TY - JOUR A1 - Herrmann, Marietta A1 - Engelke, Klaus A1 - Ebert, Regina A1 - Müller-Deubert, Sigrid A1 - Rudert, Maximilian A1 - Ziouti, Fani A1 - Jundt, Franziska A1 - Felsenberg, Dieter A1 - Jakob, Franz T1 - Interactions between muscle and bone — Where physics meets biology JF - Biomolecules N2 - Muscle and bone interact via physical forces and secreted osteokines and myokines. Physical forces are generated through gravity, locomotion, exercise, and external devices. Cells sense mechanical strain via adhesion molecules and translate it into biochemical responses, modulating the basic mechanisms of cellular biology such as lineage commitment, tissue formation, and maturation. This may result in the initiation of bone formation, muscle hypertrophy, and the enhanced production of extracellular matrix constituents, adhesion molecules, and cytoskeletal elements. Bone and muscle mass, resistance to strain, and the stiffness of matrix, cells, and tissues are enhanced, influencing fracture resistance and muscle power. This propagates a dynamic and continuous reciprocity of physicochemical interaction. Secreted growth and differentiation factors are important effectors of mutual interaction. The acute effects of exercise induce the secretion of exosomes with cargo molecules that are capable of mediating the endocrine effects between muscle, bone, and the organism. Long-term changes induce adaptations of the respective tissue secretome that maintain adequate homeostatic conditions. Lessons from unloading, microgravity, and disuse teach us that gratuitous tissue is removed or reorganized while immobility and inflammation trigger muscle and bone marrow fatty infiltration and propagate degenerative diseases such as sarcopenia and osteoporosis. Ongoing research will certainly find new therapeutic targets for prevention and treatment. KW - muscle KW - bone KW - mechanosensing KW - mechanotransduction KW - myokines KW - osteokines adaptation Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-203399 SN - 2218-273X VL - 10 IS - 3 ER - TY - THES A1 - Grüninger, Daniel T1 - Primäre Ausrissfestigkeit implantatfreier patellarer Fixationsmethoden beim MPFL-Ersatz am porcinen Modell T1 - Primary fixation strength of patellar fixation methods for medial patellofemoral ligament reconstruction in a porcine model N2 - Akute Patellaluxationen sind häufige Kniegelenksverletzungen. Sie gehen oft mit einer Verletzung des medialen patellofemoralen Ligaments (MPFL) einher, was zu rezidivierenden Patellaluxationen und patellofemoraler Instabilität führen kann. Ein möglicher Therapieansatz ist die Rekonstruktion des MPFL. Zahlreiche Operationstechniken sind hierzu in der Literatur beschrieben, darunter Fixationen mit Interferenzschrauben, Bohrkanälen, Nahtankern oder Nahtfixationen am Knochen oder Weichgewebe. Sie werden meist mit einem autologen Sehnentransplantats durchgeführt und unterscheiden sich hauptsächlich in der Art dessen patellarer Fixation. Meta-Analysen zeigen nach wie vor hohe Komplikationsraten und teilweise wenig zufriedenstellende Ergebnisse etablierter MPFL-Rekonstruktionen. Ein vielversprechender Ansatz zur Senkung der Komplikationsraten sind patellare Fixationsmethoden, die auf das Einbringen von Fremdmaterial und Bohrungen durch die Patella verzichten. Solche implantat- und/oder bohrkanalfreien Fixationsmethoden sind bereits in der Literatur beschrieben, bis jetzt existieren jedoch nur wenige Studien zu deren biomechanischen Eigenschaften. Ziel dieser Arbeit war der Vergleich biomechanischer Eigenschaften von fünf unterschiedlichen implantatfreien patellaren Fixationsmethoden beim MPFL- Ersatz mit dem nativen MPFL und mit nativen Extensorensehnen. Dazu wurde ein porcines Modell benutzt. Die Hypothese dieser Studie war, dass die patellare Weichteilfixation eines autologen Sehnentransplantats ohne Implantate oder Bohrkanal eine vergleichbare primäre Ausrissfestigkeit wie das native MPFL zeigt. 