces were analyzed. METHODS The AnyBody Modeling System was used to compute the in-vivo muscle and joint reaction forces of a musculoskeletal model. The full body model used in this study consists of 188 muscle fascicles in the lumbar spine and more than 1000 individual muscle branches in total. The model has been proposed by de Zee et al.[3], validated by Rasmussen et al.[4] and by Galibarov et al.[5]. The new model[5] determines the individual motions between vertebrae based on the equilibrium between forces acting on the vertebrae from muscles and joints and the passive stiffness in disks and ligaments, figure 1a. An adult of 1.75 m and 75 kg with a spinal implant in L4L5 was modeled. This model was subjected to a flexion-extension motion using different elastic moduli to analyze and compare to a non-implanted scenario. The analyzed variables were vertebral motion, the disc reaction forces and moments, as well as facet joint forces in the treated and the adjacent levels: L2L3, L3L4, L4L5 and L5-Sacrum. RESULTS When introducing a spinal fusion device in the L4L5 joint the reaction forces and moments decreased in this joint with stiffer devices leading to lower joint loads. However, in the adjacent joints, L3L4 and L5Sacrum, an increase was observed when implanting stiffer devices. Similar trends could be found for the L2L3 joint. The loads in the facet joints showed the same trends. While introducing a spinal fusion device reduced the facet joint forces in the treated joint, the loads in the adjacent facet joints were increased according to the stiffness of the implanted device, figure 1b. DISCUSSION While the treated disc joint showed reduced motion and loads, the adjacent levels demonstrated a significant increase. In particular, the increased facet joint forces in the adjacent levels can lead to adjacent level facet pain or accelerated facet joint degeneration. Introducing a device resulted in preventing facet contact and therefore facet joint loads, even using the device with the lowest stiffness. CONCLUSION The presented model shows that clinical complications such as facet joint degeneration in adjacent levels after implantation of spinal fusion device are consistent with the change in the mechanical-stimulus distribution in the system.}, language = {en} } @inproceedings{GalibarovDendorferChristensen, author = {Galibarov, Pavel E. and Dendorfer, Sebastian and Christensen, Soeren Toerholm}, title = {On modelling spine curvature dependent on muscular and external forces in multibody dynamics system}, series = {International Society of Biomechanics (ISB), 13th congress, 2011, Brussels, Belgium}, booktitle = {International Society of Biomechanics (ISB), 13th congress, 2011, Brussels, Belgium}, pages = {2}, abstract = {This paper presents a computational approach for investigating effect of muscular and external forces on curvature of the lumbar spine. Multibody dynamics system is used to compute the lumbar spine curvature using a force-dependent kinematics facility, e.g. this method allows releasing some degrees of freedom in order to be computed based on the current load configuration.}, language = {en} } @inproceedings{GalibarovDendorferRasmussen, author = {Galibarov, Pavel E. and Dendorfer, Sebastian and Rasmussen, John}, title = {Two Computational Models of the Lumbar Spine:}, series = {Proceedings of the 2011 ORS Annual Meeting, Long Beach, CA, vol. Marie Curie Initial Training Network "SpineFX"}, booktitle = {Proceedings of the 2011 ORS Annual Meeting, Long Beach, CA, vol. Marie Curie Initial Training Network "SpineFX"}, language = {en} } @inproceedings{GrossSuessVerkerkeetal., author = {Gross, Simon and S{\"u}ß, Franz and Verkerke, Gijsbertus Jacob and Dendorfer, Sebastian}, title = {Simulating fatigue in musculoskeletal models using surface electromyography, ECCOMAS Congress, Crete, Greece, 201}, series = {ECCOMAS Congress, Crete, Greece, 2016}, booktitle = {ECCOMAS Congress, Crete, Greece, 2016}, language = {en} } @inproceedings{GrossVerkerkeDendorfer, author = {Gross, Simon and Verkerke, Gijsbertus Jacob and Dendorfer, Sebastian}, title = {Combined Experimental and Numerical Approach to Investigate Changes in Muscle Recruitment Pattern of the Back Muscles during Exhausting Exercise}, series = {World Congress Biomechanics Dublin, 2018}, booktitle = {World Congress Biomechanics Dublin, 2018}, abstract = {In recent years, musculoskeletal computation has become a widely used tool to investigate joint and muscle forces within the human body. However, the issue of muscle fatigue is not considered adequately in most models and is a challenging task. One aspect that needs to be examined is the interaction of muscles during an exhausting task. Therefore, an experimental study was designed to analyze the changes of back muscle recruitment pattern during such exercises. In this study 38 subjects (27 male, 11 female, height = 177±8.5 cm, weight = 74.0±13.6 kg) participated. Each subject had to perform three static and three dynamic exhausting exercises where the back muscles were loaded with subject specific forces using a dynamometer adapter especially designed for the trunk muscles. To collect the muscle activity, twelve surface electromyography sensors were applied on the back, and four on the abdominal muscles. Muscle activity and fatigue were analyzed by calculating the maximum voluntary contraction normalized signal and the median frequency. At first the fatigue of m. erector spinae and m. multifidi was analyzed, since these muscles carry the main load during the exercises. Subsequently the activity of the m. trapezius, m. rectus abdominis and m. obliquus externus were