@article{EidmannKamawalLuedemannetal.2023, author = {Eidmann, Annette and Kamawal, Yama and Luedemann, Martin and Raab, Peter and Rudert, Maximilian and Stratos, Ioannis}, title = {Demographics and etiology for lower extremity amputations — experiences of an university orthopaedic center in Germany}, series = {Medicina}, volume = {59}, journal = {Medicina}, number = {2}, issn = {1648-9144}, doi = {10.3390/medicina59020200}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-304856}, year = {2023}, abstract = {Background and Objectives: Currently, the worldwide incidence of major amputations in the general population is decreasing whereas the incidence of minor amputations is increasing. The purpose of our study was to analyze whether this trend is reflected among orthopaedic patients treated with lower extremity amputation in our orthopaedic university institution. Materials and Methods: We conducted a single-center retrospective study and included patients referred to our orthopaedic department for lower extremity amputation (LEA) between January 2007 and December 2019. Acquired data were the year of amputation, age, sex, level of amputation and cause of amputation. T test and Chi² test were performed to compare age and amputation rates between males and females; significance was defined as p < 0.05. Linear regression and multivariate logistic regression models were used to test time trends and to calculate probabilities for LEA. Results: A total of 114 amputations of the lower extremity were performed, of which 60.5\% were major amputations. The number of major amputations increased over time with a rate of 0.6 amputation/year. Men were significantly more often affected by LEA than women. Age of LEA for men was significantly below the age of LEA for women (men: 54.8 ± 2.8 years, women: 64.9 ± 3.2 years, p = 0.021). Main causes leading to LEA were tumors (28.9\%) and implant-associated complications (25.4\%). Implant-associated complications and age raised the probability for major amputation, whereas malformation, angiopathies and infections were more likely to cause a minor amputation. Conclusions: Among patients in our orthopaedic institution, etiology of amputations of the lower extremity is multifactorial and differs from other surgical specialties. The number of major amputations has increased continuously over the past years. Age and sex, as well as diagnosis, influence the type and level of amputation.}, language = {en} } @article{HeinzEidmannJakuscheitetal.2023, author = {Heinz, Tizian and Eidmann, Annette and Jakuscheit, Axel and Laux, Tino and Rudert, Maximilian and Stratos, Ioannis}, title = {Demographics and trends for inbound medical tourism in Germany for orthopedic patients before and during the COVID-19 pandemic}, series = {International Journal of Environmental Research and Public Health}, volume = {20}, journal = {International Journal of Environmental Research and Public Health}, number = {2}, issn = {1660-4601}, doi = {10.3390/ijerph20021209}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-304955}, year = {2023}, abstract = {Medical tourism is a rapidly growing sector of economic growth and diversification. However, data on the demographics and characteristics of the traveling patients are sparse. In this study, we analyzed the common demographic properties and characteristics of the inbound medical tourists seeking orthopedic medical care in Germany for the years 2010 to 2019 compared to a domestic group. At the same time, we examined how the COVID-19 pandemic outbreak of 2020 changed the field of medical tourism in Germany. Calculations were performed using administrative hospital data provided by the Federal Statistical Department of Germany. Data were analyzed from the years 2010 to 2020. A total of six elective orthopedic surgery codes (bone biopsy, knee arthroplasty, foot surgery, osteotomy, hardware removal, and arthrodesis) were identified as key service indicators for medical tourism and further analyzed. Factors including residence, sex, year, and type of elective surgery were modeled using linear regression analysis. Age and sex distributions were compared between patients living inside Germany (DE) or outside Germany (non-DE). Between 2010 and 2020, 6,261,801 orthopedic procedures were coded for the DE group and 27,420 key procedures were identified for the non-DE group. Medical tourists were predominantly male and significantly younger than the domestic population. The linear regression analysis of the OPS codes over the past years showed a significantly different slope between the DE and non-DE groups only for the OPS code "hardware removal". With the COVID-19 pandemic, an overall decline in performed orthopedic procedures was observed for the non-DE and the DE group. A significant reduction below the 95\% prediction bands for the year 2020 could be shown for hardware removal and foot surgery (for DE), and for hardware removal, knee arthroplasty, foot surgery, and osteotomy (for non-DE). This study is the first to quantify inbound medical tourism in elective orthopedic surgery in Germany. The COVID-19 pandemic negatively affected many — but not all — areas of orthopedic surgery. It has to be seen how this negative trend will develop in the future.