@article{SteinertRudertSieker2014,
  author    = {Steinert, Andre F. and Rudert, Maximilian and Sieker, Jakob T.},
  title     = {"Symptomatic loosening of a total knee arthroplasty caused by a tibial chondrosarcoma - a case report"},
  doi       = {10.1186/2193-1801-3-308},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-110341},
  year      = {2014},
  abstract  = {Premature implant loosening following total knee arthroplasty (TKA) can have several causes. In this article we report on a rare case of a 74 year old male patient suffering tibial component loosening 14 month after primary TKA. The patient did neither have any malignancies nor joint arthroplasty before. Upon clinical examination the range of motion in the diseased knee was painfully restricted to 80° of knee flexion, with the patient increasingly suffering sleeping and resting pain, and also at weight bearing. In standard radiographs, loosening of the TKA due to a large osteolysis at the tibial component was evident. Local computed tomography (CT) of the right knee revealed loosening of the tibial component due to a presumably malign bone tumor. For determination of the final diagnosis a representative biopsy of the tumor was taken by open surgery prior to the tumor resection. Histopathologic evaluation of the biopsy revealed a periprosthetic myxoid chondrosarcoma of the proximal tibia. Pre-operative staging examination included CT scans of lung and abdomen, as well as a bone scintigraphy which revealed no signs of tumor metastasis in the body. Surgical management comprised wide tumor resection and implantation of a hinged tumor knee arthroplasty with replacements of the distal femur and proximal tibia, as well as a patella tendon replacement using a synthetic ligament. Revision surgery was necessary twice due to impaired wound healing and critical soft tissue coverage, and treatment included a gastrocnemius muscle flap with skin mesh graft covering. Unfortunately long-term follow-up examinations could not be obtained, as the patient deceased due to an alveolitis during rehabilitation. In summary, the specifics of this rare case of aseptic TKA loosening, and the unusual circumstances of chondrosarcoma diagnosis and treatment are informative for those providing surgical treatment of similar cases.},
  language  = {en}
}
@article{KlotzMentrupRegensburgeretal.2012,
  author    = {Klotz, Barbara and Mentrup, Birgit and Regensburger, Martina and Zeck, Sabine and Schneidereit, Jutta and Schupp, Nicole and Linden, Christian and Merz, Cornelia and Ebert, Regina and Jakob, Franz},
  title     = {1,25-Dihydroxyvitamin D3 Treatment Delays Cellular Aging in Human Mesenchymal Stem Cells while Maintaining Their Multipotent Capacity},
  series = {PLoS ONE},
  volume    = {7},
  journal   = {PLoS ONE},
  number    = {1},
  doi       = {10.1371/journal.pone.0029959},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-133392},
  pages     = {e29959},
  year      = {2012},
  abstract  = {1,25-dihydroxyvitamin D3 (1,25D3) was reported to induce premature organismal aging in fibroblast growth factor-23 (Fgf23) and klotho deficient mice, which is of main interest as 1,25D3 supplementation of its precursor cholecalciferol is used in basic osteoporosis treatment. We wanted to know if 1,25D3 is able to modulate aging processes on a cellular level in human mesenchymal stem cells (hMSC). Effects of 100 nM 1,25D3 on hMSC were analyzed by cell proliferation and apoptosis assay, beta-galactosidase staining, VDR and surface marker immunocytochemistry, RT-PCR of 1,25D3-responsive, quiescence-and replicative senescence-associated genes. 1,25D3 treatment significantly inhibited hMSC proliferation and apoptosis after 72 h and delayed the development of replicative senescence in long-term cultures according to beta-galactosidase staining and P16 expression. Cell morphology changed from a fibroblast like appearance to broad and rounded shapes. Long term treatment did not induce lineage commitment in terms of osteogenic pathways but maintained their clonogenic capacity, their surface marker characteristics (expression of CD73, CD90, CD105) and their multipotency to develop towards the chondrogenic, adipogenic and osteogenic pathways. In conclusion, 1,25D3 delays replicative senescence in primary hMSC while the pro-aging effects seen in mouse models might mainly be due to elevated systemic phosphate levels, which propagate organismal aging.},
  language  = {en}
}
@article{ReichertvonRottkayRothetal.2018,
  author    = {Reichert, Johannes C. and von Rottkay, Eberhard and Roth, Franz and Renz, Tim and Hausmann, Johannes and Kranz, Julius and Rackwitz, Lars and N{\"o}th, Ulrich and Rudert, Maximilian},
