Abstract. Purpose. Clinical registries are an important aspect of orthopaedic research in assessing the outcomes of surgical intervention and track medical devices. This study aimed to explore the research methodology available to account for patients lost to follow-up (LTFU) specifically in studies related to arthroscopic intervention and whether the rates of patient LTFU are within the acceptable margins for survey studies.
Prosthetic joint infections represent complications connected to the implantation of biomedical devices, they have high incidence, interfere with osseointegration, and lead to a high societal burden. The microbial biofilm, which is a complex structure of microbial cells firmly attached to a surface, is one of the main issues causing infections. Biofilm- forming bacteria are acquiring more and more resistances to common clinical treatments due to the abuse of antibiotics administration. Therefore, there is increasing need to develop alternative methods exerting antibacterial activities against multidrug-resistant biofilm-forming bacteria. In this context, metal-based coatings with antimicrobial activities have been investigated and are currently used in the clinical practice. However, traditional coatings exhibit some drawbacks related to the insufficient adhesion to the substrate, scarce uniformity and scarce control over the toxic metal release reducing their efficacy. Here, we propose the use of antimicrobial silver-based nanostructured thin films to discourage bacterial infections. Coatings are obtained by Ionized Jet Deposition, a plasma-assisted technique that permits to manufacture films of submicrometric thickness having a nanostructured surface texture, allow tuning silver release, and avoid delamination. To mitigate interference with osseointegration, here silver composites with bone apatite and hydroxyapatite were explored. The antibacterial efficacy of silver films was tested
Introduction and Objective. Osteoarthritis (OA) represents one of the leading cause of disability all over the world. Cell therapies, mainly based on mesenchymal stem cells (MSCs), have shown to modulate the pathogenesis of OA in basic, preclinical and clinical studies. Adipose tissue (AT) have emerged as a rich and promising source of MSCs called adipose derived stem cells (ASCs). Different systems are available for processing lipoaspirate to purify the samples from oily and haemorrhagic fractions, minimizing the risk of complications and maximizing the biological yield for subsequent grafting. However, few studies compared the efficacy of the different processing devices already used in clinical practice. This study aims to characterize the products obtained by the use of two different systems such as micro-fragmentation or nano-fragmentation comparing them with the starting material (AT) and the collagenase isolated ASCs. Materials and
Decellularised porcine superflexor tendon (pSFT) provides an off-the-shelf, cost-efficient option for ACL reconstruction (ACLR). During decellularisation, phosphate buffered saline (PBS) is used for washing out cytotoxic solutes and reagents, maintaining tissue hydration. It has been shown to increase water content in tendon, swelling the tissue reducing mechanical properties. End stage PBS washes in the standard protocol were substituted with alternative solutions to study tissue swelling and its impact on the mechanical behaviour and matrix composition of pSFTs. 25%, 100% Ringers and physiological saline test groups were used (n=6 for all groups). pSFTs were subject to tensile and confined compression testing. Relative hydroxyproline (HYP), glycosaminoglycan (GAG) and denatured collagen content (DNC) were quantified. Modified decellularised tendon groups were compared to tendons decellularised using the standard protocol and native tendons. Specimen dimensions reduced (p=0.004) post-decellularisation only in 25% Ringers group. In all other modified groups, less swelling was apparent but not statistically different from standard group. Only 25% Ringers group had higher linear modulus (p=0.0035) and UTS (p=0.013) compared to standard group. All decellularised groups properties were reduced compared to native pSFTs. Stress relaxation properties showed a significant reduction in decellularised groups compared to native. Compression testing showed no significant differences in peak stress for modified decellularised groups compared to native. A reduction (p=0.036) was observed in standard group. Quantification of GAGs and DNC showed no significant differences between groups. HYP content was higher (p<0.0001) for saline group. A significant reduction in tissue swelling could be related to improved mechanical properties of decellularised pSFTs. Alternative solutions in end stage washes had no significant effect on quantities of matrix components, but altered structure/function could explain the differences in tensile and compressive behaviour, and should be further studied. In all decellularised groups, pSFTs retained suitable mechanical properties for ACLR.Abstract