investigated to determine recruitment patterns. To gain more detailed information of these patterns a numerical model was built using the AnyBody Modeling System™. Analyzing the measurements, we can observe an increasing muscle activity during isokinetic exercises while the force is constant. Since the activity in the simulation is defined as the current force output divided by the strength of the muscle, the strength parameter was scaled down based on the measured data, assuming a linear force - activity correlation, and using a numerical algorithm considering the influence of cross talk. The results show, that changes in recruitment pattern can be divided into three major subgroups. Prior to total exhaustion, some of the subjects show additional activation of muscles in the trapezius region, while other subjects show an additional activation of abdominal muscles, increasing the intra-abdominal pressure which supports the spine. In the third group an activation in both regions can be observed. The numerical simulations show an increasing activity of abdominal muscles as well as muscles in the upper back. Especially the m. latissimus dorsi shows a significantly higher activity. The results lead to the conclusion that prior to total exhaustion, additional muscles are recruited to support the main muscles. It was shown that abdominal muscles are activated to support back muscles by pressurizing the trunk cavity to delay total exhaustion as long as possible. In conclusion, the results show that changes in muscle recruitment pattern need to be considered when introducing muscle fatigue to musculoskeletal models.}, language = {en} } @inproceedings{GrossVerkerkeDendorfer, author = {Gross, Simon and Verkerke, Gijsbertus Jacob and Dendorfer, Sebastian}, title = {Investigation of external load dependent static and dynamic muscle fatigue}, series = {23th Congress of the European Society of Biomechanics, Sevilla, Spain, 2017}, booktitle = {23th Congress of the European Society of Biomechanics, Sevilla, Spain, 2017}, language = {en} } @inproceedings{HammerDendorfer, author = {Hammer, Joachim and Dendorfer, Sebastian}, title = {Cyclic loading and microstructure of cancellous bone}, series = {Journal of Biomechanics}, volume = {41}, booktitle = {Journal of Biomechanics}, number = {Suppl. 1, July 2008}, doi = {10.1016/S0021-9290(08)70409-3}, pages = {S410}, language = {en} } @article{HoenickaLehleJacobsetal., author = {Hoenicka, M. and Lehle, Karla and Jacobs, V. R. and Dendorfer, Sebastian and Kostorz, A. and Schmid, F. X. and Birnbaum, D. E.}, title = {Mechanical and seeding properties of human umbilical vein - a potential scaffold for a tissue-engineered vessel graft}, series = {The Thoracic and Cardiovascular Surgeon}, volume = {55}, journal = {The Thoracic and Cardiovascular Surgeon}, number = {S 1}, publisher = {Thieme}, doi = {10.1055/s-2007-967592}, pages = {P_37}, abstract = {Objectives: The mechanical properties and seeding with endothelial cells were investigated in fresh and cryopreserved human umbilical vein. Methods: Human umbilical veins (HUV) were frozen in Euro-Collins/1M DMSO at -1°C/min and stored in liquid nitrogen. Stress-strain relationships of fresh and thawed veins were determined in an uniaxial tension-testing rig. HUV endothelial cells (HUVEC) were seeded onto denuded HUV under static conditions and grown for 3d. Luminal surfaces were analyzed by scanning electron microscopy. Calcein-stained cells were seeded hyperconfluently to determine the cell retention capacity of fresh and cryopreserved veins. Results: The stress-strain relationships of HUV followed a biphasic pattern typical for natural vessels. Neither the failure stress (2.71±0.36 vs. 3.25±0.97 N, n=3) nor the displacement required to achieve failure (9.73±0.9 vs. 7.43±2.07mm, n=3) were altered by cryopreservation. The burst pressure was estimated as approx. 1000mm Hg within the limitations of the uniaxial model. HUVEC seeded onto denuded HUV formed patches (at 9E3 cells per cm2) or an almost confluent endothelium (at 3E4 cells per cm2) within three days. The capacity to retain seeded HUVEC of denuded HUV was not altered by cryopreservation (1.15±0.08E5 vs. 1.26±0.14E5 cells per cm2, n=6). Conclusions: The burst pressure of HUV seems to be sufficiently high for the human arterial circulation and is not altered by cryopreservation. HUVEC can establish a confluent endothelium on denuded HUV. Therefore HUV appears to be a suitable storable scaffold for vascular tissue engineering.}, subject = {Nabelvene}, language = {en} } @inproceedings{HornerDendorferKiisetal., author = {Horner, Marc and Dendorfer, Sebastian and Kiis, Arne and Lawrenchuk, Mike and Verma, Gunjan}, title = {A Patient based simulation workflow for orthopedic device design and analysis}, series = {SBC Ortho Workshop, June 2011}, booktitle = {SBC Ortho Workshop, June 2011}, language = {en} } @article{HoelscherWeberLazarevetal., author = {H{\"o}lscher, Thomas and Weber, Tim A. and Lazarev, Igor and Englert, Carsten and Dendorfer, Sebastian}, title = {The influence of rotator cuff tears on glenohumeral stability during abduction tasks}, series = {Journal of Orthopaedic Research}, volume = {34}, journal = {Journal of Orthopaedic Research}, number = {9}, doi = {10.1002/jor.23161}, pages = {1628 -- 1635}, abstract = {One of the main goals in reconstructing rotator cuff tears is the restoration of glenohumeral joint stability, which is subsequently of utmost importance in order to prevent degenerative damage such as superior labral anterior posterior (SLAP) lesion, arthrosis, and malfunction. The goal of the current study was to facilitate musculoskeletal models