  title     = {A prospective randomized comparison of the minimally invasive direct anterior and the transgluteal approach for primary total hip arthroplasty},
  series = {BMC Musculoskeletal Disorders},
  volume    = {19},
  journal   = {BMC Musculoskeletal Disorders},
  number    = {241},
  doi       = {10.1186/s12891-018-2133-4},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-176072},
  year      = {2018},
  abstract  = {Background: The presented prospective randomized controlled single-centre study compares the clinical outcome up to 12 months after total hip arthroplasty using a minimally invasive single-incision direct anterior (DAA) and a direct transgluteal lateral approach. Methods: A total of 123 arthroplasties were evaluated utilizing the Harris Hip Score (HHS), the extra short musculoskeletal functional assessment questionnaire (XSFMA), the Short Form 36 (SF-36) health survey, a Stepwatch™ Activity Monitor (SAM), and a timed 25 m foot walk (T25-FW). Postoperative x-ray images after THA were reviewed to determine inclination and stem positioning. Results: At final follow-up, the XSFMA functional index scores were 10.3 (anterior) and 15.08 (lateral) while the bother index summed up to a score of 15.8 (anterior) and 21.66 (lateral) respectively, thus only differing significantly for the functional index (p = 0.040 and p = 0.056). The SF-36 physical component score (PCS) was 47.49 (anterior) and 42.91 (lateral) while the mental component score (MCS) summed up to 55.0 (anterior) and 56.23 (lateral) with a significant difference evident for the PCS (p = 0.017; p = 0.714). Patients undergoing THA through a DAA undertook a mean of 6402 cycles per day while those who had undergone THA through a transgluteal approach undertook a mean of 5340 cycles per day (p = 0.012). Furthermore, the obtained outcome for the T25-FW with 18.4 s (anterior) and 19.75 s (lateral) and the maximum walking distance (5932 m and 5125 m) differed significantly (p = 0.046 and p = 0.045). The average HHS showed no significant difference equaling 92.4 points in the anterior group and 91.43 in the lateral group (p = 0.477). The radiographic analysis revealed an average cup inclination of 38.6° (anterior) and 40.28° (lateral) without signs of migration. Conclusion: In summary, our outcomes show that after 1 year THA through the direct anterior approach results in a higher patient activity compared to THA utilizing a transgluteal lateral approach while no differences regarding hip function are evident.},
  language  = {en}
}
@article{SeefriedMuellerDeubertSchwarzetal.2010,
  author    = {Seefried, Lothar and Mueller-Deubert, Sigrid and Schwarz, Thomas and Lind, Thomas and Mentrup, Birgit and Kober, Melanie and Docheva, Denitsa and Liedert, Astrid and Kassem, Moustapha and Ignatius, Anita and Schieker, Matthias and Claes, Lutz and Wilke, Winfried and Jakob, Franz and Ebert, Regina},
  title     = {A small scale cell culture system to analyze mechanobiology using reporter gene constructs and polyurethane dishes},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-68099},
  year      = {2010},
  abstract  = {Mechanical forces are translated into biochemical signals and contribute to cell differentiation and phenotype maintenance. Mesenchymal stem cells and their tissuespecific offspring, as osteoblasts and chondrocytes, cells of cardiovascular tissues and lung cells are sensitive to mechanical loading but molecules and mechanisms involved have to be unraveled. It is well established that cellular mechanotransduction is mediated e.g. by activation of the transcription factor SP1 and by kinase signaling cascades resulting in the activation of the AP1 complex. To investigate cellular mechanisms involved in mechanotransduction and to analyze substances, which modulate cellular mechanosensitivity reporter gene constructs, which can be transfected into cells of interest might be helpful. Suitable small-scale bioreactor systems and mechanosensitive reporter gene constructs are lacking. To analyze the molecular mechanisms of mechanotransduction and its crosstalk with biochemically induced signal transduction, AP1 and SP1 luciferase reporter gene constructs were cloned and transfected into various cell lines and primary cells. A newly developed bioreactor and small-scale 24-well polyurethane dishes were used to apply cyclic stretching to the transfected cells. 1 Hz cyclic stretching for 30 min in this system resulted in a significant stimulation of AP1 and SP1 mediated luciferase activity compared to unstimulated cells. In summary we describe a small-scale cell culture/bioreactor system capable of analyzing subcellular crosstalk mechanisms in mechanotransduction, mechanosensitivity of primary cells and of screening the activity of putative mechanosensitizers as new targets, e.g. for the treatment of bone loss caused by both disuse and signal transduction related alterations of mechanotransduction.},