The ideal treatment method regarding various defect sizes after local aggressive tumor resection is unknown. We investigated the biomechanical properties of metaphyseal defect filling regarding different defect sizes and fixation methods. Ninety-one sheep tibias were divided into five groups as 21 tibias per four study groups and 7 tibias in the control group. Study groups were further divided into three subgroups according to 25%, 50% and 75% metaphyseal defect size. Control group tibias were left intact. In study group 1, a metaphyseal defect was created and no further process was applied. Metaphyseal defects were filled with cement without fixation in group 2. Cement filling and fixation with 2 screws were performed in group 3. In addition to cement filling, plate-screw fixation was performed in group 4. Axial loading test was applied to all tibias and the results were compared between study subgroups and control group. Plate-screw fixation was found to have the best biomechanical properties in all defect sizes. Load to failure for screw fixation was found to be significantly decreased between 25% and 50% defect size (P<0.05). However, load to failure for isolated cement filling was not affected from defect size (p>0.05). In conclusion, size of the defect predicts the fixation method in addition to filling with cement. Filling with cement in metaphyseal defects was found to be biomechanically insufficient. In addition to filling with cement, additional screw fixation in less than 25% defects and plate-screw fixation in more than 25% defects may decrease tibial plateau fracture or metaphyseal fracture risk after local aggressive tumor resection.
Metal instrumentation (rods and screws) is used to stabilise the spine after trauma, malignancy or deformity. Approx 3% become infected often necessitating removal of metal. At surgery tissue samples and metal are removed for culture, but many clinical laboratories are not equipped to process metal or use simple culture methods. The causative bacteria exist as biofilms on the metal and they are often anaerobic and slow-growing, so conventional culture methods often fail to detect them. Also, they are common contaminants leading to diagnostic uncertainty. We have established a laboratory protocol to overcome these problems. Removed metalwork was sonicated and the sonicate centrifuged and the supernatant discarded. Quantitative aerobic and anaerobic culture of the resuspended pellet for 14 days and microscopy were carried out. Metalwork from 11 suspected infected cases was culture-positive (median 2857, 60–5000cfu/mL). Microscopy revealed an infection due to Candida albicans that would not have been detected otherwise. Bacteria were isolated from 8 of 10 non-infected cases (median 15, 0–35 cfu/mL). Conventionally processed samples failed to grow in 4 infected cases. (cfu/mL infected vs noninfected cases p=0.0093) Micro-organisms on spinal metalwork grow as biofilms and they require sonication to dislodge them. The causative bacteria are slow-growing and P acnes is anaerobic and requires prolonged incubation. S epidermidis and P acnes are common contaminants and quantitative culture helps to distinguish pathogens from contaminants, removing the diagnostic uncertainty that conventional methods give. Microscopy of the sonicate can reveal micro-organisms that fail to grow on culture. We recommend that sonication of metalwork, prolonged anaerobic incubation and quantitative culture be adopted to improve diagnostic clarity for spinal instrumentation infections.
We need to shift our focus to integrating sex and gender into research proposals, so we can answer some of the most basic unanswered questions in the field of fracture management. Current evidence in guidelines indicate a near-to-linear increase from the 1990s for inclusion of sex and gender. However, these recommendations remain expressed in absolute terms, with little explanatory power, affecting uptake and implementation in clinical practice. This co-branded session, with members of the Orthopaedic Research Society – International section of fracture repair (ORS-ISFR), will provide participants with guiding principles and tools to assist researchers and grant reviewers understand what it means to include sex and gender in meaningful ways: from formulating research questions, recruitment strategies, to conducting sex-stratified analyses. In this presentation, we will consider diverse approaches, methods and, analyses to elevate sex and gender within trauma. A strong emphasis on the ways and means of including marginalized and vulnerable populations in research will be addressed.
