The osteo-inductive activity of bone-marrow-derived mononuclear cells resides within the CD14+ population and is independent of the CD34+ population.

Bone marrow mononuclear cells (BMC) seeded on a scaffold of ß-tricalcium phosphate (ß-TCP) promote bone healing in a critical-size femur defect model. Being BMC a mixed population of predominantly mature haematopoietic cells, which cell type(s) is(are) instrumental for healing remains elusive. Although clinical therapies using BMC are often dubbed as stem cell therapies, whether stem cells are relevant for the therapeutic effects is unclear and, at least in the context of bone repair, seems dubious. Instead, in light of the critical contribution of monocytes and macrophages to tissue development, homeostasis and injury repair, in the current study it was hypothesised that BMC-mediated bone healing derived from the stem cell population. To test this hypothesis, bone remodelling studies were performed in an established athymic rats critical-size femoral defect model, with ß-TCP scaffolds augmented with complete BMC or BMC immunomagnetically depleted of stem cells (CD34+) or monocytes/macrophages (CD14+). Bone healing was assessed 8 weeks after transplantation. Compared to BMC-augmented controls, when CD14- BMC, but not CD34- BMC were transplanted into the bone defect, femora possessed dramatically decreased biomechanical stability and new bone formation was markedly reduced, as measured by histology. The degree of vascularisation did not differ between the two groups. It was concluded that the monocyte fraction within the BMC provided critical osteo-inductive cues during fracture healing. Which factors were responsible at the molecular levels remained elusive. However, this study marked a significant progress towards elucidating the mechanisms by which BMC elicit their therapeutic effects, at least in bone regeneration.

Effectiveness of combined local therapy with antibiotics and fibrin vs. vacuum-assisted wound therapy in soft tissue infections: a retrospective study.

PURPOSE: Soft tissue infections can be severe and life-threatening. Their treatment consists currently in radical surgical wound debridement and combined systemic antimicrobial therapy. Different side effects are possible. Local antibiotic therapy represents a new approach to reduce side effects and improve healing. The aim of this study is to assess the effectiveness of the local sprayed use of antibiotics with fibrin sealing compared with negative pressure wound therapy as an established treatment of soft-tissue infections. METHODS: In this retrospective study, patients with soft tissue infections who underwent surgical treatment were analysed. One group consists of patients, who received local fibrin-antibiotic spray (FAS) (n = 62). Patients treated by vacuum-assisted wound therapy (VAWT) as the established treatment were the control group (n = 57). Main outcomes were differences in the success of healing, the duration until healing and the number of needed operations. RESULTS: Clinical healing could be achieved for 55 patients (98.21%) in the FAS group vs. 47 patients (92.16%) in the VAWT group (p = 0.19). Time to require this was 10.65 ± 10.38 days in the FAS group and 22.85 ± 14.02 days in the VAWT group (p < 0.001). In the FAS group, patients underwent an average of 1.44 ± 0.72 vs.3.46 ± 1.66 operations in the VAWT group (p < 0.001). CONCLUSION: Compared to vacuum-assisted wound therapy in soft tissue infections, local fibrin-antibiotic spray shows faster clinical healing and less needed operations. Leading to shorter hospital stays and more satisfied patients. The combination of sprayed fibrin and antibiotics can be seen as a promising and effective method.

L-FABP and NGAL are novel biomarkers for detection of abdominal injury and hemorrhagic shock.

INTRODUCTION: Delayed diagnosis of abdominal injuries and hemorrhagic shock leads to secondary complications and high late mortality in severely traumatized patients. The liver fatty acid-binding protein (L-FABP) is expressed in intestine, liver and kidney; the neutrophil gelatinase-associated lipocalin (NGAL) in colon and kidney. We hypothesized that l-FABP is an early biomarker for abdominal injury and hemorrhagic shock and that l-FABP and NGAL are specific markers for detection of liver and/or kidney injuries. PATIENTS AND METHODS: Traumatized patients with an age ≥18 years and an abdominal injury (AISabd≥2), independently from Injury Severity Score (ISS), were prospectively included from 04/2018 to 05/2021. 68 patients had an abdominal injury ("Abd") and 10 patients had an abdominal injury with hemorrhagic shock ("HS Abd"). 41 patients without abdominal injury and hemorrhagic shock but with an ISS ≥ 25 ("noAbd") were included as control group. Four abdominal subgroups with isolated organ injuries were defined. Plasma l-FABP and NGAL levels were measured at admission (ER) and up to two days post-trauma. RESULTS: All patient groups had a median ISS≥25. In ER, median l-FABP levels were significantly higher in "HS Abd" group (1209.2 ng/ml [IQR=575.2-1780.3]) compared to "noAbd" group (36.4 ng/ml [IQR=14.8-88.5]), and to "Abd" group (41.4 ng/ml [IQR=18.0-235.5]), p<0.001. In matched-pair-analysis l-FABP levels in the group "Abd" were significantly higher (108.3 ng/ml [IQR=31.4-540.9]) compared to "noAbd" (26.4 ng/ml [IQR=15.5-88.8]), p = 0.0016. l-FABP correlated significantly with clinical parameters of hemorrhagic shock; the optimal cut-off level of l-FABP for detection was 334.3 ng/ml (sensitivity: 90%, specificity: 78%). Median l-FABP-levels were significantly higher in patients with isolated liver or kidney injuries and correlated significantly with AST, ALT and creatinine value. Median NGAL levels in the ER were significantly higher in "HS Abd" group (115.9 ng/ml [IQR=90.6-163.8]) compared to "noAbd" group (58.5 ng/ml [IQR=41.0-89.6],p<0.001) and "Abd" group (70.5 ng/ml [IQR=53.3-115.5], p<0.05). The group "Abd" showed significant higher median NGAL levels compared to "noAbd", p = 0.019. NGAL levels correlated significantly with clinical parameters of hemorrhagic shock. CONCLUSION: L-FABP and NGAL are novel biomarkers for detection of abdominal trauma and hemorrhagic shock. l-FABP may be a useful and promising parameter in diagnosis of liver and kidney injuries, NGAL failed to achieve the same.

