A novel sophorolipids extraction method by yeast fermentation process for enhanced skin efficacy.

Aims: Oriental herbs have been used as medicines in the folk remedy for their numerous phytochemicals and bioactivities. In this study, we have selected five Korean traditional medical herbs and applied bio conversion extraction technology, named it as Bioconversion Oji complex, to identify phytochemicals and evaluate skin related efficacies.

Material And Methods: The process of two-step bio conversion was sequentially conducted.

The intra- and inter-rater reliability of measuring trunk coronal asymmetry by adjusting positioning variability: A prospective study.

Background: Chronic low back pain (LBP) can lead to muscle spasms, limited range of motion, and abnormal posture, resulting in trunk muscle asymmetry.

Objective: This study aimed to assess the intra- and inter-rater reliability of a quantitative measurement of trunk coronal asymmetry in patients with chronic LBP, minimizing unnecessary gravity and friction force using a manual table in the prone position.

Methods: This prospective study was conducted at a single center, targeting patients with chronic LBP to measure trunk coronal asymmetry on a manual table in the prone position.

Aqueous Two-Phase System (ATPS)-Based Polymersomes for Particle Isolation and Separation.

Aqueous two-phase systems (ATPSs) have been widely used in the separation, purification, and enrichment of biomolecules for their excellent biocompatibility. While ultracentrifugation and microfluidic devices have been combined with ATPS to facilitate the separation of biomolecules and achieve high recovery yields, they often lack the ability to effectively isolate and separate biomolecules in low concentrations. In this work, we present a strategy that leverages the preferential partitioning of biomolecules in ATPS droplets to efficiently separate model extracellular vesicle (EV) particles.

A Survey of Koreans on Sleep Habits and Sleeping Symptoms Relating to Pillow Comfort and Support.

The number of people who complain of sleep disturbances is steadily increasing. An understanding of sleep-related factors is required to address sleep problems. This survey study investigated the sleep habits and sleeping symptoms relating to the comfort and support characteristics of pillows and the relationship between sleep quality and pillow design factors.

Biomechanical evaluation of opening-wedge high tibial osteotomy with composite materials using finite-element analysis.

Background: Medial opening-wedge high tibial osteotomy (HTO) has been used to treat osteoarthritis of the medial compartment of the knee. However, this makes the proximal tibia a highly unstable structure and causes the plate to be a potential source of mechanical failure. Consequently, proper design and material use of the fixation device are essential in HTO, especially for overweight or full-weight-bearing patients.

Preservation of femoral and tibial coronal alignment to improve biomechanical effects of medial unicompartment knee arthroplasty: Computational study.

Background: Medial unicompartmental knee arthroplasty (UKA) could be concerned with wear of the cartilage or the wear in the polyethylene (PE) insert. Mechanical alignment determines the biomechanical effect in the long term. However, previous computational studies all found that femoral and tibial components alignment in the UKA were rare, and the results varied.

Effect of Post-Cam Design for Normal Knee Joint Kinematic, Ligament, and Quadriceps Force in Patient-Specific Posterior-Stabilized Total Knee Arthroplasty by Using Finite Element Analysis.

The purpose of this study is to investigate post-cam design via finite element analysis to evaluate the most normal-like knee mechanics. We developed five different three-dimensional computational models of customized posterior-stabilized (PS) total knee arthroplasty (TKA) involving identical surfaces with the exception of the post-cam geometry. They include flat-and-flat, curve-and-curve (concave), curve-and-curve (concave and convex), helical, and asymmetrical post-cam designs.

Patient-specific design for articular surface conformity to preserve normal knee mechanics in posterior stabilized total knee arthroplasty.

Background: Contemporary total knee arthroplasty (TKA) provides remarkable clinical benefits. However, the normal function of the knee is not fully restored. Recent improvements in imaging and manufacturing have utilized the development of customized design to fit the unique shape of individual patients.

Malpositioning of Prosthesis: Patient-specific Total Knee Arthroplasty Versus Standard Off-the-Shelf Total Knee Arthroplasty.

Introduction: A recent study has challenged the premise that a patient-specific (PS)-designed total knee arthroplasty (TKA) component has better clinical survival than an off-the-shelf (OTS) prosthesis.

