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Pförringer D, Braun KF, Mühlhofer H, Schneider J, Stemberger A, Seifried E, Pohlscheidt E, Seidel M, Edenharter G, Duscher D, Burgkart R, Obermeier A. Novel method for reduction of virus load in blood plasma by sonication. Eur J Med Res 2020; 25:12. [PMID: 32264953 PMCID: PMC7137245 DOI: 10.1186/s40001-020-00410-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 03/25/2020] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Aim of the present study is the evaluation of ultrasound as a physical method for virus inactivation in human plasma products prior to transfusion. Our study is focused on achieving a high level of virus inactivation simultaneously leaving blood products unaltered, measured by the level of degradation of coagulation factors, especially in third world countries where virus contamination of blood products poses a major problem. Virus inactivation plays an important role, especially in the light of newly discovered or unknown viruses, which cannot be safely excluded via prior testing. METHODS Taking into account the necessary protection of the relevant coagulation activity for plasma, the basis for a sterile virus inactivation under shielding gas insufflation was developed for future practical use. Influence of frequency and power density in the range of soft and hard cavitation on the inactivation of transfusion-relevant model viruses for Hepatitis-(BVDV = bovine diarrhea virus), for Herpes-(SFV = Semliki Forest virus, PRV = pseudorabies virus) and Parvovirus B19 (PPV = porcine parvovirus) were examined. Coagulation activity was examined via standard time parameters to minimize reduction of functionality of coagulation proteins. A fragmentation of coagulation proteins via ultrasound was ruled out via gel electrophoresis. The resulting virus titer was examined using end point titration. RESULTS Through CO2 shielding gas insufflation-to avoid radical emergence effects-the coagulation activity was less affected and the time window for virus inactivation substantially widened. In case of the non-lipidated model virus (AdV-luc = luciferase expressing adenoviral vector), the complete destruction of the virus capsid through hard cavitation was proven via scanning electron microscopy (SEM). This can be traced back to microjets and shockwaves occurring in hard cavitation. The degree of inactivation seems to depend on size and compactness of the type of viruses. Using our pre-tested and subsequently chosen process parameters with the exception of the small PPV, all model viruses were successfully inactivated and reduced by up to log 3 factor. For a broad clinical usage, protection of the coagulation activities may require further optimization. CONCLUSIONS Building upon the information gained, an optimum inactivation can be reached via raising of power density up to 1200 W and simultaneous lowering of frequency down to 27 kHz. In addition, the combination of the two physical methods UV treatment and ultrasound may yield optimum results without the need of substance removal after the procedure.
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Affiliation(s)
- D Pförringer
- Klinikum rechts der Isar der Technischen Universität München, Klinik und Poliklinik für Unfallchirurgie, Ismaninger Str. 22, 81675, Munich, Germany.
| | - K F Braun
- Klinikum rechts der Isar der Technischen Universität München, Klinik und Poliklinik für Unfallchirurgie, Ismaninger Str. 22, 81675, Munich, Germany.,Charite, Universitätsmedizin Berlin, Unfallchirurgie, Zentrum für Muskuloskeletale Chirurgie, Berlin, Germany
| | - H Mühlhofer
- Klinikum rechts der Isar der Technischen Universität München, Klinik für Orthopädie und Sportorthopädie, Ismaninger Str. 22, 81675, Munich, Germany
| | - J Schneider
- II. Medizinische Klinik und Poliklinik, Klinikum rechts der Isar der Technischen Universität München, Ismaninger Str. 22, 81675, Munich, Germany
| | - A Stemberger
- Klinikum rechts der Isar der Technischen Universität München, Klinik für Orthopädie und Sportorthopädie, Ismaninger Str. 22, 81675, Munich, Germany
| | - E Seifried
- DRK-Blutspendedienst, Institut für Transfusionsmedizin und Immunhämatologie, Sandhofstrasse 1, 60528, Frankfurt, Germany
| | - E Pohlscheidt
- Klinikum rechts der Isar der Technischen Universität München, Klinik für Orthopädie und Sportorthopädie, Ismaninger Str. 22, 81675, Munich, Germany
| | - M Seidel
- Institut für Wasserchemie & Chemische Balneologie, Lehrstuhl für Analytische Chemie und Wasserchemie, Technische Universität München, Marchioninistr. 17, 81377, Munich, Germany
| | - G Edenharter
- Klinikum rechts der Isar der Technischen Universität München, Klinik für Anästhesie, Munich, Germany
| | - D Duscher
- Klinikum rechts der Isar der Technischen Universität München, Klinik für Plastische Chirurgie, Ismaninger Str. 22, 81675, Munich, Germany
| | - R Burgkart
- Klinikum rechts der Isar der Technischen Universität München, Klinik für Orthopädie und Sportorthopädie, Ismaninger Str. 22, 81675, Munich, Germany
| | - A Obermeier
- Klinikum rechts der Isar der Technischen Universität München, Klinik für Orthopädie und Sportorthopädie, Ismaninger Str. 22, 81675, Munich, Germany
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Marchi G, Foehr P, Baier V, Kinne RW, Burgkart R, Roths J. Discrimination between healthy and degenerated bovine articular cartilage with a fiber Bragg grating based microindenter. J Mech Behav Biomed Mater 2019; 99:11-17. [PMID: 31323532 DOI: 10.1016/j.jmbbm.2019.07.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 07/08/2019] [Accepted: 07/08/2019] [Indexed: 10/26/2022]
Abstract
OBJECTIVE In this study we aim to show that an optical fiber Bragg grating-based microindentation system, which has the potential to be deployed arthroscopically, can differentiate between healthy and degenerated articular cartilage, which represents an important challenge in minimally-invasive surgery. DESIGN Twenty bovine osteochondral cylinders, extracted from the patellar groove of ten 24 months old animals were subjected to stepwise in vitro stress-relaxation indentation measurements. The indentation procedure comprised 15 indentation steps of 20 μm each, reaching a total depth of 300 μm. Ten samples remained untreated and served as a control group for healthy cartilage. A second group of ten samples was treated for 12 h with an aqueous trypsin solution (concentration 2.5%) to deplete the proteoglycans. For both groups and all indentation depths deeper than 100 μm, the step response functions of a two elements Maxwell-Wiechert model fitted well to the measured relaxation curves. RESULTS The standard deviations of the identified stiffness parameters within each group were much smaller than the difference of the average stiffness values between both groups. Based on the measured stiffness values, the system was capable to discriminate between healthy and degenerated cartilage with a high level of significance (p < 0.001). The experimental results are also discussed in terms of the biomechanical changes of cartilage under the action of trypsin. CONCLUSION The fiber Bragg grating microindentation system showed the capability to differentiate intact and proteoglycan depleted cartilage with high significance.
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Affiliation(s)
- G Marchi
- Munich University of Applied Sciences, Photonics Laboratory, Lothstr. 34, Munich, 80335, Germany.
| | - P Foehr
- Department of Orthopaedics and Sports Orthopaedics, Klinikum Rechts der Isar, Technical University of Munich, Ismaninger Str. 22, Munich, 81675, Germany.
| | - V Baier
- Munich University of Applied Sciences, Photonics Laboratory, Lothstr. 34, Munich, 80335, Germany.
| | - R W Kinne
- Experimental Rheumatology Unit, Department of Orthopaedics, Jena University Hospital, Waldkrankenhaus "Rudolf Elle", Klosterlausnitzer Str. 81, Eisenberg, 07607, Germany.
| | - R Burgkart
- Department of Orthopaedics and Sports Orthopaedics, Klinikum Rechts der Isar, Technical University of Munich, Ismaninger Str. 22, Munich, 81675, Germany.
| | - J Roths
- Munich University of Applied Sciences, Photonics Laboratory, Lothstr. 34, Munich, 80335, Germany.
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Marchi G, Foehr P, Consalvo S, Javadzadeh-Kalarhodi A, Lang J, Hartmann B, Alberton P, Aszodi A, Burgkart R, Roths J. Fiberoptic microindentation technique for early osteoarthritis diagnosis: an in vitro study on human cartilage. Biomed Microdevices 2019; 21:11. [DOI: 10.1007/s10544-019-0359-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Abstract
Aims Asphericity of the femoral head-neck junction is common in cam-type femoroacetabular impingement (FAI) and usually quantified using the alpha angle on radiographs or MRI. The aim of this study was to determine the natural alpha angle in a large cohort of patients by continuous circumferential analysis with CT. Methods CT scans of 1312 femurs of 656 patients were analyzed in this cross-sectional study. There were 362 men and 294 women. Their mean age was 61.2 years (18 to 93). All scans had been performed for reasons other than hip disease. Digital circumferential analysis allowed continuous determination of the alpha angle around the entire head-neck junction. All statistical tests were conducted two-sided; a p-value < 0.05 was considered statistically significant. Results The mean maximum alpha angle for the cohort was 59.0° (sd 9.4). The maximum was located anterosuperiorly at 01:36 on the clock face, with two additional maxima of asphericity at the posterior and inferior head-neck junction. The mean alpha angle was significantly larger in men (59.4°, sd 8.0) compared with women (53.5°, sd 7.4°; p = 0.0005), and in Caucasians (60.7°, sd 9.0°) compared with Africans (56.3°, sd 8.0; p = 0.007) and Asians (50.8°, sd 7.2; p = 0.0005). The alpha angle showed a weak positive correlation with age (p < 0.05). If measured at commonly used planes of the radially reconstructed CT or MRI, the alpha angle was largely underestimated; measurement at the 01:30 and 02:00 positions showed a mean underestimation of 4° and 6°, respectively. Conclusion This study provides important data on the normal alpha angle dependent on age, gender, and ethnic origin. The normal alpha angle in men is > 55°, and this should be borne in mind when making a diagnosis of cam-type morphology. Cite this article: Bone Joint J 2018;100-B:570–8.
