Purpose. In patients with multiple trauma delayed fracture healing is often diagnosed, but the pathomechanisms are not well known yet. The purpose of the study is to evaluate the effect of a severe hemorrhagic shock on fracture healing in a murine model. Methods. 10 male C57BL/6N mice per group (Fx, TH, THFx, Sham) and point in time were used. The Fx-group received an osteotomy after implantation of a fixateur extern. The TH-group got a pressure controlled hemorrhagic shock with a mean arterial blood pressure of 35 mmHg over 90 minutes. Resuscitation with 4 times the shed blood volume of Ringer solution was performed. The THFx group got both. Sham-animals received the implantation of a catheter and a fixateur extern but no blood loss or osteotomy. After 1, 2, 3, 4 or 6 weeks the animals were sacrificed. For the biomechanics the bones were analyzed via X-ray, µCT and underwent a 3-point bending test. The nondecalcified histology based on slices of Technovit 9100. The signaling pathway was analyzed via RT. 2. Profiler™ PCR Array Mouse Osteoporosis, Western Blot and Quantikine ELISA for RankL and OPG. Statistical significance was set at p < 0.05. Comparisons between groups were performed using the Mann–Whitney U (Fx vs. THFx) or Kruskal-Wallis Test (other groups). Results. The experiment showed that after 1 week the bones of the Fx- and THFx-mice were macroscopically instable. After 2 weeks the Fx-group showed macroscopically a stable bridging whereas the bones of the THFx-group were partly not stable bridged. 3 weeks after surgery the bones of both groups were stable bridged. Analysis via µCT showed that trauma hemorrhage leads to decreased density of the bone and callus and also to increased share of callus per bone volume after 2 weeks. The 3-point-bending test showed that the maximum bending moment is decreased in the group THFx compared to Fx after 2 weeks. The studies of the histology showed after 2 weeks a decrease in bone and cartilage after trauma-hemorrhage by optical analysis of photographs of the slices. The analyses of the signaling pathway pointed to an involvement of the RankL/Opg and IL6 pathway. Conclusion. A hemorrhagic shock has a negative effect on fracture healing in terms of reduced density of the bone and callus, increased share of callus per bone volume, decreased maximum bending moment, reduced mineralization of the callus and leads to changes in the RankL/Opg and IL6 pathways

The effects of extracorporeal shock waves (ESWT) on tendon healing were assessed by observing histological and biomechanical parameters in a rat model of injury to the tendo Achillis. The injury was created by inserting an 18-G needle through tendo Achillis in 48 adult Wistar albino rats. The animals were divided into three groups. The first group received radiation only after the operation. The second received no shock waves and the third had 500 15 KV shocks on the second post-operative day. All the rats were killed on the 21st day after surgery. Histopathological analysis showed an increase in the number of capillaries and less formation of adhesions in the study group compared with the control group (p = 0.03). A significantly greater force was required to rupture the tendon in the study group (p = 0.028). Our findings suggest a basis for clinical trials using ESWT

A substantial body of evidence supports the use of extracorporeal shock wave therapy (ESWT) for fracture non-unions in human medicine. However, the success rate (i.e., radiographic union at six months after ESWT) is only approximately 75%. Detailed knowledge regarding the underlying mechanisms that induce bio-calcification after ESWT is limited. The aim of the present study was to analyse the biological response within mineralized tissue of a new invertebrate model organism, the zebra mussel Dreissena polymorpha, after exposure with extracorporeal shock waves (ESWs). Mussels were exposed to ESWs with positive energy density of 0.4 mJ/mm. 2. or were sham exposed. Detection of newly calcified tissue was performed by concomitantly exposing the mussels to fluorescent markers. Two weeks later, the fluorescence signal intensity of the valves was measured. Mussels exposed to ESWs showed a statistically significantly higher mean fluorescence signal intensity within the shell zone than mussels that were sham exposed. Additional acoustic measurements revealed that the increased mean fluorescence signal intensity within the shell of those mussels that were exposed to ESWs was independent of the size and position of the focal point of the ESWs. These data demonstrate that induction of bio-calcification after ESWT may not be restricted to the region of direct energy transfer of ESWs into calcified tissue. The results of the present study are of relevance for better understanding of the molecular and cellular mechanisms that induce formation of new mineralized tissue after ESWT. Specifically, bio-calcification following ESWT may extend beyond the direct area of treatment