[The surgeon's balancing act-Teaching in the clinical routine]. / Der Chirurg im Spagat ­ Lehre im klinischen Alltag.

BACKGROUND: Thus medical students must be inspired to undertake this specialty. Students complain that the teaching is subordinate to patient care and limited by a lack of time and medical personnel. Although there are many studies assessing student perceptions, few exist that focus on the issues that teachers face. OBJECTIVE: To analyse student teaching in the daily routine and its potential' problems from the surgeon's perspectives. MATERIAL AND METHODS: In this prospective study guidelines for semistructured interviews with formulated, open questions were created, which were specified with further questions. All interviews were conducted using these guidelines and recorded. The number of interviews were a function of the concept of content saturation. RESULTS: All 22 participants perceived that the teaching in clinical practice is of paramount importance. Nevertheless, respondents described that learning goals in the clinical routine are not always achieved. The main reason is a lack of time; however, as clinical experience increases other factors will similarly become more important: Consultants and heads of departments complain about deficiencies in students' previous knowledge, including insufficient motivation. Most respondents described that they do not feel appreciated for teaching. Overall, student teaching was perceived as an additional burden but all respondents found the task to be extremely worthwhile. CONCLUSION: In addition to the lack of personnel, a lack of appreciation is the most significant obstacle towards effective teaching. It is therefore important to increase the value of teaching by rewarding good achievements and the creation of effective transparency.

[Comparable results after arthroscopic replacement of the anterior cruciate ligament : Clinical and functional results after single bundle and double bundle reconstruction]. / Vergleichbare Ergebnisse nach arthroskopischem Ersatz des vorderen Kreuzbandes : Klinische und funktionelle Ergebnisse nach Einzelbündel- und Doppelbündelrekonstruktion.

INTRODUCTION: Rupture of the anterior cruciate ligament (ACL) has been surgically reconstructed mainly arthroscopically for many years. The long-propagated single bundle replacement was followed by recommendations for the anatomical double-bundle reconstruction. The aim of this study is the evaluation of clinical follow-up results in terms of function and stability after performing an ACL reconstruction with both the single bundle (SB) and the double bundle (DB) technique. METHODOLOGY: Eighty patients receiving ACL reconstruction were included (41 SB / 39 DB). The follow-up period was 17.4 months. To assess knee joint stability, anteroposterior translation and rotation translation were determined. In addition, arthrometric measurement and the implementation of standardized scores were performed. Data were statistically evaluated using the Pearson χ2 test and Fisher's exact test (p = 0.05). RESULTS: While the Lachman test in the SB group showed a significant (p = 0.032) greater stability of the knee joints, a higher stability of the knee joints in the DB group was documented by the anterior drawer test and the stability measurement with the rolimeter. In the DB group a significantly higher number of patients with local sensitivity deficits (p = 0.045) and paresthesia as well as a significantly higher active and passive flexion deficit were noted compared to the SB group (p = 0.09 / p = 0.038, respectively). CONCLUSION: Based on the results of this study it is currently not possible to give any recommendations regarding any operating procedure after a follow-up period of at least 12 months. However, there is evidence of a higher complication rate in the DB group. Clinically, these results should be considered in the evaluation of the indications.

[Violence in the emergency department of a maximum care hospital]. / Gewalt in der Notaufnahme eines Maximalversorgers.

INTRODUCTION: The emergency department of hospitals is known as a violent place, nevertheless the true incidence of violent acts in emergency departments in the German-speaking area has been little studied. The goal of this study was to record the occurrence of violence in a university hospital located in the inner city and to evaluate parameters, such as type of violence and accumulation in certain patient groups. MATERIAL AND METHODS: Cases of violence in the emergency department were documented by the personnel over the time frame of 1 year (March 2017 to February 2018) and retrospectively evaluated. RESULTS: An increase of violence during the evening hours (10.3% vs. 67.8%) could be shown. Intoxicated patients were responsible for the highest proportion of acts of violence. In addition, intoxicated patients were shown to be significantly more frequently aggressive than sober patients (63.72% vs. 31.65%). Non-intoxicated patients were as a rule only verbally aggressive. De-escalation by emergency room personnel was shown to be successful in 62.5% of the cases. In the rest of the cases help from outside, such as security personnel or the police was necessary, especially for intoxicated patients. DISCUSSION: Violence occurs with high regularity in emergency departments. The average incidence of acts of violence of every 0.7 days shows the need for safety precautions for hospital personnel.

Autologous cell-based therapy for treatment of large bone defects: from bench to bedside.

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.