To describe clinical situations for use of modified VAC in POC based on: diagnosis, comorbidities, BMI, wound size in cm, days following trauma when VAC was first applied, total duration of uninterrupted use, frequency of change, settings, bacterial growth, outcomes To report the outcomes of mVAC use in POC within 6 months to help improve and standardize its application in the institution This study involves data gathering from inpatients handled by orthopedic surgeons in training and subspecialty rotations in POC. The data collected are highly dependent on the doctors-in-charge's complete charting, thorough reporting and accurate documentation.
Modified Vacuum Assisted Closure (mVAC) is used frequently in this study and is defined as a form of revised, adapted and reformed use of VAC based on available materials in the involved institution. The materials that are included are, but not limited to the following: sterile Uratex™ blue foam, nasogastric or suction tubing, phlegm suction machine, Bactigras™ and Opsite™ or Ioban™. A total of 58 patients were included in the study. The average age of the population was 35 and are predominantly male. The most common mechanism of injury was motorcycle accident and 37 of the patients were diagnosed with an open fracture of the lower extremity with open tibia fractures (22) being the most common. Average wound area measured was 24.12 cm3. All patients yield a bacteria growth with e. coli being the most frequent. Average during of uninterrupted use was 39 days. Of the 58 included in the study, 8 patients underwent STSG, 2 had a flap coverage surgery, 4 patients eventually underwent amputation and 33 with complete resolution of soft tissue defect after conversion to biologic dressing post-mVAC. The rest of the population were still ongoing mVAC at the end of the study. mVAC is an alternative temporary medium for soft tissue coverage for cases with or without concomitant fractures. mVAC promotes removal of exudate from the wound, supports wound apposition and granulation bed proliferation. Usage mVAC helps prepare for skin coverage procedure and on some cases leads to full resolution of defect.
Balloon kyphoplasty (BKP) is a minimally invasive surgical technique used to correct kyphosis and vertebral compression fractures. BKP uses cement to fill a void created by the inflation of a balloon in a vertebra, it can be used as an alternative to vertebroplasty to reduce cement extravasation. Issues such as poor inter digitisation of the cement and the trabecular bone can arise with the BKP method. This can be due to a compacted layer created during the procedure which can cause complications post-surgery. The primary aim of this study was to investigate alternative cement application methods which could improve the mechanical strength of the bone-cement interface. Three alternative methods were investigated, and cylindrical bone-cement specimens were created for all methods (BKP and three alternatives). An important part of this study was to replicate the compacted layer created by the inflation of the balloon tamp in BKP. Synthetic trabecular bone specimens (Sawbones®, Pacific Research Laboratories, Vashon Island, Washington, USA) were pre-loaded in compression and the resultant compacted layers were found to replicate the compacted layers found in surgery. Mechanical testing was carried out with an MTS Model 858 Bionix® Servohydraulic load frame using static tensile and torsion loads. Static tests revealed that two of the three alternative methods were an improvement on BKP, with a high statistical significance in relation to the mechanical performance of the bone-cement interface (P < 0.001). This data illustrates the potential to improve the standard BKP technique, in terms of bone-cement interface performance.
Objectives. Our objective was to perform a systematic review of the literature and conduct a meta-analysis to investigate the outcomes of open versus arthroscopic methods of ankle fusion.