We aimed to determine whether extracorporeal shock waves of varying intensity would damage the intact tendo Achillis and paratenon in a rabbit model. We used 42 female New Zealand white rabbits randomly divided into four groups as follows: group a received 1000 shock-wave impulses of an energy flux density of 0.08 mJ/mm. 2. , group b 1000 impulses of 0.28 mJ/mm. 2. , group c 1000 impulses of 0.60 mJ/mm. 2. , and group d was a control group. Sonographic and histological evaluation showed no changes in group a, and transient swelling of the tendon with a minor inflammatory reaction in group b. Group c had formation of paratendinous fluid with a significant increase in the anteroposterior diameter of the tendon. In this group there were marked histological changes with increased eosin staining, fibrinoid necrosis, fibrosis in the paratenon and infiltration of inflammatory cells. We conclude that there are dose-dependent changes in the tendon and paratenon after extracorporeal shock-wave therapy and that energy flux densities of over 0.28 mJ/mm. 2. should not be used clinically in the treatment of tendon disorders

Extracorporeal shock-wave (ESW) treatment hasbeen shown to be effective in promoting the healing of fractures. We aimed to determine whether ESW could enhance the growth of bone-marrow osteoprogenitor cells. We applied ESW to the left femur of rats 10 mm above the knee at 0.16 mJ/mm² in a range of between 250 and 2000 impulses. Bone-marrow cells were harvested after ESW for one day and subjected to assessment of colony-forming unit (CFU) granulocytes, monocytes, erythocytes, megakaryocytes (CFU-Mix), CFU-stromal cells (CFU-S) and CFU-osteoprogenitors (CFU-O).

We found that the mean value for the CFU-O colonies after treatment with 500 impulses of ESW was 168.2 CFU-O/well (sem 11.3) compared with 88.2 CFU-O/well (sem 7.2) in the control group. By contrast, ESW treatment did not affect haematopoiesis as shown by the CFU-Mix (p = 0.557). Treatment with 250 and 500 impulses promoted CFU-O, but not CFU-Mix formations whereas treatment with more than 750 impulses had an inhibiting effect. Treatment with 500 impulses also enhanced the activity of bone alkaline phosphatase in the subculture of CFU-O (p< 0.01), indicating a selective promotion of growth of osteoprogenitor cells. Similarly, formation of bone nodules in the long-term culture of bone-marrow osteoprogenitor cells was also significantly enhanced by ESW treatment with 500 impulses. The mean production of TGF-β1 was 610 pg/ml (sem 84.6) in culture supernatants from ESW-treated rats compared with 283 pg/ml (sem 36.8) in the control group.

Our findings suggest that optimal treatment with ESW could enhance rat bone-marrow stromal growth and differentiation towards osteoprogenitors presumably by induction of TGF-β1.

Introduction and Objective. Hemorrhagic shock and fractures are the most common injuries within multiple injured patients, inducing systemic and local inflammation in NF-kappaB-dependent manner. Alcohol intoxication, showing a high incidence with severe injuries, has immunomodulatory properties and implicates NF-kappaB downregulation. However, the mechanism is largely unknown. A20 deubiquitinase is a critical negative regulator of NF-kappaB activity and inflammation. Here, we investigate the role of A20 as a modifier of NF-kappaB-driven inflammation and remote lung injury in severely injured and alcohol-intoxicated mice. Materials and Methods. Mice were randomly divided into four groups. Either sodium chloride or ethanol (35%, EtOH) was administrated by intragastral gavage one hour before trauma induction. In the trauma group, the animals underwent an osteotomy with external fracture fixation (Fx) followed by a pressure-controlled hemorrhagic shock (35±5 mmHg; 90 minutes) with subsequent resuscitation (H/R). Sham-operated animals underwent only surgical procedures. Mice were sacrificed at 24 hours. Fatty vacuoles and thus, the alcohol intoxication were evaluated by Oil red O staining of the liver. To assess the lung injury, hematoxylin eosin staining, determination of total protein concentration in bronchoalveolar lavage (BALF) and calculation of the lung injury score (LIS) were performed. Lungs were stained for neutrophil elastase, CXCL1 and active caspase-3 to determine neutrophil invasion, pro-inflammatory changes and apoptosis, respectively. The expression level of A20 was evaluated by immunofluorescence microscopy. Results. EtOH induced significant fatty changes in the liver. Fx+H/R led to trauma-induced lung injury, significantly enhancing the total protein concentration in the BALF and the histomorphological LIS compared to sham animals. In turn, EtOH reduced the lung injury in Fx+H/R. The expression of CXCL1 and activated caspase-3 as well as the pulmonary neutrophil infiltration were significantly enhanced in Fx+H/R vs. sham, whereas A20 protein expression was reduced. EtOH+Fx+H/R caused reduced pulmonary neutrophil invasion, CXCL1 expression, and apoptosis compared to Fx+H/R, whereas the A20 protein expression in the lungs was increased. Conclusions. In murine Fx+H/R trauma model, EtOH ameliorates the extent of the remote lung injury. The immunosuppressive effect may be caused by elevated pulmonary levels of A20 deubiquitase, indicating a suppression of NF-kappaB activation

