Retrospective analysis of decision-making in post-traumatic posterior shoulder instability.

PURPOSE: This study aims to assess the clinical outcomes in the management of post-traumatic posterior shoulder instability (PSI) with a focus on the decision-making process for operative and conservative treatments. INTRODUCTION: PSI can result from traumatic events, impacting a patient's quality of life. This study delves to better indicate decision-making for operative indication of post-traumatic PSI patients. METHODS: Patients who sustained posterior shoulder dislocations were selected from a single surgeon's database within a five-year period. Cases of degenerative or genetically caused PSI were excluded, resulting in a cohort of 28. Patients were initially managed conservatively but indicated for surgery if they were unable to actively stabilize the shoulder or exhibited bony or cartilage defects confirmed through imaging. If conservative treatment did not yield significant improvements, it was classified as a failure, and operative intervention was recommended. The WOSI Score, ROM, and X-ray were employed to evaluate the success of treatment. RESULTS: Out of the 28 patients, 11 received conservative, seven immediate surgeries, and ten transitioned from conservative to operative treatment. The overall success rate showed 25 good to excellent results. In the persistent conservative treatment group, the initial WOSI score was significantly lower compared to the operative group. CONCLUSION: This study suggests that post-traumatic PSI can be successfully managed conservatively with initial low clinical symptoms (low WOSI score) and in the absence of absolute indications for operative treatment. When surgery is necessary, arthroscopic procedures proved effective in achieving good to excellent results in 16 out of 17 cases.

Design of a reverse shoulder implant to measure shoulder stiffness during implant component positioning.

To avoid dislocation of the shoulder joint after reverse total shoulder arthroplasty, it is important to achieve sufficient shoulder stability when placing the implant components during surgery. One parameter for assessing shoulder stability can be shoulder stiffness. The aim of this research was to develop a temporary reverse shoulder implant prototype that would allow intraoperative measurement of shoulder stiffness while varying the position of the implant components. Joint angle and torque measurement techniques were developed to determine shoulder stiffness. Hall sensors were used to measure the joint angles by converting the magnetic flux densities into angles. The accuracy of the joint angle measurements was tested using a test bench. Torques were determined by using thin-film pressure sensors. Various mechanical mechanisms for variable positioning of the implant components were integrated into the prototype. The results of the joint angle measurements showed measurement errors of less than 5° in a deflection range of ±15° adduction/abduction combined with ±45° flexion/extension. The proposed design provides a first approach for intra-operative assessment of shoulder stiffness. The findings can be used as a technological basis for further developments.

Influence of rotator cuff tears on glenohumeral stability during abduction tasks.

One of the main goals in reconstructing rotator cuff tears is the restoration of glenohumeral joint stability, which is subsequently of utmost importance in order to prevent degenerative damage such as superior labral anterior posterior (SLAP) lesion, arthrosis, and malfunction. The goal of the current study was to facilitate musculoskeletal models in order to estimate glenohumeral instability introduced by muscle weakness due to cuff lesions. Inverse dynamics simulations were used to compute joint reaction forces for several static abduction tasks with different muscle weakness. Results were compared with the existing literature in order to ensure the model validity. Further arm positions taken from activities of daily living, requiring the rotator cuff muscles were modeled and their contribution to joint kinetics computed. Weakness of the superior rotator cuff muscles (supraspinatus; infraspinatus) leads to a deviation of the joint reaction force to the cranial dorsal rim of the glenoid. Massive rotator cuff defects showed higher potential for glenohumeral instability in contrast to single muscle ruptures. The teres minor muscle seems to substitute lost joint torque during several simulated muscle tears to maintain joint stability. Joint instability increases with cuff tear size. Weakness of the upper part of the rotator cuff leads to a joint reaction force closer to the upper glenoid rim. This indicates the comorbidity of cuff tears with SLAP lesions. The teres minor is crucial for maintaining joint stability in case of massive cuff defects and should be uprated in clinical decision-making. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1628-1635, 2016.

Interferon-induced programmed death-ligand 1 (PD-L1/B7-H1) expression increases on human acute myeloid leukemia blast cells during treatment.