in order to estimate glenohumeral instability introduced by muscle weakness due to cuff lesions. Inverse dynamics simulations were used to compute joint reaction forces for several static abduction tasks with different muscle weakness. Results were compared with the existing literature in order to ensure the model validity. Further arm positions taken from activities of daily living, requiring the rotator cuff muscles were modeled and their contribution to joint kinetics computed. Weakness of the superior rotator cuff muscles (supraspinatus; infraspinatus) leads to a deviation of the joint reaction force to the cranial dorsal rim of the glenoid. Massive rotator cuff defects showed higher potential for glenohumeral instability in contrast to single muscle ruptures. The teres minor muscle seems to substitute lost joint torque during several simulated muscle tears to maintain joint stability. Joint instability increases with cuff tear size. Weakness of the upper part of the rotator cuff leads to a joint reaction force closer to the upper glenoid rim. This indicates the comorbidity of cuff tears with SLAP lesions. The teres minor is crucial for maintaining joint stability in case of massive cuff defects and should be uprated in clinical decision-making.}, subject = {Rotatorenmanschettenriss}, language = {en} } @article{IgnasiakDendorferFerguson, author = {Ignasiak, Dominika and Dendorfer, Sebastian and Ferguson, Stephen J.}, title = {Thoracolumbar spine model with articulated ribcage for the prediction of dynamic spinal loading}, series = {Journal of Biomechanics}, volume = {vol. 49}, journal = {Journal of Biomechanics}, number = {6}, publisher = {Elsevier Science}, doi = {10.1016/j.jbiomech.2015.10.010}, pages = {959 -- 966}, abstract = {Musculoskeletal modeling offers an invaluable insight into the spine biomechanics. A better understanding of thoracic spine kinetics is essential for understanding disease processes and developing new prevention and treatment methods. Current models of the thoracic region are not designed for segmental load estimation, or do not include the complex construct of the ribcage, despite its potentially important role in load transmission. In this paper, we describe a numerical musculoskeletal model of the thoracolumbar spine with articulated ribcage, modeled as a system of individual vertebral segments, elastic elements and thoracic muscles, based on a previously established lumbar spine model and data from the literature. The inverse dynamics simulations of the model allow the prediction of spinal loading as well as costal joints kinetics and kinematics. The intradiscal pressure predicted by the model correlated well (R2=0.89) with reported intradiscal pressure measurements, providing a first validation of the model. The inclusion of the ribcage did not affect segmental force predictions when the thoracic spine did not perform motion. During thoracic motion tasks, the ribcage had an important influence on the predicted compressive forces and muscle activation patterns. The compressive forces were reduced by up to 32\%, or distributed more evenly between thoracic vertebrae, when compared to the predictions of the model without ribcage, for mild thoracic flexion and hyperextension tasks, respectively. The presented musculoskeletal model provides a tool for investigating thoracic spine loading and load sharing between vertebral column and ribcage during dynamic activities. Further validation for specific applications is still necessary.}, subject = {Brustwirbels{\"a}ule}, language = {en} } @inproceedings{IgnasiakDendorferFerguson, author = {Ignasiak, Dominika and Dendorfer, Sebastian and Ferguson, Stephen J.}, title = {Thoracolumbar spine model with articulated rigcage for the prediction of dynamic spinal loading}, series = {International Workshop on Spine Loading and Deformation: From Loading to Recovery, 2-4 July 2015, Julius Wolff Institute, Charit{\´e}-Universitatsmedizin Berlin, Germany}, booktitle = {International Workshop on Spine Loading and Deformation: From Loading to Recovery, 2-4 July 2015, Julius Wolff Institute, Charit{\´e}-Universitatsmedizin Berlin, Germany}, language = {en} } @inproceedings{JungtaeublAurbachMelzneretal., author = {Jungt{\"a}ubl, Dominik and Aurbach, Maximilian and Melzner, Maximilian and Spicka, Jan and S{\"u}ß, Franz and Dendorfer, Sebastian}, title = {EMG-Based Validation of Musculoskeletal Models Considering Crosstalk}, series = {International Conference BIOMDLORE, June 28 - 30 2018, Białystok, Poland}, booktitle = {International Conference BIOMDLORE, June 28 - 30 2018, Białystok, Poland}, doi = {10.1109/BIOMDLORE.2018.8467211}, abstract = {BACKGROUND: Validation and verification of multibody musculoskeletal models sEMG is a difficult process because of the reliability of sEMG data and the complex relationship of muscle force and sEMG. OBJECTIVE: This work aims at comparing experimentally recorded and simulated muscle activities considering a numerical model for crosstalk. METHODS: For providing an experimentally derived reference data set, subjects were performing elevations of the arm, where the activities of the contemplated muscle groups were measured by sEMG sensors. Computed muscle activities were further processed and transformed into an artificial electromyographical signal, which includes a numerical crosstalk model. In order to determine whether the crosstalk model provides a better agreement with the measured muscle activities, the Pearson correlation coefficient has been computed as a qualitative way of assessing the curve progression of the data sets. RESULTS: The results show an improvement in the correlation coefficient between the experimental data and the simulated muscle activities when taking crosstalk into account. CONCLUSIONS: Although the correlation coefficient increased when the crosstalk model was utilized, it is questionable if the discretization of both, the crosstalk and the musculoskeletal model, is accurate enough.