Joint Components Research Articles

Three-Dimensional-Printed Scaffolds for Meniscus Tissue Engineering: Opportunity for the Future in the Orthopaedic World.

The meniscus is a critical component of a healthy knee joint. It is a complex and vital fibrocartilaginous tissue that maintains appropriate biomechanics. Injuries of the meniscus, particularly in the inner region, rarely heal and usually progress into structural breakdown, followed by meniscus deterioration and initiation of osteoarthritis. Conventional therapies range from conservative treatment, to partial meniscectomy and even meniscus transplantation. All the above have high long-term failure rates, with recurrence of symptoms. This communication presents a brief account of in vitro and in vivo studies and describes recent developments in the field of 3D-printed scaffolds for meniscus tissue engineering. Current research in meniscal tissue engineering tries to combine polymeric biomaterials, cell-based therapy, growth factors, and 3D-printed scaffolds to promote the healing of meniscal defects. Today, 3D-printing technology represents a big opportunity in the orthopaedic world to create more specific implants, enabling the rapid production of meniscal scaffolds and changing the way that orthopaedic surgeons plan procedures. In the future, 3D-printed meniscal scaffolds are likely to be available and will also be suitable substitutes in clinical applications, in an attempt to imitate the complexity of the native meniscus.

Re-Design of Machine Tool Joint Components Based on Polymer Fillings for High-Speed Performance.

In this paper, we report the results of an experimental study of a re-design approach using filling polymers and particulate composites with a polymer matrix, thus creating a macroscopic hybrid structure. The re-design is focused on the joint of a textile machine. It is a re-design of already existing machine parts of a joint in order to increase the damping of components, reduce the amplitudes of high-frequency vibrations and acoustic emission for high-speed operation of textile rotors, and to compare individual structural modifications of the rotor housing body and absorber of high-speed textile rotor in a spinning unit with respect to dynamic properties of that measured mechanical system. The experiments included a bump test, determination of logarithmic decrement, measurement of vibration acceleration, a wavelet analysis, and measurement of acoustic emission. When excited by high frequency signal amplitudes up to 5 g, the benefits of polymer filling were manifested by an approximately 50% reduction in amplitude vibrations, a 66% reduction in acoustic emission amplitude, and an 85% reduction of the maximum peak in the acoustic emission FFT spectrum. In the area above 10 g, the stiffness of the component dominated to reduce the magnitude of vibrations.

Patellofemoral joint degeneration: A review of current management

The patellofemoral component of the knee joint is affected by a wide range of degenerative causes without involving the other parts of the knee. It is often the presenting pathology in early knee osteoarthritis and missed due to a variable presentation. Accurate examination and focused investigation can help with early diagnosis and guide treatment. Various aspects to treatment need to be addressed after thorough evaluation. Guidelines to approach the multifactorial pathology of the patello-femoral joint are provided with focus on the degenerative component of disease.

Recovery of Post-Traumatic Temporomandibular Joint after Mandibular Fracture Immobilization: A Literature Review

Considered as one of the most common traumatic injuries of the maxillofacial region, mandibular fractures remain among the complex causes of temporomandibular joint disorders (TMDs). Due to the complexity of the temporomandibular joint, the management of TMDs represents a challenge in real-life practice; although many treatment modalities have already been proposed, ranging from conservative options to open surgical procedures, a consensus is still lacking in many aspects. Furthermore, despite continuous improvement of the management of mandible fractures, the duration of immobilization and temporary disability is not reduced, and the incidence of complications remains high. The aim of the present study is to (i) review anatomophysiological components of temporomandibular joint; (ii) review concepts of temporomandibular joint fractures; and (iii) describe methods of the recovery of the temporomandibular joint after mandibular fracture immobilization.