INTRODUCTION: While current treatment for acute myeloid leukemia is characterized by high response rates, patients' long-term outcome is still disappointing, due to frequent relapse and ineligibility of the often elderly patients for stem cell transplantation approaches. Considerable efforts have, thus, been made to incorporate immunotherapeutic approaches in the acute myeloid leukemia (AML) consolidation, with so far disappointing clinical benefit. The B7 family ligand programmed-death receptor-ligand 1 (PD-L1, B7-H1, CD274) has been recently described (with conflicting results) to be expressed on AML blast cells, and interaction with its receptor on T cells, programmed death receptor-1 (PD-1, CD279), has been shown to suppress T-cell functions and to allow survival of dormant AML cells in animal models. DESIGN AND METHODS: In this work, we analyzed freshly isolated myeloid precursor cells from healthy donors and from AML patients for PD-L1 expression with or without interferon-γ exposure at different time points during their treatment. RESULTS: While without IFN exposure, only minor differences were observed, we found IFN-γ-induced PD-L1 expression most prominent after initial treatment and independent of treatment outcome. CONCLUSIONS: Our observations support the recently suggested PD-L1-mediated adaptive immune resistance and argue for a targeting of the PD-L1/PD-1 pathway during the consolidation phase of AML treatment.

Elbow dislocations: a review ranging from soft tissue injuries to complex elbow fracture dislocations.

This review on elbow dislocations describes ligament and bone injuries as well as the typical injury mechanisms and the main classifications of elbow dislocations. Current treatment concepts of simple, that is, stable, or complex unstable elbow dislocations are outlined by means of case reports. Special emphasis is put on injuries to the medial ulnar collateral ligament (MUCL) and on posttraumatic elbow stiffness.

Insulin is essential for in vitro chondrogenesis of mesenchymal progenitor cells and influences chondrogenesis in a dose-dependent manner.

PURPOSE: Insulin is a commonly used additive in chondrogenic media for differentiating mesenchymal stem cells (MSCs). The indispensability of other bioactive factors like TGF-ß or dexamethasone in these medium formulations has been shown, but the role of insulin is unclear. The purpose of this study was to investigate whether insulin is essential for MSC chondrogenesis and if there is a dose-dependent effect of insulin on MSC chondrogenesis. METHODS: We cultivated human MSCs in pellet culture in serum-free chondrogenic medium with insulin concentrations between 0 and 50 µg/ml and assessed the grade of chondrogenic differentiation by histological evaluation and determination of glycosaminoglycan (GAG), total collagen and DNA content. We further tested whether insulin can be delivered in an amount sufficient for MSC chondrogenesis via a drug delivery system in insulin-free medium. RESULTS: Chondrogenesis was not induced by standard chondrogenic medium without insulin and the expression of cartilage differentiation markers was dose-dependent at insulin concentrations between 0 and 10 µg/ml. An insulin concentration of 50 µg/ml had no additional effect compared with 10 µg/ml. Insulin was delivered by a release system into the cell culture under insulin-free conditions in an amount sufficient to induce chondrogenesis. CONCLUSIONS: Insulin is essential for MSC chondrogenesis in this system and chondrogenic differentiation is influenced by insulin in a dose-dependent manner. Insulin can be provided in a sufficient amount by a drug delivery system. Therefore, insulin is a suitable and inexpensive indicator substance for testing drug release systems in vitro.

Arthroscopic three dimensional autologous chondrocyte transplantation with navigation-guided cartilage defect size assessment.

INTRODUCTION: The treatment of large full thickness cartilage defects with matrix guided autologous chondrocyte transplantation shows promising results. However, in many cases an arthrotomy is needed to implant the cell seeded scaffolds. Recently techniques have been developed for arthroscopically guided ACT implantation. Correct defect mapping, to assess size and depth of the chondral lesions, and precise scaffold preparation and fixation are crucial for successful chondrocyte transplantation and remain to be not sufficiently optimized. METHOD: In the present study, the geometries of two cartilage defects in cadaver knees were three times assessed, measured and transferred to biodegradable scaffolds with a navigation system by three different executors. The scaffolds were arthroscopically implanted into the cartilage defects. RESULTS: The cartilage defect assessment was reproducible between all executors for all defect geometries. The implanted scaffolds showed a correct defect filling. CONCLUSION: The study showed the feasibility of an arthroscopic implantation of scaffolds for autologous chondrocytes transplantation. Navigation was a useful tool to exactly assess the cartilage defect geometry and allowed a precise transfer of navigated cartilage defect geometries for individualized scaffold preparation. Navigation can help to accomplish and optimize arthroscopically guided chondrocyte transplantations.

Cartilage labelling for mechanical testing in T-peel configuration.