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Affiliation(s)
- H. Gollwitzer
- ECOM – Excellent Center of Medicine and
ATOS - Clinic, Munich, Germany
| | - C. Suren
- Clinic and Polyclinic for Orthopaedics
and Sports Orthopaedics, Rechts der Isar Hospital, The Technical
University of Munich
| | | | - H. Gottschling
- Clinic and Polyclinic for Orthopaedics
and Sports Orthopaedics, Rechts der Isar Hospital, The Technical
University of Munich
| | - M. Schröder
- Clinic and Polyclinic for Orthopaedics
and Sports Orthopaedics, Rechts der Isar Hospital, The Technical
University of Munich
| | - L. Gerdesmeyer
- Department of Orthopaedics and Traumatology,
Universitätsklinikum Schleswig-Holstein, Kiel, Germany
| | - P. M. Prodinger
- Clinic and Polyclinic for Orthopaedics
and Sports Orthopaedics, Rechts der Isar Hospital, The Technical
University of Munich
| | - R. Burgkart
- Clinic and Polyclinic for Orthopaedics
and Sports Orthopaedics, Rechts der Isar Hospital, The Technical
University of Munich
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Suren C, Burgkart R, Banke IJ, Hertel G, Schauwecker J, von Eisenhart-Rothe R, Gollwitzer H. [Surgical therapy of ischiofemoral impingement by lateralizing intertrochanteric osteotomy]. Oper Orthop Traumatol 2018; 30:98-110. [PMID: 29589046 DOI: 10.1007/s00064-018-0540-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 12/16/2017] [Accepted: 12/19/2017] [Indexed: 01/28/2023]
Abstract
OBJECTIVE Lateralizing, derotating intertrochanteric varus osteotomy to increase the ischiofemoral space to counter painful impingement of the lesser trochanter and the os ischium with resulting entrapment of quadratus femoris muscle. INDICATIONS Symptomatic ischiofemoral impingement (IFI) caused by Coxa valga et antetorta, Coxa valga or Coxa antetorta, or a short femoral neck. CONTRAINDICATIONS Anatomic configuration suggestive of IFI in asymptomatic patients. Symptomatic IFI caused by another underlying pathology. Valgus deformity of the knee. SURGICAL TECHNIQUE Measurement of femoral antetorsion. Planning of the osteotomy, lateralization, varus angle for correction, rotation and offset correction, leg length change, and osteosynthesis plate. General or spinal anesthesia in supine or lateral position. Skin incision (15 cm) beginning lateral of the greater trochanter tip, distally along the axis of the femur. Preparation onto the femur by L‑shaped dissection of the vastus lateralis from the bone. A Kirschner(K-)wire is then positioned along the anterior femoral neck to designate the femoral neck antetorsion. A triangle set on the lateral femoral cortexis is used to determine the osteotomy angle. In the thus determined angle, a second K‑wire is shot centrally along the femoral neck axis just inferior to its cranial cortex. About 5 mm distal to the second wire, the entry for the blade is prepared using a drill. Using the blade setting instrument, the blade is introduced into the femoral neck, then slightly pulled back. The rotation is then marked on the anterior femoral cortex proximal and distal to the planned osteotomy and the osteotomy is performed. A blade plate without displacement is impacted. The osteotomy is then reduced, the distal fragment pulled laterally onto the plate, and the screws inserted after compression of the osteotomy with a tension device. POSTOPERATIVE MANAGEMENT Touch-toe bearing for 6 weeks, then radiological assessment of osteotomy healing before an increase in weight bearing (15 kg/week). Hip flexion limited to 90° for 6 weeks. Elective implant removal after 12-18 months. RESULTS Studies of this lateralizing varus osteotomy have not been published. The 25-year results of the conventional derotating intertrochanteric varus osteotomy technique show good functional results and low complication rates, with non-union being the most common. Arthroscopic resection of the lesser trochanter has been reported as a surgical alternative in the treatment of IFI in case reports and small series. Advantages of the osteotomy are the restoration of biomechanics and preservation of iliopsoas tendon insertion.
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Affiliation(s)
- C Suren
- Klinik und Poliklinik für Orthopädie und Sportorthopädie, Klinikum rechts der Isar, Technische Universität München, München, Deutschland
| | - R Burgkart
- Klinik und Poliklinik für Orthopädie und Sportorthopädie, Klinikum rechts der Isar, Technische Universität München, München, Deutschland
| | - I J Banke
- Klinik und Poliklinik für Orthopädie und Sportorthopädie, Klinikum rechts der Isar, Technische Universität München, München, Deutschland
| | - G Hertel
- Klinik und Poliklinik für Orthopädie und Sportorthopädie, Klinikum rechts der Isar, Technische Universität München, München, Deutschland
| | - J Schauwecker
- Klinik und Poliklinik für Orthopädie und Sportorthopädie, Klinikum rechts der Isar, Technische Universität München, München, Deutschland
| | - R von Eisenhart-Rothe
- Klinik und Poliklinik für Orthopädie und Sportorthopädie, Klinikum rechts der Isar, Technische Universität München, München, Deutschland
| | - H Gollwitzer
- ECOM - Excellent Center of Medicine, Arabellastr. 17, 81925, München, Deutschland. .,Chirurgische Klinik, München-Bogenhausen, Deutschland. .,ATOS Klinik München, München, Deutschland.
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Pförringer D, Harrasser N, Mühlhofer H, Kiokekli M, Stemberger A, van Griensven M, Lucke M, Burgkart R, Obermeier A. Osteoinduction and -conduction through absorbable bone substitute materials based on calcium sulfate: in vivo biological behavior in a rabbit model. J Mater Sci Mater Med 2018; 29:17. [PMID: 29318379 DOI: 10.1007/s10856-017-6017-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2017] [Accepted: 12/05/2017] [Indexed: 06/07/2023]
Abstract
Calcium sulfate (CS) can be used as an antibiotically impregnated bone substitute in a variety of clinical constellations. Antibiotically loaded bone substitutes find specific application in orthopedic and trauma surgery to prevent or treat bone infections especially in relation to open bone defects. However, its use as a structural bone graft reveals some concerns due to its fast biodegradation. The addition of calcium carbonate and tripalmitin makes CS formulations more resistant to resorption leaving bone time to form during a prolonged degradation process. The aim of the present study was the evaluation of biocompatibility and degradation properties of newly formulated antibiotically impregnated CS preparations. Three different types of CS bone substitute beads were implanted into the tibial metaphysis of rabbits (CS dihydrate with tripalmitin, containing gentamicin (Group A) or vancomycin (Group B); Group C: tobramycin-loaded CS hemihydrate). Examinations were performed by means of x-ray, micro-computed tomography (micro-CT) and histology after 4, 6, 8 and 12 weeks. Regarding biocompatibility of the formulations, no adverse reactions were observed. Histology showed formation of vital bone cells attached directly to the implanted materials, while no cytotoxic effect in the surrounding of the beads was detected. All CS preparations showed osteogenesis associated to implanted material. Osteoblasts attached directly to the implant surface and revealed osteoid production, osteocytes were found in newly mineralized bone. Group C implants (Osteoset®) were subject to quick degradation within 4 weeks, after 6-8 weeks there were only minor remnants with little osteogenesis demonstrated by histological investigations. Group A implants (Herafill®-G) revealed similar degradation within atleast 12 weeks. In contrast, group B implants (CaSO4-V) were still detectable after 12 weeks with the presence of implant-associated osteogenesis atlatest follow-up. In all of these preparations, giant cells were found during implant degradation on surface and inside of resorption lacunae. None of the analyzed CS preparations triggered contact activation. All implants demonstrated excellent biocompatibility, with implants of Group A and B showing excellent features as osteoconductive and -inductive scaffolds able to improve mechanical stability.