}, language = {en} } @article{KronerWeiglChuRudertetal.2023, author = {Kroner-Weigl, Niklas and Chu, Jin and Rudert, Maximilian and Alt, Volker and Shukunami, Chisa and Docheva, Denitsa}, title = {Dexamethasone is not sufficient to facilitate tenogenic differentiation of dermal fibroblasts in a 3D organoid model}, series = {Biomedicines}, volume = {11}, journal = {Biomedicines}, number = {3}, issn = {2227-9059}, doi = {10.3390/biomedicines11030772}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-311234}, year = {2023}, abstract = {Self-assembling three-dimensional organoids that do not rely on an exogenous scaffold but maintain their native cell-to-cell and cell-to-matrix interactions represent a promising model in the field of tendon tissue engineering. We have identified dermal fibroblasts (DFs) as a potential cell type for generating functional tendon-like tissue. The glucocorticoid dexamethasone (DEX) has been shown to regulate cell proliferation and facilitate differentiation towards other mesenchymal lineages. Therefore, we hypothesized that the administration of DEX could reduce excessive DF proliferation and thus, facilitate the tenogenic differentiation of DFs using a previously established 3D organoid model combined with dose-dependent application of DEX. Interestingly, the results demonstrated that DEX, in all tested concentrations, was not sufficient to notably induce the tenogenic differentiation of human DFs and DEX-treated organoids did not have clear advantages over untreated control organoids. Moreover, high concentrations of DEX exerted a negative impact on the organoid phenotype. Nevertheless, the expression profile of tendon-related genes of untreated and 10 nM DEX-treated DF organoids was largely comparable to organoids formed by tendon-derived cells, which is encouraging for further investigations on utilizing DFs for tendon tissue engineering.}, language = {en} } @article{TrivanovicVolkmannStoeckletal.2023, author = {Trivanovic, Drenka and Volkmann, Noah and Stoeckl, Magdalena and Tertel, Tobias and Rudert, Maximilian and Giebel, Bernd and Herrmann, Marietta}, title = {Enhancement of immunosuppressive activity of mesenchymal stromal cells by platelet-derived factors is accompanied by apoptotic priming}, series = {Stem Cell Reviews and Reports}, volume = {19}, journal = {Stem Cell Reviews and Reports}, number = {3}, doi = {10.1007/s12015-022-10471-4}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-324669}, pages = {713-733}, year = {2023}, abstract = {The pro-inflammatory phase of bone healing, initiated by platelet activation and eventually hematoma formation, impacts bone marrow mesenchymal stromal cells (MSCs) in unknown ways. Here, we created platelet-rich plasma (PRP) hydrogels to study how platelet-derived factors modulate functional properties of encapsulated MSCs in comparison to a non-inflammatory fibrin (FBR) hydrogel environment. MSCs were isolated from human bone marrow, while PRP was collected from pooled apheresis thrombocyte concentrates and used for hydrogel preparation. After their encapsulation in hydrogels for 72 h, retrieved MSCs were analyzed for immunomodulatory activities, apoptosis, stem cell properties, senescence, CD9\(^+\), CD63\(^+\) and CD81\(^+\) extracellular vesicle (EV) release, and metabolism-related changes. PRP-hydrogels stimulated immunosuppressive functions of MSCs, along with their upregulated susceptibility to cell death in communication with PBMCs and augmented caspase 3/7 activity. We found impaired clonal growth and cell cycle progression, and more pronounced β-galactosidase activity as well as accumulation of LC3-II-positive vacuoles in PRP-MSCs. Stimuli derived from PRP-hydrogels upregulated AKT and reduced mTOR phosphorylation in MSCs, which suggests an initiation of survival-related processes. Our results showed that PRP-hydrogels might represent a metabolically stressful environment, inducing acidification of MSCs, reducing polarization of the mitochondrial membrane and increasing lipid accumulation. These features were not detected in FBR-MSCs, which showed reduced CD63\(^+\) and CD81\(^+\) EV production and maintained clonogenicity. Our data revealed that PRP-derived hematoma components cause metabolic adaptation of MSCs followed by increased immune regulatory functions. For the first time, we showed that PRP stimuli represent a survival challenge and "apoptotic priming" that are detrimental for stem cell-like growth of MSCs and important for their therapeutic consideration.