60 Patellae und Extensorensehnen wurden aus porcinen Hinterläufen extrahiert und randomisiert auf 6 Versuchsgruppen aufgeteilt (n=10). In den Gruppen 1 und 2 wurden patellare Weichteilfixationen getestet. In den Gruppen 3 und 4 wurden Bohrkanalfixationen mit unterschiedlichem Nahtmaterial durchgeführt (Gruppe 3: resorbierbarer Faden der Stärke USP 0, Gruppe 4: nicht-resorbierbarer Faden der Stärke USP 3). In Gruppe 5 erfolgte die patellare Fixation mittels V-förmigen Bohrkanal mit Durchmesser von 4,5 mm. In der sechsten Versuchsgruppe wurde zum Vergleich das native Gewebe getestet. In einer weiteren Versuchsgruppe wurden native porcine Extensorensehnen biomechanisch untersucht. Die biomechanische Testung gliederte sich in mehrere Abschnitte. Zunächst erfolgte eine Präkonditionierung mit 10 Setzzyklen mit einem Kraftintervall von 5 - 20 N. Es folgte eine zyklische Testphase von 1000 Messzyklen mit einem Kraftintervall von 5 - 50 N. Im Anschluss wurde die maximale Kraft bis zum Versagen angewendet. Dabei wurden die Parameter maximale Ausrisskraft, Yield Load, Steifigkeit, Elongation nach 1000 Zyklen sowie die Versagensart untersucht. In der Versuchsgruppe des nativen Gewebes wurde direkt die maximale Kraft bis zum Versagen angewendet. Die höchsten maximalen Ausrisskräfte wurden in Gruppen 1 und 2 gemessen (321,8 ± 53,5 N und 242,0 ± 57,4 N) und waren mit dem nativen Gewebe vergleichbar (252,1 ± 129,3 N, p > 0,05). Ein signifikant niedrigerer Yield Load im Vergleich zum nativen Gewebe zeigte sich in den Gruppen 3 (p < 0,01) und 4 (p = 0,01). Während der zyklischen Belastung war die Elongation der Präparate in Gruppe 3 signifikant höher im Vergleich zu den anderen Gruppen (5,3 ± 1 mm, p < 0,05). Alle Gruppen wiesen ähnliche Steifigkeiten wie das native Gewebe vor (p > 0,05). Die getesteten Fixationsmethoden zeigten signifikante Unterschiede in ihren biomechanischen Eigenschaften (p < 0,05). Insbesondere die Weichteilfixationen in Gruppen 1 und 2 wiesen adäquate biomechanische Eigenschaften im Vergleich zum nativen Gewebe vor. Durch die Kombination aus geringerer Invasivität, Verzicht auf das Einbringen von Fremdkörpern, einfacher Anwendbarkeit und guter Primärstabilität sind patellare Weichteilfixationen vielversprechende Alternativen bei der MPFL-Rekonstruktion. und guter Primärstabilität sind patellare Weichteilfixationen vielversprechende Alternativen bei der MPFL-Rekonstruktion. N2 - Purpose: The purpose of this study was to compare primary fixation strength and biomechanical properties of five different patellar fixation techniques without implants in medial patellofemoral ligament (MPFL)-reconstruction in a porcine model. Our hypothesis was that patellar fixation with soft tissue suture shows similar primary fixation strength to native MPFL. Methods: 60 domestic porcine patellae and extensor tendons were harvested and randomized into 6 groups. In group 1 and 2 soft tissue suture fixation techniques were used. In group 3 and 4 osseous tunnel reconstruction methods were performed with different sutures (absorbable suture USP 0 and non-absorbable suture USP 3). In group 5 fixation was performed with a v-shaped osseous tunnel with 4.5 mm diameter. In group 6 the stability of the native tissue was tested as comparison. The patella-tendon constructs were preconditioned with 5 cycles between 5 and 20 N with an afterwards cyclic stress testing of 1000 cycles in the range of 5 to 50 N. Subsequently, a maximum load until failure was applied. The native tissue group was solely tested for the maximum load to failure. Results: The highest maximum load to failure was found in group 1 and 2 (321.8 ± 53.5 N and 242.0 ± 57.4 N) and showed comparable results to the native tissue group (252.1 ± 129.3 N, p >0.05). A significantly lower Yield Load was found in group 3 (p=0.003) and 4 (p=0.011). During cyclic testing group 3 resulted in significantly higher elongation compared to the other groups (5.28 ± 1 mm, p <0.05). All groups showed similar stiffness to the native tissue (p >0.05). Conclusion: The examined implantfree patellar fixation methods differ significantly in their biomechanical properties (p <0.05). Adequate maximum values of Fmax compared to the native tissue were observed. Implantfree fixation techniques of free tendon grafts for MPFL-reconstruction are reasonable alternatives as patellar fixation methods. KW - Kniegelenk KW - Kniescheibe KW - Modell KW - Rekonstruktion KW - MPFL KW - Rekonstruktion KW - Patella KW - Biomechanik KW - Porcin Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-270345 ER - TY - JOUR A1 - Szymski, Dominik A1 - Achenbach, Leonard A1 - Siebentritt, Martin A1 - Simoni, Karola A1 - Kuner, Norbert A1 - Pfeifer, Christian A1 - Krutsch, Werner A1 - Alt, Volker A1 - Meffert, Rainer A1 - Fehske, Kai T1 - Injury epidemiology of 626 athletes in surfing, wind surfing and kite surfing JF - Open Access Journal of Sports Medicine