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Purpose This study aims at comparing the effects of symmetric and asymmetric designs for the polyethylene insert currently available and also for mobile bearing total knee arthroplasty (TKA). The investigation was performed both clinically and biomechanically through finite element analysis. Methods 303 patients, with a mobile bearing TKA, were analyzed retrospectively. All patients received the same femoral and tibial components; for the insert, 151 patients received a symmetric design (SD) and 152 an asymmetric design (AD). Additionally, a 3D finite element model of a lower leg was developed, resurfaced with the same TKAs and analysed during gait and squat activities. TKA kinematics, and bone-stresses were investigated for the two insert solutions. Results After surgery, patients’ average flexion improved from 105°, with 5° of preoperative extension deficit, to 120° (AD-group) and 115° (SD-group) at the latest follow-up. There was no postoperative extension deficit. No pain affected the AD-group, while an antero-lateral pain was reported in some patients of the SD-group. Patients of the AD-group presented a better ability to perform certain physical routines. Biomechanically, the SD induced higher tibial-bone stresses than the AD. Both designs replicated similar kinematics, comparable to literature. However, SD rotates more on the tray, reducing the motion between femoral and polyethylene components, while AD permits greater insert rotation. Conclusion The biomechanical analysis justifies the clinical findings. TKA kinematics is similar for the two designs, although the asymmetric solution shows less bone stress, thus resulting as more suitable to be cemented, avoiding lift-off issues, inducing less pain. Clinically, and biomechanically, an asymmetric mobile bearing insert could be a valid alternative to symmetric mobile bearing insert. Level of evidence Case–control study retrospective comparative study, III.

Purpose If substitution of the posterior cruciate ligament in total knee arthroplasty is necessary, there are two options available: posterior stabilized (PS) design with a post-cam mechanism or anterior-lipped ultracongruent (UC) inserts. UC inserts have the advantage that no femoral box is necessary and a standard femoral component can be used. The aim of this study was to compare the range of motion (ROM) and patient-reported outcome (PRO) after UC and PS fixed-bearing TKA. Better ROM in PS TKA and no difference in PRO between both designs was hypothesized. Methods A randomized controlled trial with 127 patients receiving a fixed-bearing UC or PS design of the same knee system was performed. Nine patients died and there were four revision surgeries. 107 patients completed the 5-year follow-up. Patient-reported outcome was assessed. Patellofemoral problems were evaluated using selected applicable questions of the Oxford Knee Score (getting up from a table, kneeling, climbing stairs). Results Surgical time was 10 min shorter in the UC group ( p  < 0.001). After 5 years, both groups demonstrated good knee function and health-related quality of life without significant differences between the groups. Both groups demonstrated a high satisfaction score and the majority of patients would undergo this surgery again. Patellofemoral problems were recognized more frequently in the PS group ( p  = 0.025). Conclusion Both designs demonstrated similar good results after 5 years. Stabilization with an anterior-lipped UC insert can be considered a safe alternative to the well-established PS design if cruciate substitution is necessary. Level of evidence 1.

