Search Results (37)

Compliant mechanisms have contributed to many advances in soft robotics, and there is strong motivation to translate these ideas to assistive devices where adaptive motion at the human interface is required. This work presents novel reconfigurable compliant joints (RCJs) as a parameterized joint element for functional biomimicry in lower-extremity joints for prosthetic knees and ankle–foot orthoses, with concepts that extend to other limb joints. The RCJ uses a rigid hub and outer ring joined by an array of flexible links with centerlines defined by cubic Bézier curves. Link shapes are organized into four Bézier classes (A–D), with base types using 10, 12, or 14 uniformly distributed link slots and variants generated by modifying active-link count and distribution, forming a structured morphology space of 12 configurations for machine design. Dual-extrusion 3D-printed prototypes are characterized by a custom testing apparatus using a 2.2 kN load cell at 25 mm/s over a 0–90° rotation range across six recorded load cycles to measure torque–angle curves and stiffness under large deformations. Angle-dependent stiffness is evaluated over three fixed intervals (0–30°, 30–60°, and 60–90°) to quantify multi-stage behavior. A 2-dimensional corotational frame model and a Simscape Multibody model, including a rolling-contact knee configuration, use the same parameterization to relate geometry, nonlinear mechanics, and system-level motion. Experiments and simulations show multi-stage torque–angle profiles and predictable stiffness modulation across all configurations, with both magnitude and transition angle tunable through Bézier class and active-link distribution, positioning the RCJ as a CAD/CAE-compatible joint architecture for assistive devices or wearable robotic systems and a basis for advancing functional biomimicry in compliant mechanism design. Full article

Degenerative mitral stenosis (MS) secondary to extensive mitral annular calcification (MAC) represents a growing clinical challenge in an aging population. These patients are often elderly, frail, and harbor a significant burden of comorbidities, rendering conventional mitral valve surgery prohibitively high-risk. While transcatheter mitral valve replacement (TMVR) has emerged as a potential alternative, the current evidence is only derived from single-arm observational registries. Therefore, the transition toward randomized controlled trials to define optimal patient selection and long-term prosthetic durability is necessary. This review examines the current landscape of TMVR for degenerative MS, focusing on the role of multimodal pre-procedural planning, procedural technique, and prevention of the principal complications. The integration of echocardiography and multi-slice computed tomography (MSCT) is essential for evaluating anatomical feasibility, particularly in predicting neo left ventricle outflow tract (neo-LVOT) obstruction, the primary determinant of procedural mortality. However, it is limited due to the absence of standardized protocol. We are showing the outcomes of off-label balloon-expandable aortic prostheses and dedicated TMVR system, which are the only two devices which data in patients with MS are available. Despite high technical success rates in specialized centers, complications, including paravalvular leak, valve thrombosis, and device migration, remain more prevalent than in aortic interventions. We present some tips and tricks to prevent and manage adverse events. TMVR represents a transformative frontier for inoperable patients with severe MAC. However, its routine clinical adoption requires further refinement of dedicated technologies and standardized imaging protocols to improve safety and bridge the gap between palliative medical therapy and definitive intervention. Full article

To address the limitations of current prosthetic knees that lack personalized adaptability to users’ gait characteristics and walking speeds, this study proposes a personalized gait parameter prediction–based speed-adaptive control method for a hybrid active–passive intelligent prosthetic knee (HAPK). The proposed system integrates a perceptron-based model to predict individualized gait parameters by mapping anthropometric data and walking speed to key points of the knee trajectory. A fuzzy logic–based damping control for the swing phase and a position–torque control for the stance extension phase are developed to achieve real-time adaptation to different walking speeds and user-specific biomechanics. The hybrid actuation system combines hydraulic damping and motor torque assistance to ensure both compliance and power delivery across gait phases. Experimental results from variable-speed walking tests demonstrate that the proposed control method improves gait symmetry indices—reducing stance and swing asymmetries by approximately 30–38%—and achieves smoother, more natural gait transitions compared to traditional fixed-gait control strategies. These findings validate the effectiveness of the proposed approach in achieving continuous, personalized, and speed-consistent gait control for intelligent prosthetic knees. Full article

This paper presents a low-cost, modular ankle–foot prosthesis that integrates an S-shaped compliant foot with a parallel spring–short-stroke actuator branch to balance energy return, impact attenuation, and rapid personalization. The design follows an FDM-oriented CAD/CAE workflow using PETG and interchangeable modules (foot, ankle unit, pylon adapter). Finite-element analyses of heel-strike, mid-stance, and toe-off load cases, supported by bench checks, show strain localization in intended flexural regions, a minimum safety factor of 15 for the housing, and peak-stress reduction after geometric refinements (increased transition radii and local ribs). The modular layout simplifies servicing and allows quick tuning of stiffness and damping without redesigning the load-bearing structure. The results indicate an engineeringly realistic path toward accessible prosthetics and provide a basis for subsequent upgrades toward semi-active control and sensor-assisted damping. Full article