  subject      = {Bioreaktor},
  language  = {en}
}
@article{NedopilDhaliwalHowelletal.2022,
  author    = {Nedopil, Alexander J. and Dhaliwal, Anand and Howell, Stephen M. and Hull, Maury L.},
  title     = {A surgeon that switched to unrestricted kinematic alignment with manual instruments has a short learning curve and comparable resection accuracy and outcomes to those of an experienced surgeon},
  series = {Journal of Personalized Medicine},
  volume    = {12},
  journal   = {Journal of Personalized Medicine},
  number    = {7},
  issn      = {2075-4426},
  doi       = {10.3390/jpm12071152},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-281842},
  year      = {2022},
  abstract  = {After starting an orthopedic practice, a surgeon with a fellowship in mechanically aligned (MA) TKA initiated this study to characterize their learning curve after they switched to unrestricted kinematic alignment (KA) TKA using manual instruments. Accordingly, the present study determined for the inexperienced (IE) surgeon the number of cases required to achieve consistent femoral resections and operating times, and whether the femoral resection accuracy, patient-reported outcome measures (PROMs), and component alignment were different from an experienced (E) surgeon. This prospective cohort study analyzed the IE surgeon's first 30 TKAs, all performed with KA, and 30 consecutive KA TKAs performed by an E surgeon. The resection accuracy or deviation was the calipered thickness of the distal and posterior medial and lateral femoral resections minus the planned resection thickness, which was the thickness of the corresponding condyle of the femoral component, minus 2 mm for cartilage wear, and 1 mm for the kerf of the blade. Independent observers recorded the femoral resection thickness, operative times, PROMs, and alignment. For each femoral resection, the deviation between three groups of patients containing ten consecutive KA TKAs, was either insignificant (p = 0.695 to 1.000) or within the 0.5 mm resolution of the caliper, which indicated no learning curve. More than three groups were needed to determine the learning curve for the operative time; however, the IE surgeon's procedure dropped to 77 min for the last 10 patients, which was 20 min longer than the E surgeon. The resection deviations of the IE and E surgeon were comparable, except for the posterolateral femoral resection, which the IE surgeon under-resected by a mean of -0.8 mm (p < 0.0001). At a mean follow-up of 9 and 17 months, the Forgotten Joint Score, Oxford Knee Score, KOOS, and the alignment of the components and limbs were not different between the IE and E surgeon (p ≥ 0.6994). A surgeon that switches to unrestricted KA with manual instruments can determine their learning curve by computing the deviation of the distal and posterior femoral resections from the planned resection. Based on the present study, an IE surgeon could have resection accuracy, post-operative patient outcomes, and component alignment comparable to an E surgeon.},
  language  = {en}
}
@article{ThibaudeauTaubenbergerHolzapfeletal.2014,
  author    = {Thibaudeau, Laure and Taubenberger, Anna V. and Holzapfel, Boris M. and Quent, Verena M. and Fuehrmann, Tobias and Hesami, Parisa and Brown, Toby D. and Dalton, Paul D. and Power, Carl A. and Hollier, Brett G. and Hutmacher, Dietmar W.},
  title     = {A tissue-engineered humanized xenograft model of human breast cancer metastasis to bone},
  series = {Disease Models \& Mechanisms},
  volume    = {7},
  journal   = {Disease Models \& Mechanisms},
  number    = {2},
  doi       = {10.1242/dmm.014076},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-117466},
  pages     = {299-309},
  year      = {2014},
  abstract  = {The skeleton is a preferred homing site for breast cancer metastasis. To date, treatment options for patients with bone metastases are mostly palliative and the disease is still incurable. Indeed, key mechanisms involved in breast cancer osteotropism are still only partially understood due to the lack of suitable animal models to mimic metastasis of human tumor cells to a human bone microenvironment. In the presented study, we investigate the use of a human tissue-engineered bone construct to develop a humanized xenograft model of breast cancer-induced bone metastasis in a murine host. Primary human osteoblastic cell-seeded melt electrospun scaffolds in combination with recombinant human bone morphogenetic protein 7 were implanted subcutaneously in non-obese diabetic/severe combined immunodeficient mice. The tissue-engineered constructs led to the formation of a morphologically intact 