Fatigue life analysis of carbon fiber reinforced polymer (CFRP) components in hybrid adhesive joints

AbstractHybrid adhesive joints of metal and composite parts are increasingly common features of lightweight structures. Efficient design of these joints requires computational methods for estimating the fatigue life of the adhesive as well as of the parts being joined – i. e. the adherends. The paper focuses on computational fatigue life prediction for carbon fiber reinforced polymer (CFRP) adherends in hybrid adhesive joints. After a brief description of the composite material considered, two modeling approaches for the fatigue life are presented. Subsequently, the experimental determination of the model parameters is discussed and the relevant values are presented. For validation, the models are applied to predict the fatigue lives of a multidirectional laminate as well as of the composite adherend in a hybrid single‐lap joint. Finally, the results for both models are compared and discussed with respect to the experimental results. Both models yield reasonable predictions for the cases considered here. For almost uniaxial stress states, the predictions of both models are very similar while for multiaxial stress states the difference is more pronounced.

Study of ultrasonically welded thermoplastic dowel-wood board assembly

• Ultrasonic welding is a fast joining of thermoplastic dowel-wood board assembly. • Density of wood board plays an important role in ultrasonic welding. • Dowel pulling force inversely proportional to the depth of the drilled hole. • Ultrasonic thermoplastic dowel welding is not suitable for wet wood boards. This study reports on an ultrasonic welding application for the assembly of a thermoplastic dowel and a wood board. Three types of medium density particleboards (MDP) and fiberboards (MDF) were used to indicate applicability of ultrasonic welding to fix a plastic wedge dowel into the wood boards: light-weight, standard, and heavy. Plastic wedge dowels made of resin nylon thermoplastic polyamide PA66 were used to compose ultrasonically welded wood boards’ joints. Ultrasonic welding is a joining technique without any additional substances, such as adhesives or solvents. It possesses local heating of only the joint area, short cycle times in the range of just a few seconds, and comparatively low cost-efficiency. During the ultrasonic consolidation process, energy generated from an ultrasonic transducer is transferred to the joint components (dowel – wood board) in the form of ultrasonic oscillation. The quality of the welded joint is mainly influenced by the density of the wood board, the quality of wood particles bonding, the depth and diameter of the drilled hole. The size of the contact area of the drilled hole (hole geometry, density and the size of hole walls) is also very important because the molten thermoplastic requires enough space to penetrate and settle to form a solid assembly.

Investigating the Effect of Screw Size on the Stress Level in MERO Joint for Space Frame Structures

Space frame structures satisfy the ever-increasing requirements of societies for providing a variety of structural forms and architectural spaces with special characteristics, such as aesthetic and free-form features, population-wise capacities, and structural performance, among others. Structural behavior of these systems largely depend on the type of joints and their components which are to be considered appropriately in design and analysis. Screws comprise one of the key components of joints in these structures and play a pivotal role in the total cost of the structure, as well as the maximum stress level created in joints. The present study aims to evaluate the effect of screw size on the maximum stress generated in three MERO double-layer ball joints with diameters of 98, 110, and 132 mm as a sample numerical analysis case to pinpoint this fact. Numerical simulations were conducted using ANSYS workbench software. Based on the results, in order to achieve the maximum factor of safety (FOS), the minimum stress, and keeping the total construction cost optimal, it is recommended to use M16, M20, and M24 screws for the ball joints of diameters 98, 110, and 132 mm, respectively.

An experimental investigation on bearing behavior and failure mechanism of bolted composite interference-fit joints under thermal effects

This paper reports an experimental investigation on bearing behavior and failure mechanism of single-lap bolted composite interference-fit joints under thermal effects. To achieve this target, testing temperatures ranged from −25 to 110 ℃ were designed to simulate thermal service environments. The unidirectional composite lamina was tested longitudinally and transversely to figure out potential change of material properties induced by thermal loading. The residual effects of stacking sequence, interference-fit size and tightening torque on bearing strength and stiffness of composite joints after exposed to thermal conditions were evaluated. Microscopic studies applying X-ray technique on damage areas to monitor damage evolution were conducted to comprehend the thermal failure mechanism. The results evidence that the bearing performance of composite joints was slightly enhanced by low temperature due to cold hardening of matrix resin but greatly weakened by high temperature owing to the combined effects of heat softening of resin, residual stress relaxation and thermal expansion of joint components. Tightening torque to enhance bearing performance is the most beneficial at room temperature, whereas the interference-fit remains the dominant influence at sub-freezing environments. In conclusion, thermal loading plays an important role in bolted composite interference-fit joints. It is an unneglectable factor that would enlarge damage area, alter failure mode and should be understood thoroughly.