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Affiliation(s)
- D Pförringer
- Klinikum rechts der Isar der Technischen Universität München, Klinik und Poliklinik für Unfallchirurgie, München, Germany.
| | - N Harrasser
- Klinikum rechts der Isar der Technischen Universität München, Klinik für Orthopädie und Sportorthopädie, München, Germany
| | - H Mühlhofer
- Klinikum rechts der Isar der Technischen Universität München, Klinik für Orthopädie und Sportorthopädie, München, Germany
| | - M Kiokekli
- Klinikum rechts der Isar der Technischen Universität München, Klinik für Orthopädie und Sportorthopädie, München, Germany
| | - A Stemberger
- Klinikum rechts der Isar der Technischen Universität München, Klinik für Orthopädie und Sportorthopädie, München, Germany
| | - M van Griensven
- Klinikum rechts der Isar der Technischen Universität München, Klinik und Poliklinik für Unfallchirurgie, München, Germany
| | - M Lucke
- Chirurgisches Klinikum München Süd, München, Germany
| | - R Burgkart
- Klinikum rechts der Isar der Technischen Universität München, Klinik für Orthopädie und Sportorthopädie, München, Germany
| | - A Obermeier
- Klinikum rechts der Isar der Technischen Universität München, Klinik für Orthopädie und Sportorthopädie, München, Germany
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Schmitt A, Csiki R, Tron A, Saldamli B, Tübel J, Florian K, Siebenlist S, Balmayor E, Burgkart R. Optimized protocol for whole organ decellularization. Eur J Med Res 2017; 22:31. [PMID: 28886732 PMCID: PMC5591503 DOI: 10.1186/s40001-017-0272-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 08/29/2017] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND The idea of tissue decellularization to gain matrices for tissue engineering is promising. The aim of the present study is to establish a safe and reproducible protocol for solid tissue decellularization that prevents the architecture of the matrix with the inherent vascular network. METHODS The study was performed in rat kidneys which were decellularized by a SDS-based perfusion protocol. Perfusion time and SDS concentration were systematically changed to obtain the shortest and most gentle protocol that leads to complete decellularization. RESULTS We investigated kinetics of protein elution, decellularization success, and remaining cell toxicity. This resulted in a reproducible protocol, leading to safe decellularization with prevention of the inherent vascular network, without remaining detectable cell toxicity. The established protocol leads to solid tissue decellularization in only 7 h, which is by far shorter than the previously published methods. CONCLUSION The established technique has the potential to become a relevant platform technology for tissue engineering of solid tissues. It provides a solution for the yet-unsolved problem of vascularization.
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Affiliation(s)
- A Schmitt
- Department of Sports Orthopedics, Klinikum rechts der Isar der Technischen Universität München, Munich, Germany.
| | - R Csiki
- Department of Orthopedics, Klinikum rechts der Isar der Technischen Universität München, Munich, Germany
| | - A Tron
- Department of Orthopedics, Klinikum rechts der Isar der Technischen Universität München, Munich, Germany
| | - B Saldamli
- Department of Orthopedics, Klinikum rechts der Isar der Technischen Universität München, Munich, Germany
| | - J Tübel
- Department of Orthopedics, Klinikum rechts der Isar der Technischen Universität München, Munich, Germany
| | - K Florian
- Department of Orthopedics, Klinikum rechts der Isar der Technischen Universität München, Munich, Germany
| | - S Siebenlist
- Department of Orthopedics, Klinikum rechts der Isar der Technischen Universität München, Munich, Germany
| | - E Balmayor
- Department of Experimental Traumatology, Klinikum rechts der Isar der Technischen Universität München, Munich, Germany
| | - R Burgkart
- Department of Orthopedics, Klinikum rechts der Isar der Technischen Universität München, Munich, Germany
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Rossetti L, Kuntz LA, Kunold E, Schock J, Müller KW, Grabmayr H, Stolberg-Stolberg J, Pfeiffer F, Sieber SA, Burgkart R, Bausch AR. The microstructure and micromechanics of the tendon-bone insertion. Nat Mater 2017; 16:664-670. [PMID: 28250445 DOI: 10.1038/nmat4863] [Citation(s) in RCA: 168] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 01/17/2017] [Indexed: 05/28/2023]
Abstract
The exceptional mechanical properties of the load-bearing connection of tendon to bone rely on an intricate interplay of its biomolecular composition, microstructure and micromechanics. Here we identify that the Achilles tendon-bone insertion is characterized by an interface region of ∼500 μm with a distinct fibre organization and biomolecular composition. Within this region, we identify a heterogeneous mechanical response by micromechanical testing coupled with multiscale confocal microscopy. This leads to localized strains that can be larger than the remotely applied strain. The subset of fibres that sustain the majority of loading in the interface area changes with the angle of force application. Proteomic analysis detects enrichment of 22 proteins in the interfacial region that are predominantly involved in cartilage and skeletal development as well as proteoglycan metabolism. The presented mechanisms mark a guideline for further biomimetic strategies to rationally design hard-soft interfaces.
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Affiliation(s)
- L Rossetti
- Lehrstuhl für Zellbiophysik, Technische Universität München, D-85748 Garching, Germany
| | - L A Kuntz
- Lehrstuhl für Zellbiophysik, Technische Universität München, D-85748 Garching, Germany
- Klinik für Orthopädie und Sportorthopädie, Klinikum rechts der Isar, Technische Universität München, D-81675 München, Germany
| | - E Kunold
- Center for Integrated Protein Science (CIPSM), Department of Chemistry, Technische Universität München, D-85747 Garching, Germany
| | - J Schock
- Lehrstuhl für Biomedizinische Physik, Physik-Department &Institut für Medizintechnik, Technische Universität München, D-85748 Garching, Germany
| | - K W Müller
- Institute for Computational Mechanics, Technische Universität München, D-85748 Garching, Germany
- Structural and Applied Mechanics Group, Computational Engineering Division, Lawrence Livermore National Laboratory, 7000 East Ave, Livermore, California 94550, USA
| | - H Grabmayr
- Lehrstuhl für Zellbiophysik, Technische Universität München, D-85748 Garching, Germany
- Department of Physics and Center for Nanoscience, Ludwig Maximilian University, D-80539 Munich, Germany
| | - J Stolberg-Stolberg
- Klinik für Orthopädie und Sportorthopädie, Klinikum rechts der Isar, Technische Universität München, D-81675 München, Germany
- University Hospital Münster, Department of Trauma-, Hand- and Reconstructive Surgery, Albert-Schweitzer-Campus 1, Building W1, D-48149 Münster, Germany
| | - F Pfeiffer
- Lehrstuhl für Biomedizinische Physik, Physik-Department &Institut für Medizintechnik, Technische Universität München, D-85748 Garching, Germany
- Institut für diagnostische und interventionelle Radiologie, Klinikum rechts der Isar, Technische Universität München, D-81675 München, Germany
| | - S A Sieber
- Center for Integrated Protein Science (CIPSM), Department of Chemistry, Technische Universität München, D-85747 Garching, Germany
| | - R Burgkart
- Klinik für Orthopädie und Sportorthopädie, Klinikum rechts der Isar, Technische Universität München, D-81675 München, Germany
| | - A R Bausch
- Lehrstuhl für Zellbiophysik, Technische Universität München, D-85748 Garching, Germany
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Postl LK, Ahrens P, Beirer M, Crönlein M, Imhoff AB, Foehr P, Burgkart R, Braun C, Kirchhoff C. Pull-out stability of anchors for rotator cuff repair is also increased by bio-absorbable augmentation: a cadaver study. Arch Orthop Trauma Surg 2016; 136:1153-8. [PMID: 27290655 DOI: 10.1007/s00402-016-2484-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Indexed: 11/29/2022]
Abstract
INTRODUCTION Osteoporosis is a highly focused issue in current scientific research and clinical treatment. Especially in rotator cuff repair, the low bone quality of patients suffering from osteoporosis is an important issue. In this context, non-biological solutions using PMMA for anchor augmentation have been developed in the recent past. The aim of this study was to evaluate whether augmentation of suture anchors using bio-absorbable osteoconductive fiber-reinforced calcium phosphate results in improved failure load of suture anchors as well. MATERIALS AND METHODS Altogether 24 suture anchors (Corkscrew FT 1 Suture Anchors, Arthrex, Naples, FL, USA) were evaluated by applying traction until pullout in 12 paired fresh frozen human cadaver humeri using a servo-hydraulic testing machine. Inclusion criteria were an age of more than 64 years, a macroscopically intact RC and an intact bone. The anchors were evaluated at the anterolateral and posteromedial aspect of the greater tuberosity. 12 suture anchors were augmented and 12 suture anchors were conventionally inserted. RESULTS The failure load was significantly enhanced by 66.8 % by the augmentation method. The fiber-reinforced calcium phosphate could be easily injected and applied. CONCLUSION The bio-absorbable cement in this study could be a promising augmentation material for RC reconstructions, but further research is necessary-the material has to be evaluated in vivo.
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Affiliation(s)
- L K Postl
- Department of Trauma Surgery, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Str. 22, 81675, Munich, Germany
| | - P Ahrens
- Department of Trauma Surgery, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Str. 22, 81675, Munich, Germany
| | - M Beirer
- Department of Trauma Surgery, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Str. 22, 81675, Munich, Germany
| | - M Crönlein
- Department of Trauma Surgery, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Str. 22, 81675, Munich, Germany
| | - A B Imhoff
- Department of Orthopedics and Sportorthopedics, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Str. 22, 81675, Munich, Germany
| | - P Foehr
- Department of Orthopedics and Sportorthopedics, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Str. 22, 81675, Munich, Germany
| | - R Burgkart
- Department of Orthopedics and Sportorthopedics, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Str. 22, 81675, Munich, Germany
| | - C Braun
- Department of Forensic Medicine, Ludwig-Maximilians-Universitaet, Campus Innenstadt, Nussbaumstrasse 26, 80336, Munich, Germany
| | - Chlodwig Kirchhoff
- Department of Trauma Surgery, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Str. 22, 81675, Munich, Germany.