Protocols for processing of tissue from arthroplasty infections vary and might affect the recovery of bacteria. We compared homogenization, bead beating and enzymatic disruption for recovery of live bacteria from tissue samples. Suspensions of Staphylococcus aureus and Escherichia coli were prepared as controls. Three samples were taken from each and the first was bead beaten, the second homogenized, and Proteinase K was added for 10 and 30 minutes to the third sample before culturing. In addition, artificially inoculated pork tissue and known infected human tissue samples were processed by either homogenization or bead beating prior to cultures and results were compared. Number of cycles of bead beating and homogenization and duration of Proteinase K treatment had significant effects. Bead beating for 2 and 4 cycles reduced the yield of S.aureus to 52% and 20% of control, and E.coli to 33% and 8%. Homogenization for 2 and 4 cycles reduced S.aureus to 86% and 65% of control, and E.coli to 90% and 87%. Proteinase K for 10 minutes and 30 minutes reduced the yield of S.aureus to 75% and 33% of control, and E.coli to 91% and 49% respectively. Inoculated Pork tissue showed a reduction in S.aureus recovery of 90% for bead beating compared to homogenization, and 80% in the case of E.coli. Bead beating of infected human tissue samples reduced the yield by 58% compared to homogenization. Bead-beating is a common recommended method of processing tissue from arthroplasty cases. However, even though it produces a homogeneous sample, it does so at the cost of significant loss of viable bacteria. Homogenization and 10 minutes of Proteinase K incubation are almost equivalent, but the homogenizer is preferred being more controllable and cheaper. This should help to define guidelines for diagnosing infections using tissue samples.
Mesenchymal stem cell (MSC) exosomes are intracellular vesicles, which can regulate transcription and control gene expression through the molecules they carry, easily enter into the target cell, contain no regenerative effect, and do not produce an immune response. There are different methods in the literature to obtain these vesicles. However, studies on the isolation of MSC-derived exosomes and their comparative characterization using magnetically active cell sorting (MACS) and ultracentrifugation methods are lacking. The most appropriate isolation method for MSC-derived exosomes can be determined by comparing the isolation and characterization parameters of mesenchymal stem cells using magnetically active cell sorting and ultracentrifugation methods. The aim of this study was to define the advantages and disadvantages of the methods used for determining the purpose-oriented method. Human bone marrow-derived mesenchymal stem cells were cultured in standard MSC culture conditions (37ºC and 5% CO 2). Exosomal contamination was prevented by removal of exosomes from the serum that used in the standard growth medium. For exosome isolation of the cells reaching sufficient density, the media were replaced with new ones every two days, the old media were collected in liquid refrigerated with liquid nitrogen and stored at −80ºC. Part of the accumulated exosomes were isolated by using the MACS method, while the other was isolated by using the ultracentrifugation method, which included serial centrifugation steps. The amount of protein contained in the phosphate buffer solution in which the exosomes were reconstituted was determined by microplate reader using the BCA kit. Based on the protein concentration obtained, exosomes were read by means of a dye flow cytometer with fluorescent antibodies attached to surface markers specific to CD9, CD63, and CD81 specific for exosomes by latex beads. Finally, the exosomes were stained with uranyl acetate and phosphotungstic acid and then placed on 200 mesh and formvar-carbon film coated grids. Exosomes were isolated using both ultracentrifugation and MACS methods. While ultra-large amounts of exosomes can be isolated by ultracentrifugation method, MACS method provides a lower amount of isolation. Exosomes with magnetically active cell sorting are selected with specific surface markers, therefore, exosomal purity is thought to be higher. Exosomes which were isolated by both ultracentrifugation and MACS methods were monitored by using transmission electron microscopy and they were not found to be morphologically different. In conclusion, MACS and ultracentrifugation are effective methods for the isolation of human bone marrow-derived MSC exosomes. Both methods have advantages and disadvantages. Exosomes can be isolated together with magnetic beads using the MACS method. In the ultracentrifuge method, cleaner exosomes can be isolated. While the exosomes are isolated by MACS, they can also be characterized by beads.