Background: Sitting and standing with conventional hip–knee–ankle–foot (HKAF) prostheses are demanding tasks for hip disarticulation (HD) amputees due to the passive nature of current prosthetic hip joints that cannot assist with moment generation. This study developed a sitting and standing control strategy for a motorized hip joint and evaluated whether providing active assistance reduces the intact side demand of these activities. Methods: A dedicated control strategy was developed and implemented for a motorized hip prosthesis (Power Hip) compatible with existing prosthetic knees, feet, and sockets. One HD participant was trained to perform sitting and standing tasks using the Power Hip. Its performance was compared with the participant’s prescribed passive HKAF prosthesis through measurements of ground reaction forces (GRFs), joint moments, and activity durations. GRFs were collected using force plates, kinematics were captured via Theia3D markerless motion capture, and joint moments were computed in Visual3D. Results: The Power Hip enabled more symmetric limb loading and faster stand-to-sit transitions (1.22 ± 0.08 s vs. 2.62 ± 0.41 s), while slightly prolonging sit-to-stand (1.69 ± 0.49 s vs. 1.22 ± 0.40 s) compared to the passive HKAF. The participant exhibited reduced intact-side loading impulses during stand-to-sit (4.97 ± 0.78 N∙s/kg vs. 15.06 ± 2.90 N∙s/kg) and decreased reliance on upper-limb support. Hip moment asymmetries between the intact and prosthetic sides were also reduced during both sit-to-stand (−0.18 ± 0.09 N/kg vs. −0.69 ± 0.67 N/kg) and stand-to-sit transitions (0.77 ± 0.20 N/kg vs. 2.03 ± 0.58 N/kg). Conclusions: The prototype and control strategy demonstrated promising improvements in sitting and standing performance compared to conventional passive prostheses, reducing the physical demand on the intact limb and upper body. Full article

To enhance the adaptability and human-machine coordination of intelligent prosthetic knees, this study proposes a motion intention mapping direct myoelectric control method based on an LSTM network and a human-machine coupling model. Multichannel surface electromyography (sEMG) and knee joint angle data were collected during level-ground walking. Time-domain features were extracted to construct an LSTM prediction model, enabling temporal mapping between muscle activity and joint kinematics. Experimental results show that the LSTM model outperforms traditional neural networks in terms of prediction accuracy and temporal consistency. Furthermore, by integrating the human-machine coupling dynamics model with a hydraulic actuation system, a direct myoelectric control framework for a variable-damping prosthetic knee was established, achieving continuous damping adjustment and smooth gait transition. The results verify the feasibility and effectiveness of the proposed method in human-machine coordinated control. Full article

Background: Subcrestally placed implants (SPIs) present advantages for bone preservation and soft tissue support but pose challenges in maintaining peri-implant soft tissue health. This case explores the role of Crest to Restoration Distance (CRD) in the development and resolution of peri-implant mucositis. Case Presentation: A 57-year-old woman received two SPIs—one in the upper left and one in the lower right first molar region. Despite similar implant systems and prosthetic protocols, the upper left implant developed mucositis, characterized by bleeding on probing and discomfort, while the lower right implant remained stable. Three-dimensional analysis using cone-beam computed tomography (CBCT) revealed excessive CRD at the affected site. Results: After prosthodontic revision to reduce the CRD, clinical signs of mucositis resolved, with probing depths reduced to less than 1 mm and no bleeding on probing. The control site remained healthy throughout the observation period. Practical Implications: This case highlights CRD as a modifiable prosthetic factor influencing soft tissue stability. A three-zone model—comprising the sulcus, transitional zone (TZ), and subcrestal zone (SZ)—is introduced to provide a biologically grounded framework for understanding soft tissue adaptation around SPIs. Full article