Introduction. The management of pathologic fractures (PF) following osteomyelitis (especially acute subtype) has not been widely investigated. This is challenging due to the infection-induced destructive process causing bone architecture defects. Therefore, this study aims to assess a stepwise treatment plan for the acute incidence of PF in long bone following pediatric acute Hematogenous osteomyelitis(AHO) (the most common mechanism in children). Method. This case series was conducted in a tertiary pediatric center. Patients with fracture incidence within the first 10 days after AHO diagnosis were included. Patients’ characteristics were retrospectively reviewed. Result. Nine patients (7 boys, involved bone: the femur(4), tibia(3), Radius(1), and Ulna(1)) were included, with a mean age of 52.56±66.18 months (7-216) and a follow-up time of 11.62±3.61 years (6.5-16 years). The etiology in all patients was hematological(Methicillin-resistant Staphylococcus aureus). Our stepwise treatment plan was as follows:. 1. Intravenous antibiotics until ESR<20, then oral to ESR<5. 2. Debridemnt surgery was performed if abscesses were detected. 3. Fracture type determined initial fixation: external fixation (4 patients, 2 unions) or casting (2 patients, both unions). 4. If the union was not obtained, internal fixation (with (2 patients) or without (2 patients) bone graft) was applied (all obtained union). 5. Circular external fixation was applied if the union was not obtained or leg length discrepancy occurred (1 case). A mean of 3.2 surgical procedures (1-6) was required to control the infection, and 1.4 surgical procedures (0-4) were required to obtain union. Except for one patient who died of septic shock, all other patients (88.8%) reached complete recovery (average length of hospital stay of 19.2 days (5-35).), and the union was obtained (the average union time of 17.25 months(4-36)) without long-term sequelae of osteomyelitis. Conclusion. The outcome of the stepwise plan in this study suggests that acute PF following AHO in pediatrics can be managed efficiently

Menisci are crucial structures for knee homeostasis: they provide increase of congruence between the articular surfaces of the distal femur and tibial plateau, bear loading, shock absorption, lubrication, and proprioception. After a meniscal lesion, the golden rule, now, is to save as much meniscus as possible: only the meniscus tissue which is identified as unrepairable should be excised and meniscal sutures find more and more indications. Several different methods have been proposed to improve meniscal healing. They include very basic techniques, such as needling, abrasion, trephination and gluing, or more complex methods, such as synovial flaps, meniscal wrapping, or the application of fibrin clots. Basic research of meniscal substitutes has also become very active in the last decades. The features needed for a meniscal scaffold are: promotion of cell migration, it should be biomimetic and biocompatible, it should resist forces applied and transmitted by the knee, it should slowly biodegrade and should be easy to handle and implant. Several materials have been tested, that can be divided into synthetic and biological. The first have the advantage to be manufactured with the desired shapes and sizes and with precise porosity dimension and biomechanical characteristics. To date, the most common polymers are polylactic acid (PGA); poly-(L)-lactic acid (PLLA); poly- (lactic-co-glycolic acid) (PLGA); polyurethane (PU); polyester carbon and polycaprolactone (PCL). The possible complications, more common in synthetic than natural polymers are poor cell adhesion and the possibility of developing a foreign body reaction or aseptic inflammation, leading to alter the joint architecture and consequently to worsen the functional outcomes. The biological materials that have been used over time are the periosteal tissue, the perichondrium, the small intestine submucosa (SIS), acellular porcine meniscal tissue, bacterial cellulose. Although these have a very high biocompatibility, some components are not suitable for tissue engineering as their conformation and mechanical properties cannot be modified. Collagen or proteoglycans are excellent candidates for meniscal engineering, as they maintain a high biocompatibility, they allow for the modification of the porosity texture and size and the adaptation to the patient meniscus shape. On the other hand, they have poor biomechanical characteristics and a more rapid degradation rate, compared to others, which could interfere with the complete replacement by the host tissue. An interesting alternative is represented by hydrogel scaffolds. Their semi-liquid nature allows for the generation of scaffolds with very precise geometries obtained from diagnostic images (i.e. MRI). Promising results have been reported with alginate and polyvinyl alcohol (PVA). Furthermore, hydrogel scaffolds can be enriched with growth factors, platelet-rich plasma (PRP) and Bone Marrow Aspirate Concentrate (BMAC). In recent years, several researchers have developed meniscal scaffolds combining different biomaterials, to optimize the mechanical and biological characteristics of each polymer. For example, biological polymers such as chitosan, collagen and gelatin allow for excellent cellular interactions, on the contrary synthetic polymers guarantee better biomechanical properties and greater reliability in the degradation time. Three-dimensional (3D) printing is a very interesting method for meniscus repair because it allows for a patient-specific customization of the scaffolds. The optimal scaffold should be characterized by many biophysical and biochemical properties as well as bioactivity to ensure an ECM-like microenvironment for cell survival and differentiation and restoration of the anatomical and mechanical properties of the native meniscus. The new technological advances in recent years, such as 3D bioprinting and mesenchymal stem cells management will probably lead to an acceleration in the design, development, and validation of new and effective meniscal substitutes