}, language = {en} } @inproceedings{JungtaeublSchmitzGrossetal., author = {Jungt{\"a}ubl, Dominik and Schmitz, Paul and Gross, Simon and Dendorfer, Sebastian}, title = {FEA of the transiliacal internal fixator as an osteosynthesis of pelvic ring fractures}, series = {CMBEBIH 2017, Proceedings of the International Conference on Medical and Biological Engineering 2017}, booktitle = {CMBEBIH 2017, Proceedings of the International Conference on Medical and Biological Engineering 2017}, editor = {Badnjevic, Almir}, publisher = {Springer}, address = {Singapore}, isbn = {978-981-10-4165-5}, doi = {10.1007/978-981-10-4166-2_32}, pages = {212 -- 217}, abstract = {Common Schanz screw systems can be used to stabilize pelvic ring fractures. In order to accommodate for different patient's requirements, implants can be placed in cranio-caudal direction into the os ilium (T1), or into the supraacetabular bone canal, and thus, in dorso-ventral direction (T2). Whereas both techniques are currently used, no data of the biomechanical behavior is available up to this date. The aim of this study is to analyze, whether T2 shows biomechanical advantages with respect to tissue and implant stresses due to the enlarged bone-implant interface. Forces acting on the pelvis were analyzed using motion capture data of a gait cycle obtained by the utilization of a musculoskeletal simulation program. A three dimensional finite element (FE) model of the pelvis with grayscale-based material properties was generated. The muscle and joint reaction forces at toe-off were applied to the FE model and instable pelvis fractures were implemented. The osteosynthesis systems were positioned within the model in order to enable the comparison between the two different surgical techniques. Stresses and displacements were analyzed for bone tissue, fracture zone and implant. T2 lead to approx. 30\% larger displacements in the fracture zone. Von-Mises stresses were larger for T2 in the implant (80 MPa vs. 227 MPa), whereas T1 leads to larger stresses in the bone tissue (200 MPa vs. 140 MPa). Both implantation techniques showed a good biomechanical behavior. Differences could be found with respect to tissue strains and deformations in the fracture zone. If bone quality or fracture healing are of concern, T2 or T1 should be used, respectively. However, both techniques seem to be applicable for cases with no special requirements. Further analyses aim to investigate the behavior under cyclic loading.}, subject = {Beckenbruch}, language = {en} } @inproceedings{KubowitschDendorfer, author = {Kubowitsch, Simone and Dendorfer, Sebastian}, title = {Psychologie und Biomechanik - Integrierte Betrachtung von Muskelrekrutierung}, series = {Jahrestagung der Deutschen Gesellschaft f{\"u}r Biofeedback e. V., Regensburg, 2018}, booktitle = {Jahrestagung der Deutschen Gesellschaft f{\"u}r Biofeedback e. V., Regensburg, 2018}, language = {de} } @inproceedings{KubowitschSuessJansenetal., author = {Kubowitsch, Simone and S{\"u}ß, Franz and Jansen, Petra and Dendorfer, Sebastian}, title = {Comparison of dynamic muscular imbalances in back pain patients and healthy controls}, series = {World Congress Biomechanics Dublin, 2018}, booktitle = {World Congress Biomechanics Dublin, 2018}, language = {en} } @inproceedings{KubowitschSuessJansenetal., author = {Kubowitsch, Simone and S{\"u}ß, Franz and Jansen, Petra and Dendorfer, Sebastian}, title = {Muscular imbalances during experimentally induced stress}, series = {23th Congress of the European Society of Biomechanics, Sevilla, Spain, 2017}, booktitle = {23th Congress of the European Society of Biomechanics, Sevilla, Spain, 2017}, language = {en} } @misc{KubowitschSuessJansenetal., author = {Kubowitsch, Simone and S{\"u}ß, Franz and Jansen, Petra and Dendorfer, Sebastian}, title = {Effect of dual tasking on muscular imbalances}, series = {European Society of Biomechanics meeting 2019, Vienna, Austria}, journal = {European Society of Biomechanics meeting 2019, Vienna, Austria}, language = {en} } @misc{KoeglerIsmailRusavyetal., author = {K{\"o}gler, Michael and Ismail, Khaled M. and Rusavy, Zdenek and Kalis, Vladimir and S{\"u}ß, Franz and Dendorfer, Sebastian}, title = {Influence of bed height and stance on accoucheurs lower back and glenohumeral load during simulated childbirth}, series = {31st meeting of Czech Urogynaecological Society, Prague, 2022}, journal = {31st meeting of Czech Urogynaecological Society, Prague, 2022}, language = {en} } @misc{LautenschlaegerLeisDendorferetal., author = {Lautenschl{\"a}ger, Toni and Leis, Alexander and Dendorfer, Sebastian and Palm, Christoph and Schreiner, Rupert and Langer, Christoph and Prommesberger, Christian and Ławrowski, Robert Damian and Dams, Florian and Bornmann, Benjamin and Navitski, Aliaksandr and Serbun, Pavel and M{\"u}ller, G{\"u}nter and Liebetruth, Thomas and Kohlert, Dieter and Pernsteiner, Jochen and Schreier, Franz and Heerklotz, Sabrina and Heerklotz, Allwin and Boos, Alexander and Herwald, Dominik and Monkman, Gareth J. and Treiber, Daniel and Mayer, Matthias and H{\"o}rner, Eva and Bentz, Alexander and Shamonin (Chamonine), Mikhail and Johansen, S{\o}ren Peter and Reichel, Marco and Stoll, Andrea and Briem, Ulrich and Dullien, Silvia and Renkawitz, Tobias and Weber, Tim and Dendorfer, Sebastian and Grifka, Joachim and