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Boettcher K, Kienle S, Nachtsheim J, Burgkart R, Hugel T, Lieleg O. The structure and mechanical properties of articular cartilage are highly resilient towards transient dehydration. Acta Biomater 2016; 29:180-187. [PMID: 26432435 DOI: 10.1016/j.actbio.2015.09.034] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 09/07/2015] [Accepted: 09/28/2015] [Indexed: 11/26/2022]
Abstract
Articular cartilage is a mechanically highly challenged material with very limited regenerative ability. In contrast to elastic cartilage, articular cartilage is exposed to recurring partial dehydration owing to ongoing compression but maintains its functionality over decades. To extend our current understanding of the material properties of articular cartilage, specifically the interaction between the fluid and solid phase, we here analyze the reversibility of tissue dehydration. We perform an artificial dehydration that extends beyond naturally occurring levels and quantify material recovery as a function of the ionic strength of the rehydration buffer. Mechanical (indentation, compression, shear, and friction) measurements are used to evaluate the influence of de- and rehydration on the viscoelastic properties of cartilage. The structure and composition of native and de/rehydrated cartilage are analyzed using histology, scanning electron microscopy, and atomic force microscopy along with a 1,9-dimethylmethylene blue (DMMB) assay. A broad range of mechanical and structural properties of cartilage can be restored after de- and rehydration provided that a physiological salt solution is used for rehydration. We detect only minor alterations in the microarchitecture of rehydrated cartilage in the superficial zone and find that these alterations do not interfere with the viscoelastic and tribological properties of the tissue. STATEMENT OF SIGNIFICANCE We here demonstrate the sturdiness of articular cartilage towards changes in fluid content and show that articular cartilage recovers a broad range of its material properties after dehydration. We analyze the reversibility of tissue dehydration to extend our current understanding of how the material properties of cartilage are established, focusing on the interaction between the fluid and solid phase. Our findings suggest that the high resilience of the tissue minimizes the risk of irreversible material failure and thus compensates, at least in part, its poor regenerative abilities. Tissue engineering approaches should thus not only reproduce the correct tissue mechanics but also its pronounced sturdiness to guarantee a similar longevity.
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Obermeier A, Schneider J, Föhr P, Wehner S, Kühn KD, Stemberger A, Schieker M, Burgkart R. In vitro evaluation of novel antimicrobial coatings for surgical sutures using octenidine. BMC Microbiol 2015; 15:186. [PMID: 26404034 PMCID: PMC4583139 DOI: 10.1186/s12866-015-0523-4] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2015] [Accepted: 09/18/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Sutures colonized by bacteria represent a challenge in surgery due to their potential to cause surgical site infections. In order to reduce these type of infections antimicrobially coated surgical sutures are currently under development. In this study, we investigated the antimicrobial drug octenidine as a coating agent for surgical sutures. To achieve high antimicrobial efficacy and required biocompatibility for medical devices, we focused on optimizing octenidine coatings based on fatty acids. For this purpose, antimicrobial sutures were prepared with either octenidine-laurate or octenidine-palmitate at 11, 22, and 33 μg/cm drug concentration normalized per length of sutures. Octenidine containing sutures were compared to the commercial triclosan-coated suture Vicryl® Plus. The release of octenidine into aqueous solution was analyzed and long-term antimicrobial efficacy was assessed via agar diffusion tests using Staphylococcus aureus. For determining biocompatibility, cytotoxicity assays (WST-1) were performed using L-929 mouse fibroblasts. RESULTS In a 7 days elution experiment, octenidine-palmitate coated sutures demonstrated much slower drug release (11 μg/cm: 7%; 22 μg/cm: 5%; 33 μg/cm: 33%) than octenidine-laurate sutures (11 μg/cm: 82%; 22 μg/cm: 88%; 33 μg/cm: 87%). Furthermore sutures at 11 μg/cm drug content were associated with acceptable cytotoxicity according to ISO 10993-5 standard and showed, similar to Vicryl® Plus, relevant efficacy to inhibit surrounding bacterial growth for up to 9 days. CONCLUSIONS Octenidine coated sutures with a concentration of 11 μg/cm revealed high antimicrobial efficacy and biocompatibility. Due to their delayed release, palmitate carriers should be preferred. Such coatings are candidates for clinical testing in regard to their safety and efficacy.
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Affiliation(s)
- A Obermeier
- Klinikum rechts der Isar, Technische Universität München, Klinik für Orthopädie und Sportorthopädie, Ismaninger Str. 22, 81675, Munich, Germany.
| | - J Schneider
- Klinikum rechts der Isar, Technische Universität München, Institut für Mikrobiologie, Immunologie und Hygiene, Trogerstr. 30, 81675, Munich, Germany.
| | - P Föhr
- Klinikum rechts der Isar, Technische Universität München, Klinik für Orthopädie und Sportorthopädie, Ismaninger Str. 22, 81675, Munich, Germany.
| | - S Wehner
- Klinikum rechts der Isar, Technische Universität München, Klinik für Orthopädie und Sportorthopädie, Ismaninger Str. 22, 81675, Munich, Germany.
| | - K-D Kühn
- Universitätsklinik für Orthopädie und Orthopädische Chirurgie, Medizinische Universität, Auenbruggerplatz 5, 8036, Graz, Austria.
| | - A Stemberger
- Klinikum rechts der Isar, Technische Universität München, Klinik für Orthopädie und Sportorthopädie, Ismaninger Str. 22, 81675, Munich, Germany.
| | - M Schieker
- Klinikum der Universität München, Klinik für Chirurgie, Experimentelle Chirurgie und Regenerative Medizin, Nußbaumstr. 20, 80336, Munich, Germany.
| | - R Burgkart
- Klinikum rechts der Isar, Technische Universität München, Klinik für Orthopädie und Sportorthopädie, Ismaninger Str. 22, 81675, Munich, Germany.
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Tübel J, Marthen C, Kuntz L, Wiest I, Alexiou C, Jeschke U, Burgkart R. Untersuchungen zur Beeinflussung von Estradiol auf den Methylierungsstatus des ER Alpha Promotors in SAOS-2 Zellen in vitro als Modell zur Evaluation osteoporotischer Prozesse. Geburtshilfe Frauenheilkd 2015. [DOI: 10.1055/s-0035-1555031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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13
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Thomas P, Stauner K, Schraml A, Mahler V, Banke IJ, Gollwitzer H, Burgkart R, Prodinger PM, Schneider S, Pritschet M, Mazoochian F, Schopf C, Steinmann A, Summer B. [Characteristics of 200 patients with suspected implant allergy compared to 100 symptom-free arthroplasty patients]. Orthopade 2014; 42:607-13. [PMID: 23907451 DOI: 10.1007/s00132-012-2038-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
BACKGROUND Data on implant allergies are incomplete; therefore, we compared the data on allergy history, patch test (PT) and lymphocyte transformation test (LTT) results in a patient series from the Munich implant allergy outpatient department with symptom-free arthroplasty patients. PATIENTS AND METHODS In this study 200 arthroplasty patients with complaints involving the prosthesis (130 female, 187 knee and 13 hip prostheses) and in parallel 100 symptom-free patients (75 female, 47 knee and 53 hip prostheses) were investigated. A questionnaire-aided history including implant type, cementing, intolerance of dental materials, atopy, cutaneous metal intolerance (CMI) and PT, including a standard series with Ni, Co, Cr, seven bone cement components, including gentamicin and benzoyl peroxide and LTT for Ni, Co and Cr. RESULTS In the knee arthroplasty patients with complaints 9.1% showed dental material intolerance, 23.5% atopy, 25.7% CMI, 18.2% metal allergies, 7.4% gentamicin allergy and 27.8% positive metal LTT (mostly to Ni). In symptom-free patients 0% showed dental material intolerance, 19.1% atopy, 12.8% CMI, 12.8% metal allergy, 0% gentamicin allergy and 17% positive metal LTT. CONCLUSIONS Characteristics of the patients with complaints were increased intolerance of dental materials, higher rates of atopy, CMI, metal and gentamicin allergy and LTT reactivity.
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Affiliation(s)
- P Thomas
- Klinik und Poliklinik für Dermatologie und Allergologie, Klinikum der Ludwig-Maximilians-Universität München, Frauenlobstr. 9-11, 80337, München, Deutschland.