We undertook a study of the anti-tumour effects of hyperthermia, delivered via magnetite cationic liposomes (MCLs), on local tumours and lung metastases in a mouse model of osteosarcoma. MCLs were injected into subcutaneous osteosarcomas (LM8) and subjected to an alternating magnetic field which induced a heating effect in MCLs. A control group of mice with tumours received MCLs but were not exposed to an AMF. A further group of mice with tumours were exposed to an AMF but had not been treated with MCLs. The distribution of MCLs and local and lung metastases was evaluated histologically. The weight and volume of local tumours and the number of lung metastases were determined. Expression of heat shock protein 70 was evaluated immunohistologically. Hyperthermia using MCLs effectively heated the targeted tumour to 45°C. The mean weight of the local tumour was significantly suppressed in the hyperthermia group (p = 0.013). The mice subjected to hyperthermia had significantly fewer lung metastases than the control mice (p = 0.005). Heat shock protein 70 was expressed in tumours treated with hyperthermia, but was not found in those tumours not exposed to hyperthermia. The results demonstrate a significant effect of hyperthermia on local tumours and reduces their potential to metastasise to the lung

Meniscus has many important functions in the knee joint such as load bearing, shock absorption, joint stability, joint lubrication and proprioception. In the recent years, meniscus injuries have been the focus of orthopaedic surgeons and musculoskeletal tissue engineering applications because of its avascular nature. In this study, we aimed to compare the regeneration capacities of two composite scaffolds in a New Zealand Rabbit meniscal defect model. The first scaffold consists Poly-Lactic Acid (PLA) + chitosan + loofah and the second PLA + Hydroxyapatite (HAp) + loofah. In order to produce these scaffolds; 4% chitosan, 4% PLA and 4% HAp solutions were seperately prepared. The loofah pieces were saturated with these solutions and vacuum-dried for 14 days and sterilized with ethylene oxide. There were several characterizations performed such as Fourier Transform Infrared Spectroscopy (FTIR) for the investigation of chemical structure, Scanning Electron Microscopy (SEM) for morphological analysis, thermogravimetric differential thermal analysis (TGA/DTA) for thermal properties, mechanical compression and swelling ratio analysis. Moreover, in order to investigate biocompatibility of the scaffolds, WST-1 colorimetric assay at days 3, 7, 10, 14 and 21 was conducted. After these biocompatibility analysis, a 1.5-mm cylindrical defect was created in the avascular portion of the anterior horn of the medial meniscus in 14 New Zealand rabbits (2.5–3 kg weight) which were randomly grouped in two. The scaffolds were implanted at the defect site with the help of a freshly prepared fibrin glue. 8 weeks after the operation, the rabbits were sacrificed and their tissues were kept for further mechanical, radiological and histological analysis. In conclusion, we succeeded to produce a new meniscus scaffold. The proliferation ability of PLA + chitosan + loofah scaffold is higher than PLA + HAp + loofah scaffold. However, there was no statistically significant difference among them

