Electromyography and range-of-motion measurements in German soldiers wearing different types of body armour while marching.

INTRODUCTION: In this study, we used surface electromyography (EMG) electrodes in order to measure and compare activity in the neck, back and thigh muscles of soldiers wearing two different types of body armour. A secondary objective was to analyse shoulder and hip ranges of motion using inertial motion sensors. METHODS: Fourteen male soldiers were instructed to march 6 km on a treadmill while wearing different types of body armour. All participants wore shorts and a T-shirt and the same size vest regardless of their body size. We measured back and thigh muscle activity as well as shoulder and hip ranges of motion at regular intervals during the march. RESULTS: Over the course of a 6 km march, muscle activity was already increased to 1.3 to 2.0 times after putting on the vest and increased by up to 13 times during the march with equipment. The new vest with hip belt required higher levels of muscle activity. CONCLUSIONS: Body armour with hip belt placed higher levels of stress on back and neck muscles during a 6 km march than without. There was no major difference between the two types of body armour in terms of thigh muscle activity. TRIAL REGISTRATION NUMBER: DRKS00016005.

RETURN TO SPORT AFTER SURGICAL TREATED TIBIAL PLATEAU FRACTURES.

Tibial plateau fractures (TPF) comprise 1% of all fractures, despite their limited frequency, due to their intraarticular nature they commonly result in significant functional morbidity. Generally, younger, and middle-aged men (64%) tend to have fractures as a result of high-energy trauma, such as high-speed motor vehicle accidents or falls from a considerable height, while older women have low-energy fractures (35%). While there is growing evidence on the clinical and radiological outcomes of surgical techniques, there remains limited evidence on return to sport following TPF. Aim of this retrospective study is to determine the sporting abilities of patients after operative treatment of TPF. 47 Patients (20 women, 27 men) who underwent surgical treatment for a TPF were surveyed by a questionnaire to determine their sporting activity were followed- up a mean of 47.6 months (Min: 12, Max: 115). All the patients fractures were systematically assessed using AO- Classification. The Lysholm-Gillquist scores, IKDC Score, Injury - Psychological Readiness to Return to Sport (I-PRRS) scales and ACL-Return to Sport Injury Scale (ACL-RSI) were used to assess clinical outcomes. All fractures united, and no revision surgeries were required. There were no intraoperative complications. Mean postoperative IKDC score was 75 (Min:13, Max: 100), mean postoperative Lysholm score was 82 (Min: 5, Max: 100), mean ACL-Return to Sport Injury Scale (ACL-RSI) was 66 (Min: 0, Max: 100), Injury-Psychological Readiness to Return to Sport Scale (I-PRRS-Scale) was 39 (Min: 0, Max: 80). 31/47 patients were able to return to their former -sports- activity level, 8/47 did not achieve their former sports activity level before injury, 2/47 cases changed their kind of sport and 6/47 stopped sporting activities. Tibial plateau fractures -a severe injury- have a great effect on patients in terms of quality and quantity of sporting activity. Nevertheless, most of our surgical treated patients were satisfied with the outcome with good values in the Lysholm- score, I-PRRS- Scale, IKDC score and ACL-Return to Sport Injury Scale.

Introduction and evaluation of a novel multi-camera surface topography system.