PURPOSE: The purpose of this study was to find a suitable method of labelling cartilage samples for the measurement of distraction distances in biomechanical testing. METHODS: Samples of bovine cartilage were labelled using five different methods: hydroquinone and silver nitrate (AgNO3), potassium permanganate (KMnO4) with sodium thiosulphate (Na2S2O3), India ink, heat, and laser energy. After the labelling, we analysed the cartilage samples with regard to cytotoxity by histochemical staining with ethidiumbromide homodimer (EthD-1) and calcein AM. Furthermore, we tested cartilages labelled with India ink and heat in a T-peel test configuration to analyse possible changes in the mechanical behaviour between marked and unlabelled samples. RESULTS: Only the labelling methods with Indian ink or a heated needle showed acceptable results in the cytotoxity test with regard to labelling persistence, accuracy, and the influence on consistency and viability of the chondrocytes. In the biomechanical T-peel configuration, heat-labelled samples collapsed significantly earlier than unlabelled samples. CONCLUSION: Labelling bovine cartilage samples with Indian ink in biomechanical testing is a reliable, accurate, inexpensive, and easy-to-perform method. This labelling method influenced neither the biomechanical behaviour nor the viability of the tissue compared to untreated bovine cartilage.

Occipital condyle fractures. Prospective follow-up of 31 cases within 5 years at a level 1 trauma centre.

PURPOSE: Prospective investigation of incidence and outcome of occipital condyle fractures (OCF) in a level 1 trauma centre. METHODS: Over a period of 5 years, we prospectively recorded all cases of OCF, and performed a 1-year post-injury radiological and clinical follow-up using CT imaging, SF-36 and Neck Disability Index, respectively. RESULTS: A total of 31 patients with OCF were identified. Based on a total of 2,616 CT scans that had been performed during this period, the incidence was 1.19%. There were 27 unilateral and 4 bilateral OCFs. Furthermore, 3 out of 31 patients (9.7%) were additionally diagnosed with atlanto-occipital dislocation (AOD), one of which was dorsally stabilised in a surgical procedure. All other patients were treated conservatively. 5 out of 31 patients (16.1%) died due to the severity of associated injuries. 22 out of 31 patients (70.9%) were prospectively followed-up for 1 year after trauma. During this period, CT imaging showed bony consolidation of fractures in all cases except for one, with no evidence of secondary dislocation or nonunion. Evaluation of the Neck Disability Index showed moderate disability. The SF-36 questionnaire showed an impaired quality of life in all areas; however, these were determined by associated injuries and independent of the type of fracture. CONCLUSIONS: Both unilateral and bilateral OCFs represent a stable injury regardless of the type of fracture. If AOD has been diagnosed in addition, it requires surgical stabilisation-independent of the OCF-and it is a significant predictor for poor outcomes. The patients quality of life 1 year after trauma has not been affected by the OCF, but by the overall pattern of the injury and by comorbidities. Based on our results, we introduce a new, simple and practical classification for OCFs.

Post-traumatic fulminant paradoxical fat embolism syndrome in conjunction with asymptomatic atrial septal defect: a case report and review of the literature.

INTRODUCTION: Fat embolism syndrome with respiratory failure after intramedullary nailing of a femur fracture is a rare but serious complication in trauma patients. CASE PRESENTATION: We present the case of a 20-year-old Caucasian man who experienced paradoxical cerebral fat embolism syndrome with fulminant progression after intramedullary nailing of a femur fracture, in conjunction with a clinically asymptomatic atrial septal defect in a high position resulting in a right-to-left shunt. CONCLUSION: Fat embolism syndrome may occur as a fulminant complication following femoral fracture repair in the presence of a concomitant atrial septal defect with right-to-left shunt. Thus, in patients with cardiac right-to-left shunts, femurs should not be nailed intramedullary, not even in cases of isolated injuries.

Arthroplasty of the lunate using bone marrow mesenchymal stromal cells.

Mesenchymal stromal cells have the potential to differentiate into a variety of mesenchymal tissues such as bone, cartilage and ligaments. The potential for the regeneration of bone with cartilage coverage has still not been achieved. We evaluated the ability of bone marrow mesenchymal stromal cells to regenerate osteochondral defects in the cavity of the lunate in an animal model. Autologous mesenchymal stromal cells were harvested from the iliac crest of New Zealand white rabbits and expanded in vitro. Total lunate excision was performed in 24 animals and the isolated cells were loaded onto scaffolds. Cell-free scaffolds were implanted in the lunate space of the right wrists of all animals, and the left lunate spaces were filled with predifferentiated, cell-loaded scaffolds. Radiographic and histological analyses were performed after two, six and 12 weeks. In addition, the animals were injected with a fluorescent agent every five days, starting at day 30. After two and six weeks there was no radiographic evidence of ossification, whereas after 12 weeks all animals showed radiographic evidence of ossification. Histological sections showed increasing evidence of cartilage-like cell formation at the edges and new bone tissue in the centre of the newly formed tissue in all groups. The histological examinations showed that bone tissue was located around the newly incorporated vascularisation. This study demonstrated that newly formed vascularisation is necessary for the regeneration of bone tissue with cell-loaded scaffolds.