N2 - Introduction/Background Surfing, wind surfing and kite surfing enjoy a growing popularity with a large number of athletes worldwide. The aim of this study was to identify and compare the injury profiles and compare the injury profiles of these three extreme water sports. Materials and Methods These data for this retrospective cohort study were collected through an online standardised questionnaire during the 2017–18 season. The questionnaire included questions about anthropometry, skill level, injury diagnosis, injury mechanism, environmental conditions and training regimes. Results The 626 athletes included reported 2584 injuries. On average, each athlete sustained 4.12 injuries during the season. The most frequent injury location was in the lower extremity, in particular the foot, with 49 (16.4%) injuries in surfing, 344 (18.3%) in wind surfing and 79 (19.7%) in kite surfing. Surfing demonstrated a particularly high rate of head injuries (n = 37; 12.4%). Other frequent injury types were skin lesions (up to 42.1%) and contusions (up to 40.5%). The most common injury across all surfing sports was skin lesions of the foot (wind surfing: 11.7%; kite surfing: 13.2%; surfing: 12.7%). In surfing, skin lesions of the head were frequently observed (n = 24; 8.0%). In surfing, a ‘too large wave’ (n = 18; 24.7%) was main cause of the injury, while in wind surfing (n = 189; 34.5%) and kite surfing (n = 65; 36.7%) ‘own incompetence’ led to the most injuries. Conclusion This unique study compares injury epidemiology and mechanism in the three most popular surfing sports: wind surfing, kite surfing and surfing. Overall, injuries were sustained mainly in the lower extremity, while surfing also demonstrated a high rate of head injuries. KW - water sports KW - injury KW - training KW - ankle KW - foot KW - epidemiology Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-261545 VL - 12 ER - TY - JOUR A1 - Boelch, Sebastian Philipp A1 - Rüeckl, Kilian A1 - Streck, Laura Elisa A1 - Szewczykowski, Viktoria A1 - Weißenberger, Manuel A1 - Jakuscheit, Axel A1 - Rudert, Maximilian T1 - Diagnosis of chronic infection at total hip arthroplasty revision is a question of definition JF - Biomed Research International N2 - Purpose. Contradicting definitions of periprosthetic joint infection (PJI) are in use. Joint aspiration is performed before total hip arthroplasty (THA) revision. This study investigated the influence of PJI definition on PJI prevalence at THA revision. Test quality of prerevision aspiration was evaluated for the different PJI definitions. Methods. 256 THA revisions were retrospectively classified to be infected or not infected. Classification was performed according to the 4 different definitions proposed by the Musculoskeletal Infection Society (MSIS), the Infectious Diseases Society of America (IDSA), the International Consensus Meeting (ICM), and the European Bone and Joint Infection Society (EBJIS). Only chronic PJIs were included. Results. PJI prevalence at revision significantly correlated with the applied PJI definition (p=0.01, Cramer's V=0.093). PJI prevalence was 20.7% for the MSIS, 25.4% for the ICM, 28.1% for the IDSA, and 32.0% for the EBJIS definition. For synovial fluid white blood cell count, the best ROC-AUC for predicting PJI was 0.953 in combination with the MSIS definition. Conclusion. PJI definition significantly influences the rate of diagnosed PJIs at THA revision. Synovial fluid white blood cell count is a reliable means to rule out PJI. In cases with a borderline high synovial white blood cell count before THA revision as the only sign of chronic PJI, an extended diagnostic work-up should be considered. KW - periprosthetic joint infection KW - algorithm KW - consensus Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-265762 VL - 2021 ER - TY - JOUR A1 - Achenbach, Leonard A1 - Le Hanneur, Malo A1 - Camenzind, Roland S. A1 - Bouyer, Michael A1 - Pottecher, Pierre A1 - Lafosse, Thibault T1 - Systematic bifocal decompression for isolated long thoracic nerve paresis: A case series of 12 patients JF - Interdisciplinary Neurosurgery N2 - To date, no consensus exists regarding the best surgical management of isolated, micro-traumatic long thoracic nerve (LTN) paresis. Our hypothesis was that a combined decompression of the LTN at two potential locations for entrapment would be effective in the management of dynamic LTN paresis. We report on