BACKGROUND: Surface topography can be used for the evaluation of spinal deformities without any radiation. However, so far this technique is limited to posterior trunk measurements due to the use of a single posterior camera. RESEARCH QUESTION: Purpose of this study was to introduce a new multi camera surface topography system and to test its reliability and validity. METHODS: The surface topograph uses a two-camera system for imaging and evaluating the subjects front and back simultaneously. Inter- and intra-rater reliability was tested on 40 human subjects by two observers. For validation human, subjects were scanned by MRI and surface-topography. For additional validation we used a phantom with an anthropomorphic body which was scanned by CT and surface topography. RESULTS: Inter- (0.97-0.99) and intra-rater reliability (0.81-0.98) testing revealed good and excellent results in the detection of the body surface structures and measurement of areas and volumes. CT based validation revealed good correspondence between systems in the imaging and evaluation of the phantom model (0.61-10.52 %). Results on validation of human subjects revealed good to moderate results in the detection and measurements of almost all body surface structures (1.36-13.34 %). Only measurements using jugular notch as a reference showed moderate results in validity (0.62-27.5%) testing. SIGNIFICANCE: We have introduced a novel and innovative surface topography system that allows for simultaneous anterior and posterior trunk measurements. The results of our reliability and validity tests are satisfactory. However, in particular around the jugular notch region further improvements in the surface topography reconstruction are needed.

Psychological factors outmatched morphological markers in predicting limitations in activities of daily living and participation in patients with lumbar stenosis.

BACKGROUND: Recent demographic changes have led to a large population of older adults, many of whom experience degenerative disc diseases. Degenerative lumbar spinal stenosis (DLSS) is associated with considerable discomfort and limitations in activities of daily living (ADL). Symptomatic DLSS is one of the most frequent indications for spinal surgery. The aim of this study was to identify sociodemographic variables, morphological markers, depression as well as fear of movement that predict ADL performance and participation in social life in patients with DLSS. METHODS: Sixty-seven patients with DLSS (mean age 62.5 years [11.7], 50.7% females) participated in the study. Predictor variables were age, gender, duration of disease, three morphological markers (severity of the lumbar stenosis, the number of affected segments and presence of spondylolisthesis) as well as self-reported depression and fear of movement. Dependent variables were pain interference with the performance of ADLs, ADLs and participation in social life. Correlations between predictor and dependent variables were calculated before stepwise, linear regression analyses. Only significant correlations were included in the linear regression analyses. RESULTS: Variance explained by the predictor variables ranged between 12% (R2 = .12; pain interference-physical) and 40% (R2 = .40; ADL requiring lower extremity functioning; participation). Depression and fear of movement were the most powerful predictors for all dependent variables. Among the morphological markers only stenosis severity contributed to the prediction of ADLs requiring lower extremity functioning. CONCLUSION: Depression and fear of movement were more important predictors of the execution of ADLs and participation in social life compared to morphological markers. Elevated depressive symptoms and fear of movement might indicate limited adaptation and coping regarding the disease and its consequences. Early monitoring of these predictors should therefore be conducted in every spine centre. Future studies should investigate whether psychological screening or a preoperative psychological consultation helps to avoid operations and enables better patient outcomes.

Development of a new 360-degree surface topography application.

BACKGROUND: Surface-topography has been used for almost two decades in the radiation-free clinical evaluation of spinal posture. So far, it was limited to the analysis of back surface and spine. In order to better understand, diagnose and treat complex spinal pathologies, it is important to measure the whole torso. RESEARCH QUESTION: Purpose of this study was to introduce and test an application that allows 360° reconstruction and analysis of the patient's torso. METHODS: The application uses the information gathered from eight distinct scans and angles. For validation we used an Alderson phantom as an anthropomorphic body. Defined areas and volumes were measured by CT and surface-topography. Inter- and intra-rater reliability was tested in 35 healthy subjects by two observers. RESULTS: The results revealed good correspondence between systems in the imaging and evaluation of the Alderson model (5.3-0.5%). Inter- (0.9-0.98) and intra-rater reliability (0.8-0.95) testing revealed good and excellent results in the detection of almost all body surface structures and measurement of areas and volumes. Only area and volume measurements using jugular notch as a reference showed partly moderate results in reliability (0.62-0.93) testing. SIGNIFICANCE: We were able to introduce a novel 360° torso scan application using surface topography to reconstruct torso measurements. The results of our study showed its high validity and reliability. In the future, this application needs to be tested in patients with spinal pathologies. In summary, this new application may help to better understand, diagnose and treat patients with pathologies of torso and spine.