The development of hydrophilic biodegradable polymers is crucial for a range of biomedical applications, including targeted drug delivery and prosthetics. Ring-opening polymerization of substituted ε-caprolactone monomers provides an efficient method for the synthesis of polyesters with tailored properties. In this work, a synthetic approach for the preparation of ester- and morpholinoamido-disubstituted ε-caprolactone monomers was developed. Poorly defined polymers were obtained from the monomers, bearing two ester groups due to the competitive transesterification of the pendant substituents. On the other hand, the disubstituted morpholinoamido-ε-caprolactone was polymerized in a controlled manner by ring-opening polymerization, and amorphous homopolymers with a high glass transition temperature (112 °C) and good solubility in water were obtained. Statistical and block copolymers with the unsubstituted ε-caprolactone were also prepared, and DLS analysis of the amphiphilic block copolymers in water shows the presence of self-assembled particles. These results demonstrate the potential of morpholinoamido-functionalized ε-caprolactone derivatives as building blocks for the development of biodegradable polymeric materials for biomedical applications. Full article

Inguinal hernia repair is one of the most commonly performed surgical procedures worldwide, with over 20 million cases annually. The evolution of hernia surgery has transitioned from tension-based techniques to tension-free approaches, significantly reducing recurrence rates. This review explores the history, advancements, and current trends in minimally invasive inguinal hernia repair, focusing on laparoscopic techniques such as transabdominal preperitoneal (TAPP), totally extraperitoneal (TEP), single-incision laparoscopic surgery (SILS), and robotic-assisted repair. The importance of prosthetic meshes is emphasized, detailing their mechanical properties, pore size, weight classifications, and biocompatibility. Additionally, various mesh fixation methods—including tacks, sutures, and glues—are analyzed, with a discussion on their impact on postoperative complications such as chronic pain, adhesions, and infection risk. The debate between TAPP and TEP techniques is examined, highlighting the ongoing quest to determine the most effective approach. Emerging advancements, including drug-loaded meshes and dual-layered prosthetics, aim to improve integration and reduce complications. Despite significant progress, no universally superior technique or mesh exists, underscoring the need for individualized surgical approaches. Future research should focus on optimizing materials, refining fixation strategies, and enhancing patient outcomes in minimally invasive hernia repair. Full article

Background: In recent decades, aortic valve surgery has transitioned from conventional median sternotomy (MS) to minimally invasive techniques, including partial upper mini-sternotomy (PUMS) and right anterolateral mini-thoracotomy (RAMT). This study retrospectively compares the outcomes of aortic valve replacement (AVR) using PUMS during the learning phase with those of standard MS. Methods: A retrospective analysis was conducted on patients (n = 211) who underwent AVR for aortic stenosis. They were divided into MS (n = 119) and PUMS (n = 92) groups. Various preoperative, surgical and postoperative parameters, including survival, were examined. Results: Preoperatively, the main difference was age, with PUMS patients being older (67.5 ± 7 vs. 66.5 ± 9.6; p = 0.010). PUMS patients also had longer cardiopulmonary bypass (CPB) and cross-clamping times (99 ± 25 vs. 80 ± 16 min; p < 0.002; 79 ± 18 vs. 65 ± 13 min; p < 0.024). There were no significant differences in body mass index, prosthesis size, indexed effective orifice area, hospitalisation duration or any other monitored parameter. Echocardiographic follow-up found no differences in prosthetic pressure gradients, flow velocity or paravalvular leak between the PUMS and MS groups. Survival rates were similar over 1000 days. Conclusions: The data suggest that PUMS offers comparable surgical outcomes to MS for AVR with additional cosmetic benefits, undeterred by a learning curve. Full article

Background and Objectives: Complete dentures remain a primary solution for oral rehabilitation in aging and medically compromised populations. The integration of digital workflows, regenerative materials, and smart technologies is propelling prosthodontics towards a new era, transcending the limitations of traditional static prostheses. Materials and Methods: This narrative review synthesizes historical developments, current practices, and future innovations in complete denture therapy. A comprehensive review of literature from PubMed, Scopus, and Web of Science (2000–2025) was conducted, with a focus on materials science, digital design, patient-centered care, artificial intelligence (AI), and sustainable fabrication. Results: Innovations in the field include high-performance polymers, CAD–CAM systems, digital impressions, smart sensors, and bioactive liners. Recent trends in the field include the development of self-monitoring prostheses, artificial intelligence (AI)-driven design platforms, and bioprinted regenerative bases. These advances have been shown to enhance customization, durability, hygiene, and patient satisfaction. However, challenges persist in terms of accessibility, clinician training, regulatory validation, and ethical integration of digital data. Conclusions: The field of complete denture therapy is undergoing a transition toward a new paradigm of prosthetics that are personalized, intelligent, and sustainable. To ensure the integration of these technologies into standard care, ongoing interdisciplinary research, clinical validation, and equitable implementation are imperative. Full article