Penzkofer, Rainer and Barnsteiner, K. and Jovanovik, M. and Wernecke, P. and V{\"o}gele, A. and Bachmann, T. and Pl{\"o}tz, Martin and Schliekmann, Claus and Wels, Harald and Helmberger, Paul and Kaspar, M. and H{\"o}nicka, M. and Schrammel, Siegfried and Enser, Markus and Schmidmeier, Monika and Schroll-Decker, Irmgard and Haug, Sonja and Gelfert, Verena and Vernim, Matthias}, title = {Forschungsbericht 2012}, editor = {Baier, Wolfgang}, address = {Regensburg}, organization = {Ostbayerische Technische Hochschule Regensburg}, doi = {10.35096/othr/pub-783}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-7834}, pages = {64}, language = {de} } @article{LazarevRiabokonHalleretal., author = {Lazarev, I. A. and Riabokon, P. V. and Haller, M. and Dendorfer, Sebastian}, title = {Effect of the Displacement of Calcaneal Bone Peripheral Fragment in its Fracture on the Function of the Three-Headed Calf Muscle}, series = {TRAUMA}, volume = {16}, journal = {TRAUMA}, number = {2}, publisher = {Zaslavsky}, doi = {10.22141/1608-1706.2.16.2015.80247}, pages = {20 -- 24}, abstract = {In the structure of musculoskeletal injuries, calcaneal fractures account for up to 4 \% of all skeletal fractures and up to 60 \% of hindfoot fractures. The effect of the displacement of the peripheral fragment of the calcaneus on the calf muscles's reaction forces at the time of the adoption of the simplified squatting position was investigated by modeling in AnyBody Modeling System 6.0 software. M.gastrocnemius (lateralis et medialis) in the initial phase of motion in all variants of the peripheral fragment displacement did not develop sufficient muscular effort in comparison to the intact calcaneus. M.soleus medialis et lateralis showed significant increase in muscle activity rates in the initial phase of motion (41.87 ± 1.90 H and 52.07 ± 2.10 H) before reaching its maximum values, as compared with those of the intact calcaneus. In the final phase of the movement, upon muscle reaches its maximum length, muscular strength indicators of the m.soleus returned to their original values or were significantly below them. The decline in muscle strength was due to shortening of the moment arm or muscle excursion in case of convergence of muscle attachment points. When the peripheral fragment is displaced, due to putting down the heel to the surface of the support in terms of anatomical muscle lengthening, it takes extra effort to achieve rest length and its maximum power. In all types of the displacement of the peripheral fragment, the function of three-headed calf muscle is disturbed with involvement of additional muscular effort and energy expenditure. This fact should motivate the surgeon on the need for accurate repositioning of bone fragments in calcaneal fractures with the displacement of the peripheral fragment.}, language = {en} } @article{LazarevRyabokonHalleretal., author = {Lazarev, I.A. and Ryabokon, P.V. and Haller, M. and Dendorfer, Sebastian}, title = {Effect of the fractured calcaneus's peripheral fragment displacement on the triceps surae function}, series = {ЖУРНАЛ «ТРАВМА» Ukrainian Trauma Journal}, volume = {2, TOM 16}, journal = {ЖУРНАЛ «ТРАВМА» Ukrainian Trauma Journal}, language = {en} } @article{LenichBachmeierDendorferetal., author = {Lenich, Andreas and Bachmeier, S. and Dendorfer, Sebastian and Mayr, E. and Nerlich, Michael and F{\"u}chtmeier, Bernd}, title = {Development of a test system to analyze different hip fracture osteosyntheses under simulated walking}, series = {Biomedizinische Technik. Biomedical engineering}, volume = {57}, journal = {Biomedizinische Technik. Biomedical engineering}, number = {2}, doi = {10.1515/bmt-2011-0999}, pages = {113 -- 119}, abstract = {The mechanical complications of osteosyntheses after hip fractures are previously investigated by mostly static or dynamic uniaxial loading test systems. However, the physiologic loading of the hip joint during a normal gait is a multiplanar, dynamic movement. Therefore, we constructed a system to test osteosyntheses for hip fractures under physiologic multiplanar loading representative of normal gait. To evaluate the testing system, 12 femora pairs were tested under 25,000 cycles with two standard osteosyntheses (Proximal Femoral Nail Antirotation/Gamma3 Nail). For angular movement, the varus collapse to cut out (∝CO) (∝CO=4.8°±2.1° for blade and ∝CO=7.8°±3.8° for screw) was the dominant failure mode, and only slight rotational angle shifts (∝Rot) (∝Rot=1.7°±0.4° for blade and ∝Rot=2.4°±0.3° for screw) of the femoral head around the implant axis were observed. Angular displacements in varus direction and rotation were higher in specimens reinforced with screws. Hence, the cut out model and the migration directions showed a distinction between helical blade and hip screw. However, there were no significant differences between the different implants. The new setup is able to create clinical failures and allows to give evidence about the anchorage stability of different implant types under dynamic gait motion pattern.