'organ' bone incorporating a high amount of mineralized tissue, live osteocytes and bone marrow spaces. The newly formed bone was largely humanized, as indicated by the incorporation of human bone cells and human-derived matrix proteins. After intracardiac injection, the dissemination of luciferase-expressing human breast cancer cell lines to the humanized bone ossicles was detected by bioluminescent imaging. Histological analysis revealed the presence of metastases with clear osteolysis in the newly formed bone. Thus, human tissue-engineered bone constructs can be applied efficiently as a target tissue for human breast cancer cells injected into the blood circulation and replicate the osteolytic phenotype associated with breast cancer-induced bone lesions. In conclusion, we have developed an appropriate model for investigation of species-specific mechanisms of human breast cancer-related bone metastasis in vivo.},
  language  = {en}
}
@article{NedopilHowellHull2022,
  author    = {Nedopil, Alexander J. and Howell, Stephen M. and Hull, Maury L.},
  title     = {A TKA insert with a lateral flat articular surface maximizes external and internal tibial orientations without anterior lift-off relative to low- and ultracongruent surfaces},
  series = {Journal of Personalized Medicine},
  volume    = {12},
  journal   = {Journal of Personalized Medicine},
  number    = {8},
  issn      = {2075-4426},
  doi       = {10.3390/jpm12081274},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-286142},
  year      = {2022},
  abstract  = {Background: In total knee arthroplasty (TKA), inserts can have different levels of medial and lateral congruency determined by the acuteness of the upslopes of the anterior and posterior articular surfaces. The present study evaluated an insert with different levels of lateral congruency and a medial ball-in-socket congruency to test the hypothesis that a lateral flat (F) insert maximizes external tibial orientation at extension and internal orientation at 90° flexion and lowers the incidence of anterior lift-off relative to low-congruent (LC) and ultracongruent (UC) lateral inserts. Methods: Two surgeons treated 23 patients with unrestricted caliper-verified kinematic alignment (KA) and posterior cruciate ligament (PCL) retention. They randomly trialed inserts with a medial radial dial that functioned as a built-in goniometer by measuring the tibial orientation relative to a sagittal line on the femoral trial component. Anterior lift-off of the insert from the baseplate indicated PCL tightness. Results: The F insert's mean of 9° of external tibial orientation was higher than that of the LC (5°, p < 0.0001) and UC inserts (2°, p < 0.0001). The -13° of internal tibial orientation at 90° flexion was higher than that of the LC (-9°, p < 0.0001) and UC inserts (-7°, p < 0.0001). The 0\% incidence of anterior lift-off was less than that of the LC (26\%) and UC inserts (57\%) (p < 0.0001). Conclusions: Surgeons and implant manufacturers should know that adding congruency to the lateral articular surface limits external tibial orientation in extension and internal tibial orientation at 90° flexion and overtightens the PCL. These rotational limitations and flexion space tightness can adversely affect patellofemoral tracking and knee flexion.},
  language  = {en}
}
@article{StaabHottowitzSohnsetal.2014,
  author    = {Staab, Wieland and Hottowitz, Ralf and Sohns, Christian and Sohns, Jan Martin and Gilbert, Fabian and Menke, Jan and Niklas, Andree and Lotz, Joachim},
  title     = {Accelerometer and Gyroscope Based Gait Analysis Using Spectral Analysis of Patients with Osteoarthritis of the Knee},
  series = {Journal of Physical Therapy Science},
  volume    = {26},
  journal   = {Journal of Physical Therapy Science},
  number    = {7},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-115907},
  pages     = {997-1002},
  year      = {2014},
  abstract  = {[Purpose] A wide variety of accelerometer tools are used to estimate human movement, but there are no adequate data relating to gait symmetry parameters in the context of knee osteoarthritis. This study's purpose was to evaluate a 3D-kinematic system using body-mounted sensors (gyroscopes and accelerometers) on the trunk and limbs. This is the first study to use spectral analysis for data post processing. [Subjects] Twelve patients with unilateral knee osteoarthritis (OA) (10 male) and seven age-matched controls (6 male) were studied. [Methods] Measurements with 3-D accelerometers and gyroscopes were compared to video analysis with marker positions tracked by a six-camera optoelectronic system (VICON 460, Oxford Metrics). Data were recorded using the 3D-kinematic system. [Results] The results of both gait analysis systems were significantly correlated. Five parameters were significantly different between the knee OA and control groups. To overcome time spent in expensive post-processing routines, spectral analysis was performed for fast differentiation between normal gait and pathological gait signals using the 3D-kinematic system. [Conclusions] The 3D-kinematic system is objective, inexpensive, accurate and portable, and allows long-term recordings in clinical, sport as well as ergonomic or functional capacity evaluation (FCE) settings. For fast post-processing, spectral analysis of the recorded data is recommended.},