Hypoxic downregulation of cellular proliferation and loss of phenotype stability in human osteoblasts is mediated by HIF-1α.

Both, skeletal development and fracture healing depend on an orchestrated sequence of cellular growth and differentiation processes. Regional changes in tissue oxygen tension were proposed as key regulators of osteoblast proliferation and phenotype. Hypoxia results in the stabilization of hypoxia-inducible factor-1α (HIF-1α), thus influencing expression of a multitude of genes required for cellular adaptation. In the present study we dissected the effects of HIF-1α on cellular proliferation and gene expression of primary human osteoblasts. Primary human osteoblasts were studied by transfecting siRNA and plasmids coding for human HIF-1α. Gene expression was analyzed by western blot and quantitative PCR. Functional assays were performed to study HIF-1α function, i.e. proliferation and cell cycle analysis. As previously reported exposure to hypoxia led to a stabilization of HIF-1α on protein level and resulted in reduced rates of proliferation and osteocalcin expression. Furthermore, the expression of the proproliferative gene survivin was significantly reduced (p < 0.01). Knock down of HIF-1α attenuated hypoxic downregulation of proliferation (p < 0.05), and osteocalcin (p < 0.05) as well as survivin (p < 0.05) expression significantly. Importantly, the isolated overexpression of HIF-1α impaired proliferative activity and led to significantly reduced rates of expression of osteocalcin (p < 0.05) and survivin (p < 0.01). The present study shows that HIF-1α might reduce proliferation and survivin expression in primary human osteoblasts independently from cellular hypoxia. Furthermore, HIF-1α promoted the loss of the characteristic osteoblastic marker, osteocalcin in vitro. These findings underline the important role of HIF-1α in bone physiology and pathophysiology. Modulating HIF-1α function in hypoxic environments could be of value for future therapeutic approaches.

Characterization of esterified hyaluronan-gelatin polymer composites suitable for chondrogenic differentiation of mesenchymal stem cells.

Composite scaffolds of homogeneously mixed esterified hyaluronan (HY) and gelatin (G) were manufactured with variable component compositions (HY100%; HY95%/G5%; HY70%/G30%). The goals of this study were to analyze the produced composite scaffolds using physical and chemical methods, for example, scanning electron microscopy, IR-spectroscopy, water contact angle, protein assay, and tensile testing as well as to assess the effects of adding gelatin to the composite scaffolds on attachment, proliferation, and chondrogenic differentiation of human mesenchymal stem cells. Numbers of attached cells were significantly higher on the composite material compared to pure hyaluronan at different time points of two-dimensional or three-dimensional cell culture (p< 0.02). In composite scaffolds, a significantly greater amount of cartilage-specific extracellular matrix components was deposited after 28 days in culture (glycosaminoglycan: p < 0.001; collagen: p < 0.001) as compared with 100% hyaluronan scaffolds. Additionally, gelatin-containing composite scaffolds displayed stronger promotion of collagen type II expression than pure hyaluronan scaffolds. The mechanism, based on which gelatin influences cell adhesion, was examined. The effect was inhibited by collagenase treatment of the composites or by addition of alpha5beta1-integrin blocking antibodies to the cell suspension. In summary, the results describe the establishment of a class of composite polymer scaffolds, consisting of esterified hyaluronan and gelatin, which are potentially useful for cell-based tissue engineering approaches using mesenchymal stem cells for chondrogenic differentiation.

Mechanical characteristics of articular cartilage bonds.