Comparison of two different designs of forefoot off-loader shoes and their influence on gait and spinal posture.

BACKGROUND: The purpose of forefoot off-loader shoes (FOS) is to unload the operated region of the foot in order to allow early mobilization and rehabilitation. However, little is known about the actual biomechanical effects of different designs of FOS on gait, pelvis and spine. RESEARCH QUESTION: Aim of this study was to analyse and compare the effects of two different designs of forefoot unloader shoes. METHODS: Ortho-Wedge (FOS A) and Relief-Dual® (FOS B) were evaluated in this study during standing and while walking. Changes of the pelvic position and spinal posture were measured with a surface topography system and an instrumented treadmill. Gait phases were detected automatically by a built-in pressure plate. RESULTS: Both FOS resulted in a significant increase of pelvic obliquity, pelvic torsion, lateral deviation and surface rotation (p < 0.001) while standing. Between both shoe models, pelvic obliquity and lateral deviation (p < 0.05) were significantly different. During walking, both FOS had a significant effect on spine and pelvis (p < 0.05), however only minor differences were found between the designs. All gait parameters were affected more, wearing FOS A than B. Step length were significantly longer by wearing FOS (p < 0.005). However stance phase raised and swing phase is reduced on the leg wearing FOS A (p < 0.001). SIGNIFICANCE: The study showed that FOS lead to significant changes in pelvic position and spinal posture during standing and while walking. A compensating shoe on the contralateral side is therefore recommend. Gait parameters however were affected more by the traditional FOS A half-shoe. The sole- design and shape of FOS B leads to a more physiological roll-over of the foot.

[Total hip replacement in avascular femoral head necrosis]. / Endoprothetik bei aseptischer Femurkopfnekrose.

BACKGROUND: Avascular necrosis of the femoral head is a progressive perfusion disorder of the hip joint. Progress in avascular necrosis causes structural damage to the affected joint, often requiring total hip replacement. AIM: This article is intended to give the reader an overview of the current literature on total hip replacement of patients with an avascular necrosis of the femoral head. RESULTS: Before 1990, patients with avascular necrosis of the femoral head had significantly higher revision rates after total hip replacement. Recent studies, however, showed no significant differences in clinical outcomes after total hip replacement in femoral head necrosis and primary osteoarthritis. Despite the young age of the patients, good long-term clinical results can be expected even in patients with an avascular necrosis of the femoral head after total hip replacement.

[Current overview of cartilage regeneration procedures]. / Aktuelle Übersicht knorpelregenerativer Verfahren.

BACKGROUND: Cartilage is an avascular, alymphatic and non-innervated tissue with limited intrinsic repair potential. The high prevalence of cartilage defects and their tremendous clinical importance are a challenge for all treating physicians. AIM: This article provides the reader with an overview about current cartilage treatment options and their clinical outcome. METHODS: Microfracture is still considered the gold standard in the treatment of small cartilage lesions. Small osteochondral defects can be effectively treated with the autologous osteochondral transplantation system. Larger cartilage defects are successfully treated by autologous membrane-induced chondrogenesis (AMIC) or by membrane-assisted autologous chondrocyte implantation (MACI). CONCLUSION: Despite limitations of current cartilage repair strategies, such procedures can result in short- and mid-term clinical improvement of the patients. Further developments and clinical studies are necessary to improve the long-term outcome following cartilage repair.

[Cartilage repair of the knee joint]. / Knorpelreparative Eingriffe am Kniegelenk.