  language  = {en}
}
@article{ArnholdtKamawalHorasetal.2020,
  author    = {Arnholdt, J{\"o}rg and Kamawal, Yama and Horas, Konstantin and Holzapfel, Boris M. and Gilbert, Fabian and Ripp, Axel and Rudert, Maximilian and Steinert, Andre F.},
  title     = {Accurate implant fit and leg alignment after cruciate-retaining patient-specific total knee arthroplasty},
  series = {BMC Musculoskeletal Disorders},
  volume    = {21},
  journal   = {BMC Musculoskeletal Disorders},
  doi       = {10.1186/s12891-020-03707-2},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-230012},
  year      = {2020},
  abstract  = {Background For improved outcomes in total knee arthroplasty (TKA) correct implant fitting and positioning are crucial. In order to facilitate a best possible implant fitting and positioning patient-specific systems have been developed. However, whether or not these systems allow for better implant fitting and positioning has yet to be elucidated. For this reason, the aim was to analyse the novel patient-specific cruciate retaining knee replacement system iTotal (TM) CR G2 that utilizes custom-made implants and instruments for its ability to facilitate accurate implant fitting and positioning including correction of the hip-knee-ankle angle (HKA). Methods We assessed radiographic results of 106 patients who were treated with the second generation of a patient-specific cruciate retaining knee arthroplasty using iTotal\(^{TM}\) CR G2 (ConforMIS Inc.) for tricompartmental knee osteoarthritis (OA) using custom-made implants and instruments. The implant fit and positioning as well as the correction of the mechanical axis (hip-knee-ankle angle, HKA) and restoration of the joint line were determined using pre- and postoperative radiographic analyses. Results On average, HKA was corrected from 174.4 degrees +/- 4.6 degrees preoperatively to 178.8 degrees +/- 2.2 degrees postoperatively and the coronal femoro-tibial angle was adjusted on average 4.4 degrees. The measured preoperative tibial slope was 5.3 degrees +/- 2.2 degrees (mean +/- SD) and the average postoperative tibial slope was 4.7 degrees +/- 1.1 degrees on lateral views. The joint line was well preserved with an average modified Insall-Salvati index of 1.66 +/- 0.16 pre- and 1.67 +/- 0.16 postoperatively. The overall accuracy of fit of implant components was decent with a measured medial overhang of more than 1 mm (1.33 mm +/- 0.32 mm) in 4 cases only. Further, a lateral overhang of more than 1 mm (1.8 mm +/- 0.63) (measured in the anterior-posterior radiographs) was observed in 11 cases, with none of the 106 patients showing femoral notching. Conclusion The patient-specific iTotal\(^{TM}\) CR G2 total knee replacement system facilitated a proper fitting and positioning of the implant components. Moreover, a good restoration of the leg axis towards neutral alignment was achieved as planned. Nonetheless, further clinical follow-up studies are necessary to validate our findings and to determine the long-term impact of using this patient- specific system.},
  language  = {en}
}
@article{HolzapfelProdingerPilgeetal.2013,
  author    = {Holzapfel, Boris Michael and Prodinger, Peter M. and Pilge, Hakan and Banke, Ingo J. and B{\"u}rklein, Dominik and Miethke, Thomas and Gradinger, Reiner},
  title     = {Acute Osteomyelitis of the Humerus mimicking Malignancy: Streptococcus pneumoniae as Exceptional Pathogen in an Immunocompetent Adult},
  series = {BMC Infectious Diseases},
  journal   = {BMC Infectious Diseases},
  doi       = {10.1186/1471-2334-13-266},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-95790},
  year      = {2013},
  abstract  = {Background Chronic osteomyelitis due to direct bone trauma or vascular insufficiency is a frequent problem in orthopaedic surgery. In contrast, acute haematogenous osteomyelitis represents a rare entity that almost exclusively affects prepubescent children or immunodeficient adults. Case Presentation In this article, we report the case of acute pneumococcal osteomyelitis of the humerus in an immunocompetent and otherwise healthy 44-year-old male patient presenting with minor inflammation signs and misleading clinical features. Conclusions The diagnosis had to be confirmed by open biopsy which allowed the initiation of a targeted therapy. A case of pneumococcal osteomyelitis of a long bone, lacking predisposing factors or trauma, is unique in adults and has not been reported previously.},
