TY - JOUR A1 - Akbari Shandiz, Mohsen A1 - Boulos, Paul A1 - Sævarsson, Stefan A1 - Ramm, Heiko A1 - Fu, Chun Kit A1 - Miller, Stephen A1 - Zachow, Stefan A1 - Anglin, Carolyn T1 - Changes in Knee Shape and Geometry Resulting from Total Knee Arthroplasty JF - Journal of Engineering in Medicine N2 - 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. Y1 - 2018 UR - http://journals.sagepub.com/eprint/ZVgNrNESA9EjIcaFWSjb/full U6 - https://doi.org/10.1177/0954411917743274 VL - 232 IS - 1 SP - 67 EP - 79 ER - TY - JOUR A1 - Saevarsson, Stefan A1 - Sharma, Gulshan A1 - Amiri, Shahram A1 - Montgomery, Sigrun A1 - Ramm, Heiko A1 - Lichti, Derek A1 - Lieck, Robert A1 - Zachow, Stefan A1 - Anglin, Carolyn T1 - Radiological method for measuring patellofemoral tracking and tibiofemoral kinematics before and after total knee replacement JF - Bone and Joint Research Y1 - 2012 UR - http://www.bjr.boneandjoint.org.uk/content/1/10/263.short U6 - https://doi.org/10.1302/2046-3758.110.2000117 VL - 1 IS - 10 SP - 263 EP - 271 ER - TY - JOUR A1 - Hildebrandt, Thomas A1 - Goubergrits, Leonid A1 - Heppt, Werner A1 - Bessler, Stefan A1 - Zachow, Stefan T1 - Evaluation of the Intranasal Flow Field through Computational Fluid Dynamics (CFD) JF - Journal of Facial and Plastic Surgery Y1 - 2013 UR - https://www.thieme-connect.de/DOI/DOI?10.1055/s-0033-1341591 U6 - https://doi.org/10.1055/s-0033-1341591 VL - 29 IS - 2 SP - 93 EP - 98 PB - Thieme ER - TY - JOUR A1 - Saevarsson, Stefan A1 - Sharma, Gulshan A1 - Ramm, Heiko A1 - Lieck, Robert A1 - Hutchison, Carol A1 - Werle, Jason A1 - Montgomery, Sigrun A1 - Romeo, Carolina A1 - Zachow, Stefan A1 - Anglin, Carolyn T1 - Kinematic Differences Between Gender Specific And Traditional Knee Implants JF - The Journal of Arthroplasty Y1 - 2013 U6 - https://doi.org/10.1016/j.arth.2013.01.021 VL - 28 IS - 9 SP - 1543 EP - 1550 ER - TY - GEN A1 - Sharma, Gulshan A1 - Ho, Karen A1 - Saevarsson, Stefan A1 - Ramm, Heiko A1 - Lieck, Robert A1 - Zachow, Stefan A1 - Anglin, Carolyn T1 - Knee Pose and Geometry Pre- and Post-Total Knee Arthroplasty Using Computed Tomography T2 - 58th Annual Meeting of the Orthopaedic Research Society (ORS) Y1 - 2012 CY - San Francisco, CA ER - TY - GEN A1 - Sharma, Gulshan A1 - Saevarsson, Stefan A1 - Amiri, Shahram A1 - Montgomery, Sigrun A1 - Ramm, Heiko A1 - Lichti, Derek A1 - Zachow, Stefan A1 - Anglin, Carolyn T1 - Sequential-Biplane Radiography for Measuring Pre and Post Total Knee Arthroplasty Kinematics T2 - 58th Annual Meeting of the Orthopaedic Research Society (ORS) Y1 - 2012 CY - San Francisco, CA ER - TY - CHAP A1 - Stefan, Saevarsson A1 - Gulshan, Sharma A1 - Sigrun, Montgomery A1 - Karen, Ho A1 - Ramm, Heiko A1 - Lieck, Robert A1 - Zachow, Stefan A1 - Hutchison, Carol A1 - Jason, Werle A1 - Carolyn, Anglin T1 - Kinematic Comparison Between Gender Specific and Traditional Femoral Implants T2 - 67th Canadian Orthopaedic Association (COA) Annual Meeting Y1 - 2012 ER - TY - JOUR A1 - Ho, Karen A1 - Saevarsson, Stefan A1 - Ramm, Heiko A1 - Lieck, Robert A1 - Zachow, Stefan A1 - Sharma, Gulshan A1 - Rex, Erica A1 - Amiri, Shahram A1 - Wu, Barnabas A1 - Leumann, Andre A1 - Anglin, Carolyn T1 - Computed tomography analysis of knee pose and geometry before and after total knee arthroplasty JF - Journal of biomechanics Y1 - 2012 UR - http://www.ncbi.nlm.nih.gov/pubmed/22796002 U6 - https://doi.org/10.1016/j.jbiomech.2012.06.004 VL - 45 IS - 13 SP - 2215 EP - 21 ER - TY - JOUR A1 - Xie, Kunpeng A1 - Gruber, Lennart Johannes A1 - Crampen, Martin A1 - Li, Yao A1 - Ferreira, André A1 - Tappeiner, Elias A1 - Gillot, Maxime A1 - Schepers, Jan A1 - Xu, Jiangchang A1 - Pankert, Tobias A1 - Beyer, Michel A1 - Shahamiri, Negar A1 - ten Brink, Reinier A1 - Dot, Gauthier A1 - Weschke, Charlotte A1 - van Nistelrooij, Niels A1 - Verhelst, Pieter-Jan A1 - Guo, Yan A1 - Xu, Zhibin A1 - Bienzeisler, Jonas A1 - Rashad, Ashkan A1 - Flügge, Tabea A1 - Cotton, Ross A1 - Vinayahalingam, Shankeeth A1 - Ilesan, Robert A1 - Raith, Stefan A1 - Madsen, Dennis A1 - Seibold, Constantin A1 - Xi, Tong A1 - Bergé, Stefaan A1 - Nebelung, Sven A1 - Kodym, Oldřich A1 - Sundqvist, Osku A1 - Thieringer, Florian A1 - Lamecker, Hans A1 - Coppens, Antoine A1 - Potrusil, Thomas A1 - Kraeima, Joep A1 - Witjes, Max A1 - Wu, Guomin A1 - Chen, Xiaojun A1 - Lambrechts, Adriaan A1 - Cevidanes, Lucia H Soares A1 - Zachow, Stefan A1 - Hermans, Alexander A1 - Truhn, Daniel A1 - Alves, Victor A1 - Egger, Jan A1 - Röhrig, Rainer A1 - Hölzle, Frank A1 - Puladi, Behrus T1 - Beyond Benchmarks: Towards Robust Artificial Intelligence Bone Segmentation in Socio-Technical Systems JF - Expert Systems With Applications N2 - Despite the advances in automated medical image segmentation, AI models still underperform in various clinical settings, challenging real-world integration. In this multicenter evaluation, we analyzed 20 state-of-the-art mandibular segmentation models across 19,218 segmentations of 1,000 clinically resampled CT/CBCT scans. We show that segmentation accuracy varies by up to 25% depending on socio-technical factors such as voxel size, bone orientation, and patient conditions such as osteosynthesis or pathology. Higher sharpness, isotropic smaller voxels, and neutral orientation significantly improved results, while metallic osteosynthesis and anatomical complexity led to significant degradation. Our findings challenge the common view of AI models as “plug-and-play” tools and suggest evidence-based optimization recommendations for both clinicians and developers. This will in turn boost the integration of AI segmentation tools in routine healthcare. Y1 - 2025 UR - https://www.medrxiv.org/content/10.1101/2025.06.11.25329022v1 U6 - https://doi.org/10.1016/j.eswa.2025.130031 VL - 299 IS - Part D ER - TY - GEN A1 - Deuflhard, Peter A1 - Dössel, Olaf A1 - Louis, Alfred A1 - Zachow, Stefan T1 - Mehr Mathematik wagen in der Medizin N2 - Der Artikel gibt einen Einblick in das reiche Feld der Zusammenarbeit zwischen Mathematik und Medizin. Beispielhaft werden drei Erfolgsmodelle dargestellt: Medizinische Bildgebung, mathematische Modellierung und Biosignalverarbeitung im Bereich der Dynamik des Herzens sowie mathematische Modellierung und Simulation in der Krebstherapie Hyperthermie und der Mund-Kiefer-Gesichts-Chirurgie. In allen Fällen existiert ein Gleichklang der Interessen von Medizin und Mathematik: Beide Disziplinen wollen die Resultate schnell und zuverlässig. Für die Klinik heißt das, dass notwendige Rechnungen in möglichst kurzer Zeit, und zwar auf dem PC, ablaufen müssen und dass die Resultate so genau und belastbar sein müssen, dass medizinische Entscheidungen darauf aufbauen können. Für die Mathematik folgt daraus, dass höchste Anforderungen an die Effizienz der verwendeten Algorithmen und die darauf aufbauende Software in Numerik und Visualisierung zu stellen sind. Jedes Kapitel endet mit einer Darstellung der Perspektive des jeweiligen Gebietes. Abschließend werden mögliche Handlungsoptionen für Politik und Wirtschaft diskutiert. T3 - ZIB-Report - 08-25 Y1 - 2008 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-10776 SN - 1438-0064 ER -