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Meeting abstract : Deutscher Kongress für Orthopädie und Unfallchirurgie (DKOU 2012), 23.10.-26.10.2012, Berlin.
Fragestellung: Die Behandlung langstreckiger Knochendefekte ist eine große Herausforderung. Die Masquelet-Technik zur Behandlung solcher Defekte ist eine zweizeitige Operationstechnik. Zuerst erfolgt die Insertion eines PMMA (Polymethylmethacrylat)-Zementspacers in den Knochendefekt, der die Bildung einer Membran induziert. Diese Membran enthält Wachstumsfaktoren und regenerative Zellen, die möglicherweise die Knochenheilung unterstützen. Nach einigen Wochen wird der Zementspacer entfernt und der induzierte Membranschlauch mit Beckenkammspongiosa aufgefüllt. Im weiteren Verlauf kommt es zu einer kompletten Knochenheilung. Ziele dieser Untersuchung waren die Etablierung der Masquelettechnik am Rattenmodell und die Definition eines Zeitpunkts, an welchem die Membran eine ausreichende Festigkeit sowie einen signifikanten Gehalt von Vorläuferzellen aufweist.
Methodik: Nach Genehmigung der Experimente wurden die Femura von 24 männlichen SD-Ratten osteotomiert. Die Lücke (10 mm) wurde mit PMMA-Zement aufgefüllt und mittels Miniplatte stabilisiert. Parallel wurden den Versuchstieren gleich große PMMA-Spacer subcutan unter die Rückenhaut implantiert. Nach 2, 4, bzw. 6 Wochen (W) erfolgte die Entnahme der Membranen. Ein Teil der Membran wurde für (immun)histologische Untersuchungen aufbereitet (CD34, vWF, van Giesson), ein Teil für die in vitro Kultur. Auswachsende Vorläuferzellen in vitro wurden über CD34 und STRO-1-Färbung nachgewiesen. Statistik: Mediane, Kruskal-Wallis-Test, p<0,05 ist signifikant.
Ergebnisse und Schlussfolgerungen: Im zeitlichen Verlauf nahmen die Vaskularisierung (vWF-positive Fläche [%]: 2 W: 1,8; 4 W:1.6 vs 6 W: 6,4), die Dicke der Membran ([µm]: 2 W: 350 vs 4W: 517, 6 W: 592) und der Bindegewebsanteil ([µm]: 2W: 201 vs 4W: 324, 6W: 404) signifikant zu. Der Hauptanteil elastischer Fasern war auf der dem Zement zugewandten Seite, Vaskularisierung war eher auf der Weichteil zugewandten Seite zu finden. Der Anteil CD34 positiver Zellen nahm signifikant ab (2W: 5%, 4 W: 4% vs 6 W: 1%). Auswachsende STRO-1 positive Zellen konnten nur in zweiwöchigen Membranen nachgewiesen werden. Ältere Membranen wiesen einen zunehmenden Anteil seneszenter Zellen auf. Subcutan induzierte Membranen waren vergleichbar, wiesen jedoch tendentiell eine geringere Dicke und keine STRO-1 positiven Zellen auf.
Mit dieser Studie wurde erstmalig die Induktion einer Membran nach Masquelet im Rattenmodell etabliert. Es konnte nachgewiesen werden, dass der strukturelle Aufbau sowie die zellulären Komponenten zeitlichen Änderungen unterliegen und der Ort der Induktion Einfluss auf die zellulären Komponenten der Membran hat. Junge Membranen (2W) enthielten CD34 und STRO-1 positive Zellen. 4W-Membranen enthielten nur CD34 positive Zellen wiesen aber einen signifikanten Bindegewebsanteil auf, der für eine erhöhte mechanische Stabilität spricht. Ob 2 bzw. 4 Wochen alte Membranen den Knochenheilungsprozess fördern, muss in weiterführenden Studien untersucht werden.
Early vascularization is a prerequisite for successful bone healing and endothelial progenitor cells (EPC), seeded on appropriate biomaterials, can improve vascularization. The type of biomaterial influences EPC function with bioglass evoking a vascularizing response. In this study the influence of a composite biomaterial based on polylactic acid (PLA) and either 20 or 40% bioglass, BG20 and BG40, respectively, on the differentiation and survival of EPCs in vitro was investigated. Subsequently, the effect of the composite material on early vascularization in a rat calvarial critical size defect model with or without EPCs was evaluated. Human EPCs were cultured with β-TCP, PLA, BG20 or BG40, and seeding efficacy, cell viability, cell morphology and apoptosis were analysed in vitro. BG40 released the most calcium, and improved endothelial differentiation and vitality best. This effect was mimicked by adding an equivalent amount of calcium to the medium and was diminished in the presence of the calcium chelator, EGTA. To analyze the effect of BG40 and EPCs in vivo, a 6-mm diameter critical size calvarial defect was created in rats (n = 12). Controls (n = 6) received BG40 and the treatment group (n = 6) received BG40 seeded with 5×105 rat EPCs. Vascularization after 1 week was significantly improved when EPCs were seeded onto BG40, compared to implanting BG40 alone. This indicates that Ca2+ release improves EPC differentiation and is useful for enhanced early vascularization in critical size bone defects.