}, language = {en} } @article{EidmannHeinzOberfeldetal.2023, author = {Eidmann, Annette and Heinz, Tizian and Oberfeld, Jan and Weißenberger, Manuel and Rudert, Maximilian and Stratos, Ioannis}, title = {Epidemiology and trends in cartilage surgery of the foot and ankle in Germany: an analysis of national healthcare billing and reporting data from 2006 to 2020}, series = {Medicina}, volume = {59}, journal = {Medicina}, number = {7}, issn = {1648-9144}, doi = {10.3390/medicina59071256}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-362835}, year = {2023}, abstract = {Background and objectives: Cartilage surgery constitutes a standard intervention in foot and ankle procedures. Currently, there is a lack of epidemiological data on its frequency, age distribution, and surgical options for cartilage surgery. This study aimed to investigate the current landscape of cartilage surgery in Germany and identify the most common procedures from an epidemiological standpoint. Materials and methods: Medical billing and reporting data from the Federal Statistical Office of Germany, encompassing the period 2006-2020, was examined, including all foot and ankle cartilage surgical procedures (summarized under OPS codes 5-812 and 5-801). The dataset incorporated information on the affected joint, patient age and sex, and surgery type. Each surgical procedure was categorized as "debridement", "regeneration" or "refixation". Linear and nonlinear regression analyses were employed, with a statistical significance threshold of 0.05. Results: From the total of 136,501 procedures conducted during the study period, the most frequently performed interventions were microfracture (58,252) and chondroplasty (56,135), and thus, debridement procedures were in the leading position. The use of acellular membranes was the most used regenerative technique (n = 11,414). At the ankle joint, interventions were mostly arthroscopic and in men, while foot cartilage surgeries were preferably performed via open surgery and mostly in women. Age distribution analysis revealed two primary peaks: the first in the 20-25-year-old group (ankle and foot) and the second in the 45-50-year-old group (ankle) and 55-60-year-old group (foot). Refixation and regenerative procedures were more frequent among younger individuals, while debriding procedures were more frequent among older individuals. Regenerative procedures, particularly in the ankle, significantly increased over time. Conclusions: Cartilage surgery of the foot and ankle was common, with two primary age groups predominantly affected. Notably, recent years have witnessed a considerable rise in cartilage regenerative procedures.}, language = {en} } @article{HeinzWildEidmannetal.2023, author = {Heinz, Tizian and Wild, Moritz and Eidmann, Annette and Weißenberger, Manuel and Rak, Dominik and Nedopil, Alexander Johannes and Rudert, Maximilian and Stratos, Ioannis}, title = {Impact of COVID-19 on fracture incidence in germany: a comparative age and gender analysis of pre- and post-outbreak periods}, series = {Healthcare}, volume = {11}, journal = {Healthcare}, number = {15}, issn = {2227-9032}, doi = {10.3390/healthcare11152139}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-362686}, year = {2023}, abstract = {In March 2020, Germany imposed a nationwide lockdown to curb the spread of COVID-19, prompting questions about the impact on the incidence of common fractures. This study examined 15 fracture types in pre-outbreak (2010-2019) and post-outbreak (2020-2021) periods, using data categorized by age (18-64 years, 65 years) and sex (male, female). Linear regression assessed annual growth rates, and mean fracture numbers were compared across periods for significant differences. Results indicated a positive correlation between fracture incidence rates and time for various types, such as cervical, thoracic, lumbar, and pelvic spine fractures, rib fractures, femoral neck, pertrochanteric femur, femoral shaft, and ankle fractures. Frequencies of proximal humerus, distal radius, femoral neck, pertrochanteric femur, femoral shaft, and ankle fractures in 2020 and 2021 were within predicted ranges from previous years. However, rib fractures and spinal fractures (cervical, thoracic, lumbar, and pelvic spine) occurred less frequently during this time. Notably, this study found a consistent decline in most fracture types for individuals aged 18-64 after the pandemic's onset, while the fracture incidence of hip fractures, often referred to as fragility fractures, for those over 65 remained unchanged. Fibula fractures showed the most considerable decrease in both age groups. In conclusion, the COVID-19 pandemic substantially impacted fracture incidence, with lower rates among individuals under 65 and unchanged fragility fractures in the elderly population.