twelve patients with isolated LTN parersis, with tenderness at two entrapment sites, who underwent bifocal LTN decompression after undergoing unsuccessful conservative treatment for at least 6 months; all patients had preoperative electrodiagnostic studies that confirmed the paresis and ruled out peripheral neuritis. Clinical and electrical improvements were observed in eight patients (67%) regarding shoulder flexion, shoulder abduction, and Quick-DASH scores. Four patients (33%) did not improve after surgery. The results corroborate our hypothesis that a bifocal LTN decompression can be an effective and reliable therapeutic option in more than half of a very selective patient population suffering from serratus anterior muscle deficiency. KW - entrapment, traction KW - serratus anterior KW - scapular winging KW - scapula alata KW - dyskinesia KW - peripheral nerve KW - nerve compression KW - micro-traumatic KW - neurolysis Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-265085 VL - 27 ER - TY - JOUR A1 - Achenbach, Leonard A1 - Klein, Christian A1 - Luig, Patrick A1 - Bloch, Hendrik A1 - Schneider, Dominik A1 - Fehske, Kai T1 - Collision with opponents - but not foul play - dominates injury mechanism in professional men's basketball JF - BMC Sports Science Medicine and Rehabilitation N2 - Background To identify injury patterns and mechanisms in professional men’s basketball by means of video match analysis. Methods In Germany, injuries are registered with the statutory accident insurance for professional athletes (VBG) by clubs or club physicians as part of occupational accident reporting. Moderate and severe injuries (absence of > 7 days) sustained during basketball competition in one of four seasons (2014–2017 and 2018–2019) in the first or second national men’s league in Germany were prospectively analyzed using a newly developed standardized observation form. Season 2017–2018 was excluded because of missing video material. Results Video analysis included 175 (53%) of 329 moderate and severe match injuries. Contact patterns categorized according to the different body sites yielded eight groups of typical injury patterns: one each for the head, shoulders, and ankles, two for the thighs, and three for the knees. Injuries to the head (92%), ankles (76%), shoulders (70%), knees (47%), and thighs (32%) were mainly caused by direct contact. The injury proportion of foul play was 19%. Most injuries (61%) occurred in the central zone below the basket. More injuries occurred during the second (OR 1.8, p = 0.018) and fourth quarter (OR 1.8, p = 0.022) than during the first and third quarter of the match. Conclusion The eight identified injury patterns differed substantially in their mechanisms. Moderate and severe match injuries to the head, shoulders, knees, and ankles were mainly caused by collision with opponents and teammates. Thus, stricter rule enforcement is unlikely to facilitate safer match play. KW - epidemiology KW - mechanism KW - contact KW - non-contact´ KW - injury prevention KW - match load Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-261765 VL - 13 ER - TY - JOUR A1 - Pereira, Ana Rita A1 - Trivanović, Drenka A1 - Stahlhut, Philipp A1 - Rudert, Maximilian A1 - Groll, Jürgen A1 - Herrmann, Marietta T1 - Preservation of the naïve features of mesenchymal stromal cells in vitro: Comparison of cell- and bone-derived decellularized extracellular matrix JF - Journal of Tissue Engineering N2 - The fate and behavior of bone marrow mesenchymal stem/stromal cells (BM-MSC) is bidirectionally influenced by their microenvironment, the stem cell niche, where a magnitude of biochemical and physical cues communicate in an extremely orchestrated way. It is known that simplified 2D in vitro systems for BM-MSC culture do not represent their naïve physiological environment. Here, we developed four different 2D cell-based decellularized matrices (dECM) and a 3D decellularized human trabecular-bone scaffold (dBone) to evaluate BM-MSC behavior. The obtained cell-derived matrices provided a reliable tool for cell shape-based analyses of typical features associated with osteogenic differentiation at high-throughput level. On the other hand, exploratory proteomics analysis identified native bone-specific proteins selectively expressed in dBone but not in dECM models. Together with its architectural complexity, the physico-chemical properties of dBone triggered the