Purpose No systematic review has compared the clinical outcome of anterior stabilized ultra-congruent and standard cruciate-retaining inserts in fixed-bearing primary total knee arthroplasty. This study aimed to compare the outcomes and establish the superiority or equivalence of these inserts. Methods Pubmed, EMBASE, Medline, AMED, ERIC, and Proquest databases were searched electronically. PRISMA guidelines were followed in the conduct of the study. The clinical outcomes compared in the meta-analysis were overall knee score, WOMAC, score for knee function, score for knee pain, SF-12 PCS, knee flexion, manipulation under anaesthesia for postoperative knee stiffness, revision total knee arthroplasty or change of polyethylene insert for post-operative instability (relative risk [RR]) and survivorship. Study quality was evaluated using the Newcastle Ottawa Scale and the Modified Jadad scale. Results Fourteen studies comprising 9989 knees (three RCTs and 11 comparative case-cohort studies) were included for qualitative and quantitative analysis. The pooled analysis of the ultracongruent insert and the standard cruciate retaining insert was based on a cohort of 2860 and 7129 TKA, respectively. Knee pain was significantly better in patients that had standard inserts ( p  = 0.02; 95% CI − 1.06 to − 0.10), and the physical component of health-related quality of life was also significantly better in patients that had standard inserts ( p  = 0.02; 95% CI − 6.43 to − 0.64). There was a 72% lesser chance of revision TKA or change of insert for postoperative instability in knees that had been implanted with ultracongruent inserts (RR = 0.28; p  = 0.0002; 95% CI 0.15–0.55). There was no difference in the otheroutcome measures. There was no significant difference between the two inserts, considering the minimal clinically important difference or absolute ratio. Conclusion Differences observed between the two types of inserts were not clinically significant. Therefore, based on current evidence, arthroplasty surgeons can use either of these inserts with cruciate-retaining knee prosthesis. Level of evidence Therapeutic study, Level II.

Tool based manufacturing processes like injection moulding allow fast and high-quality mass-market production, but for optical polymer components the production of the necessary tools is time-consuming and expensive. In this paper a process to fabricate metal-inserts for tool based manufacturing with smooth surfaces via a casting and replication process from fused silica templates is presented. Bronze, brass and cobalt-chromium could be successfully replicated from shaped fused silica replications achieving a surface roughnesses of R q 8 nm and microstructures in the range of 5 µm. Injection moulding was successfully performed, using a commercially available injection moulding system, with thousands of replicas generated from the same tool. In addition, three-dimensional bodies in metal could be realised with 3D-Printing of fused silica casting moulds. This work thus represents an approach to high-quality moulding tools via a scalable facile and cost-effective route surpassing the currently employed cost-, labour- and equipment-intensive machining techniques. Production of tools for polymer replication in the field of optical applications is still time-consuming and cost-intensive. Here the authors develop an efficient metal casting process, and demonstrate manufacturing of structures of complex shapes with a surface roughness of few nanometres.

The aim of this paper is to give a scope about aluminium cutting tools. During experiments we compared different inserts in two common aluminium alloys EN-AW6082-T6 and EN-AW7075-T6. The main goal was to compare inserts of which one is advised for aluminium machining and the other is not. For the experiment we used the same parameters for both cutting tools. We measured the surface roughness after each run and checked the surfaces under microscope. After collecting all the data, we draw conclusions.

This paper analyzes the layup design and manufacture of composite laminate with inserts on the surface of revolution, and points out that both the interior surfaces and the outer surfaces should be laid as a full-body ply. Utilize 3D design software Catia and composite design software Fibersim, carry out digital layup and producibility simulation of the product, design wrapped plies for the interior surface and outer surface with complex structures, simulate and adjust the laying process, and make the fiber deformation of the entire surface reasonable. Flat patterns of the plies are provided for material cutting. For the layup of thicker area and transition area of the product, the layup design and production data and suggestions are also given. The scheme and data of layup are well used in guiding production and improving production efficiency and product quality.

Advances in modern sequencing technologies allow us to generate sufficient data to analyze hundreds of bacterial genomes from a single machine in a single day. This potential for sequencing massive numbers of genomes calls for fully automated methods to produce high-quality assemblies and variant calls. We introduce Pilon, a fully automated, all-in-one tool for correcting draft assemblies and calling sequence variants of multiple sizes, including very large insertions and deletions. Pilon works with many types of sequence data, but is particularly strong when supplied with paired end data from two Illumina libraries with small e.g., 180 bp and large e.g., 3-5 Kb inserts. Pilon significantly improves draft genome assemblies by correcting bases, fixing mis-assemblies and filling gaps. For both haploid and diploid genomes, Pilon produces more contiguous genomes with fewer errors, enabling identification of more biologically relevant genes. Furthermore, Pilon identifies small variants with high accuracy as compared to state-of-the-art tools and is unique in its ability to accurately identify large sequence variants including duplications and resolve large insertions. Pilon is being used to improve the assemblies of thousands of new genomes and to identify variants from thousands of clinically relevant bacterial strains. Pilon is freely available as open source software.