BACKGROUND: Cartilage defects around the knee joint frequently occur in the region of the medial femoral condyle and the retropatellar cartilage surface. The distinction between local cartilage defects and large area degenerative cartilage lesions is very important for both prognosis and surgical therapy. The size and position of the lesion, the underlying pathomechanism and the age of the patient are very important factors which should be considered in the therapy algorithm for optimal cartilage defect restoration. Important cofactors such as stability, long leg axis and muscle balance should be taken into account. AIM: Current procedures for cartilage repair of the knee joint and their results are summarized in this article. In addition, the necessity of precise and comprehensive preoperative clinical and radiological diagnostics is displayed to be able to treat co-pathologies in order to enable a successful repair of the cartilage defect. RESULTS AND CONCLUSIONS: Preoperative planning of cartilage-repair techniques usually includes x­ray images and a magnetic resonance imaging (MRI) examination. If MRI is not available, an arthro-computed tomography could be an alternative. Modern and routinely used procedures for cartilage repair at the knee joint are microfracture, autologous matrix-induced chondrogenesis, autologous chondrocyte transplantation, matrix-induced autologous chondrocyte implantation and osteochondral transplantation. Successful surgical cartilage-repair surgeries require a correct and individualized indication, addressing of copathologies and a standardized rehabilitation that is adapted to the surgical procedure. Evidence-based criteria for an exact time point for the return to sports according to individually operative cartilage repair techniques currently do not exist.

A comparative study of mechanical properties of fresh and frozen-thawed porcine intervertebral discs in a bioreactor environment.

Limited availability of fresh intervertebral discs (IVDs) necessitates the use of frozen-thawed samples in biomechanical investigations. Several authors have reported the mechanical properties of frozen-thawed IVDs, but few studies have investigated the effects of storage temperature and cooling rate. The validity and reliability of the applied freezing-thawing procedures are still relatively unknown. The study aims to compare the mechanical responses of fresh porcine IVDs and porcine IVDs, which were frozen at different freezing temperatures with a controlled-rate cooling process and then thawed. The specimens were obtained from pigs aged 6 months. A total of 18 functional spine units (FSUs) were taken from seven porcine lumbar spines (L1-L6). The specimens were then split into three groups. The first group was tested fresh immediately and the other two groups were frozen at the same cooling rate and stored at -20°C and -80°C, respectively, before testing. The period of storage ranged between 12 and 43 days. The frozen specimens were thawed for 9h at room temperature before the tests. A special IVD bioreactor, which maintained the realistic behaviour of IVDs under various loading conditions, was developed. The analysis of variance (ANOVA) was used to determine if the observed results were statistically significant. The results indicated that frozen storage at -20°C decreases the comprehensive stiffness. In contrast, freezing to -80°C did not seem to have any effect on the mechanical properties of IVDs. No significant differences in outcome were observed for the samples, which had different spine levels. The study confirmed the reliability and usability of frozen-thawed samples stored at -80°C for biomechanical investigations.

[Hip arthroplasty after corrective osteotomies : Pelvis and proximal femur]. / Hüftendoprothetik nach korrigierenden Osteotomien : Becken und proximales Femur.

BACKGROUND: Pelvic and femoral osteotomies are frequently performed in patients with hip dysplasia. The aim of these surgeries are optimal biomechanical conditions of the hip joint thereby avoiding the occurrence of hip osteoarthritis or the delay of initial hip osteoarthritis progression. THERAPY: Nevertheless even with good biomechanical conditions of the hip joint, progression of hip osteoarthritis can be recognized postoperatively. A total hip arthroplasty is indicated even more after a time period with conservative treatment. In preparation for the operation, a detailed documentation of the initial clinical situation, appropriate imaging, implant selection and preoperative planning are mandatory. In addition, a biomechanical model representing the desired pre- and postoperative situation can be included in the preoperative planning. According to the previous osteotomy, the size and shape of the acetabulum after the osteotomy and the current pivot centre of the hip joint should be considered. Depending on these observations the acetabular cup can be directly inserted into the bone stock of the acetabulum or an acetabular plasty is necessary before implantation of the acetabular cup. With respect to the previous osteotomy of the femur, it needs to be clarified wether hardware removal will be necessary before total hip replacement; moreover, the anatomy of the proximal femur is critical. In addition, if necessary, a re-osteotomy of the femur is required to enable a hip stem implantation. CONCLUSION: Cementless total hip replacement should be preferred due to the younger patient age. The load of the hip replacement depends on the osseous anchoring and primary stability of the acetabular and femoral component.

