@article{AkbariShandizBoulosSavarssonetal.2017, author = {Akbari Shandiz, Mohsen and Boulos, Paul and S{\ae}varsson, Stefan and Ramm, Heiko and Fu, Chun Kit and Miller, Stephen and Zachow, Stefan and Anglin, Carolyn}, title = {Changes in Knee Shape and Geometry Resulting from Total Knee Arthroplasty}, series = {Journal of Engineering in Medicine}, volume = {232}, journal = {Journal of Engineering in Medicine}, number = {1}, doi = {10.1177/0954411917743274}, pages = {67 -- 79}, year = {2017}, abstract = {Changes in knee shape and geometry resulting from total knee arthroplasty can affect patients in numerous important ways: pain, function, stability, range of motion, and kinematics. Quantitative data concerning these changes have not been previously available, to our knowledge, yet are essential to understand individual experiences of total knee arthroplasty and thereby improve outcomes for all patients. The limiting factor has been the challenge of accurately measuring these changes. Our study objective was to develop a conceptual framework and analysis method to investigate changes in knee shape and geometry, and prospectively apply it to a sample total knee arthroplasty population. Using clinically available computed tomography and radiography imaging systems, the three-dimensional knee shape and geometry of nine patients (eight varus and one valgus) were compared before and after total knee arthroplasty. All patients had largely good outcomes after their total knee arthroplasty. Knee shape changed both visually and numerically. On average, the distal condyles were slightly higher medially and lower laterally (range: +4.5 mm to -4.4 mm), the posterior condyles extended farther out medially but not laterally (range: +1.8 to -6.4 mm), patellofemoral distance increased throughout flexion by 1.8-3.5 mm, and patellar thickness alone increased by 2.9 mm (range: 0.7-5.2 mm). External femoral rotation differed preop and postop. Joint line distance, taking cartilage into account, changed by +0.7 to -1.5 mm on average throughout flexion. Important differences in shape and geometry were seen between pre-total knee arthroplasty and post-total knee arthroplasty knees. While this is qualitatively known, this is the first study to report it quantitatively, an important precursor to identifying the reasons for the poor outcome of some patients. Using the developed protocol and visualization techniques to compare patients with good versus poor clinical outcomes could lead to changes in implant design, implant selection, component positioning, and surgical technique. Recommendations based on this sample population are provided. Intraoperative and postoperative feedback could ultimately improve patient satisfaction.}, language = {en} } @article{SaevarssonSharmaAmirietal.2012, author = {Saevarsson, Stefan and Sharma, Gulshan and Amiri, Shahram and Montgomery, Sigrun and Ramm, Heiko and Lichti, Derek and Lieck, Robert and Zachow, Stefan and Anglin, Carolyn}, title = {Radiological method for measuring patellofemoral tracking and tibiofemoral kinematics before and after total knee replacement}, series = {Bone and Joint Research}, volume = {1}, journal = {Bone and Joint Research}, number = {10}, doi = {10.1302/2046-3758.110.2000117}, pages = {263 -- 271}, year = {2012}, language = {en} } @misc{SharmaHoSaevarssonetal.2012, author = {Sharma, Gulshan and Ho, Karen and Saevarsson, Stefan and Ramm, Heiko and Lieck, Robert and Zachow, Stefan and Anglin, Carolyn}, title = {Knee Pose and Geometry Pre- and Post-Total Knee Arthroplasty Using Computed Tomography}, series = {58th Annual Meeting of the Orthopaedic Research Society (ORS)}, journal = {58th Annual Meeting of the Orthopaedic Research Society (ORS)}, address = {San Francisco, CA}, year = {2012}, language = {en} } @misc{SharmaSaevarssonAmirietal.2012, author = {Sharma, Gulshan and Saevarsson, Stefan and Amiri, Shahram and Montgomery, Sigrun and Ramm, Heiko and Lichti, Derek and Zachow, Stefan and Anglin, Carolyn}, title = {Sequential-Biplane Radiography for Measuring Pre and Post Total Knee Arthroplasty Kinematics}, series = {58th Annual Meeting of the Orthopaedic Research Society (ORS)}, journal = {58th Annual Meeting of the Orthopaedic