Buzz-based honeybee colony fingerprint

Non-intrusive remote monitoring has its applications in a variety of areas. For industrial surveillance case, devices are capable of detecting anomalies that may threaten machine operation. Similarly, agricultural monitoring devices are used to supervise livestock or provide higher yields. Modern IoT devices are often coupled with Machine Learning models, which provide valuable insights into device operation. However, the data preparation step for ML models has to be addressed differently for industrial and agriculture cases. Animals are characterized by their circadian rhythms and seasonal dependence, which can bias the accuracy of classifiers. In the presented work, a Design-of-Experiment (DoA) approach for extracting valuable bee colony audio data is described. With the presented methods, it is possible to precisely define the most distinctive bee hours where unique colony sounds are emitted. The first step of the data filtering process is based on identifying the ambient temperatures that are conducive to its operation. The second step provides the unique hours specification based on the hives’ characteristics comparison where dissimilar time periods are being marked. For this comparison, the most noticeable difference between the colonies is calculated with MSE integral and thus the trend’s joint component is removed. A new concept of a bees’ fingerprint was introduced for the identification of the particular bee colony.

Comparative Study of Efficacy of Muscle Energy Technique and Positional Release Therapy in Post ACL Reconstruction in Young Adults: A Randomised Clinical Trial

The anterior cruciate ligament (ACL), it is a dense connective tissue band originating from the medial wall of the lateral femoral condyl and inserts into the middle of the intercondylar region on the tibia. It is regarded as a crucial component in the knee joint because it resists anterior tibial translation and rotational load. Young athletes who participate in sports that demand turning, decelerating, and jumping are at high risk for ACL injury. People who participate in Pivoting sports are likely to have them (e.g. football, basketball, netball, soccer, European team handball, gymnastics, downhill skiing). Environmental (e.g., high friction between shoes and the playing surface) and anatomical variables are also risk factors for ACL injury (e.g. narrow femoral intercondylar notch). Knee instability causes a reduction in activity, which can result in a decrease in knee-related quality of life. ACL injury risk factors have been classified as either internal or external to a person. Type of competition, footwear and surface, and environmental conditions are all external risk factors. Anatomical, hormonal, and neuromuscular risk factors are all internal risk factors.
 Aim and Objective: to compare the efficacy of Myofacial Release Technique versus Positional Release Therapy on range of motion post ACL reconstruction.
 Methodology: In this study total 45 patients with post ACL reconstruction will be divided into two groups, one group will receive muscle energy technique and other group will received positional release therapy. The treatment will be given for 5 sessions per week for six weeks. The assessment will be done at day one of treatment at the end of treatment at the end of first week and at the end of six week.
 Discussion: This study will find the better technique for improving Range of motion Post ACL reconstruction.
 Conclusion: Conclusion of the study will be drawn after the statistical analysis of the data gathered from the individuals enrolled in the study.

Progress on nonlinear ultrasonic evaluation of damages within the adhesively bonded composites