  language  = {en}
}
@article{EbertBenischKrugetal.2015,
  author    = {Ebert, Regina and Benisch, Peggy and Krug, Melanie and Zeck, Sabine and Meißner-Weigl, Jutta and Steinert, Andre and Rauner, Martina and Hofbauer, Lorenz and Jakob, Franz},
  title     = {Acute phase serum amyloid A induces proinflammatory cytokines and mineralization via toll-like receptor 4 in mesenchymal stem cells},
  series = {Stem Cell Research},
  volume    = {15},
  journal   = {Stem Cell Research},
  doi       = {10.1016/j.scr.2015.06.008},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-148491},
  pages     = {231-239},
  year      = {2015},
  abstract  = {The role of serum amyloid A (SAA) proteins, which are ligands for toll-like receptors, was analyzed in human bone marrow-derived mesenchymal stem cells (hMSCs) and their osteogenic offspring with a focus on senescence, differentiation andmineralization. In vitro aged hMSC developed a senescence-associated secretory phenotype (SASP), resulting in enhanced SAA1/2, TLR2/4 and proinflammatory cytokine (IL6, IL8, IL1\(\beta\), CXCL1, CXCL2) expression before entering replicative senescence. Recombinant human SAA1 (rhSAA1) induced SASP-related genes and proteins in MSC, which could be abolished by cotreatment with the TLR4-inhibitor CLI-095. The same pattern of SASP-resembling genes was stimulated upon induction of osteogenic differentiation, which is accompanied by autocrine SAA1/2 expression. In this context additional rhSAA1 enhanced the SASP-like phenotype, accelerated the proinflammatory phase of osteogenic differentiation and enhanced mineralization. Autocrine/paracrine and rhSAA1 via TLR4 stimulate a proinflammatory phenotype that is both part of the early phase of osteogenic differentiation and the development of senescence. This signaling cascade is tightly involved in bone formation and mineralization, but may also propagate pathological extraosseous calcification conditions such as calcifying inflammation and atherosclerosis.},
  language  = {en}
}
@article{HochleitnerJuengstBrownetal.2015,
  author    = {Hochleitner, Gernot and J{\"u}ngst, Tomasz and Brown, Toby D and Hahn, Kathrin and Moseke, Claus and Jakob, Franz and Dalton, Paul D and Groll, J{\"u}rgen},
  title     = {Additive manufacturing of scaffolds with sub-micron filaments via melt electrospinning writing},
  series = {Biofabrication},
  volume    = {7},
  journal   = {Biofabrication},
  number    = {3},
  doi       = {10.1088/1758-5090/7/3/035002},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-254053},
  year      = {2015},
  abstract  = {The aim of this study was to explore the lower resolution limits of an electrohydrodynamic process combined with direct writing technology of polymer melts. Termed melt electrospinning writing, filaments are deposited layer-by-layer to produce discrete three-dimensional scaffolds for in vitro research. Through optimization of the parameters (flow rate, spinneret diameter, voltage, collector distance) for poly-ϵ-caprolactone, we could direct-write coherent scaffolds with ultrafine filaments, the smallest being 817 ± 165 nm. These low diameter filaments were deposited to form box-structures with a periodicity of 100.6 ± 5.1 μm and a height of 80 μm (50 stacked filaments; 100 overlap at intersections). We also observed oriented crystalline regions within such ultrafine filaments after annealing at 55 °C. The scaffolds were printed upon NCO-sP(EO-stat-PO)-coated glass slide surfaces and withstood frequent liquid exchanges with negligible scaffold detachment for at least 10 days in vitro.},
  language  = {en}
}
@article{RudertHolzapfelJakubietz2011,
  author    = {Rudert, Maximilian and Holzapfel, Boris Michael and Jakubietz, Michael},
  title     = {Adjuvant Radiotherapy},
  series = {Deutsches {\"A}rzteblatt International},
  volume    = {108},
  journal   = {Deutsches {\"A}rzteblatt International},
  number    = {33},
  doi       = {10.3238/arztebl.2011.0553a},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-133571},
  pages     = {553},
  year      = {2011},
  abstract  = {No abstract available.},
  language  = {en}
}
@article{Trivanović2022,
  author    = {Trivanović, Drenka},
  title     = {Adult stem cells in aging},
  series = {Journal of Personalized Medicine},
  volume    = {12},
  journal   = {Journal of Personalized Medicine},
  number    = {5},
  issn      = {2075-4426},
  doi       = {10.3390/jpm12050795},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-275226},