Bone marrow mononuclear cells (BMCs) are suitable for bone tissue engineering. Comparative data regarding the needs of BMC for the adhesion on biomaterials and biocompatibility to various biomaterials are lacking to a large extent. Therefore, we evaluated whether a surface coating would enhance BMC adhesion and analyze the biocompatibility of three different kinds of biomaterials. BMCs were purified from human bone marrow aspirate samples. Beta tricalcium phosphate (β-TCP, without coating or coated with fibronectin or human plasma), demineralized bone matrix (DBM), and bovine cancellous bone (BS) were assessed. Seeding efficacy on β-TCP was 95% regardless of the surface coating. BMC demonstrated a significantly increased initial adhesion on DBM and β-TCP compared to BS. On day 14, metabolic activity was significantly increased in BMC seeded on DBM in comparison to BMC seeded on BS. Likewise increased VEGF-synthesis was observed on day 2 in BMC seeded on DBM when compared to BMC seeded on BS. The seeding efficacy of BMC on uncoated biomaterials is generally high although there are differences between these biomaterials. Beta-TCP and DBM were similar and both superior to BS, suggesting either as suitable materials for spatial restriction of BMC used for regenerative medicine purposes in vivo.
BACKGROUND: Local implantation of ex vivo concentrated, washed and filtrated human bone marrow-derived mononuclear cells (BMC) seeded onto β-tricalciumphosphate (TCP) significantly enhanced bone healing in a preclinical segmental defect model. Based on these results, we evaluated in a first clinical phase-I trial safety and feasibility of augmentation with preoperatively isolated autologous BMC seeded onto β-TCP in combination with angle stable plate fixation for the therapy of proximal humeral fractures as a potential alternative to autologous bone graft from the iliac crest.
METHODS: 10 patients were enrolled to assess whether cell therapy with 1.3 × 106 autologous BMC/ml/ml β-TCP, collected on the day preceding the definitive surgery, is safe and feasible when seeded onto β-TCP in patients with a proximal humeral fracture. 5 follow-up visits for clinical and radiological controls up to 12 weeks were performed.
RESULTS: β-tricalciumphosphate fortification with BMC was feasible and safe; specifically, neither morbidity at the harvest site nor at the surgical wound site were observed. Neither local nor systemic inflammation was noted. All fractures healed within the observation time without secondary dislocation. Three adverse events were reported: one case each of abdominal wall shingles, tendon loosening and initial screw perforation, none of which presumed related to the IND.
CONCLUSIONS: Cell therapy with autologous BMC for bone regeneration appeared to be safe and feasible with no drug-related adverse reactions being described to date. The impression of efficacy was given, although the study was not powered nor controlled to detect such. A clinical trial phase-II will be forthcoming in order to formally test the clinical benefit of BMC-laden β-TCP for PHF patients. Trial registration The study was registered in the European Clinical Trial Register as EudraCT No. 2012-004037-17. Date of registration 30th of August 2012. Informed consent was signed from all patients enrolled.
Objectives: Reconstruction of long segmental bone defects is demanding for patients and surgeons, and associated with long-term treatment periods and substantial complication rates in addition to high costs. While defects up to 4–5 cm length might be filled up with autologous bone graft, heterologous bone from cadavers, or artificial bone graft substitutes, current options to reconstruct bone defects greater than 5 cm consist of either vascularized free bone transfers, the Masquelet technique or the Ilizarov distraction osteogenesis. Alternatively, autologous cell transplantation is an encouraging treatment option for large bone defects as it eliminates problems such as limited autologous bone availability, allogenic bone immunogenicity, and donor-site morbidity, and might be used for stabilizing loose alloplastic implants.
Methods: The authors show different cell therapies without expansion in culture, with ex vivo expansion and cell therapy in local bone defects, bone healing and osteonecrosis. Different kinds of cells and scaffolds investigated in our group as well as in vivo transfer studies and BMC used in clinical phase I and IIa clinical trials of our group are shown.
Results: Our research history demonstrated the great potential of various stem cell species to support bone defect healing. It was clearly shown that the combination of different cell types is superior to approaches using single cell types. We further demonstrate that it is feasible to translate preclinically developed protocols from in vitro to in vivo experiments and follow positive convincing results into a clinical setting to use autologous stem cells to support bone healing.