}, language = {en} } @article{MunawarZhouPrommersbergeretal.2023, author = {Munawar, Umair and Zhou, Xiang and Prommersberger, Sabrina and Nerreter, Silvia and Vogt, Cornelia and Steinhardt, Maximilian J. and Truger, Marietta and Mersi, Julia and Teufel, Eva and Han, Seungbin and Haertle, Larissa and Banholzer, Nicole and Eiring, Patrick and Danhof, Sophia and Navarro-Aguadero, Miguel Angel and Fernandez-Martin, Adrian and Ortiz-Ruiz, Alejandra and Barrio, Santiago and Gallardo, Miguel and Valeri, Antonio and Castellano, Eva and Raab, Peter and Rudert, Maximilian and Haferlach, Claudia and Sauer, Markus and Hudecek, Michael and Martinez-Lopez, J. and Waldschmidt, Johannes and Einsele, Hermann and Rasche, Leo and Kort{\"u}m, K. Martin}, title = {Impaired FADD/BID signaling mediates cross-resistance to immunotherapy in Multiple Myeloma}, series = {Communications Biology}, volume = {6}, journal = {Communications Biology}, doi = {10.1038/s42003-023-05683-4}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-357609}, year = {2023}, abstract = {The treatment landscape in multiple myeloma (MM) is shifting from genotoxic drugs to immunotherapies. Monoclonal antibodies, immunoconjugates, T-cell engaging antibodies and CART cells have been incorporated into routine treatment algorithms, resulting in improved response rates. Nevertheless, patients continue to relapse and the underlying mechanisms of resistance remain poorly understood. While Impaired death receptor signaling has been reported to mediate resistance to CART in acute lymphoblastic leukemia, this mechanism yet remains to be elucidated in context of novel immunotherapies for MM. Here, we describe impaired death receptor signaling as a novel mechanism of resistance to T-cell mediated immunotherapies in MM. This resistance seems exclusive to novel immunotherapies while sensitivity to conventional anti-tumor therapies being preserved in vitro. As a proof of concept, we present a confirmatory clinical case indicating that the FADD/BID axis is required for meaningful responses to novel immunotherapies thus we report impaired death receptor signaling as a novel resistance mechanism to T-cell mediated immunotherapy in MM.}, language = {en} } @article{RakKlannHeinzetal.2023, author = {Rak, Dominik and Klann, Lukas and Heinz, Tizian and Anderson, Philip and Stratos, Ioannis and Nedopil, Alexander J. and Rudert, Maximilian}, title = {Influence of mechanical alignment on functional knee phenotypes and clinical outcomes in primary TKA: a 1-year prospective analysis}, series = {Journal of Personalized Medicine}, volume = {13}, journal = {Journal of Personalized Medicine}, number = {5}, issn = {2075-4426}, doi = {10.3390/jpm13050778}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-313646}, year = {2023}, abstract = {In total knee arthroplasty (TKA), functional knee phenotypes are of interest regarding surgical alignment strategies. Functional knee phenotypes were introduced in 2019 and consist of limb, femoral, and tibial phenotypes. The hypothesis of this study was that mechanically aligned (MA) TKA changes preoperative functional phenotypes, which decreases the 1-year Forgotten Joint (FJS) and Oxford Knee Score (OKS) and increases the 1-year WOMAC. All patients included in this study had end-stage osteoarthritis and were treated with a primary MA TKA, which was supervised by four academic knee arthroplasty specialists. To determine the limb, femoral, and tibial phenotype, a long-leg radiograph (LLR) was imaged preoperatively and two to three days after TKA. FJS, OKS, and WOMAC were obtained 1 year after TKA. Patients were categorized using the change in functional limb, femoral, and tibial phenotype measured on LLR, and the scores were compared between the different categories. A complete dataset of preoperative and postoperative scores and radiographic images could be obtained for 59 patients. 42\% of these patients had a change of limb phenotype, 41\% a change of femoral phenotype, and 24\% a change of tibial phenotype of more than ±1 relative to the preoperative phenotype. Patients with more than ±1 change of limb phenotype had significantly lower median FJS (27 points) and OKS (31 points) and higher WOMAC scores (30 points) relative to the 59-, 41-, and 4-point scores of those with a 0 ± 1 change (p < 0.0001 to 0.0048). Patients with a more than ±1 change of femoral phenotype had significantly lower median FJS (28 points) and OKS (32 points) and higher WOMAC scores (24 points) relative to the 69-, 40-, and 8-point scores of those with a 0 ± 1 change (p < 0.0001). A change in tibial phenotype had no effect on the FJS, OKS, and WOMAC scores. Surgeons performing MA TKA could consider limiting coronal alignment corrections of the limb and femoral joint line to within one phenotype to reduce the risk of low patient-reported satisfaction and function at 1-year.