BACKGROUND: Sutures for adaptation of articular cartilage are used in arthritis therapy techniques. However, little is known about the mechanical functionality of these sutures. The objective of the present work was to compare the mechanical properties of articular cartilage bonds either generated by suture, or, alternatively, by chemical cross-linking of the opposing surfaces or in vitro integrative repair of cartilage blocks. METHODS: Bonding was achieved by suture in varying numbers, positions and orientations, by surface cross-linking using carbodiimide in combination with pepsin or guanidine (immediate bonding), or by cultivation for 14 days, either with or without testosterone. The mechanical properties of the cartilage bonds were measured under tensile loading. FINDINGS: Suture led to the highest maximal load at failure and by far to the highest strain and lowest stiffness of the bonded samples. Immediate bonding by chemical cross-linking in combination with pepsin led to a low force at failure, but the highest stiffness, as compared to all other groups. Cultivation in the presence of testosterone led to a higher force at failure and a higher strain than chemical cross-linking. INTERPRETATION: Suture technique for bonding of cartilage surfaces leads to a very elastic adaptation which allows synovial fluid flow in between the interface of cartilage wounds. Long-term bonding of cartilage wounds would be counteracted by a fluid flow through the interface during motion of the joint. Immediate bonding of cartilage wounds by chemical cross-linking reagents might be a useful alternative tool. Even more promising, with regard to the mechanical properties, appears to be integrative repair of cartilage blocks stimulated by testosterone.

Proliferation of osteoblasts and fibroblasts on model surfaces of varying roughness and surface chemistry.

Physical and chemical properties of the surfaces of implants are of considerable interest for dental and orthopedic applications. We used self-assembled monolayers (SAMs) terminated by various functional chemical groups to study the effect of surface chemistry on cell behavior. Cell morphology and proliferation on silicon wafers of various roughnesses and topographies created by chemical etching in caustic solution and by corundum sandblasting were analyzed as well. Water contact angle data indicated that oxidized wafer surfaces displayed high hydrophilicity, modification with poly(ethylene glycol) (PEG) created a hydrophilic surface, and an amino group (NH2) led to a moderately wettable surface. A hydrophobic surface was formed by hydrocarbon chains terminated by CH3, but this hydrophobicity was even further increased by a fluorocarbon (CF3) group. Cell proliferation on these surfaces was different depending primarily on the chemistry of the terminating groups rather than on wettability. Cell proliferation on CH3 was as high as on NH2 and hydrophilic oxidized surfaces, but significantly lower on CF3. Precoating of silicon wafers with cell culture serum had no significant influence on cell proliferation. Scanning electron microscopy indicated a very weak initial cell-surface contact on CF3. The cell number of osteoblasts was significantly lower on sandblasted surfaces compared with other rough surfaces but no differences were detected with 3T3 mouse fibroblasts. The different surface roughnesses and topographies were recognized by MG-63 osteoblasts. The cells spread well on smooth surfaces but appeared smaller on a rough and unique pyramid-shaped surface and on a rough sandblasted surface.

Bonding of articular cartilage using a combination of biochemical degradation and surface cross-linking.

After trauma, articular cartilage often does not heal due to incomplete bonding of the fractured surfaces. In this study we investigated the ability of chemical cross-linkers to facilitate bonding of articular cartilage, either alone or in combination with a pre-treatment with surface-degrading agents. Articular cartilage blocks were harvested from the femoropatellar groove of bovine calves. Two cartilage blocks, either after pre-treatment or without, were assembled in a custom-designed chamber in partial apposition and subjected to cross-linking treatment. Subsequently, bonding of cartilage was measured as adhesive strength, that is, the maximum force at rupture of bonded cartilage blocks divided by the overlap area. In a first approach, bonding was investigated after treatment with cross-linking reagents only, employing glutaraldehyde, 1-ethyl-3-diaminopropyl-carbodiimide (EDC)/N-hydroxysuccinimide (NHS), genipin, or transglutaminase. Experiments were conducted with or without compression of the opposing surfaces. Compression during cross-linking strongly enhanced bonding, especially when applying EDC/NHS and glutaraldehyde. Therefore, all further experiments were performed under compressive conditions. Combinations of each of the four cross-linking agents with the degrading pre-treatments, pepsin, trypsin, and guanidine, led to distinct improvements in bonding compared to the use of cross-linkers alone. The highest values of adhesive strength were achieved employing combinations of pepsin or guanidine with EDC/NHS, and guanidine with glutaraldehyde. The release of extracellular matrix components, that is, glycosaminoglycans and total collagen, from cartilage blocks after pre-treatment was measured, but could not be directly correlated to the determined adhesive strength. Cytotoxicity was determined for all substances employed, that is, surface degrading agents and cross-linkers, using the resazurin assay. Taking the favourable cell vitality after treatment with pepsin and EDC/NHS and the cytotoxic effects of guanidine and glutaraldehyde into account, the combination of pepsin and EDC/NHS appeared to be the most advantageous treatment in this study. In conclusion, bonding of articular cartilage blocks was achieved by chemical fixation of their surface components using cross-linking reagents. Application of compressive forces and prior modulation of surface structures enhanced cartilage bonding significantly. Enzymatic treatment in combination with cross-linkers may represent a promising addition to current techniques for articular cartilage repair.