}, subject = {H{\"u}ftgelenk}, language = {en} } @misc{MauererRexhepajMonkmanetal., author = {Mauerer, Wolfgang and Rexhepaj, Tanja and Monkman, Gareth J. and Sindersberger, Dirk and Diermeier, Andreas and Neidhart, Thomas and Wolfrum, Dominik and Sterner, Michael and Heberl, Michael and Nusko, Robert and Maier, Georg and Nagl, Klaus and Reuter, Monika and Hofrichter, Andreas and Lex, Thomas and Lesch, Florian and Kieninger, B{\"a}rbel and Szalo, Alexander Eduard and Zehner, Alexander and Palm, Christoph and Joblin, Mitchell and Apel, Sven and Ramsauer, Ralf and Lohmann, Daniel and Westner, Markus and Strasser, Artur and Munndi, Maximilian and Ebner, Lena and Elsner, Michael and Weiß, Nils and Segerer, Matthias and Hackenberg, Rudolf and Steger, Sebastian and Schmailzl, Anton and Dostalek, Michael and Armbruster, Dominik and Koch, Fabian and Hierl, Stefan and Thumann, Philipp and Swidergal, Krzysztof and Wagner, Marcus and Briem, Ulrich and Diermeier, Andreas and Spreitzer, Stefan and Beiderbeck, Sabrina and Hook, Christian and Zobel, Martin and Weber, Tim and Groß, Simon and Penzkofer, Rainer and Dendorfer, Sebastian and Schillitz, Ingo and Bauer, Thomas and Rudolph, Clarissa and Schmidt, Katja and Liebetruth, Thomas and Hamer, Markus and Haug, Sonja and Vernim, Matthias and Weber, Karsten and Saßmannshausen, Sean Patrick and Books, Sebastian and Neuleitner, Nikolaus and Rechenauer, Christian and Steffens, Oliver and Kusterle, Wolfgang and G{\"o}mmel, Roland and Wellnitz, Felix and Stierstorfer, Johannes and Stadler, Dominik and Hofmann, Matthias J. and Motschmann, Hubert and Shamonin (Chamonine), Mikhail and Bleicher, Veronika and Fischer, Sebastian and Hackenberg, Rudolf and Horn, Anton and Kawasch, Raphael and Petzenhauser, Michael and Probst, Tobias and Udalzow, Anton and Dams, Florian and Schreiner, Rupert and Langer, Christoph and Prommesberger, Christian and Ławrowski, Robert Damian}, title = {Forschungsbericht 2016}, editor = {Baier, Wolfgang}, address = {Regensburg}, organization = {Ostbayerische Technische Hochschule Regensburg}, doi = {10.35096/othr/pub-1384}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-13840}, language = {de} } @misc{MelznerDendorfer, author = {Melzner, Maximilian and Dendorfer, Sebastian}, title = {Biomechanik und muskuloskeletale Simulation}, series = {Jahreskongress des ISPO Deutschland e.V., 2./3. Juni 2022, Hedelberg}, journal = {Jahreskongress des ISPO Deutschland e.V., 2./3. Juni 2022, Hedelberg}, organization = {International Society for Prosthetics and Orthotics}, language = {de} } @misc{MelznerEngelhardtSuessetal., author = {Melzner, Maximilian and Engelhardt, Leonard and S{\"u}ß, Friedrich and Dendorfer, Sebastian}, title = {Sensitivity evaluation of a musculoskeletal hand model using Latin hypercube sampling}, series = {ESMAC 2020 Abstracts}, volume = {81}, journal = {ESMAC 2020 Abstracts}, number = {Suppl. 1}, publisher = {Elsevier}, doi = {10.1016/j.gaitpost.2020.08.008}, language = {en} } @inproceedings{MelznerEngelhardtHavelkovaetal., author = {Melzner, Maximilian and Engelhardt, Lucas and Havelkova, Leonard and Simon, Ulrich and Dendorfer, Sebastian}, title = {A new musculoskeletal AnyBody detailed hand model validated by electromyography}, series = {16th International Symposium on Computer Methods in Biomechanics and Biomedical Engineering (CMBBE) 2019, New York City, USA}, booktitle = {16th International Symposium on Computer Methods in Biomechanics and Biomedical Engineering (CMBBE) 2019, New York City, USA}, abstract = {The AnyBody™ Modeling System (AMS) [1], is an universally used musculoskeletal simulation software using inverse dynamics. Until now, no complete human hand model is known in the AMS. Also considering other musculoskeletal software platforms, just one detailed entire hand model is recently published [2] but is only based on one subject. The aim of this work is to implement a full detailed hand model for the AMS including all extrinsic and intrinsic muscles using data by the UWB gained through an anatomical study of ten cadaver hands.}, language = {en} } @article{MelznerEngelhardtSimonetal., author = {Melzner, Maximilian and Engelhardt, Lucas and Simon, Ulrich and Dendorfer, Sebastian}, title = {Electromyography-Based Validation of a Musculoskeletal Hand Model}, series = {Journal of Biomechanical Engineering}, volume = {144}, journal = {Journal of Biomechanical Engineering}, number = {2}, publisher = {American Society of Mechanical Engineers, ASME}, doi = {10.1115/1.4052115}, pages = {8}, abstract = {Regarding the prevention of injuries and rehabilitation of the human hand, musculoskeletal simulations using an inverse dynamics approach allow for insights of the muscle recruitment and thus acting forces on the hand. Currently, several hand models from various research groups are in use, which are mainly validated by the comparison of numerical and anatomical moment arms. In contrast to this validation and model-building technique by cadaver studies, the aim of this study is to further validate a recently published hand model [1] by analyzing numerically calculated muscle activities in comparison to experimentally measured electromyographical signals of the muscles. Therefore, the electromyographical signals of 10 hand muscles of five test subjects performing seven different hand movements were measured. The kinematics of these tasks were used as input for the hand model, and the numerical muscle activities were computed. To analyze the relationship between simulated and measured activities, the time difference of the muscle on- and off-set points was calculated, which resulted in a mean on- and off-set time difference of 0.58 s between the experimental data and the model. The largest differences were detected for movements that mainly addressed the wrist. One major issue comparing simulated and measured muscle activities of the hand is cross-talk. Nevertheless, the results show that the hand model fits the experiment quite accurately despite some limitations and is a further step toward patient-specific modeling of the upper extremity.