  year      = {2022},
  abstract  = {No abstract available},
  language  = {en}
}
@article{HolzapfelRechlLehneretal.2011,
  author    = {Holzapfel, Boris Michael and Rechl, Hans and Lehner, Stefan and Pilge, Hakan and Gollwitzer, Hans and Steinhauser, Erwin},
  title     = {Alloplastic Reconstruction of the Extensor Mechanism after Resection of Tibial Sarcoma [Research Article]},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-69072},
  year      = {2011},
  abstract  = {Reconstruction of the extensor mechanism is essential for good extremity function after endoprosthetic knee replacement following tumor resection. Only a few biological methods have been able to reliably restore a functional extensor mechanism, but they are often associated with significant complication rates. Reattachment of the patellar tendon to the prosthesis using an alloplastic patellar ligament (Trevira cord) can be an appropriate alternative. In vivo and in vitro studies have already shown that complete fibrous ingrowth in polyethylene chords can be seen after a period of six months. However, until now, no biomechanical study has shown the efficacy of an alloplastic cord and its fixation device in providing sufficient stability and endurance in daily life-activity until newly formed scar tissue can take over this function. In a special test bench developed for this study, different loading regimes were applied to simulate loads during everyday life. Failure loads and failuremodes were evaluated. The properties of the cord were compared before and after physiological conditioning. It was shown that rubbing was the mode of failure under dynamic loading. Tensile forces up to 2558N did not result in material failure. Thus, using an artificial cord together with this fixation device, temporary sufficient stable fixation can be expected.},
  subject      = {Medizin},
  language  = {en}
}
@article{NedopilShekharHowelletal.2021,
  author    = {Nedopil, Alexander J. and Shekhar, Adithya and Howell, Stephen M. and Hull, Maury L.},
  title     = {An insert with less than spherical medial conformity causes a loss of passive internal rotation after calipered kinematically aligned TKA},
  series = {Archives of Orthopaedic and Trauma Surgery},
  volume    = {141},
  journal   = {Archives of Orthopaedic and Trauma Surgery},
  number    = {12},
  issn      = {1434-3916},
  doi       = {10.1007/s00402-021-04054-0},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-266710},
  pages     = {2287-2294},
  year      = {2021},
  abstract  = {Introduction In total knee arthroplasty (TKA), the level of conformity, a medial stabilized (MS) implant, needs to restore native (i.e., healthy) knee kinematics without over-tensioning the flexion space when the surgeon chooses to retain the posterior cruciate ligament (PCL) is unknown. Whether an insert with a medial ball-in-socket conformity and lateral flat surface like the native knee or a less than spherical medial conformity restores higher and closer to native internal tibial rotation without anterior lift-off, an over-tension indicator, when implanted with calipered kinematic alignment (KA), is unknown. Methods and Materials Two surgeons treated 21 patients with calipered KA and a PCL retaining MS implant. Validated verification checks that restore native tibial compartment forces in passive flexion without release of healthy ligaments were used to select the optimal insert thickness. A goniometer etched onto trial inserts with the ball-in-socket and the less than spherical medial conformity measured the tibial rotation relative to the femoral component at extension and 90° and 120° flexion. The surgeon recorded the incidence of anterior lift-off of the insert. Results The insert with the medial ball-in-socket and lateral flat surface restored more internal tibial rotation than the one with less than spherical medial conformity, with mean values of 19° vs. 17° from extension to 90° flexion (p < 0.01), and 23° vs. 20°-120° flexion (p < 0.002), respectively. There was no anterior lift-off of the insert at 90° and 120° flexion. Conclusion An MS insert with a medial ball-in-socket and lateral flat surface that matches the native knee's spherical conformity restores native tibial internal rotation when implanted with calipered KA and PCL retention without over-tensioning the flexion space.},
  language  = {en}
}
@article{PereiraTrivanovićHerrmann2019,
  author    = {Pereira, A. R. and Trivanović, D. and Herrmann, M.},
  title     = {Approaches to mimic the complexity of the skeletal mesenchymal stem/stromal cell niche in vitro},
  series = {European Cells and Materials},
  volume    = {37},
  journal   = {European Cells and Materials},
  issn      = {1473-2262},