Introduction. Proteomic analysis has the ability to reveal both the different types and abundances of proteins in a sample. To date, proteomic analysis has received limited attention in the field of tendon research, with mainly ex vivo investigations being undertaken to characterize the tendon proteome. A significant development would be the ability to detect in vivo changes in the proteomic composition as this could have clearer and more direct understanding on the efficiency of therapies. It is well documented that sample preparation is one of the most crucial steps in obtaining high quality resolution of proteins in mass spectrometry. Biological samples can vary in complexity, and minimization of this through sample handling and cleaning can drastically improve the resolved peptide spectra. During this investigation, samples of microdialysis media from the peritendinous space of the Achilles tendon pre or post shockwave therapy were used to establish whether the in vivo identification and quantification of proteins was possible. Materials and Methods. Six microdialysis samples were obtained from human subjects before (controls) or after shock wave therapy on their achilles tendon. Samples were concentrated and intefering substances removed using StrataClean™ resin. Reduction, alkylation and an In-solution tryptic digestion was performed with the prior addition of 1% Rapigest SF solution. Samples were then analysed by Liquid Chromatography Mass Spectrometry/Mass Spectrometry. Data files were searched using IPI-human database using Mascot Search Engine. Relative quantification was performed between groups by ProgenesisQI. Results. An increase in protein concentration within dialysis media following treatment was observed. Protein identifications included extracellular matrix proteins such as collagens and proteoglycans, and cellular proteins. In total there were 93 quantifiable proteins identified, of these 80 proteins had a p<0.05 and 2 fold change difference; 61 higher and 19 lower in post shock wave therapy. Discussion. We are able to identify a range of differentially expressed proteins in dialysis fluid subsequent to shock-wave therapy of the Achilles tendon. This type of analysis could be used to monitor efficiencies, and identify mechanisms of therapies by detection of specific biomarkers

Purpose. Collagen-rich structures of the knee are prone to damage through acute injury or chronic “wear and tear”. Collagen becomes more disorganised in degenerative tissue e.g. osteoarthritis. An alignment index (AI) used to analyse orientation distribution of collagen-rich structures is presented. Method. A healthy caprine knee was scanned in a Siemens Verio 3T Scanner. The caprine knee was rotated and scanned in nine directions to the main magnetic field B. 0. A 3D PD SPACE sequence with isotropic 1×1×1mm voxels (TR1300ms, TE13ms, FOV256mm,) was optimised to allow for a greater angle-sensitive contrast. For each collagen-rich voxel the orientation vector is computed using Szeverenyi and Bydder's method. Each orientation vector reflects the net effect of all the fibres comprised within a voxel. The assembly of all unit vectors represents the fibre orientation map. Alignment Index (AI) in any direction is defined as a ratio of the fraction of orientations within 20° (solid angle) centred in that direction to the same fraction in a random (flat) case. In addition, AI is normalised in such a way that AI=0 indicates isotropic collagen alignment. Increasing AI values indicate increasingly aligned structures: AI=1 indicates that all collagen fibres are orientated within the cone of 20° centred at the selected direction. AI = (nM - nRnd)/(nTotal - nRnd) if nM >= nRnd. AI = 0 if nM < nRnd. Where:. nM is a number of reconstructed orientations that are within a cone of 20° centred in selected direction. nRnd is a number of random orientations within a cone of 20° around selected direction. nTotal is a number of collagen reach voxels. By computing AI for a regular gridded orientation space we are able to visualise change of AI on a hemisphere facilitating understanding of the collagen fibre orientation distribution. Results. The patella tendon had an AI=0.6453. The Anterior Cruciate Ligament (ACL) had an AI=0.2732. The meniscus had an AI=0.1847. Discussion. The most aligned knee structure is the patella tendon where the collagen fibres align with the skeleton to transmit forces through bones and muscles. This structure had the AI closest to 1. The ACL had the second highest AI and is composed of two fibre bundles aligned diagonally across the knee. The meniscus acts as a shock absorber and is made up of vertical, radial and circumferential fibres which disperse forces more equally. The complexity of the meniscal structure resulted in the lowest AI. To date, this technique has only been performed with healthy tissue; the AI may become closer to zero if there is damage disrupting the collagen fibre alignment. The AI can further our understanding of collagen orientation distribution and could be used as a quantitative, non-invasive measure of structural health