upregulation of stemness associated genes and niche-related protein expression, proving in vitro conservation of the naïve features of BM-MSC. KW - decellularization KW - bone model KW - stem cell niche KW - stemness KW - osteogenesis KW - 3D models Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-268835 VL - 13 ER - TY - JOUR A1 - Pereira, A. R. A1 - Trivanović, D. A1 - Herrmann, M. T1 - Approaches to mimic the complexity of the skeletal mesenchymal stem/stromal cell niche in vitro JF - European Cells and Materials N2 - Mesenchymal stem/stromal cells (MSCs) are an essential element of most modern tissue engineering and regenerative medicine approaches due to their multipotency and immunoregulatory functions. Despite the prospective value of MSCs for the clinics, the stem cells community is questioning their developmental origin, in vivo localization, identification, and regenerative potential after several years of far-reaching research in the field. Although several major progresses have been made in mimicking the complexity of the MSC niche in vitro, there is need for comprehensive studies of fundamental mechanisms triggered by microenvironmental cues before moving to regenerative medicine cell therapy applications. The present comprehensive review extensively discusses the microenvironmental cues that influence MSC phenotype and function in health and disease – including cellular, chemical and physical interactions. The most recent and relevant illustrative examples of novel bioengineering approaches to mimic biological, chemical, and mechanical microenvironmental signals present in the native MSC niche are summarized, with special emphasis on the forefront techniques to achieve bio-chemical complexity and dynamic cultures. In particular, the skeletal MSC niche and applications focusing on the bone regenerative potential of MSC are addressed. The aim of the review was to recognize the limitations of the current MSC niche in vitro models and to identify potential opportunities to fill the bridge between fundamental science and clinical application of MSCs. KW - Mesenchymal stem/stromal cells KW - skeletal progenitor cells KW - niche KW - in vitro models KW - bone KW - tissue engineering Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-268823 SN - 1473-2262 VL - 37 ER - TY - JOUR A1 - Stratos, Ioannis A1 - Heller, Karl-Dieter A1 - Rudert, Maximilian T1 - German surgeons' technical preferences for performing total hip arthroplasties: a survey from the National Endoprosthesis Society JF - International Orthopaedics N2 - Purpose The goal of our study was to conduct an online survey that highlights patterns of practice during total hip arthroplasty (THA). Methods The survey was conducted in June and August 2020. Three hundred thirteen members of the German Society for Endoprosthesis participated in the survey. Results The anterolateral approach is by far the most popular approach used for primary total hip arthroplasty, followed by the anterior approach during minimally invasive (55% for the anterolateral and 29% for the anterior) and regular surgery (52% for the anterolateral and 20% for the anterior). Two-thirds of the orthopaedic surgeons do not use drainages during THA. Moreover, 80% of the survey participants routinely apply tranexamic acid during surgery. Surgeons who perform minimally invasive surgery for THA use more frequently fast-track-concepts for post-operative rehabilitation. According to the interviewees, the application of fast-track-concepts leads to reduced periods of hospital stay after THA. Conclusion Our data demonstrate that patterns of practice during THA in Germany are in line with the evidence provided by current literature. This study can be seen as a stimulus to conduct similar surveys in other countries in order to promote minimally invasive surgery for THA. KW - tranexamic acid KW - total hip arthroplasty KW - approach KW - fast-track-concepts KW - minimally invasive surgery KW - drain Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-266350 VL - 46 IS - 4 ER - TY - JOUR A1 - Stratos, Ioannis A1 - Scarlat, Marius M. A1 - Rudert, Maximilian T1 - Bibliometrics of orthopaedic articles published by authors of Germanophone countries JF - International Orthopaedics N2 - No abstract available. KW - scientific publications KW - orthopaedics KW - germanophone Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-266343 VL - 45 IS - 5 ER -