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14
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Tübel J, Marthen C, Hofmann S, Jeschke U, Burgkart R. Die altersabhängige Stimulierbarkeit des Vitamin D Rezeptors in primären humanen Osteoblasten. Geburtshilfe Frauenheilkd 2013. [DOI: 10.1055/s-0033-1347791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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15
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Jilg S, König J, Höckendorf U, Schauwecker J, Huberle C, Müller-Thomas C, Schmidt B, Burgkart R, Götze K, Kolb H, Peschel C, Jost P. P-016 Resistance to apoptosis in high-risk myelodysplastic syndrome can be overcome by pro-apoptotic drug treatment using ABT-737. Leuk Res 2013. [DOI: 10.1016/s0145-2126(13)70065-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Baum T, Gräbeldinger M, Grande Garcia E, Burgkart R, Patsch J, Rummeny EJ, Link TM, Bauer JS. Trabekuläre Knochenstrukturanalyse von Wirbelkörpern mittels klinischen MDCT: Kann damit die mechanische Versagenslast vorhergesagt werden? ROFO-FORTSCHR RONTG 2013. [DOI: 10.1055/s-0033-1346285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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17
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Föhr P, Hautmann V, Prodinger P, Pohlig F, Kaddick C, Burgkart R. [Design of a high-dynamic closed-loop controlled cartilage test system]. Orthopade 2013; 41:820-6. [PMID: 23052848 DOI: 10.1007/s00132-012-1953-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Articular cartilage repair methods, in particular scaffold-based autologous chondrocyte implantation, are already in clinical use. In the coming years, the European guidelines on human cell-based medicinal products by the European Medical Agency (EMA) will extend today's quality control mechanisms by additional structural analyses. As articular cartilage has complex biphasic and viscoelastic mechanical properties, a high-performance material test system is required and has already been implemented. To characterize the recovery of cartilage and cartilage replacement materials, it is necessary to measure the dynamic recovery profile. A measurement system for an application like this requires an axis acceleration of more then 50 m/s(2). Furthermore, the test system needs custom-made components to fix the biological specimen while testing. A software package consisting of a graphical user interface and an axis controller leads to highly reproducible tests. The software makes use of a position and velocity controller as well as a force controller at kilohertz speed. While using the high performance force controller it is possible to apply static and dynamic loading profiles that are independent from position or speed set points and signals.
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Affiliation(s)
- P Föhr
- Abteilung für Biomechanik, Klinik für Orthopädie und Sportorthopädie , Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675, München, Deutschland.
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Obermeier A, Matl FD, Schwabe J, Zimmermann A, Kühn KD, Lakemeier S, von Eisenhart-Rothe R, Stemberger A, Burgkart R. Novel fatty acid gentamicin salts as slow-release drug carrier systems for anti-infective protection of vascular biomaterials. J Mater Sci Mater Med 2012; 23:1675-1683. [PMID: 22476651 DOI: 10.1007/s10856-012-4631-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2012] [Accepted: 03/21/2012] [Indexed: 05/31/2023]
Abstract
Infections of vascular prostheses are still a major risk in surgery. The current work presents an in vitro evaluation of novel slow release antibiotic coatings based on new gentamicin fatty acid salts for polytetrafluoroethylene grafts. These grafts were coated with gentamicin sodium dodecyl sulfate, gentamicin laurate and gentamicin palmitate. Drug release kinetics, anti-infective characteristics, biocompatibility and haemocompatibility of developed coatings were compared to commercially available gelatin sealed PTFE grafts (SEALPTFE™) and knitted silver coated Dacron(®) grafts (InterGard(®)). Each gentamicin fatty acid coating showed a continuous drug release in the first eight hours followed by a low continuous release. Grafts coated with gentamicin fatty acids reduced bacterial growth even beyond pathologically relevant high concentrations. Cytotoxicity levels depending on drug formulation bringing up gentamicin palmitate as the most promising biocompatible coating. Thrombelastography studies, ELISA assays and an amidolytic substrate assay confirmed haemocompatibility of developed gentamicin fatty acid coatings comparable to commercially available grafts.
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Affiliation(s)
- A Obermeier
- Klinik für Orthopädie und Sportorthopädie, Klinikum r.d. Isar, Technische Universität München, Muskuloskelettale Forschung, Ismaninger Str. 22, 81675, Munich, Germany.
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Obermeier A, Kuchler S, Matl FD, Pirzer T, Stemberger A, Mykhaylyk O, Friess W, Burgkart R. Magnetic Drug Targeting as New Therapeutic Option for the Treatment of Biomaterial Infections. J Biomater Sci Polym Ed 2012; 23:2321-36. [PMID: 22182398 DOI: 10.1163/156856211x616183] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Implant-associated infections are a challenging problem in surgery. Bacteria in biofilms are difficult to treat as they are less susceptible to antibiotics or antiseptics which require high drug concentrations at the site of infection. We present a novel strategy to concentrate high antibiotic doses systemically at the target site using newly developed antibiotic-functionalized nanoparticles directed by a magnetic drug-targeting system. The important and effective antibiotic gentamicin served as antimicrobial substance and was ionically or covalently attached to magnetic nanoparticles. Subsequently, the particles were characterized thoroughly. Anti-infective properties with regard to Staphylococcus aureus and the degree of cytotoxicity concerning human umbilical vein endothelial cells were determined. The enrichment of the magnetic nanoparticles at the surface of model tubes in circulatory experiments was investigated. We describe a promising technique for the loading of magnetic nanoparticles to treat systemic infections. Gentamicin-coated magnetic nanoparticles reduced bacterial growth even beyond pathologically relevant concentrations within 24 h. Excellent concentration independent biocompatibility was found for the nanoparticles themselves and we demonstrate that the magnetic nanoparticles can be navigated and concentrated on surfaces of model implants using a permanent magnetic field.
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Affiliation(s)
- A Obermeier
- a Klinik fur Orthopadie und Unfallchirurgie, Klinikum rechts der Isar, Technische Universitat Munchen , Ismaninger Str. 22 , D-81675 , Munich , Germany
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20
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Tübel J, Saldamli B, Wiest I, Jeschke U, Burgkart R. Expression of the tumor markers sialyl Lewis A, sialyl Lewis X, Lewis Y, Thomsen-Friedenreich antigen, galectin-1 and galectin-3 in human osteoblasts in vitro. Anticancer Res 2012; 32:2159-2164. [PMID: 22593503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
AIM Lewis antigens and the Thomsen-Friedenreich (TF) antigen are complex glycan structures that modulate processes such as cell adhesion and proliferation and tumor metastasis. The aim of our study was to analyze the expression of sialyl Lewis A (sLeA), sialyl Lewis X (sLeX), Lewis Y (LeY), TF, galectin-1 (Gal-1) and galectin-3 (Gal-3) in human osteoblasts in vitro. MATERIALS AND METHODS The expression of the tumor markers sLeA, sLeX, LeY, TF, Gal-1 and Gal-3 was studied by means of immunohistochemistry on cells grown on chamber slides (2D) and on paraffin sections three-dimensional scaffold-free cultures (3D). The results of the stainings were evaluated semiquantitatively with the immunoreactive scoring system (IRS). RESULTS Analysis of sLeA expression in both types of culture, 2D and 3D showed no detectable staining. After 5 days, in the 2D culture, expression of sLeX was weak, but the 3D culture (after 56 weeks) displayed a strong expression. LeY was expressed very slightly in the 2D culture, however LeY was not detectable in the 3D culture. The TF epitope was identified in the 2D cell culture model. In the 3D model, however, TF was completely lacking. Gal-1 was expressed very strongly in 2D culture, but in the 3D culture was not detectable. In contrast, Gal-3 was expressed in 3D culture but not in 2D. CONCLUSION Within this study, we present a systematic analysis of the expression of sLeA, sLeX, LeY, TF, Gal-1 and Gal-3 in human osteoblasts grown in 2D and in 3D scaffold-free cultures. Summarizing the results of our study, we suggest that Lewis antigens and Gal-1 and -3 might play an important role in cell-cell and cell-matrix interactions of osteoblastic cells.
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Affiliation(s)
- J Tübel
- Clinic of Orthopedics and Sportorthopedics, Klinikum rechts der Isar, Technical University of Munich, Ismaninger Strasse 22, 81675 Munich, Germany
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Bloecker K, Wirth W, Hudelmaier M, Burgkart R, Frobell R, Eckstein F. Morphometric differences between the medial and lateral meniscus in healthy men - a three-dimensional analysis using magnetic resonance imaging. Cells Tissues Organs 2011; 195:353-64. [PMID: 21709397 PMCID: PMC3696373 DOI: 10.1159/000327012] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/16/2011] [Indexed: 11/19/2022] Open
Abstract
The objective of this work was to characterize tibial plateau coverage and morphometric differences of the medial (MM) and lateral meniscus (LM) in a male reference cohort using three-dimensional imaging. Coronal multiplanar reconstructions of a sagittal double-echo steady state with water excitation magnetic resonance sequence (slice thickness: 1.5 mm, and in-plane resolution: 0.37 × 0.70 mm) were analyzed in 47 male participants without symptoms, signs or risk factors of knee osteoarthritis of the reference cohort of the Osteoarthritis Initiative. The medial and lateral tibial (LT) plateau cartilage area and the tibial, femoral and external surfaces of the MM and LM were manually segmented throughout the entire knee. This process was assisted by parallel inspection of a coronal intermediately weighted turbo spin echo sequence. Measures of tibial coverage, meniscus size, and meniscus position were computed three-dimensionally for the total menisci, the body, and the anterior and the posterior horn. The LM was found to cover a significantly greater (p < 0.001) proportion of the LT plateau (59 ± 6.8%) than the MM of the medial plateau (50 ± 5.5%). Whereas the volume of both menisci was similar (2.444 vs. 2.438 ml; p = 0.92), the LM displayed larger tibial and femoral surface areas (p < 0.05) and a smaller maximal (7.2 ± 1.0 vs. 7.7 ± 1.1 mm; p < 0.01) and mean thickness (2.7 ± 0.3 vs. 2.8 ± 0.3 mm; p < 0.001) than the medial one. Also, the LM displayed less (physiological) extrusion than the medial one. These data may guide strategies for meniscal tissue engineering and transplantation aiming to restore normal joint conditions.