}, subject = {Elektromyographie}, language = {en} } @article{MelznerIsmailRušavyetal., author = {Melzner, Maximilian and Ismail, Khaled and Rušavy, Zdenek and Kališ, Vladim{\´i}r and S{\"u}ß, Franz and Dendorfer, Sebastian}, title = {Musculoskeletal lower back load of accoucheurs during childbirth - A pilot and feasibility study}, series = {European Journal of Obstetrics \& Gynecology and Reproductive Biology}, journal = {European Journal of Obstetrics \& Gynecology and Reproductive Biology}, number = {264}, publisher = {Elsevier}, doi = {10.1016/j.ejogrb.2021.07.042}, pages = {306 -- 313}, abstract = {Introduction: Back problems represent one of the leading causes of accouchers' work-related musculoskeletal morbidities. The correct execution of birth-related maneuvers including manual perineal protection is crucial not only for the mother and child but also for obstetricians and midwives to reduce any strain on their musculoskeletal system. Therefore, the overall aim of this study was to test the feasibility of determining the effect of different accouchers' postures (standing and kneeling) on their musculoskeletal system. Methods: The biomechanical analysis is based on musculoskeletal simulations that included motion recordings of real deliveries as well as deliveries conducted on a birthing simulator. These simulations were then used to determine individual joints' loads. Results: In the kneeling posture, both a low intra-operator variability and a lower average maximum load of the lower back was observed. For the standing position the spine load was reduced by pivoting the elbow on the accouchers' thigh, which in turn was associated with a significantly greater load on the shoulder joint. Conclusion: The study demonstrated the feasibility of our technique to assess joints loads. It also provided initial data indicating that a posture that reduces spinal flexion and tilt, achieved in this study by the kneeling, can significantly reduce the strain on the practitioner's musculoskeletal system.}, language = {en} } @misc{MelznerIsmailRušavyetal., author = {Melzner, Maximilian and Ismail, Khaled and Rušav{\´y}, Zdeněk and Kališ, Vladim{\´i}r and S{\"u}ß, Franz and Dendorfer, Sebastian}, title = {Musculoskeletal Lower Back Load of Accoucheurs During Delivery}, series = {26th Congress of the European Society of Biomechanics, July 11-14, 2021, Milan, Italy}, journal = {26th Congress of the European Society of Biomechanics, July 11-14, 2021, Milan, Italy}, address = {Milan}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-20208}, abstract = {With the progress in modern medicine, it was possible to significantly reduce the risks of birth for mother and child. One aspect that has received less attention so far is the risk of injury to the accoucheurs (obstetricians and midwives) during the birth process. Indeed, studies indicate that 92\% of midwives suffer from musculoskeletal disorders, with the lower back being the main cause of complaints (72\%). The aim of this study was to investigate two commonly used postural techniques used by accoucheurs during childbirth and to analyze the resulting load on the lower back using the AnyBodyTM musculoskeletal simulation software.}, language = {en} } @misc{MelznerPfeiferAltetal., author = {Melzner, Maximilian and Pfeifer, Christian and Alt, V. and S{\"u}ß, Franz and Dendorfer, Sebastian}, title = {{\"A}nderung der Gelenkreaktionskraft bei Sch{\"a}digung des medialen Bandapparates im Ellenbogen}, series = {Zeitschrift fur Orthopadie und Unfallchirurgie}, volume = {158}, journal = {Zeitschrift fur Orthopadie und Unfallchirurgie}, number = {S01}, publisher = {Thieme}, doi = {10.1055/s-0040-1717270}, language = {de} } @misc{MelznerPfeiferSuessetal., author = {Melzner, Maximilian and Pfeifer, Christian and S{\"u}ß, Franz and Dendorfer, Sebastian}, title = {Muskuloskeletal analysis of elbow stability for common injury patterns}, series = {27th Congress of the European Society of Biomechanics, 26 - 29 June 2022, Porto, Portugal}, journal = {27th Congress of the European Society of Biomechanics, 26 - 29 June 2022, Porto, Portugal}, pages = {654}, language = {en} } @article{MelznerPfeifferSuessetal., author = {Melzner, Maximilian and Pfeiffer, Christian and Suess, Franz and Dendorfer, Sebastian}, title = {Musculoskeletal simulation of elbow stability for common injury patterns}, series = {Journal of Orthopaedic Research}, volume = {41}, journal = {Journal of Orthopaedic Research}, number = {6}, publisher = {Wiley}, issn = {1554-527X}, doi = {10.1002/jor.25460}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-54819}, pages = {1356 -- 1364}, abstract = {Elbow stability is derived from a combination of muscular, ligamentous, and bony structures. After an elbow trauma the stability of the joint is an important decision criterion for the subsequent treatment. The decision regarding non-operative/operative care depends mostly on subjective assessments of medical experts. Therefore, the aim of this study is to use musculoskeletal simulations as an objective assessment tool to investigate the extent to which failure of different stabilizers affects the elbow stability and how these observations correspond to the assessment from clinical practice. A musculoskeletal elbow simulation model was developed for this aim. To investigate the stability of the elbow, varus/valgus moments were applied under 0°, 45°and 90° flexion while the respective cubital angle was analyzed. This was performed for nine different injury scenarios, which were also evaluated for stability by clinical experts. With the results, it can be determined by which injury pattern and under which flexion angle the elbow stability is impaired regarding varus/valgus moments. The scenario with a complete failure of the medial and lateral ligaments and a fracture of the radial head was identified as having the greatest instability. The study presented a numerical determination of elbow stability against varus/valgus moments regarding clinical injury patterns, as well as a comparison of the numerical outcome with experience gained in clinical practice. The numerical predictions agree well with the assessments of the clinical specialists. Thus, the results from musculoskeletal simulation can make an important contribution to a more objective assessment of the elbow stability.