[Fusion in adolescent idiopathic scoliosis : Anterior, posterior or combined? One-stage or two-stage?]. / Korrekturspondylodesen von adoleszenter idiopathischer Skoliose : Ventral, dorsal, ventrodorsal? Einzeitig oder zweizeitig?

Scoliosis is a complex, three-dimensional spinal deformity with various causes. Adolescent idiopathic scoliosis (AIS) is the most common form. Surgical treatment is indicated for curves greater than 45-50° meaured using the Cobb method. We can distinguish among posterior, anterior or combined surgical procedures. Today, the posterior, transpedicular approach has revolutionized scoliosis surgery. This review gives an overview of current surgical options in scoliosis treatment.

[Adolescent scoliosis : From deformity to treatment]. / Skoliose im Wachstumsalter : Von der Deformität zur Therapie.

Scoliosis affects up to 6 % of the population. The resulting spine deformity, the increasing risk of back pain, cosmetic aspects, pulmonary disorders if the Cobb angle is > 80°, and the progress of the deformity to > 50° after the end of growth indicate non-operative or operative therapy. In daily clinical practice, the classifications of scoliosis allow the therapy to be adapted. Classifications consider deformity, topography of the scoliosis, and the age at diagnosis. This publication gives an overview of the relevant and most common classifications in the treatment of adolescent scoliosis. For evaluation, the deformity measurement on the coronary radiographic projection of the total spine (Cobb angle) is relevant to therapy. The classification of topography, form, and the sagittal profile of the deformity of the spine are useful for preoperative planning of the fusion level. Classifications that take into account the age at the time of the diagnosis of scoliosis differentiate among early onset scoliosis (younger than 10 years of age), adolescent scoliosis (up to the end of growth), and adult scoliosis. Early onset scoliosis is subdivided by age and etiology. Therapy is derived from the classification of clinical and radiological findings. Classifications that take into account clinical and radiological parameters are essential components of modern scoliosis therapy.

[Radiation-free diagnosis of scoliosis : An overview of the surface and spine topography]. / Strahlenfreie Diagnostik bei Skoliosen : Ein Überblick über die Oberflächen- und Wirbelsäulentopographie.

BACKGROUND: Scoliosis is a complex three-dimensional deformity of the spine, which usually occurs during childhood and adolescence. Up to now, whole spine X-rays have been the therapeutic gold standard in the diagnosis and follow-up of scoliosis. AIM: This review gives a brief overview of the history, technical background and possible fields of use for video-rasterstereography METHODS: Alternative measurement systems have been developed over the past few years for the treatment of scoliosis, because of the risk of radiation exposure of X-rays. The rasterstereographic system Formetric (Diers International GmbH, Schlagenbad) allows a radiation-free, three-dimensional analysis of the back surface and the spine. OUTLOOK: Even dynamic measurements can now be conducted with this rasterstereographic system, which will help to further understand and analyze the human spine.

[Multidisciplinary Rehabilitation and Fast-track Rehabilitation after Knee Replacement: Faster, Better, Cheaper? A Survey and Systematic Review of Literature]. / Multidisziplinäre Rehabilitation und multimodale Fast-Track-Rehabilitation in der Knieendoprothetik: Schneller, besser, günstiger? Eine Umfrage und systematische Literaturrecherche.