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Affiliation(s)
- K Bloecker
- Institute of Anatomy and Musculoskeletal Research, Paracelsus Medical University, Salzburg, Austria.
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22
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Tübel J, Wiest I, Saldamli B, Jeschke U, Burgkart R. Das Genexpressionsmuster von Sexsteroidhormonrezeptoren und osteogenen Differenzierungsmarkern in Osteosarkomzellen. Geburtshilfe Frauenheilkd 2011. [DOI: 10.1055/s-0031-1278553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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Matl FD, Obermeier A, Zlotnyk J, Friess W, Stemberger A, Burgkart R. Augmentation of antibiotic activity by low-frequency electric and electromagnetic fields examining Staphylococcus aureus in broth media. Bioelectromagnetics 2011; 32:367-77. [DOI: 10.1002/bem.20667] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2009] [Accepted: 02/24/2011] [Indexed: 11/10/2022]
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Gröger A, Mang A, Burgkart R, Gradinger R. [Individual and function-dependent therapeutic concept for the ruptured anterior cruciate ligament]. Sportverletz Sportschaden 2010; 24:85-90. [PMID: 20517800 DOI: 10.1055/s-0029-1245412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The knee joint is a ligament guided and muscular stabilized joint. Therefore the rupture of the anterior cruciate ligament (ACL) causes a functional deficit with change of the knee kinematics and the dynamic muscle stabilization. The muscular dysfunction can be the result of inadequate muscle strength, a neuro-muscular control defizit, a propriozeptive dysfunction or often the combination of these causes. Due to the complex anatomy of the ACL an exact, patient specific operative anatomical reconstruction is not possible. Therefore we suggest primarily a conservative therapeutic approach. If this approach fails the reconstruction will be performed after the first rehabilitation phase. Independently from the conservative or surgical approach, the rehabilitation program consists of four function-based phases and the overall therapy goal is to achieve the same or even higher activity level than before the lesion.
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Theelke B, Kuntz M, Zipperle M, Eichhorn S, Boxleitner T, Pandorf T, Burgkart R. Development of Osseointegrative Ceramic Coatings Based on ZPTA—Mechanical Characterization and Influence on the Substrate. ACTA ACUST UNITED AC 2010. [DOI: 10.4303/bda/d101202] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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26
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Schmidmayr M, Magdolen U, Tübel J, Kiechle M, Burgkart R, Seifert-Klauss V. Progesteron verstärkt die Differenzierung primärer humaner Osteoblasten in Langzeit-Kulturen. Geburtshilfe Frauenheilkd 2008. [DOI: 10.1055/s-2008-1038711] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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Abstract
Osteochondrosis juvenilis is caused by a dysfunction of endochondral ossification. Several epiphyses and apophyses can be affected, but osteochondrosis juvenilis of the medial malleolus has not been reported. We describe a 12-year-old boy with bilateral pes planovalgus who was affected by this condition. Conservative management was successful. The presentation, aetiology and treatment are described and the importance of including it in the differential diagnosis is discussed.
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Affiliation(s)
- R Klein
- Department of General Medicine, Klinikum rechts der Isar, Munich, Germany
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Eckstein F, Ateshian G, Burgkart R, Burstein D, Cicuttini F, Dardzinski B, Gray M, Link TM, Majumdar S, Mosher T, Peterfy C, Totterman S, Waterton J, Winalski CS, Felson D. Proposal for a nomenclature for magnetic resonance imaging based measures of articular cartilage in osteoarthritis. Osteoarthritis Cartilage 2006; 14:974-83. [PMID: 16730462 DOI: 10.1016/j.joca.2006.03.005] [Citation(s) in RCA: 184] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2005] [Accepted: 03/11/2006] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Magnetic resonance imaging (MRI) of articular cartilage has evolved to be an important tool in research on cartilage (patho)physiology and osteoarthritis (OA). MRI provides a wealth of novel and quantitative information, but there exists no commonly accepted terminology for reporting these metrics. The objective of this initiative was to propose a nomenclature for definitions and names to be used in scientific communications and to give recommendations as to which minimal methodological information should be provided when reporting MRI-based measures of articular cartilage in OA. METHODS An international group of experts with direct experience in MRI measurement of cartilage morphology or composition reviewed the existing literature. Through an iterative process that included a meeting with a larger group of scientists and clinicians (December 2nd, 2004, Chicago, IL, USA), they discussed, refined, and proposed a nomenclature for MRI-based measures of articular cartilage in OA. RESULTS The group proposes a nomenclature that describes: (1) the anatomical location and (2) the structural feature being measured, each name consisting of a metric variable combined with a tissue label. In addition, the group recommends minimal methodological information that should be described. CONCLUSIONS Utilization of this nomenclature should facilitate communication within the scientific community. Further, the uniform adoption of comprehensive nomenclature to describe quantitative MRI- features of articular cartilage should strengthen epidemiological, clinical, and pharmacological studies in OA.
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Affiliation(s)
- F Eckstein
- Institute of Anatomy & Musculoskeletal Research, Paracelsus Private Medical University, Salzburg, Austria.
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Abstract
The increasing implantation rates of knee arthroplasties are associated with a growing prevalence of complications like periprosthetic fractures. Underlying patient, implant and/or operation technique-related risk factors contribute to these fractures which often occur after minor trauma. In the diagnostic process, fracture dislocation, implant stability, and integrity of the extensor mechanism have to be assessed. Valid classification systems are available to guide treatment decisions. Treatment goals are precise reposition, stable fixation, restoration of function, and early mobilization. In the case of an operative revision, the surgeon has to know the implanted device and has to be prepared for extended procedures and revision arthroplasty. Less invasive fixation devices like retrograde nailing or LISS are often sufficient to stabilize femoral supracondylar fractures, while loosening of the implant often requires extended exchange arthroplasty. Tibial fractures are often associated with osteolysis and bone loss which has to be addressed with bone grafts or augmented revision implants. Long-stemmed implants allow bypassing of the reconstructed defect and provide a stable solution for early mobilization. Patella fractures with stable or asymptomatic implants and continuity of the extensor mechanism should be treated conservatively. If reconstruction becomes necessary, results are often associated with significant functional limitations.
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Affiliation(s)
- P Diehl
- Klinik für Orthopädie und Sportorthopädie, Klinikum rechts der Isar, Technische Universität, Ismaninger Strasse 22, 81675, München.
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30
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Hudelmaier M, Glaser C, Hausschild A, Burgkart R, Eckstein F. Effects of joint unloading and reloading on human cartilage morphology and function, muscle cross-sectional areas, and bone density - a quantitative case report. J Musculoskelet Neuronal Interact 2006; 6:284-90. [PMID: 17142951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Recent studies have shown that thinning of human cartilage occurs with unloading, but no data are available on the effect of remobilization (after immobilization) on knee joint cartilage status in humans. We examined a 36-year-old patient after 6 weeks of unilateral immobilization. Knee joint cartilage morphology (patella and tibia), patellar cartilage deformation, and thigh muscle cross-sectional areas were assessed with quantitative MR imaging and bone density with peripheral quantitative computed tomography (pQCT) during 24 months of remobilization. The immobilized limb displayed lower muscle cross-sectional areas (MCSA) of the knee extensors (-36%), lower bone density of the femur and tibia (-12/-6%), lower patellar cartilage thickness (-14%), but no side differences of tibial cartilage thickness. During remobilization, side differences decreased to -4% for knee extensor MCSAs, to -6%/-3% for femoral and tibial BMD, and to -8% for patellar cartilage thickness. No change was observed in tibial cartilage. Patellar deformation decreased from 9% to 4% after 15 months. In conclusion, we observed substantial changes of thigh MCSAs, but little (patella) to no (tibia) change in cartilage thickness during remobilization. These preliminary results indicate that human cartilage macro-morphology may be less adaptive to variations of the mechanical loading than muscle and bone.
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Affiliation(s)
- M Hudelmaier
- Institute of Anatomy and Musculoskeletal Research, Paracelsus Medical Private University, Salzburg, Austria.