<p indent="0mm">Adhesively bonded composite structures are widely used in aerospace, shipbuilding and automotive industries because of such advantages as lower structural weight and more uniformly distributed stresses. As an important component of the adhesive joints, properties of the adhesive interface determine the integrity of the whole adhesive structure, making the research on damage detection and evaluation of the adhesive interface an extensively concerned topic in the related fields. The ultrasonic nondestructive testing technique, which has a long history of development since its appearance, is an effective technology for testing, evaluating and characterizing material properties and damages. Because of the advantage of realizing the detection without causing additional destruction to the structure and materials, the ultrasonic nondestructive testing has been widely used in engineering practice. However, the existing traditional ultrasonic nondestructive testing technology mainly concerns the initiation and accumulation of material damages, final failure of the structure on service. It is difficult in characterizing the bonding strength, bonding force, early degradation and micro-damage of the bonding surface directly and quantitatively, which is not capable of realizing the structural health monitoring and life prediction of the adhesive joints. It is promising that the nonlinear ultrasonic technology developed in recent years can effectively solve the problems mentioned above. When nonlinear waves are employed, this technique has higher sensitivity in characterizing the change of micro-structure of materials and micro-damages, whose spatial dimension is much smaller than the wavelength of ultrasonic waves. Considering these advantages, nondestructive testing and evaluation employing nonlinear waves have been widely investigated in recent years; a series of new methods have appeared and many important achievements have been obtained. Detection and evaluation of damages within bonded composite structures and adhesively jointed interfaces are more complicated. There are two types of adhesive failure: Adhesion failure in the interface layer between the adhesive and the adhered, and cohesion failure in the adhesive layer. Due to the existence of adhesive interfaces, complex refraction, reflection and scattering will occur when ultrasonic waves propagate in the adhesive composite structure and interfaces, particularly the existence of the adhesive layer will increase the attenuation of the wave energy. These problems make the investigation of wave propagation in the adhesively bonded structure even more complicated. Based on the nonlinear ultrasonic technique, many investigations have been carried out and many fruitful achievements have been obtained in examining and evaluating the early degradation of the bonded interface. Generally, bulk waves, guided waves and mixing waves are employed in theoretical and experimental research. Bulk waves can be excited and received without much difficulty, and guided waves are effective in examining plate and shell structures. In both cases, the magnitude of high-order harmonic waves and related nonlinear parameters are used in the process of evaluation and characterization. As to the mixing wave method, the amplitude of the mixing resonance waves and the nonlinear parameter based on the mixing resonance waves are employed in evaluating and locating the early damage within the composite structure and the adhesively bonded interface. In this paper, we review the progress of applying the nonlinear ultrasonic waves in evaluating early degradation and micro-damage of the adhesively bonded composite structures and interface damage, including the theoretical and experimental investigations of employing transmitted bulk waves, guided waves and mixed waves. Furthermore, future research related to the characterization of composite structures and adhesive joints is suggested.

Numerical investigation of galvanic corrosion between galvanized steel and mild steel in bolted joint

The galvanic corrosion between galvanized steel and mild steel coupled in the bolted joint was studied in this research, by varying different environmental conditions such as pH. The corrosion parameters of the joint components were used for numerical simulation using COMSOL ® Multiphysics software to analyze galvanic corrosion behavior at the contact zone between the bolt head and endplate. The pH values (pH. 4, pH,7, and pH 9.2) were considered for the study. Experiments were carried out by using a Potentiostat to obtain TAFEL Polarisation. The results obtained from the TAFEL Polarization were used as boundary conditions in the COMSOL ® Multiphysics Software. The maximum thickness loss of anode in 6 months for pH 4 was observed to be 3 mm. The maximum thickness loss of anode in 6 months for pH 7 was observed to be 0.22 mm. The maximum thickness loss of anode in 6 months for pH 9.2 was observed to be 0.2 mm. Thus total thickness loss due to corrosion is observed maximum for Ph. 4 and minimum for pH. 9.2. With Increasing pH, the severity of corrosion is reduced. The maximum corrosion was observed at lower pH(acidic) and the least corrosion was observed at higher pH(basic). Polarization study helps to find out the corrosion rate of the galvanic couple.

Two-component feedstock based on ultra-high molecular weight polyethylene for additive manufacturing of medical products

Abstract Ultra-high molecular weight polyethylene (UHMWPE) possesses distinctive properties, but has an extremely low melt flow rate (MFR) of about zero, which makes it unsuitable for processing by standard methods for polymers. The aim of this paper was to investigate the tribological properties of two-component UHMWPE-based composites with different content of isotactic PP. The composites were fabricated by three methods: a) hot pressing of the powder mixtures; b) hot compression of granules; and c) 3D printing (FDM). It was shown that the UHMWPE-based composites obtained by extrusion compounding (hot compression of granules and 3D printing) in terms of the mechanical and tribological properties (wear resistance, the friction coefficient, Young's modulus, and yield strength) were superior to the ones manufactured by hot pressing of the powder mixtures. The most effective was the ‘UHMWPE+20% PP’ composite in terms of maintaining high tribological and mechanical properties and the necessary melt flow rate (MFR) in a wide range of loads. It was recommended as a feedstock for additive manufacturing of complex-shaped products (joint components) for friction units in orthopedics.