INTRODUCTION: The aim of multidisciplinary rehabilitation after total knee replacement (TKA) is to reduce postoperative complications and costs and enable faster convalescence. The goals of fast-track rehabilitation, as a multidisciplinary concept, are to reduce the length of hospital stay and achieve early functional improvements by optimizing the perioperative setting. METHOD: A literature review was carried out for the years 1960-2013. The search terms were: "rehabilitation", "training", "physiotherapy", "physical therapy", "recovery", "exercise program", "knee surgery", "TKA", "total knee replacement", "arthroplasty", "intensive", "multidisciplinary", "accelerated", "rapid" or "fast track". Only randomized controlled trials and metaanalyses were included. A survey was also performed to assess care as actually offered in orthopaedic rehabilitation clinics in North Rhine-Westphalia. RESULTS: A total of 729 articles were identified of which 11 studies were included. Fast-track rehabilitation can significantly reduce both the duration of hospital stay and costs after TKA. Current studies showed that a better short-/middle-term clinical outcome might be achieved with multidisciplinary rehabilitation. However, a difference in the long-term outcome could not be observed. Our survey shows that most patients are admitted to a rehabilitation clinic in a state of poor general condition as well as decreased mobility and knee range of motion. CONCLUSIONS: Fast-track rehabilitation facilitates a shortened hospital stay as well as cost saving. It probably can be used to optimize the condition of the patient before admission to a rehabilitation facility.

[Pathophysiology of traumatic bone marrow edema]. / Pathophysiologie des traumatischen Knochenmarködems.

BACKGROUND: Morphologically, bone marrow edema (BME) is an accumulation of fluid in the bone marrow. The BME is per se non-specific but can be identified at an early stage with magnetic resonance imaging (MRI). The underlying pathomechanism remains unclear. The BME can occur as an individual entity and as an accompanying condition of many diseases. The BME can be divided into three groups, ischemic, reactive and mechanical BME. Mechanical BME occurs after trauma or repetitive strain. Typical histological changes are present and there is no clear boundary between edema and microfracture. Some forms of trauma show BME in typical localizations. Both the trauma and the possible accompanying injuries can be indirectly indicated in this way in cases with an unknown trauma mechanism. CONCLUSION: The BME can be present as an isolated entity or as a comorbidity. For initiation of therapy, a comprehensive medical history and targeted diagnostics are indispensable. In some cases BME is indicative of the trauma mechanism and possible further accompanying injuries.

Hyperbaric oxygen therapy improves angiogenesis and bone formation in critical sized diaphyseal defects.

Besides the use of autologous bone grafting several osteoconductive and osteoinductive methods have been reported to improve bone healing. However, persistent non-union occurs in a considerable number of cases and compromised angiogenesis is suspected to impede bone regeneration. Hyperbaric oxygen therapy (HBO) improves angiogenesis. This study evaluates the effects of HBO on bone defects treated with autologous bone grafting in a bone defect model in rabbits. Twenty-four New-Zealand White Rabbits were subjected to a unilateral critical sized diaphyseal radius bone defect and treated with autologous cancellous bone transplantation. The study groups were exposed to an additional HBO treatment regimen. Bone regeneration was evaluated radiologically and histologically at 3 and 6 weeks, angiogenesis was assessed by immunohistochemistry at three and six weeks. The additional administration of HBO resulted in a significantly increased new bone formation and angiogenesis compared to the sole treatment with autologous bone grafting. These results were apparent after three and six weeks of treatment. The addition of HBO therapy to autologous bone grafts leads to significantly improved bone regeneration. The increase in angiogenesis observed could play a crucial role for the results observed.

The treatment of the acute Essex-Lopresti injury.