Steroid hormones strongly support bovine articular cartilage integration in the absence of interleukin-1beta.

OBJECTIVE: Posttraumatic integration of articular cartilage at fracture sites is essential for mechanical stability of cartilage, and ruptured cartilage is a prerequisite for early osteoarthritis. This study was undertaken to investigate effects on articular cartilage integration mediated by steroid hormones, interleukin-1beta (IL-1beta), and combinations thereof. METHODS: Articular cartilage blocks were cultured in partial apposition for 2 weeks with ascorbic acid, testosterone, 17beta-estradiol, and dehydroepiandrosterone (DHEA), with or without IL-1beta. Mechanical integration was measured as adhesive strength, i.e., the maximum force at rupture of integrated cartilage blocks divided by the overlap area. Glycosaminoglycan content was used to study synthesized extracellular matrix. RESULTS: Culture in medium without supplements did not lead to integration (adhesive strength 0 kPa). With administration of ascorbic acid (100 microg/ml), the median adhesive strength was 49 kPa. In comparison with ascorbic acid alone, all steroid hormones induced a strong, concentration-dependent stimulation of integration (with maximum values observed with DHEA at 3 x 10(-5)M, testosterone at 10(-8)M, and 17beta-estradiol at 10(-11)M). For testosterone and 17beta-estradiol, this was also reflected by an increase of glycosaminoglycan content. Adhesive strength was increased with IL-1beta at 10 pg/ml, but not at 1 pg/ml or 100 pg/ml. In the presence of both IL-1beta and sex hormones, integration of articular cartilage was reduced. CONCLUSION: This is the first study to demonstrate that steroid hormones such as 17beta-estradiol, DHEA, and testosterone stimulate articular cartilage integration. This effect is abrogated by low concentrations of IL-1beta. In the absence of IL-1beta or after neutralization of IL-1beta, steroid hormones might be favorable adjuvant compounds to optimize cartilage integration.

Pyogenic spinal infections and outcome according to the 36-item short form health survey.

OBJECT: Pyogenic vertebral infections are rare. In most papers investigators have focused on risk factors, clinical characteristics, and diagnostic findings, and discussed different management strategies. The optimal strategy for dealing with spinal infections, however, remains controversial. Additionally, outcome data regarding quality of life (QOL) after pyogenic spinal infections are sparse. The aim of this study was to provide further data in this field. METHODS: The authors retrospectively investigated 62 patients suffering from pyogenic spinal infections. In 37 patients (59%), lumbar lesions were observed; thoracic and thoracolumbar infections were documented in 19 (31%) and a cervical infection was demonstrated in six patients (10%). Overall 28 patients (45%) underwent conservative treatment, and 34 (55%) underwent surgery with or without the placement of instrumentation. At follow-up examination the authors recorded each patient's satisfaction as well as QOL according to the 36-Item Short Form Health Survey. Quality of life after treatment of pyogenic spine infections did not reach the level of the normative sample. Most patients continued to suffer some sort of pain. Despite different indications, the surgically treated patients experienced a slightly better QOL and self-reported satisfaction levels, as well as a statistically significant better outcome, than patients treated conservatively. CONCLUSIONS: The results obtained in the present study suggest that surgery, especially in conjunction with the placement of instrumentation, may be more beneficial than conservative treatment in patients with a spinal infection.

Influence of surface pretreatment of titanium- and cobalt-based biomaterials on covalent immobilization of fibrillar collagen.

Collagen type-I is a major component of the extracellular matrix of most tissues and it is increasingly utilized for surface engineering of biomaterials to accelerate receptor-mediated cell adhesion. In the present study, coatings with layers of fibrillar type-I collagen were prepared on titanium, titanium alloy, and cobalt alloy to improve initial osteoblast adhesion and implant-tissue integration. To suppress the quick in vivo degradation rate of collagen the deposited layers were covalently immobilized at the metal surfaces as well as chemically cross-linked. The application of different oxidation techniques to the metallic substrates resulted in surfaces with varying hydroxyl group contents, which directly influenced the amount of immobilized silane coupling agents. It was found that a high density of surface-bound coupling agents increased the stability of the covalently linked collagen layers. After coating of metallic biomaterials with a cross-linked collagen layer, an improved cellular response of human osteoblast-like cells (MG-63) in vitro could be recognized.