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31
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Gerdesmeyer L, Gollwitzer H, Diehl P, Burgkart R, Steinhauser E. [Reconstruction of the extensor tendons in revision total knee arthroplasty and tumor surgery]. Orthopade 2006; 35:169-75. [PMID: 16362139 DOI: 10.1007/s00132-005-0906-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Reconstruction of the extensor mechanism in extended revision after total knee replacement and tumor surgery remains a clinically relevant problem. Due to large tibial bone defects with resection of the extensor insertion area, the specific problem of patella ligament refixation frequently arises. Several biological approaches and augmentation techniques have been published. Most of these are associated with a high rate of revision surgery because of failed replacement of the extensor mechanism and unsatisfactory functional outcome. Surgical reconstruction of these tendon defects is complicated by the difficulty of completely neutralizing tensional force across the repair. To overcome this problem, methods have been developed to reinforce the reconstruction with overlapping flaps; in addition, artificial materials are being increasingly used for tension neutralization. These artificial strips need special fixation mechanisms on the tibial component and specific technical modifications of the prosthesis. The present study gives an overview of reconstruction modalities of the extensor mechanism and provides an improved technology for better reconstruction by using artificial strips combined with specific modifications of the tibial component.
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Affiliation(s)
- L Gerdesmeyer
- Klinik für Orthopädie und Unfallchirurgie, Technische Universität, München.
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32
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Abstract
Arthrofibrosis is one of the most common complications after total knee arthroplasty with an overall incidence of approximately 10%. Nevertheless, published data are rare and clinical trials mostly include small and heterogeneous patient series resulting in controversial conclusions. Clinically, arthrofibrosis after knee arthroplasty is defined as (painful) stiffness with scarring and soft tissue proliferation. Differentiation between local (peripatellar) and generalized fibrosis is therapeutically relevant. Histopathology typically shows subsynovial fibrosis with synovial hyperplasia, chronic inflammatory infiltration, and excessive and unregulated proliferation of collagen and fibroblasts. Diagnostic strategies are based on the exclusion of differential causes for painful knee stiffness, and especially the exclusion of low-grade infections represents a diagnostic challenge. Early and intensive physiotherapy combined with sufficient analgesia should be initiated as a basic therapy. The next therapeutic steps for persisting arthrofibrosis include closed manipulation and open arthrolysis. Arthroscopic interventions should be limited to local fibrosis. Revision arthroplasty represents a rescue surgery, often associated with recurrence of fibrosis. Prevention of arthrofibrosis by sufficient analgesia and early physiotherapy remains the best treatment option for painful stiffness after knee arthroplasty.
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Affiliation(s)
- H Gollwitzer
- Abteilung für Unfall- und Wiederherstellungschirurgie, Berufsgenossenschaftliche Unfallklinik, Murnau.
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33
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Abstract
Total knee arthroplasty (TKA) is one of the most frequent orthopaedic surgical procedures. Despite continuous improvements in the endoprostheses, instruments, and operative techniques, revision TKA has a rate of about 10% of overall TKA. In addition to the restoration of the periprosthetic bone stock and a precise alignment, the choice of an adequate implant, which meets the patient's specific requirements, has high impact on the outcome. The most significant differences between implants involve the degree of reconstructed joint area (uni-, bi-, tri-compartimental) and the order of the constraining forces between the femoral and tibial component. Implants for revision TKA commonly range from un- or semiconstrained resurfacing implants to fully constrained hinged endoprostheses. In case of severe osseous, ligamentous, and/or muscular defects, special tumor endoprostheses or implants for arthrodesis might be an alternative option.
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Affiliation(s)
- E Steinhauser
- Abteilung Biomechanik, Klinik für Orthopädie und Unfallchirurgie, Technische Universität, München.
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34
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Riener R, Panchaphongsaphak B, Burgkart R. New tangible interface devices for medical education. J Biomech 2006. [DOI: 10.1016/s0021-9290(06)83782-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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35
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Gottschling H, Roth M, Schweikard A, Burgkart R. Intraoperative, fluoroscopy-based planning for complex osteotomies of the proximal femur. Int J Med Robot 2006; 1:67-73. [PMID: 17518392 DOI: 10.1002/rcs.29] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Intertrochanteric osteotomy of the proximal femur is a surgical technique that aims at changing the orientation of the proximal part of the femur in the hip joint by removing a bone wedge between the trochanters. Due to its six degrees of freedom, it presents a complex planning problem for the surgeon. In this paper, we propose an intraoperative planning system for proximal femur osteotomies. Based on two fluoroscopic images taken during the procedure, a primitive femur model is reconstructed, which then allows the user to interactively determine the osteotomy parameters and perform the intervention with the help of a navigation system. Besides the fluoroscopic images, no other imaging is needed. Compared to the traditional approach, this system allows the intervention to be performed with higher precision and less radiation exposure for both patient and surgeon, requiring only little time overhead. An in vitro study has demonstrated the high accuracy and ease of use of this system.
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36
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Abstract
Fluoroscopic C-arms are common devices for acquiring images during surgery. Manual positioning is time consuming and requires considerable experience. Trained users must often take several images to find the best viewing direction. If a second image must be taken from the same position, e.g. for postoperative control, the C-arm must be moved to the exact same position. Without guidance, this is often difficult to accomplish. We developed the idea to completely "robotize" a standard C-arm, i.e. to equip all joints with motors and encoders. A software environment provides for intelligent control. To archive this goal a complete kinematic analysis of the fluoroscope was necessary. On the basis of this analysis a number of clinical applications have been developed: (1) simplified positioning via cartesian control; (2) automatic acquisition of panoramic images; (3) 3D CT with arbitrary viewing angles; (4) 4D intraoperative CT with/without respiration triggering; (5) automated anatomy-oriented positioning. The goal of this research is thus three-fold: minimise radiation exposure of the OR staff, reduce positioning time and offer enhanced imaging capability.
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Affiliation(s)
- N Binder
- Institute for Robotics and Cognitive Systems, University of Lübeck, Lübeck, Germany.
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37
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Gerdesmeyer L, Lampe R, Veihelmann A, Burgkart R, Göbel M, Gollwitzer H, Wagner K. [Chronic radiculopathy. Use of minimally invasive percutaneous epidural neurolysis according to Racz]. Schmerz 2005; 19:285-95. [PMID: 15549419 DOI: 10.1007/s00482-004-0371-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Treatment of chronic low back pain exhibiting radicular symptoms poses a clinical problem that has not yet been solved. The technique of percutaneous minimally invasive neurolysis described by Racz is being performed increasingly to treat chronic radiculopathy. A total of 61 patients with corresponding symptomatology after screening for inclusion and exclusion criteria in the region of the lumbar spinal nerve were treated with the Racz catheter technique. Distinct clinical improvement was observed at the 3- and 6-month follow-ups after percutaneous minimally invasive epidural neurolysis. Subjective pain perception, quantified by the McNab score, clearly improved after 3 as well as 6 months. With the exception of partial catheter shearing in two cases and one occurrence of infection, no relevant side effects were noted. The Racz catheter technique for treatment of chronic radiculopathy following disk surgery is suitable with minimal side effects.
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Affiliation(s)
- L Gerdesmeyer
- Klinik für Orthopädie und Sportorthopädie, Klinikum rechts der Isar der TU München.
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38
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Burgkart R, Gottschling H, Roth M, Gradinger R, Schweikard A. Fluoroskopiebasierte 3D-Navigation komplexer Korrekturosteotomien des proximalen Femurs. Orthopäde 2005; 34:1137-43. [PMID: 16136338 DOI: 10.1007/s00132-005-0859-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
BACKGROUND Despite great advances in hip alloarthroplasty there are still numerous indications for joint-saving procedures such as correction osteotomies. Often these procedures include complex 3D rearrangements of the proximal femur, which are for the surgeon technically very demanding. The project aim was to develop a precise intraoperative virtual 3D planning tool including a detailed biomechanical analysis and enable the surgeon to realize exactly this plan by using computer-assisted techniques. METHODS Using only two different angled fluoro frames a simplified femoral model was inversely constructed. For navigation a passive optical system was used with a C-arm calibration kit and PC-based software. For in vitro evaluation complex osteotomies were performed on ten femora under simulated OR conditions. RESULTS The mean difference between the planning and real surgical outcome for the wedge size was less then 2 degrees and for the femur head center position less then 4 mm. No implant penetrated the femur neck isthmus. CONCLUSION Without changing the standard operative procedure the method can be of high clinical importance to improve planning accuracy and consecutive operative realization for precise fragment positioning and plate location without penetrating the isthmus of the femoral neck. And -- besides precision -- it can potentially help to reduce intraoperative complications such as implant penetration and minimize X-ray use.
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Affiliation(s)
- R Burgkart
- Klinik für Orthopädie und Sportorthopädie, Technische Universität, München.