The Essex-Lopresti injury (ELI) of the forearm is a rare and serious condition which is often overlooked, leading to a poor outcome. The purpose of this retrospective case study was to establish whether early surgery can give good medium-term results. From a group of 295 patients with a fracture of the radial head, 12 patients were diagnosed with ELI on MRI which confirmed injury to the interosseous membrane (IOM) and ligament (IOL). They were treated by reduction and temporary Kirschner (K)-wire stabilisation of the distal radioulnar joint (DRUJ). In addition, eight patients had a radial head replacement, and two a radial head reconstruction. All patients were examined clinically and radiologically 59 months (25 to 90) after surgery when the mean Mayo Modified Wrist Score (MMWS) was 88.4 (78 to 94), the mean Mayo Elbow Performance Scores (MEPS) 86.7 (77 to 95) and the mean disabilities of arm, shoulder and hand (DASH) score 20.5 (16 to 31): all of these indicate a good outcome. In case of a high index of suspicion for ELI in patients with a radial head fracture, we recommend the following: confirmation of IOM and IOL injury with an early MRI scan; early surgery with reduction and temporary K-wire stabilisation of the DRUJ; preservation of the radial head if at all possible or replacement if not, and functional bracing in supination. This will increase the prospect of a good result, and avoid the complications of a missed diagnosis and the difficulties of late treatment.

The early phase influence of bone marrow concentrate on metaphyseal bone healing.

Bone marrow concentrate (BMC) contains high densities of progenitor cells. Therefore, in critical size defects BMC may have the potency to support bone healing. The aim of this study was to investigate the effect of BMC in combination with calcium phosphate granules (CPG) on bone defect healing in a metaphyseal long bone defect in mini-pigs. A metaphyseal critical-size bone defect at the proximal tibia of 24 mini-pigs was filled with CPG combined with BMC, CPG solely (control group) or with an autograft. Radiological and histomorphometrical evaluations after 6 weeks (42 days) showed significantly more bone formation in the BMC group in the central area of the defect zone and the cortical defect zone compared to the CPG group. At the same time the resorption rate of CPG increased significantly in the BMC group. Nevertheless, compared to the BMC group the autograft group showed a significantly higher new bone formation radiologically and histomorphometrically. In BMC the count of mononuclear cells was significantly higher compared to the bone marrow aspirate (3.5-fold). The mesenchymal progenitor cell characteristics of the cells in BMC were confirmed by flow cytometry. Cells from BMC created significantly larger colonies of alkaline phosphatase-positive colony forming units (CFU-ALP) (4.4-fold) compared to cells from bone marrow aspirate. Nevertheless, even in the BMC group complete osseous bridging was only detectable in isolated instances of the bone defects. Within the limitations of this study the BMC+CPG composite promotes bone regeneration in the early phase of bone healing significantly better than the isolated application of CPG. However, the addition of BMC does not lead to a solid fusion of the defect in the early phase of bone healing an still does not represent an equal alternative to autologous bone.

Bone marrow concentrate for autologous transplantation in minipigs. Characterization and osteogenic potential of mesenchymal stem cells.

Autologous bone marrow plays an increasing role in the treatment of bone, cartilage and tendon healing disorders. Cell-based therapies display promising results in the support of local regeneration, especially therapies using intra-operative one-step treatments with autologous progenitor cells. In the present study, bone marrow-derived cells were concentrated in a point-of-care device and investigated for their mesenchymal stem cell (MSC) characteristics and their osteogenic potential. Bone marrow was harvested from the iliac crest of 16 minipigs. The mononucleated cells (MNC) were concentrated by gradient density centrifugation, cultivated, characterized by flow cytometry and stimulated into osteoblasts, adipocytes, and chondrocytes. Cell differentiation was investigated by histological and immunohistological staining of relevant lineage markers. The proliferation capacity was determined via colony forming units of fibroblast and of osteogenic alkaline-phosphatase-positive-cells. The MNC could be enriched 3.5-fold in nucleated cell concentrate in comparison to bone marrow. Flow cytometry analysis revealed a positive signal for the MSC markers. Cells could be differentiated into the three lines confirming the MSC character. The cellular osteogenic potential correlated significantly with the percentage of newly formed bone in vivo in a porcine metaphyseal long-bone defect model. This study demonstrates that bone marrow concentrate from minipigs display cells with MSC character and their osteogenic differentiation potential can be used for osseous defect repair in autologous transplantations.