Seismic Behavior Experimental Study on the Joint of Circular Tubed Steel-Reinforced Concrete Columns

A new type joint of Circular Tubed Steel-Reinforced Concrete (CTSRC) columns was designed in this paper. The structural characteristics, manufacturing process, and mechanical properties of raw materials of the new joint were introduced. In order to simulate the earthquake action, two joint specimens were subjected to low-cycle cyclic loading at the end of the column. Based on the in-depth study of the failure characteristics, load-displacement hysteretic curve, skeleton curve, ductility index, load-strain hysteretic curve in the core area of the joint, energy dissipation performance, strength and stiffness degradation performance, and shear deformation in the core area of the joint during the whole loading process, the seismic behavior of this new type of joint was investigated. The results show that the new joint has reasonable failure characteristics, high bearing capacity, good ductility, excellent seismic energy dissipation performance, and strong resistance to strength and stiffness degradation, which meets the seismic design principle of “strong joint and weak component” and is suitable for the results with special requirements for seismic performance. In addition, preliminary design recommendations were put forward. The research results of this paper can provide a theoretical basis for the application of this kind of new structure.

Case Report: Digital analysis of occlusion with T-Scan Novus in occlusal splint treatment for a patient with bruxism

Bruxism is a disease with a multifactorial etiology. Its clinical manifestations are most often an unaesthetic smile with abraded tooth surfaces, temporomandibular disorders and muscle hyperactivity. Here we present a case of bruxism where proper articulation of the occlusal splint was performed using the T-scan Novus system. A patient with bruxism underwent treatment with stabilization splint made by 3D printer technology. Intraoral scanning was performed using Trios Color (3Shape, 2014), and the digital design was achieved using the 3Shape Dental system design - splint studio. Formlabs Form 2 printer with biocompatible resin Dental LT Clear Resin was used for printing. The T-Scan Novus system with software attached to it, version 9.1, was used for digital examination of the occlusion. A 2.7 mm thick occlusal splint was developed, and the software adapted the occlusion with antagonists. After adjustment with T-Scan Novus, a reduction in disocclusion time of the patient was achieved, which is a desired result in the treatment of bruxism. The position of the joint components was proven radiologically. The treatment of bruxism with splint therapy continues to be the main method of treatment. Using digital technology allows for more accurate constructions and precise balancing of occlusal relationships.

Image based quantification of the proximal femur shape deformities in 3D by using the contralateral healthy shape structure: A preliminary study

As a result of the several hip joint disorders seen on the hip joint components, shape deformities occur in the morphological structure of the proximal femurs and femoral heads. Quantification of the shape deformities in related hip joint components is a crucial task since it may provide assistive information to clinical experts and surgeons in clinical treatment, assessment and prognosis processes. In this article, a preliminary study handling the 3D shape deformity quantification of the abnormal proximal femurs is presented. The shape deformity of the abnormal proximal femurs in bilateral hip joint images are quantified directly by using the morphological structure of the contralateral healthy proximal femurs without a need for a statistical shape model. For this purpose, segmentation maps of the bilateral proximal femurs are registered in 3D by performing a rigid transform method, and the regions outside the intersection volume are quantified as the shape deformities. To evaluate the proposed study, a total of 13 bilateral hip magnetic resonance imaging (MRI) sequences of 13 patients with Legg-Calve-Perthes disease (LCPD) were used. The deformity ratios observed in experiments are quite promising and consistent with the Waldenstrom classification system stages of the LCPD. The shape deformity ratios of the pathological proximal femurs in 3D were quantified as 18.02% (±04.84), 26.41% (±07.54), 31.21% (±11.07), and 36.84% (±09.33), respectively for the Initial, Fragmentation, Reossification, and Remodelling stages of LCPD in this preliminary study.