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39
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Goebel M, Burgkart R, Gerdesmeyer L, Diehl P, Schmitt-Sody M, Plötz W, Gradinger R. [Diagnosis specific differences in knee joint geometry. A challenge for the correct axial implantation of long stems in total knee arthroplasty]. Orthopade 2005; 34:1150-2, 1154-9. [PMID: 16133153 DOI: 10.1007/s00132-005-0857-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
BACKGROUND Arthrotic deformities with changes in knee geometry can produce difficulties in implanting long stem knee prosthesis systems using intramedullary alignment. They can result in incorrect lower limb axis and prosthesis positioning. The aim of the presented study was to measure knee geometry in patients with varus and valgus gonarthrosis in order to define diagnosis related differences. METHODS A total of 75 patients with indication for total knee arthroplasty were divided in two groups using the weight bearing lower limb axis: patients with varus gonarthrosis (n=43) and with valgus gonarthrosis (n=32). Angles and extensions, important for knee prosthesis implantation, were measured, digitalized and analyzed. The results were investigated for diagnosis specific differences. RESULTS After regulation of the measured extension in mean femur/tibia lengths, significant diagnosis specific differences were found: femur condyles were widened towards pathologic weight bearing (P<0.044), and the mechanical tibia axis of the varus gonarthrosis group is transferred to the lateral side (P<0.046) and in projection over the lateral internal cortical substance. CONCLUSION The significant differences in deformed arthrotic knees indicate that for an optimal postoperative result the use of standard implants is not always sufficient. Modular knee prosthesis systems can provide adequately for individual demands.
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Affiliation(s)
- M Goebel
- Klinik für Orthopädie und Sportorthopädie, Klinikum rechts der Isar, Technische Universität München.
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40
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Gottschling H, Roth M, Schweikard A, Burgkart R. Intraoperative, fluoroscopy-based planning for complex osteotomies of the proximal femur. Int J Med Robot 2005. [DOI: 10.1581/mrcas.2005.010303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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42
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Abstract
Numerous publications provide measured biomechanical data relating to synovial joints. However, in general, they do not reflect the non-linear elastic joint properties in detail or do not consider all degrees of freedom (DOF), or the quantity of data is sparse. To perform more comprehensive, extended measurements of elastic joint properties, an optimised robot-based approach was developed. The basis was an industrial, high-precision robot that was capable of applying loads to the joint and measuring the joint displacement in 6 DOF. The system was equipped with novel, custom-made control hardware. In contrast to the commonly used sampling rates that are below 100 Hz, a rate of 4 kHz was realised for each DOF. This made it possible to implement advanced, highly dynamic, quasi-continuous closed-loop controllers. Thus oscillations of the robot were avoided, and measurements were speeded up. The stiffness of the entire system was greater than 44 kNm(-1) and 22 Nm deg(-1), and the maximum difference between two successive measurements was less than 0.5 deg. A sophisticated CT-based referencing routine facilitated the matching of kinematic data with the individual anatomy of the tested joint. The detailed detection of the elastic varus-valgus properties of a human knee joint is described, and the need for high spatial resolution is demonstrated.
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Affiliation(s)
- M Frey
- Institute of Automatic Control Engineering, Technische Universität München, Germany.
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43
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Grüttner B, Frohnauer G, Burgkart R. [Prosthetic possibilities after amputations in the upper extremities]. MMW Fortschr Med 2004; 146:44, 46, 49. [PMID: 15529692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/01/2023]
Abstract
Whereas passive prostheses are fitted onto the patient after the amputation of an arm, hand or finger and are mostly cosmetic in function, active prostheses have much more potential. They can transform the movements of other body regions to movement in the artificial limb. Belts or harnesses, for example, effect the direct transfer of the power from the muscle to the prosthesis. The range of movement possible depends upon the level of the amputation, the length of the residual limb, the age of the patient, his body build and fitness. Myoelectrically controlled prostheses possess their own drive and power source. They control movement through the electrical action potentials of the residual limb muscles, which are detected, amplified and transmitted with help of electrodes.
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Affiliation(s)
- B Grüttner
- Klinikwerkstatt für Orthopädietechnik der Technischen Universität München.
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44
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Ruckhäberle E, Obst T, Riener R, Schneider KTM, Burgkart R. Prototyp eines neuartigen, multimodalen Geburtssimulators. Z Geburtshilfe Neonatol 2004. [DOI: 10.1055/s-2003-818118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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45
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Burgkart R, Glaser C, Hinterwimmer S, Hudelmaier M, Englmeier KH, Reiser M, Eckstein F. Feasibility of T and Z scores from magnetic resonance imaging data for quantification of cartilage loss in osteoarthritis. ACTA ACUST UNITED AC 2003; 48:2829-35. [PMID: 14558088 DOI: 10.1002/art.11259] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE T scores (an indicator of the difference between patients and young healthy subjects) and Z scores (an indicator of the difference between patients and age-matched healthy subjects) are used in the diagnosis of osteoporosis and form the current basis for the definition of osteoporosis by the World Health Organization. We tested the feasibility of using T and Z scores derived from quantitative cartilage imaging with magnetic resonance imaging (MRI) for the diagnosis of osteoarthritis (OA). METHODS High-resolution MR images of tibial cartilage were acquired from 126 young healthy adults (ages 20-35 years), 24 age-matched elderly healthy adults (ages 50-75 years), 7 OA patients prior to tibial osteotomy, and 7 OA patients prior to knee arthroplasty. Cartilage volume, thickness, surface area, and original joint surface area (before onset of disease) were determined in the medial and lateral tibia. RESULTS The cartilage volume of the medial tibia of osteotomy patients with varus malalignment displayed moderate T scores (-1.0), and more negative T scores (-3.8) were observed in knee arthroplasty patients with varus malalignment. Normalization of the cartilage volume to the original joint surface area substantially enhanced the scores in patients undergoing osteotomy (-2.3) and in patients undergoing knee arthroplasty (-5.5), and this was superior to the normalization ratios of cartilage volume to body height and cartilage volume to body weight, in terms of distinguishing the loss of articular cartilage. CONCLUSION Quantitative analysis of OA by MRI is feasible using T and Z scores. However, cartilage volume should be normalized to the individual joint surface area in order to maximize the discriminatory power of this technique for the diagnosis of OA.
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Affiliation(s)
- R Burgkart
- Technische Universität München, Munich, Germany.
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46
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Gerdesmeyer L, Lampe R, Göbel M, Henne M, Burgkart R. [Leading symptom elbow pain. Differential diagnosis]. MMW Fortschr Med 2003; 145:32-6. [PMID: 14649070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
Abstract
Pain affecting the elbow joint may be caused by a number of different pathologies. In principle, these can be grouped by causality criteria into degenerative causes, inflammatory causes, tumor disease, congenital disease and the sequelae of trauma. The majority of these latter are associated with typical clinical symptoms that can be established with the aid of a systematic clinical examination, history-taking, inspection, palpation, an examination of joint mobility, and finally radiography. In this way, the diagnosis can rapidly be established.
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Affiliation(s)
- L Gerdesmeyer
- Klinik für Orthopädie und Sportorthopädie, Klinikum rechts der Isar, TU München.
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47
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Burgkart R, Lampe R, Gerdesmeyer L, Gradinger R. [Congenital clubfoot]. MMW Fortschr Med 2003; 145:33-6. [PMID: 15072276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
Owing to the relatively high incidence of this condition (2 in 1,000 neonates) and the poor functional outcome of inadequate treatment, clubfoot represents a major clinical problem. Although its etiology is not fully known, modern three-dimensional analyses have led to a better understanding of the pathomorphology and provide a new basis for a differentiated therapeutic strategy. Of central importance is early diagnosis and immediate postpartum initiation of primarily conservative treatment taking the form of intensive redressment measures. Depending on the residual deformity, an appropriate surgical procedure aimed at achieving complete correction should be done between the age of 4 to 6 months. To ensure a lasting positive outcome, rigorous follow-up physiotherapeutic treatment and close surveillance are essential.
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Affiliation(s)
- R Burgkart
- Klinik für Orthopädie und Sportorthopädie, Technische Universität München.
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48
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Lampe R, Burgkart R, Gerdesmeyer L, Mitternacht J, Werber KD. [Syndactylies of the hand]. MMW Fortschr Med 2003; 145:31-2. [PMID: 15072275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Affiliation(s)
- R Lampe
- Orthopädische Abteilung, Klinik für Orthopädie und Sportorthopädie, Klinikum rechts der Isar, Technische Universität München.
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49
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Abstract
In orthopaedics more than 50 different clinical knee joint evaluation tests exist that have to be trained in orthopaedic education. Often it is not possible to obtain sufficient practical training in a clinical environment. The training can be improved by Virtual Reality technology. In the frame of the Munich Knee Joint Simulation project an artificial leg with anatomical properties is attached by a force-torque sensor to an industrial robot. The recorded forces and torques are the input for a simple biomechanical model of the human knee joint. The robot is controlled in such way that the user gets the feeling he moves a real leg. The leg is embedded in a realistic environment with a couch and a patient on it.
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Affiliation(s)
- M Frey
- Lehrstuhl für Steuerungs- und Regelungstechnik, Technische Universität München, Deutschland.
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50
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Obst T, Burgkart R, Ruckhäberle E, Riener R. GEBURTSHILFE-SIMULATOR FÜR DIE PRAKTISCHE AUSBILDUNG. BIOMED ENG-BIOMED TE 2003. [DOI: 10.1515/bmte.2003.48.s1.198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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