  doi       = {10.22203/eCM.v037a07},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-268823},
  pages     = {88-112},
  year      = {2019},
  abstract  = {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.},
  language  = {en}
}
@article{StratosScarlatRudert2021,
  author    = {Stratos, Ioannis and Scarlat, Marius M. and Rudert, Maximilian},
  title     = {Bibliometrics of orthopaedic articles published by authors of Germanophone countries},
  series = {International Orthopaedics},
  volume    = {45},
  journal   = {International Orthopaedics},
  number    = {5},
  doi       = {10.1007/s00264-021-05052-y},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-266343},
  pages     = {1121-1124},
  year      = {2021},
  abstract  = {No abstract available.},
  language  = {en}
}
@article{RamirezRodriguezPereiraHerrmannetal.2021,
  author    = {Ram{\´i}rez-Rodr{\´i}guez, Gloria Bel{\´e}n and Pereira, Ana Rita and Herrmann, Marietta and Hansmann, Jan and Delgado-L{\´o}pez, Jos{\´e} Manuel and Sprio, Simone and Tampieri, Anna and Sandri, Monica},
  title     = {Biomimetic mineralization promotes viability and differentiation of human mesenchymal stem cells in a perfusion bioreactor},
  series = {International Journal of Molecular Sciences},
  volume    = {22},
  journal   = {International Journal of Molecular Sciences},
  number    = {3},
  issn      = {1422-0067},
  doi       = {10.3390/ijms22031447},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-285804},
  year      = {2021},
  abstract  = {In bone tissue engineering, the design of 3D systems capable of recreating composition, architecture and micromechanical environment of the native extracellular matrix (ECM) is still a challenge. While perfusion bioreactors have been proposed as potential tool to apply biomechanical stimuli, its use has been limited to a low number of biomaterials. In this work, we propose the culture of human mesenchymal stem cells (hMSC) in biomimetic mineralized recombinant collagen scaffolds with a perfusion bioreactor to simultaneously provide biochemical and biophysical cues guiding stem cell fate. The scaffolds were fabricated by mineralization of recombinant collagen in the presence of magnesium (RCP.MgAp). The organic matrix was homogeneously mineralized with apatite nanocrystals, similar in composition to those found in bone. X-Ray microtomography images revealed isotropic porous structure with optimum porosity for cell ingrowth. In fact, an optimal cell repopulation through the entire scaffolds was obtained after 1 day of dynamic seeding in the bioreactor. Remarkably, RCP.MgAp scaffolds exhibited higher cell viability and a clear trend of up-regulation of osteogenic genes than control (non-mineralized) scaffolds. Results demonstrate the potential of the combination of biomimetic mineralization of recombinant collagen in presence of magnesium and dynamic culture of hMSC as a promising strategy to closely mimic bone ECM.},
  language  = {en}
}
@article{PrasseStratosNiehoffetal.2022,
  author    = {Prasse, Tobias and Stratos, Ioannis and Niehoff, Anja and Christ, Hildegard and Heck, Vincent and Meyer, Carolin and Mittlmeier, Thomas},
  title     = {Bisphenol A-related effects on bone morphology and biomechanical properties in an animal model},
  series = {Toxics},
  volume    = {10},
  journal   = {Toxics},
  number    = {2},
  issn      = {2305-6304},
  doi       = {10.3390/toxics10020086},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-262216},
  year      = {2022},
  abstract  = {Bisphenol A (BPA), which is contained in numerous plastic products, is known to act as an endocrine-disruptive, toxic, and carcinogenic chemical. This experimental series sought to determine the influence of BPA exposure on the femoral bone architecture and biomechanical properties of male and female Wistar rats. BPA was applied subcutaneously by using osmotic pumps. After 12 weeks, the bones were analyzed by micro-computed tomography (micro-CT) and a three-point bending test. Comparing the female low- and high-dose groups, a significantly greater marrow area (p = 0.047) was identified in the group exposed to a higher BPA concentration. In addition, the trabecular number tended to be higher in the female high-dose group when compared to the low-dose group (p > 0.05). The area moment of inertia also tended to be higher in the male high-dose group when compared to the male low-dose group (p > 0.05). Considering our results, BPA-related effects on the bone morphology in female Wistar rats are osteoanabolic after high-dose exposure, while, in male rats, a tendency toward negative effects on the bone morphology in terms of a reduced cross-sectional cortical area and total area could be demonstrated.},
  language  = {en}
}