Behaviour of Steel Tube Knee Joint Inserts used in Aluminium Portal Frames

AbstractUsually, prefabricated aluminium halls use portal frame structures with a high strength steel tension tie element. Due to the high reduction of aluminium strength induced by welding, aluminium joints of prefabricated halls are almost exclusively formed using bolts in combination with steel reinforcements. The most convenient type of reinforcement is a steel tube knee joint insert. In these joints, the transmission of forces is realized partially through bolts and partially through a complex contact mechanism between aluminium members and the steel tube knee joint insert. Detailed overview of the behaviour of such joints is still unknown and simple expressions for the assessment of their behaviour are lacking. With that in mind, as a first phase of the research, laboratory tests of steel tube welded knee joints with bolted tie element were performed under the application of static loading. Numerical simulations in ANSYS were performed to enable a deeper insight into the complex interaction of different joint components. Due to the limitations of laboratory equipment and the fact that only a ‘rigid’ tie element (circular tube) was utilized in tests, numerical simulations were also applied to extend experimental results and include different, more realistic, levels of axial stiffness of the tie element. Obtained structural properties of the tested joint type are provided and discussed regarding the advancement of understanding underlying behaviour parameters and outlining further research phases.

Evaluation of condylar changes in relation to various malocclusions

Introduction: Variability in the size and shape of mandibular condyles among individuals of different sexes and ages may appear as a remodeling process to accommodate malocclusion. Hence, the aim of this study was to assess whether or not associations exist between different types of malocclusions and morphological modifications of the mandibular condyle. Materials and Methods: A systematic literature search was conducted on the Medline database via PubMed interface and supplemented by a manual search via Google Scholar to identify more articles reporting the subject of the review. A combination of controlled vocabulary was used in the search strategy and the final update was stopped on January 2021. The risk of bias was assessed based on the Newcastle–Ottawa Scale. Results and Discussion: Considering the preestablished inclusion and exclusion criteria, 20 articles were retained with 2607 human subjects (967 males/1299 females and 341 not specified, age: 4–60 years). Eighty percent of the selected articles reported associations between malocclusion and morphological changes of the condylar head. Sagittal plane malocclusions produce more changes to the temporomandibular joint components (head of condyle and joint space) (71.93%), while vertical malocclusions lead to the most severe manifestations. Conclusions: Cone-beam computed tomography is the most useful tool for the assessment of osseous morphology of mandibular head condyles and detection of cortical erosion (21.7%). Associations between morphological changes of the condylar head and specific types of malocclusions were proven. However, there is still a need for more clinical studies.

Experimental and numerical research on fabricated joint for CFST set in underground construction

The quantitative design of fabricated joint is a key issue to realize the effective mechanized assembly of tunnel steel set. However, there is no reported research on the failure mechanism and quantitative design method of fabricated joint for underground support structures. Taking a type of fabricated joint used for concrete-filled steel tubular (CFST) set as research object, the refined finite element model is constructed in this paper considering the complex nonlinear characteristics of joints. The simulation scheme is verified and validated based on four-point flexural and eccentric compression experiments. Failure modes and bearing mechanism of fabricated joint are obtained through above methods. Research results prove that there are two primary failure modes: the destruction of joint components and the tearing fracture at joint-CFST junction, the latter of which might lead to overall brittle failure of tunnel support structures. Parametric studies of joint specimen are carried out accordingly to establish an analytical model for fabricated joint design. The research results could provide basis for the design and application of mechanized assembly construction in tunnel excavation.

Influence of diamond-like carbon coatings on the wear of the press joint components

• The coatings are distinguished by the low coefficient of friction and wear • Wear traces suggesting fretting appear on the coatings • Coating damage consists in micropullouts, abrasions and material buildups in places • No traces of fretting wear are noted on the CrN-a:C:H:W:Ti coating