}, language = {en} } @article{HeinzMellerLuetkensetal.2023, author = {Heinz, Tizian and Meller, Felix and Luetkens, Karsten Sebastian and Anderson, Philip Mark and Stratos, Ioannis and Horas, Konstantin and Rudert, Maximilian and Reppenhagen, Stephan and Weißenberger, Manuel}, title = {The AMADEUS score is not a sufficient predictor for functional outcome after high tibial osteotomy}, series = {Journal of Experimental Orthopaedics}, volume = {10}, journal = {Journal of Experimental Orthopaedics}, doi = {10.1186/s40634-023-00575-2}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-357765}, year = {2023}, abstract = {Purpose The Area Measurement And Depth Underlying Structures (AMADEUS) classification system has been proposed as a valuable tool for magnetic resonance (MR)-based grading of preoperatively encountered chondral defects of the knee joint. However, the potential relationship of this novel score with clinical data was yet to determine. It was the primary intention of this study to assess the correlative relationship of the AMADEUS with patient reported outcome scores in patients undergoing medial open-wedge high tibial valgus osteotomy (HTO). Furthermore, the arthroscopic ICRS (International Cartilage Repair Society) grade evaluation was tested for correlation with the AMADEUS classification system. Methods This retrospective, monocentric study found a total of 70 individuals that were indicated for HTO due to degenerative chondral defects of the medial compartment between 2008 and 2019. A preoperative MR image as well as a pre-osteotomy diagnostic arthroscopy for ICRS grade evaluation was mandatory for all patients. The Knee Osteoarthritis Outcome Score (KOOS) including its five subscale scores (KOOS-ADL, KOOS-QOL, KOOS-Sports, KOOS-Pain, KOOS-Symptoms) was obtained preoperatively and at a mean follow-up of 41.2 ± 26.3 months. Preoperative chondral defects were evaluated using the AMADEUS classification system and the final AMADEUS scores were correlated with the pre- and postoperative KOOS subscale sores. Furthermore, arthroscopic ICRS defect severity was correlated with the AMADEUS classification system. Results There was a statistically significant correlation between the AMADEUS BME (bone marrow edema) subscore and the KOOS Symptoms subscore at the preoperative visit (r = 0.25, p = 0.04). No statistically significant monotonic association between the AMADEUS total score and the AMADEUS grade with pre- and postoperative KOOS subscale scores were found. Intraoperatively obtained ICRS grade did reveal a moderate correlative relation with the AMADEUS total score and the AMADEUS grade (r = 0.28, p = 0.02). Conclusions The novel AMADEUS classification system largely lacks correlative capacity with patient reported outcome measures in patients undergoing HTO. The MR tomographic appearance of bone marrow edema is the only parameter predictive of the clinical outcome at the preoperative visit.}, language = {en} } @article{HeinzEidmannAndersonetal.2023, author = {Heinz, Tizian and Eidmann, Annette and Anderson, Philip and Weißenberger, Manuel and Jakuscheit, Axel and Rudert, Maximilian and Stratos, Ioannis}, title = {Trends in computer-assisted surgery for total knee arthroplasty in Germany: an analysis based on the operative procedure classification system between 2010 to 2021}, series = {Journal of Clinical Medicine}, volume = {12}, journal = {Journal of Clinical Medicine}, number = {2}, issn = {2077-0383}, doi = {10.3390/jcm12020549}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-304879}, year = {2023}, abstract = {Alignment strategies for primary total knee arthroplasty (TKA) have changed significantly over time with a shift towards a more individualized alignment goal. At the same time, computer-assisted surgery (CAS) has gained interest for intraoperative control and accuracy in implant positioning and limb alignment. Despite the often discussed benefits and drawbacks of robotics and navigation for TKA, the routine use of these new devices on a day-to-day basis remains obscure. Therefore, nationwide hospital billing data based on the Operation Procedure Classification System (OPS) were retrieved from the Federal Statistical Office of Germany for the period from 2010 to 2021. OPS codes for primary total knee arthroplasty (OPS code: 5-822*) were further analyzed regarding the usage of computer navigation (additional OPS code: 5-988) or robotic devices (additional OPS code: 5-987). Gender and age at the time of surgery were also assessed. The results show a total of 2,226,559 primary TKAs were implanted between 2010 and 2021, of which 2,044,914 were performed conventionally (91.84\% of all TKAs). A total of 170,276 TKAs were performed using navigation technique (7.65\% of all TKAs) and another 11,369 TKAs were performed using robotics (0.51\% of all TKAs). For the period from 2018 to 2021, a substantial increase in robot-assisted TKA (R-TKA) was observed, with an average increase rate of 84.74\% per year, while the number of navigated TKAs declined (-3.67\% per year). Computer-assisted surgery, and particularly robotics for TKA, are seeing growing popularity and stepwise translation into routine clinical use in Germany, with a steep increase rate of more than 80\% per year since 2018. Nevertheless, the majority of TKAs are still performed using manual instrumentation, rendering conventional TKA the currently unchanged gold standard.}, language = {en} }