Background: Recent research has shown an increased risk of accidents and injuries in ADHD patients, which could potentially be reduced by stimulant treatment. Therefore, the first aim of our study was to evaluate the prevalence of adult ADHD in a trauma surgery population. The second aim was to investigate accident mechanisms and circumstances which could be specific to ADHD patients, in comparison to the general population.
Methods: We screened 905 accident victims for ADHD using the ASRS 18-item self-report questionnaire. The basic demographic data and circumstances of the accidents were also assessed.
Results: Prevalence of adult ADHD was found to be 6.18% in our trauma surgery patient sample. ADHD accident victims reported significantly higher rates of distraction, stress and overconfidence in comparison to non-ADHD accident victims. Overconfidence and being in thoughts as causal mechanisms for the accidents remained significantly higher in ADHD patients after correction for multiple comparison. ADHD patients additionally reported a history of multiple accidents.
Conclusion: The majority of ADHD patients in our sample had not previously been diagnosed and were therefore not receiving treatment. The results subsequently suggest that general ADHD screening in trauma surgery patients may be useful in preventing further accidents in ADHD patients. Furthermore, psychoeducation regarding specific causal accident mechanisms could be implemented in ADHD therapy to decrease accident incidence rate.
Purpose: Fractures of the humerus account for 5%–8% of all fractures. Nonunion is found with an incidence of up to 15%, depending on the location of the fracture. In case of a manifest nonunion the surgeon faces a challenging problem and has to conceive a therapy based on the underlying pathology. The aim of this study was to describe our treatment concepts for this entity and present our results of the last five years.
Methods: Twenty-six patients were treated for nonunion of the humerus between January 2013 and December 2017. Their charts were reviewed retrospectively and demographic data, pathology, surgical treatment and outcome were assessed.
Results: The most frequent location for a nonunion was the humeral shaft, with the most common trauma mechanism being multiple falls. Most often atrophic nonunion (n = 14), followed by hypertrophic and infection-caused nonunion (each n = 4), were found. Our treatment concept could be applied in 19 patients, of which in 90% of those who were available for follow-up consolidation could be achieved.
Conclusion: Humeral nonunion is a heterogeneous entity that has to be analyzed precisely and be treated correspondingly. We therefore present a treatment concept based on the underlying pathology.
The Masquelet technique for the treatment of large bone defects is a two‐stage procedure based on an induced membrane. The size of a scaffold is reported to be a critical factor for bone healing response. We therefore aimed to investigate the influence of the granule size of a bone graft substitute on bone marrow derived mononuclear cells (BMC) supported bone healing in combination with the induced membrane. We compared three different sizes of Herafill® granules (Heraeus Medical GmbH, Wehrheim) with or without BMC in vivo in a rat femoral critical size defect. A 10 mm defect was made in 126 rats and a membrane induced by a PMMA‐spacer. After 3 weeks, the spacer was taken out and membrane filled with different granule sizes. After 8 weeks femurs were taken for radiological, biomechanical, histological, and immunohistochemical analysis. Further, whole blood of the rat was incubated with granules and expression of 29 peptide mediators was assessed. Smallest granules showed significantly improved bone healing compared to larger granules, which however did not lead to an increased biomechanical stability in the defect zone. Small granules lead to an increased accumulation of macrophages in situ which could be assigned to the inflammatory subtype M1 by majority. Increased release of chemotactic respectively proangiogenic active factors in vitro compared to syngenic bone and beta‐TCP was observed. Granule size of the bone graft substitute Herafill® has significant impact on bone healing of a critical size defect in combination with Masquelet's technique in terms of bone formation and inflammatory.
Treatment of large bone defects is one of the great challenges in contemporary orthopedic and traumatic surgery. Grafts are necessary to support bone healing. A well-established allograft is demineralized bone matrix (DBM) prepared from donated human bone tissue. In this study, a fibrous demineralized bone matrix (f-DBM) with a high surface-to-volume ratio has been analyzed for toxicity and immunogenicity. f-DBM was transplanted to a 5-mm, plate-stabilized, femoral critical-size-bone-defect in Sprague-Dawley (SD)-rats. Healthy animals were used as controls. After two months histology, hematological analyses, immunogenicity as well as serum biochemistry were performed. Evaluation of free radical release and hematological and biochemical analyses showed no significant differences between the control group and recipients of f-DBM. Histologically, there was no evidence of damage to liver and kidney and good bone healing was observed in the f-DBM group. Reactivity against human HLA class I and class II antigens was detected with mostly low fluorescence values both in the serum of untreated and treated animals, reflecting rather a background reaction. Taken together, these results provide evidence for no systemic toxicity and the first proof of no basic immunogenic reaction to bone allograft and no sensitization of the recipient.