Methods: We developed the finite element models for PS TKA and OTS TKA with 5° varus and valgus malalignment and 5° internal and external malrotations.

Results: Contact stress on the medial side of the insert increased with internal femoral malrotation and varus tibial malalignment, but it decreased with external femoral malrotation and varus tibial malalignment in both PS TKA and OTS TKA.

Flexed femoral component improves kinematics and biomechanical effect in posterior stabilized total knee arthroplasty.

Purpose: The kinematics and biomechanics of the knee joint are important in ensuring patient satisfaction and functional ability after total knee arthroplasty (TKA). There has been no study on knee joint mechanics with regard to the sagittal alignment of the femoral component. The objective of this study is to determine the extent of the impact of the femoral component's sagittal alignment on kinematics and biomechanics.

Comparison of Kinematics in Cruciate Retaining and Posterior Stabilized for Fixed and Rotating Platform Mobile-Bearing Total Knee Arthroplasty with respect to Different Posterior Tibial Slope.

Reconstructed posterior tibial slope (PTS) plays a significant role in kinematics restoration after total knee arthroplasty (TKA). However, the effect of increased and decreased PTS on prosthetic type and design has not yet been investigated. We used a finite element model, validated using in vitro data, to evaluate the effect of PTS on knee kinematics in cruciate-retaining (CR) and posterior-stabilized (PS) fixed TKA and rotating platform mobile-bearing TKA.

Effects of posterior condylar offset and posterior tibial slope on mobile-bearing total knee arthroplasty using computational simulation.

Background: Postoperative changes of the femoral posterior condylar offset (PCO) and posterior tibial slope (PTS) affect the biomechanics of the knee joint after fixed-bearing total knee arthroplasty (TKA). However, the biomechanics of mobile-bearing is not well known. Therefore, the aim of this study was to investigate whether alterations to the PCO and PTS affect the biomechanics for mobile-bearing TKA.

Tibiofemoral conformity variation offers changed kinematics and wear performance of customized posterior-stabilized total knee arthroplasty.

Purpose: Posterior-stabilized (PS)-total knee arthroplasty (TKA) can be applied in any of several variations in terms of the tibiofemoral conformity and post-cam mechanism. However, previous studies have not evaluated the effect of the condylar surface radii (tibiofemoral conformity) on wear in a customized PS-TKA. The present study involved evaluating the wear performance with respect to three different conformities of the tibiofemoral articular surface in a customized PS-TKA by means of a computational simulation.

Multi-objective design optimization of high tibial osteotomy for improvement of biomechanical effect by using finite element analysis.

Medial opening wedge high tibial osteotomy (HTO) makes the proximal tibia a highly unstable structure and causes plates and screws to be the potential sources for mechanical failure. However, asymmetrical callus and incomplete bone formations underneath the plates (TomoFix) have been recent concerns in clinical and experimental studies related to HTO due to the high stiffness. The purpose of this study was to evaluate the biomechanical effect of the TomoFix plate system with respect to changes in design using a computational simulation.

Effect of femoral component position on biomechanical outcomes of unicompartmental knee arthroplasty.

Background: The positions of unicompartmental femoral components do not always follow the neutral center of the medial distal femoral condyle. The biomechanical effect of the center of the distal femoral condyle has not yet been evaluated, and the optimal femoral position in unicompartmental knee arthroplasty (UKA) is yet to be biomechanically justified. The purpose of this study was to evaluate, using finite element analysis, the effect of the center of the distal femoral component on the biomechanical outcomes of UKA with respect to the contact stresses in the polyethylene (PE) insert and articular cartilage.

The increase in posterior tibial slope provides a positive biomechanical effect in posterior-stabilized total knee arthroplasty.

Purpose: This study aims to clarify the influence of the posterior tibial slope (PTS) on knee joint biomechanics after posterior-stabilized (PS) total knee arthroplasty (TKA) using a computer simulation.

Methods: A validated TKA computational model was used to evaluate and quantify the effects of an increased PTS. In order to conduct a squat simulation, models with a - 3° to 15° PTS using increments of 3° were developed.

Effect of joint line preservation on mobile-type bearing unicompartmental knee arthroplasty: finite element analysis.