}, language = {en} } @article{MelznerSuessDendorfer, author = {Melzner, Maximilian and Suess, Franz and Dendorfer, Sebastian}, title = {The impact of anatomical uncertainties on the predictions of a musculoskeletal hand model - a sensitivity study}, series = {Computer Methods in Biomechanics and Biomedical Engineering}, volume = {25}, journal = {Computer Methods in Biomechanics and Biomedical Engineering}, number = {2}, publisher = {Taylor \& Francis}, issn = {1476-8259}, doi = {10.1080/10255842.2021.1940974}, pages = {156 -- 164}, abstract = {Outputs of musculoskeletal models should be considered probabilistic rather than deterministic as they are affected by inaccuracies and estimations associated with the development of the model. One of these uncertainties being critical for modeling arises from the determination of the muscles' line of action and the physiological cross-sectional area. Therefore, the aim of this study was to evaluate the outcome sensitivity of model predictions from a musculoskeletal hand model in comparison to the uncertainty of these input parameters. For this purpose, the kinematics and muscle activities of different hand movements (abduction of the fingers, abduction of the thumb, and flexion of the thumb) were recorded. One thousand simulations were calculated for each movement using the Latin hypercube sampling method with a corresponding variation of the muscle origin/insertion points and the cross-sectional area. Comparing the standard hand to simulations incorporating uncertainties of input parameters shows no major deviations in on- and off-set time point of muscle activities. About 60\% of simulations are located within a ± 30\% interval around the standard model concerning joint reaction forces. The comparison with the variation of the input data leads to the conclusion that the standard hand model is able to provide not over-scattered outcomes and, therefore, can be considered relatively stable. These results are of practical importance to the personalization of a musculoskeletal model with subject-specific bone geometries and hence changed muscle line of action.}, subject = {Biomechanik}, language = {en} } @article{MoragKieningerEissnertetal., author = {Morag, Sarah and Kieninger, Martin and Eissnert, Christoph and Auer, Simon and Dendorfer, Sebastian and Popp, Daniel and Hoffmann, Johannes and Kieninger, B{\"a}rbel}, title = {Comparison of different techniques for prehospital cervical spine immobilization: Biomechanical measurements with a wireless motion capture system}, series = {PLOS ONE}, volume = {18}, journal = {PLOS ONE}, number = {11}, publisher = {PLOS}, address = {San Francisco, California}, doi = {10.1371/journal.pone.0292300}, pages = {1 -- 14}, language = {en} } @inproceedings{MuehlingEnglertDendorfer, author = {Muehling, M. and Englert, Carsten and Dendorfer, Sebastian}, title = {Influence of biceps tenotomy and tenodesis on post-operative shoulder strength}, series = {Jahrestagung der Deutschen Gesellschaft f{\"u}r Biomechanik, March 2017, Hannover, Germany}, booktitle = {Jahrestagung der Deutschen Gesellschaft f{\"u}r Biomechanik, March 2017, Hannover, Germany}, language = {en} } @article{PenzkoferBarnsteinerDendorfer, author = {Penzkofer, Rainer and Barnsteiner, K. and Dendorfer, Sebastian}, title = {The influence of age, shoe type and kicking direction on the severity of head trauma}, series = {Journal of Forensic Biomechanics}, volume = {5}, journal = {Journal of Forensic Biomechanics}, number = {1}, doi = {10.4172/2090-2697.1000116}, abstract = {In the last few years, increasingly kicks to the head were observed as a criminal offense. This study examined the influence of age, shoe type and kicking direction on the severity of head trauma. Male test persons were divided into two groups "Old" and "Young". Both groups were equipped with light sneakers and combat boots. A standard laboratory crash dummy was used to simulate the victim's body. First, the dummy's head, free floating above the ground, was kicked vertically. Second, the dummy's head was kicked horizontally. Established injury criteria were used to quantify the injury risk. No influence concerning the type of foot wear and no difference between the groups "Old" and "Young" could be found. For all analyses, kicking vertically generally lead to a higher risk for the subject compared to kicking horizontally. In this study, only the integral effect of the kicks could be analyzed. A detailed injury pattern cannot directly be derived from the data. Nevertheless, the presented data show the massive potential of injuries associated with head kicks.}, subject = {Kopfverletzung}, language = {en} } @inproceedings{PenzkoferGrechenigKujatetal., author = {Penzkofer, Rainer and Grechenig, S. and Kujat, Richard and Angele, Peter and Dendorfer, Sebastian}, title = {Biomechanical comparison of the dorsal femur condyles and the iliac crest in terms of failure behavior}, series = {XXV Congress of the International Society of Biomechanics, Glasgow, UK, 12th-16th July 2015}, booktitle = {XXV Congress of the International Society of Biomechanics, Glasgow, UK, 12th-16th July 2015}, language = {en} }