Background. Surgical wound closure is not the surgeon”s favorite part of the total knee arthroplasty (TKA) surgery however it has vital rule in the success of surgery. Knee arthoplasty wounds are known to be more prone to infection, breakdown or delayed healing compared to hip arthroplasty wounds, and this might be explained by the increased tensile force applied on the wound with knee movement. This effect is magnified by the enhanced recovery protocols which aim to obtain high early range of movement. Most of the literature concluded that there is no difference between different closure methods. Objectives. We conducted an independent study comparing the complication rate associated with using barbed suture (Quill-Ethicon), Vicryl Rapide (polyglactins910-Ethicon) and skin staples for wound closure following TKA. Study Design &
Scaffold-based bone tissue engineering holds great promise for the future of osseous defects therapies. Prepare the suitable scaffold properties are physiochemical modifications in terms of porosity, mechanical strength, cell adhesion, biocompatibility, cell proliferation, mineralization and osteogenic differentiation are required. We produce various bone tissue scaffolds with different techniques such as lyophilization, 3D printing and electrospinning. We wish to overview all the different novel scaffold methods and materials. To improve scaffolds poor mechanical properties, while preserving the porous structure, it is possible to coat the scaffold with synthetic or natural polymers. An increasing interest in developing materials in bone tissue engineering is directed to the organic/inorganic composites that mimic natural bone. Specifically, bone tissue is a composite of an organic and inorganic matrix. Using PLLA, loofah, chitin and cellulose biomaterials we produced bone tissue scaffold with lyophilization technique. Also, using fish scale powder and wet electrospun Poly(3-hydroxybutyrate-
Summary Statement. Creep behaviour can only be quantified accurately when the testing time exceeds the estimated time constant of the creep process. The new parameters obtained in this paper can be used to describe normal behaviour up to 24 hrs. Background. Diurnal loading on the human spine consists of 16hrs loading and 8hrs rest. After an initial load increase, due to rising in the morning, an axial loading is maintained throughout the day. As a consequence subsidence of the intervertebral disc (IVD) occurs during the day while disc height recovers during the night. This behaviour is time dependent (non-linear). In literature different constitutive equations have been used to describe creep. A stretched exponential (Kolraush-Wilson-Watts, KWW) and a double Voight (DV) model have both been used to quantify the creep behaviour. Using these models, time constants and the deformation at equilibrium are estimated. It is unsure whether these different approaches yield to valid predictions. In this study we compared the validity of different equations for the prediction of creep behavior. Materials and
This was a retrospective study of registry data from a National Orthopaedic Hospital for all THRs with 10-year follow-up data. Inclusion criteria were all THRs with a minimum of 10-year follow-up data. All metal-on-metal (MoM) THRs and MoM resurfacings were excluded from the analysis due to the high rate of revision associated with these bearings. Univariate and multivariate analyses controlling for confounding variables were performed to compare outcomes. A total of 1,697 THRs were performed in 1,553 patients. The four significant predictors for revision were fixation type (p<0.01), surface bearing type (p<0.01), age (P<0.05) and head size (p<0.05). Gender, BMI and approach had no effect on revision rates. The lowest 10-year all-cause revision rates were seen in cemented THRs at 1.7%. Ceramic-on-poly bearings had the lowest revision rate at only 1.2%. Metal-on-poly bearings had a 1.7% revision rate. Ceramic on ceramic bearings had a 7.1% revision rate with 1 revision for squeak and 1 revision for ceramic head fracture. The causes for revision in order of decreasing frequency were as follows: Infection (n=13, 0.7%), dislocation (n=7, 0.4%), periprosthetic fracture (n=3, 0.2%) and aseptic loosening (n=2, 0.1%). There were 2 re-revisions at 10 years in total. The smaller 22.225mm head sizes had a significantly lower revision rate than other head sizes (p<0.05). Ceramic-on-poly bearings, cemented fixation and smaller head sizes perform better in the experience of this registry. However, with multivariate analysis, these differences were shown to be insignificant.
The purpose of this study was to develop a novel, minimally invasive therapy for nucleus pulposus augmentation without the need for major surgical incision. Two optimum patented self-assembling peptides based on natural amino acids were mixed with glycosaminoglycans (GAGs) to form reversible, tunable hydrogels that mimic the vital biological osmotic pumping action and aid in swelling pressure of the intervertebral disc (IVD). Separate peptide and GAG solutions can be switched from fluid to gel upon mixing inside the body. The gels were analysed using a series of complementary techniques (FTIR, TEM & rheometry) to determine their cross-length scale structure and properties. Approaches to developing a clinical product were then developed including the incorporation of a fluorescent probe and a CT contrast agents to aid visualization of the gels, and a semi-automatic syringe driver rig, incorporating a pressure sensor, for the delivery of the solutions into the intervertebral discs. The efficacy of the procedure in restoring disc height and biomechanics was examined using chemically degenerated bovine caudal samples. It was found the presence of the GAGs stabilized the peptides forming stiffer gels, even upon injection through a long (∼10cm) small gauge needle. The injected gels were easily visualized post injection by microCT and by eye during dissection under visible and UV light. It was also noted that following injection, the disc height of the degenerated samples was restored to a similar level of that observed for native discs. A hydrogel has been developed that is injected through a narrow bore needle using a semi-automatic delivery rig and forms a self-assembled gel in situ which has shown to restore the disc height. Further tests are now underway to examine their biomechanical performance across more physiological time periods.