A large number of total hip arthroplasties (THA) are performed each year, of which 60 % use cementless femoral fixation. This means that the implant is press-fitted in the bone by hammer blows. The initial fixation is one of the most important factors for a long lasting fixation [Gheduzzi 2007]. It is not easy to obtain the point of optimal initial fixation, because excessively press-fitting the implant by the hammer blows can cause peak stresses resulting in femoral fracture. In order to reduce these peak stresses during reaming, IMT Integral Medizintechnik (Luzern, Switzerland) designed the Woodpecker, a pneumatic reaming device using a vibrating tool. This study explores the feasibility of using this Woodpecker for implant insertion and detection of optimal fixation by analyzing the vibrational response of the implant and Woodpecker. The press-fit of the implant is quantified by measuring the strain in the cortical bone surrounding the implant. An in vitro study is presented. Two replica femur models (Sawbones Europe AB, Malmo Sweden) were used in this study. One of the femur models was instrumented with three rectangular strain gauge rosettes (Micro-Measurements, Raleigh, USA). The rosettes were placed medially, posteriorly and anteriorly on the proximal femur. Five paired implant insertions were performed on both bone models, alternating between standard hammer blow insertions and using the Woodpecker. The vibrational response was measured during the insertion process, at the implant and Woodpecker side using two shock accelerometers (PCB Piezotronics, Depew, NY, USA). The endpoint of insertion was defined as the point when the static strain stopped increasing. Significant trends were observed in the bandpower feature that was calculated from the vibrational spectrum at the implant side during the Woodpecker insertion. The bandpower is defined as the percentage power of the spectrum in the band 0–1000 Hz. Peak stress values calculated from the strain measurement during the insertion showed to be significantly (p < 0.05) lower at two locations using the Woodpecker compared to the hammer blows at the same level of static strain. However, the final static strain at the endpoint of insertion was approximately a factor two lower using the Woodpecker compared to the hammer. A decreasing trend was observed in the bandpower feature, followed by a stagnation. This point of stagnation was correlated with the stagnation of the periprosthetic stress in the bone measured by the strain gages. The behavior of this bandpower feature shows the possibility of using vibrational measurements during insertion to assess the endpoint of insertion. However it needs to be taken into account that it was not possible to reach the same level of static strain using the Woodpecker as with the hammer insertion. This could mean that either extra hammer blows or a more powerful pneumatic device could be needed for proper implant insertion

For the treatment of irreparable meniscal injuries, we developed a novel multilayer meniscal scaffold, consisting of collagen, strontium and cellulose derived from Luffa Cylindirica; and we evaluated its effects on meniscal regeneration and arthritic changes in a rabbit partial meniscectomy model. The meniscus has a key role in shock absorbtion, load distribution, chondroprotection and stability of the knee joint. Meniscal injuries are one of the most common orthopedic injuries and may lead to degenerative cartilage changes and eventually osteoarthritis. Repair of the meniscal tissue is the treatment of choice for patients with a meniscus lesion, however, this is not always possible, especially for degenerative tears or injuries located on the inner avascular zone. To overcome the devastating outcomes of meniscectomy for such injuries, several materials have been developed and tried to replace the resected meniscal tissue. These scaffolds were designed primarily to relieve pain after meniscectomy, and later on were aimed to prevent osteoarthritis and cartilage damage that may develop in the future. In the quest for optimum scaffold material small intestine, tendons and other isolated tissues, collagen and polyurethane have been researched. Nevertheless, none of these materials have absolutely proven satisfying identical replacement of resected meniscal tissue. Therefore, we developed and investigated a novel multilayer meniscal scaffold, consisting of collagen, strontium and cellulose derived from Luffa Cylindirica (a cucumber shaped and sized plant, known as sponge gourd). The aim of the study was to evaluate the meniscal regeneration and arthritic changes after partial meniscectomy and application of novel multilayer meniscal scaffold in a rabbit model and to compare the results with clinically used polyurethane scaffold (Actifit, Orteq Ltd, London, UK). Sixteen male, mature, NewZealand rabbits weighing between 2600–3500 g were randomly divided into three groups. All groups underwent knee surgery via a medial parapatellar approach and a reproducible 1.5-mm cylindrical defect was created in the avascular zone of the anterior horn of the medial meniscus bilaterally. Defects were filled with the polyurethane scaffold in Group 1 and novel multilayer scaffold was applied to fill the defects in Group 2(n:6). Four rabbits in Group 3 did not receive any treatment and defects were left empty. Animals were sacrified after 8 weeks and bilateral knee joints were taken for macroscopic, biomechanical, and histological analysis. No signs of inflammation or infection were observed in all animals. Macroscopic evaluation of tibial plateaus after excision of menisci was performed with digital images of inked condylar surfaces. No significant degenerative changes were detected between groups. Digital photographs of excised menisci were also obtained and surface areas were measured by a computer software (Image J version 1.46, National Institute of Health, Bethesda, MD). There was a slightly larger meniscus area in the first two groups than the no treatment group, however, this was not found significant. Indentation testing of the tibial condyle and compression tests for the relevant meniscal areas with a diameter of 3mm was also performed in all groups. Histological analysis was made and all specimens were stained with safranin O and scored according to a scoring system. In this study, the initial evaluation of novel multilayer meniscal scaffold demonstrated promising biomechanical and histological results; besides no adverse events related to scaffold material was observed