This study reports the synthesis of aluminum-doped ZnO nanoparticles (Al-ZnO NPs) via a top-down mechanochemical solid-state reaction (SSR) approach using high-energy ball milling (HEBM) as a rapid, controllable, and efficient method. Al-ZnO samples were characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and UV-Vis diffuse reflectance spectroscopy. Significantly, the band gap decreased by 0.215 eV when transitioning from pure ZnO to 9 wt.% Al-doped ZnO (Al-ZnO9). TEM analysis showed that after 4 h of milling at 1000 rpm, the particle size was reduced to 59 nm, exhibiting a spherical morphology crucial for enhanced bioactivity. The antimicrobial properties of the Al-ZnO NPs were evaluated using the well diffusion method against various pathogenic microorganisms, with a particular focus on Staph. aureus ATCC 29213 and Staph. epidermidis ATCC 12228, given their clinical significance as common pathogens in infections related to medical implants and prosthetics. Al-ZnO9 demonstrated superior antibacterial performance, producing inhibition zones of 13 mm and 15 mm against Staph. aureus and Staph. epidermidis, respectively. Moreover, exposure to visible light further amplified the antimicrobial activity. This research underscores the potential for the scalable production of Al-ZnO NPs, presenting a promising solution for addressing infections linked to implanted medical devices. Full article

Objectives: This study aimed to establish reference values for bite force in individuals with various prosthetic restorations and to examine the relationship between prosthetic treatment groups (PTGs) and bite force as an indicator of masticatory muscle function. Materials and Methods: In a cross-sectional study from November 2021 to March 2023, 198 participants aged 18 to 95 years were recruited from multiple dental and geriatric centers. The participants were assigned to seven PTGs based on their dental and prosthetic statuses. Bite force was measured using the Occlusal Force Meter GM10, with three recordings on each side of the jaw, and analyzed using ANOVA. Results: The bite force decreased with fewer teeth and the transition from fixed to removable dentures. Fully dentate participants exhibited the highest bite forces, differing significantly from the other groups (p < 0.001). For the fully dentate individuals (547 ± 240 N), the bite force decreased progressively with the extent of prosthetic restoration, reaching 55 ± 45 N in edentulous individuals with complete dentures in both jaws. However, edentulous participants with two interforaminal implants demonstrated higher bite forces than those with partial dentures. Conclusions: Bite force is significantly impacted by prosthetic restoration type. Fully dentate individuals have the highest bite forces, while edentulous patients with implant-supported dentures also show considerable bite forces, similar to those with partial dentures. Full article

The coupled-adaptive underactuated finger offers two motion modes: pre-grasping and self-adaptive grasping. It can execute anthropomorphic pre-grasp motions before the proximal phalanx contacts an object and transitions to adaptive enveloping once contact occurs. The key to designing a coupled-adaptive finger lies in its configuration and parameter, which are crucial for achieving a more human-like design for the prosthetic hand. Thus, this paper proposes a configuration topology and parameter optimization design method for a three-joint coupled-adaptive underactuated finger. The finger mechanism utilizes a combination of prismatic pairs and a compression spring to facilitate the transition between coupled motion and adaptive motion. This enables the underactuated finger to perform coupled movements in free space and adaptive grasping motions once it makes contact with an object. Furthermore, this paper introduces a finger linkage parameter optimization method that takes the joint motion angles and overall dimensions as constraints, aiming to linearize the joint coupling motion ratios as the primary optimization objective. The design method proposed in this paper not only presents a novel linkage mechanism but also outlines and compares its isomorphic types. Furthermore, the optimization results provide an accurate maximum motion value for the finger. Full article

Background/Objectives: The Agenesis of maxillary lateral incisors occurs with a variable prevalence in different ethnic groups, and there is a need for a temporary replacement until maturity has been reached in patients for whom the replacement solution has been chosen. This study aims to analyze the scientific evidence available to date concerning the use of mini-screw implant (MSI)-supported pontics for the transitional management of permanent maxillary lateral incisors’ agenesis in developmental age subjects. Methods: Electronic research was conducted using four databases: PubMed, Clarivate Analytics/Web of Science Core Collection, Scopus, and the Wiley/Cochrane Library. Six studies were included in the final review. Data were extracted based on the first and second author, year of publication, study design, sample characteristics, mini-screw implant (MSI) characteristics, MSI insertion and loading protocol, characteristics of the prosthetic component, and outcomes during the follow-up time. Results: Clinical outcomes were proven positive in all studies. In only one study did MSIs show mobility and consequent failure after one month. Discoloration of the prosthetic part proved to be the main complication. Conclusions: The comparison with conventional removable prostheses and fixed dental prostheses revealed that MSI-supported pontics are a viable alternative and a promising temporary solution until the end of growth. Further studies to standardize protocols and assess long-term outcomes are needed. Full article