Purpose The aim of this study was the comparison of intraoperative kinematics, stability, and range of motion (ROM) between the native osteoarthritic knee and cruciate-substituting fixed-bearing total knee arthroplasty (TKA) using both an ultracongruent (UC) and a posterior-stabilized (PS) insert design in the same patient. We hypothesized less knee flexion and less antero-posterior stability in the UC TKA. Methods Intraoperative measurements of kinematics, stability, and ROM were performed in 40 patients before soft-tissue release and bone cuts, and after implantation of the final femoral and tibial implants with both a UC insert and a PS insert. All measurements were performed using a navigation system. Results Kinematics changed significantly from a constant posterior femoral rollback before surgery to a paradoxical anterior translation during initial knee flexion with both inserts, but less pronounced with the PS insert ( p  < 0.001). There was significantly more posterior femoral rollback with the PS insert compared to the UC insert ( p  < 0.01). Stability measurements demonstrated no differences at full extension and 30° of knee flexion but significantly increased antero-posterior translation in 60° and 90° of knee flexion with the UC insert compared to the PS insert ( p  < 0.001). ROM measurements demonstrated improvement of knee flexion from 118° at the beginning of the surgery to 123° with the UC insert and 128° with the PS insert ( p  < 0.001). Conclusion The use of a UC insert intraoperatively resulted in less antero-posterior stability and slightly less knee flexion compared to a PS insert. Surgeons should be aware of these differences when deciding for one of these options to substitute the posterior cruciate ligament (PCL). The impact of these findings on clinical outcome needs further investigation. Level of evidence II.

In the present study, an attempt has been made to investigate the influence of cutting speed, depth of cut, and feed rate on surface roughness during machining of 7075 Al alloy and 10 wt.% SiC particulate metal-matrix composites. The experiments were conducted on a CNC Turning Machine using tungsten carbide and polycrystalline diamond (PCD) inserts. Surface roughness of 7075Al alloy with 10 wt.% SiC composite during machining by tungsten carbide tool was found to be lower in the feed range of 0.1 to 0.3 mm/rev and depth of cut (DOC) range of 0.5 to 1.5 mm as compared to surface roughness at other process parameters considered. Above cutting speed of 220 m/min surface roughness of SiC composite during machining by PCD tool was less as compared to surface roughness at other values of cutting speed considered. Wear of tungsten carbide and PCD inserts was analyzed using a metallurgical microscope and scanning electron microscope. Flanks wear of carbide tool increased by a factor of 2.4 with the increase of cutting speed from 180 to 240 m/min at a feed of 0.1 mm/rev and a DOC of 0.5 mm. On the other hand, flanks wear of PCD insert increased by only a factor of 1.3 with the increase of cutting speed from 180 to 240 m/min at feed of 0.1 mm/rev and DOC 0.5 mm.

A novel cutting manner is presented to control regenerative chatter vibration in double inserts cutting, in which the forward and the backward inserts cut workpiece simultaneously with phase difference in the modulation of finished surface. In double inserts cutting, the forward insert is clamped above the backward insert. Both the inserts are positioned symmetrically with a height offset with respect to the workpiece rotation center. The forward insert mainly removes the material; while the backward insert cuts a part of the inner modulation to lose the regular excitation. The exciting force is also reduced with the cutting thickness of the forward insert after a workpiece revolution. Because the theoretical position offset of the inserts in the feed direction is small, the side cutting edges of inserts are aligned in the same position. The process parameters are determined by estimating the removal volume of the backward insert with the phase shift. The range of the cutting speed and the height offset are given by the frequency of the chatter vibration, which is nearly the same as the natural frequency of the workpiece in single degree of freedom. The proposed cutting manner is validated using comparison between the single insert and double inserts cuttings.