Background. Intervertebral disc cells exist in a challenging physiological environment. Disc degeneration occurs early in life implying that disc cells may no longer be able to maintain a functional tissue. We hypothesise that disc cells have a stress response different from most other cells because of the disc environment. We have compared the stress response of freshly isolated and cultured bovine nucleus pulposus (NP) cells with bovine dermal fibroblasts, representative of cells from a vascularised tissue. Methods. Freshly isolated and passaged bovine NP cells and dermal fibroblasts were cultured for 3 days then subjected to either thermal stress at 45°C for 1h followed by recovery times of 6, 24 and 48h or nutrient stress involving culture without serum for 6, 24 and 48 h. At each time point, cell number and viability were assessed and heat shock protein 70 (Hsp70) measured in cell lysates by an enzyme-linked immunosorbent assay. Results. In response to thermal stress, both freshly isolated and passaged dermal fibroblasts and also passaged NP cells showed a rapid elevation of Hsp70. In contrast, freshly isolated NP cells exhibited an attenuated Hsp70 response. With nutrient stress, Hsp70 increased with time in all dermal fibroblasts and passaged NP cells after 24 h, but freshly isolated NP cells responded differently again, producing less Hsp70 than controls. Conclusion. Freshly isolated bovine NP cells have a reduced response to applied stresses. This pilot study suggests that NP disc cells may have adapted to their physiologically challenging in vivo environment by attenuating their response to environmental stress. No conflicts of interest. Sources of Funding: The Wolfson Charitable Trust and Genodisc (EC's 7. th. Framework Programme (FP7, 2007–2013) under grant agreement no. HEALTH-F2-2008-201626). This abstract has not been previously published in whole or substantial part nor has it been presented previously at a national meeting

Summary. Staphylococcus aureus isolates from Fracture fixation device related infections contained fewer isolates that form a strong biofilm in comparison with isolates from Prosthetic joint infections. Both orthopaedic implant related infection groups possessed fnbB and sdrE more frequently than the non-implant related infection groups. Introduction. One of the most common pathogen causing musculoskeletal infections is Staphylococcus aureus. The aim was to characterise S. aureus isolated from these infections and to look for differences between the isolates from orthopaedic implant related infections (OIRI) and those in non-implant related infections (NIRI). The OIRI are further differentiated in those associated with fracture fixation (FFI) devices and those found in prosthetic joint infections (PJI). Methods. Three-hundred and five S. aureus isolates were collected from different Swiss and French hospitals (FFI, n=112; PJI, n=105; NIRI, n=88). The cases of NIRI were composed of 27 osteomyelitis (OM), 23 diabetic foot infections (DFI), 27 soft tissue infections (STI) and 11 postoperative spinal infections (SI). Isolates were tested for their ability to form a biofilm. They were typed by agr (accessory gene regulator) group and genes coding for the 13 most relevant MSCRAMMs, Panton-Valentine leukocidin (PVL), PIA (polysaccharide intercellular adhesin), γ-haemolysin, the five most relevant Staphylococcal enterotoxins (SEA-SEE), exfoliative toxins A and B (ETA and ETB) and toxic shock protein (TST) were screened for by PCR. Results. The majority of the S. aureus isolates were methicillin susceptible (MSSA) with 83.4% for the OIRI and 93.2% for the NIRI. All isolates were able to produce a biofilm. A strong biofilm was produced in 13.8% of the OIRI isolates compared to 10.2% of the NIRI isolates. The difference between the isolates of the PJI versus the FFI was statistically significant (20% vs 8%; p=0.011). All four agr types were present in all groups. agrI predominated in the OIRI (42.4%) as well as in the NIRI (44.4%). Comparing OIRI with NIRI, agrII was present in a higher prevalence in OIRI (30.9% vs 14.8%) and agrIII in a lower incidence (21.2% vs 30.7%). Genes cna, clfA and bbp were exhibited predominantly by isolates from the NIRI, while the fnbB and the sdrE gene were more frequently observed among OIRI. Conclusions. Methicillin susceptible S. aureus (MSSA) was more prevalent than methicillin resistant S. aureus (MRSA) in this collection. Possible trends for the orthopaedic device associated infection groups FFI and PJI could be observed whereby isolates from PJI produced stronger biofilm than isolates from the FFI group. The agr type agrII, the fnbB gene and sdrE gene were more prevalent present in the OIRI compared to the NIRI. In contrast, agrIII, and the bbp gene were more prevalent in the NIRI than in the OIRI