In this study, we performed a virtual mobile-bearing unicompartmental knee arthroplasty (UKA) on the contact pressure in the tibial insert and articular cartilage by using finite element (FE) analysis to understand clinical observations and elaborate on the potential risks associated with a joint line preservation such as wear on tibial insert and osteoarthritis on other compartment. Neutral position of the knee joint was defined in 0 mm joint line, and contact pressure between tibial insert and articular cartilage varies with respect to changes of joint line. Therefore, evaluation of contact pressure may provide the degree of joint line preservation.

Femoral component alignment in unicompartmental knee arthroplasty leads to biomechanical change in contact stress and collateral ligament force in knee joint.

Background: In recent years, the popularity of unicompartmental knee arthroplasty (UKA) has increased. However, the effect of femoral component positioning in UKA continues to invite a considerable debate. The purpose of this study involved assessing the biomechanical effect of mal-alignment in femoral components in UKA under dynamic loading conditions using a computational simulation.

Biomechanical Effects of Posterior Condylar Offset and Posterior Tibial Slope on Quadriceps Force and Joint Contact Forces in Posterior-Stabilized Total Knee Arthroplasty.

This study aimed to determine the biomechanical effect of the posterior condylar offset (PCO) and posterior tibial slope (PTS) in posterior-stabilized (PS) fixed-bearing total knee arthroplasty (TKA). We developed ±1, ±2, and ±3 mm PCO models in the posterior direction and -3°, 0°, 3°, and 6° PTS models using a previously validated FE model. The influence of changes in the PCO and PTS on the biomechanical effects under deep-knee-bend loading was investigated.

Influence of Increased Posterior Tibial Slope in Total Knee Arthroplasty on Knee Joint Biomechanics: A Computational Simulation Study.

Background: The reconstructed posterior tibial slope (PTS) plays a significant role in restoring knee kinematics in cruciate-retaining-total knee arthroplasty (TKA). A few studies have reported the effect of the PTS on biomechanics.

Methods: This study investigates the effect of the PTS on tibiofemoral (TF) kinematics, patellofemoral (PF) contact stress, and forces at the quadriceps, posterior cruciate ligament (PCL) and collateral ligament after cruciate-retaining-TKA using computer simulations.

Biomechanical analysis of lumbar decompression surgery in relation to degenerative changes in the lumbar spine - Validated finite element analysis.

Background: There are no studies about the biomechanical analysis of lumbar decompression surgery in relation to degenerative changes of the lumbar spine. Therefore, the purpose of this study was to compare, by using finite element (FE) analysis, the biomechanical changes of the lumbar spine in terms of annulus stress and nucleus pressure after two different kinds of lumbar decompression surgery in relation to disc degenerative changes.

Methods: The validated intact and degenerated FE models (L2-5) were used in this study.

Validation of a computational knee joint model using an alignment method for the knee laxity test and computed tomography.

Background: Computational models have been identified as efficient techniques in the clinical decision-making process. However, computational model was validated using published data in most previous studies, and the kinematic validation of such models still remains a challenge. Recently, studies using medical imaging have provided a more accurate visualization of knee joint kinematics.

The Effect of Patient-Specific Instrumentation Incorporating an Extramedullary Tibial Guide on Operative Efficiency for Total Knee Arthroplasty.

This retrospective study was to determine if patient-specific instrumentation (PSI) for total knee arthroplasty (TKA) leads to shortened surgical time through increased operating room efficiency according to different tibial PSI designs. 166 patients underwent primary TKA and were categorized into three groups as follows: PSI without extramedullary (EM) tibial guide (group 1, = 48), PSI with EM tibial guide (group 2, = 68), and conventional instrumentation (CI) group (group 3, = 50). Four factors were compared between groups, namely, operative room time, thickness of bone resection, tibial slope, and rotation of the component.

Wear predictions for UHMWPE material with various surface properties used on the femoral component in total knee arthroplasty: a computational simulation study.

The wear of ultrahigh-molecular weight polyethylene (UHMWPE) tibial inserts in total knee arthroplasty (TKA) remains a major limitation that hinders the longevity of clinically successful devices. Surface properties significantly affect the overall performance of TKA, and surface modification with mechanically and chemically stable materials is an effective method for overcoming the wear of TKA. However, wear tests are not cost-efficient or time-efficient; thus, the effects of geometric, loading, and alignment perturbations are often evaluated via parametric studies.