Patient specific knee modelling has the potential to help understand the development of the mechanically induced degenerative disease, Osteoarthritis. A full joint contact model of the knee involves modelling the bones, ligaments, articular cartilage (AC) and meniscus, as well as, the kinematics and geometry of real joints. These finite element models will inevitably require great computational resource to run and it is desirable to find resource effective material model formulations which can accurately describe the mechanical behaviour of the soft tissues. Biphasic models (BIMs) have long been established as an effective formulation for modelling AC. However, the swelling behaviour caused by changes in the ionic phase is a major recovery mechanism and is neglected in the BIMs. It is therefore believed that BIMs alone are insufficient to fully describe the mechanical behaviour of AC. Instead, a thermal analogy method which is generically a BIM that includes the swelling behaviour has been thought to be suitable and has been validated against literature data using material parameters optimized to match the numerical and experimental results. To ensure the model is suitable for patient specific modelling where it will have the ability to reflect the individual AC material properties of the patients in the mechanical behaviour it predicts, two experiments have been planned and are currently being carried out using bovine AC. The first experiment is to investigate the diffusivity of the tissue in solutions of different molarity by measuring the change in tissue weight over time. Eleven explants are taken from the same bovine articular joint using a 6mm biopsy punch and are left in 10mM of PBS overnight to ensure ionic equilibrium has been reached before experiments are carried out. The explants are then placed in PBS solutions of molarities ranging from 0mM to 10mM and weighed at regular time intervals. In the final stage, the explants are then lyophilized and weighed for determining the volume of water in the tissues. Using Archimedes principle, the change in porosity of the tissue is found. A preliminary study has shown that explants submerged in a solution of 5mM has an approximately 4% change in weight after the first 24h and a further 1.73% change in the following 24h. Control specimens left in a solution of 10mM had a 0% change in weight. The second experiment is to carry out mechanical loading on the AC specimens while submerged in a solution of different ion concentrations. Experiments with various loading conditions are being investigated to explore their efficacy for validation. Preliminary compression tests have been carried out where steps of 1% strain was applied, giving a total of 10% strain. Between each step, strain was held constant until full relaxation has been achieved. The reaction force measured from the second experiment in conjunction with data collected from the first experiment will be compared to results predicted in the numerical model. This will allow the determination of whether thermal analogy is adequate or whether more complex triphasic models need to be considered. Furthermore, the development of these experimental methods will contribute to the validation of other AC material models in the future.
Summary Statement. Supercritical fluid (SCF) sterilization produces clean and osteoconductive allograft bone capable of healing a critical-sised bony defect. SCF treated graft induces an increased anabolic response and decreased catabolic reponse compared to gamma irradiated graft. Introduction. Clinically, allogeneic bone graft is used extensively because it avoids the donor site morbidity associated with autograft. However, there are concerns over the optimal sterilization method to eliminate immunological risks whilst maintaining the biological efficacy of the graft. This study compared the effect of Supercritical fluid (SCF) sterilization and gamma irradiation on the osteoconductivity of allograft bone in a bilateral critical-sised defect rabbit model.
Aims. This study intended to investigate the effect of vericiguat (VIT) on titanium rod osseointegration in aged rats with iron overload, and also explore the role of VIT in osteoblast and osteoclast differentiation.