Introduction. Ischaemic preconditioning (IPC) is a phenomenon whereby a tissue is more tolerant to an insult if it is first subjected to short bursts of sublethal ischaemia and reperfusion. The potential of this powerful mechanism has been realised in many branches of medicine where there is an abundance of ongoing research. However, there has been a notable lack of development of the concept in Orthopaedic surgery. The routine use of tourniquet-controlled limb surgery and traumatic soft tissue damage are just two examples of where IPC could be utilised to beneficial effect in Orthopaedic surgery. Methods. We conducted a randomized controlled clinical trial looking at the role of a delayed remote IPC stimulus on a cohort of patients undergoing a total knee arthroplasty (TKA). We measured the effect of IPC by analysing gene expression in skeletal muscle samples from these patients. Specifically we looked at the expression of Heat shock protein-90 (HSP-90), Catalase and Cyclo-oxygenase-2 (COX-2) at the start of surgery and at one hour into surgery. Gene analysis was performed using real time polymerase chain reaction amplification. As a second arm to the project we developed an in-vitro model of IPC using a human skeletal muscle cell line. A model was developed, tested and subsequently used to produce a simulated IPC stimulus prior to a simulated ischaemia-reperfusion (IR) injury. The effect of this on cell viability was investigated using crystal violet staining. Results. In the clinical arm of the study 4 patients were randomized to a control group and 4 randomized to IPC. Operative and post-operative periods were without any adverse incident. For each gene in question there was a different pattern in expression. COX-2 showed an initial up-regulation of 1.43 (p=0.83) at the start of surgery and a subsequent down-regulation of 0.07 (p=0.01) at one hour into surgery. Catalase expression was lower than control at the start of surgery (0.62, p= 0.46) and at one hour into surgery (0.5, p=0.1). HSP-90 expression was initially lower than control at the start of surgery (0.59, p= 0.07) then up-regulated at one hour into surgery (1.13, p=0.62). In the in-vitro section of the study we found that 15 hours of simulated ischaemia was required for a cell death of approximately 50 % (p=0.00001). The introduction of a simulated IPC stimulus increased cell death at a 1 hour reperfusion time-point (IPC group had 18% more cell death than IR group, p=0.003) and at a 24 hour reperfusion time-point (IPC group had 19% more cell death than IR group, p= 0.00001). At a 72 hours reperfusion time-point the IPC group had a 30% greater survival than the IR group (p=0.000006). Conclusion. Our clinical study was subject to small sample size. Despite this it suggests a particular importance of COX-2 in the IPC mechanism. The in-vitro model we developed is an essential resource for further studies into IPC in Orthopaedic Surgery. Preliminary results from this model point towards the ‘second window of protection’ of IPC as a stronger phenomenon than immediate preconditioning

Objectives

Intra-articular injections of local anaesthetics (LA), glucocorticoids (GC), or hyaluronic acid (HA) are used to treat osteoarthritis (OA). Contrast agents (CA) are needed to prove successful intra-articular injection or aspiration, or to visualize articular structures dynamically during fluoroscopy. Tranexamic acid (TA) is used to control haemostasis and prevent excessive intra-articular bleeding. Despite their common usage, little is known about the cytotoxicity of common drugs injected into joints. Thus, the aim of our study was to investigate the effects of LA, GC, HA, CA, and TA on the viability of primary human chondrocytes and tenocytes in vitro.