Research Society (ORS)}, address = {San Francisco, CA}, year = {2012}, language = {en} } @inproceedings{StefanGulshanSigrunetal.2012, author = {Stefan, Saevarsson and Gulshan, Sharma and Sigrun, Montgomery and Karen, Ho and Ramm, Heiko and Lieck, Robert and Zachow, Stefan and Hutchison, Carol and Jason, Werle and Carolyn, Anglin}, title = {Kinematic Comparison Between Gender Specific and Traditional Femoral Implants}, series = {67th Canadian Orthopaedic Association (COA) Annual Meeting}, booktitle = {67th Canadian Orthopaedic Association (COA) Annual Meeting}, year = {2012}, language = {en} } @article{HoSaevarssonRammetal.2012, author = {Ho, Karen and Saevarsson, Stefan and Ramm, Heiko and Lieck, Robert and Zachow, Stefan and Sharma, Gulshan and Rex, Erica and Amiri, Shahram and Wu, Barnabas and Leumann, Andre and Anglin, Carolyn}, title = {Computed tomography analysis of knee pose and geometry before and after total knee arthroplasty}, series = {Journal of biomechanics}, volume = {45}, journal = {Journal of biomechanics}, number = {13}, doi = {10.1016/j.jbiomech.2012.06.004}, pages = {2215 -- 21}, year = {2012}, language = {en} } @article{HildebrandtGoubergritsHepptetal.2013, author = {Hildebrandt, Thomas and Goubergrits, Leonid and Heppt, Werner and Bessler, Stefan and Zachow, Stefan}, title = {Evaluation of the Intranasal Flow Field through Computational Fluid Dynamics (CFD)}, series = {Journal of Facial and Plastic Surgery}, volume = {29}, journal = {Journal of Facial and Plastic Surgery}, number = {2}, publisher = {Thieme}, doi = {10.1055/s-0033-1341591}, pages = {93 -- 98}, year = {2013}, language = {en} } @article{SaevarssonSharmaRammetal.2013, author = {Saevarsson, Stefan and Sharma, Gulshan and Ramm, Heiko and Lieck, Robert and Hutchison, Carol and Werle, Jason and Montgomery, Sigrun and Romeo, Carolina and Zachow, Stefan and Anglin, Carolyn}, title = {Kinematic Differences Between Gender Specific And Traditional Knee Implants}, series = {The Journal of Arthroplasty}, volume = {28}, journal = {The Journal of Arthroplasty}, number = {9}, doi = {10.1016/j.arth.2013.01.021}, pages = {1543 -- 1550}, year = {2013}, language = {en} } @misc{KoberSaderZeilhoferetal., author = {Kober, Cornelia and Sader, Robert and Zeilhofer, Hans-Florian and Prohaska, Steffen and Zachow, Stefan and Deuflhard, Peter}, title = {Anisotrope Materialmodellierung f{\"u}r den menschlichen Unterkiefer}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-6574}, number = {01-31}, abstract = {Im Rahmen der biomechanischen Simulation kn{\"o}cherner Organe ist die Frage nach einer befriedigenden Materialbeschreibung nach wie vor ungel{\"o}st. Computertomographische Datens{\"a}tze liefern eine r{\"a}umliche Verteilung der (R{\"o}ntgen-)Dichte und erm{\"o}glichen damit eine gute Darstellung der individuellen Geometrie. Weiter k{\"o}nnen die verschiedenen Materialbestandteile des Knochens, Spongiosa und Kortikalis, voneinander getrennt werden. Aber die richtungsab{\"a}ngige Information der Materialanisotropie ist verloren. In dieser Arbeit wird ein Ansatz f{\"u}r eine anisotrope Materialbeschreibung vorgestellt, die es erm{\"o}glicht, den Einfluss der individuellen kn{\"o}chernen Struktur auf das makroskopische Materialverhalten abzusch{\"a}tzen.}, language = {de} } @misc{HegeMerzkyZachow, author = {Hege, Hans-Christian and Merzky, Andre and Zachow, Stefan}, title = {Distributed Visualization with OpenGL Vizserver: Practical Experiences}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-5992}, number = {00-31}, abstract = {The increasing demand for distributed solutions in computing technology does not stop when it comes to visualization techniques. However, the capabilities of todays applications to perform remote rendering are limited by historical design legacys. Especially the popular X11 protokoll, which has been proven to be extremely flexible and usefull for remote 2D graphics applications, breaks down for the case of remote 3D rendering. In this white paper, we give a short overview of generic remote rendering technologies available today, and compare their performance to the recently released vizserver by SGI: a network extension to the SGI OpenGL rendering engines.}, language = {en} }