Mechanical stability of the proximal tibia with different bone formations after plate removal in medial opening-wedge high tibial osteotomy: a finite element analysis.

Background: No clear agreement exists on the degree of bone formation required to remove a metal plate without correction loss after medial opening-wedge high tibial osteotomy (MOWHTO). We aimed to investigate the mechanical stability of the proximal tibia with different bone formations after plate removal in MOWHTO using finite element models and determine the extent of bone formation when the plate can be removed without correction loss.

Methods: The MOWHTO models with 5, 10, and 15 mm opening gaps were generated.

Biomechanical evaluation of a newly designed locking plate for opening wedge high tibial osteotomy: stress distribution and stability in the presence of lateral hinge fracture.

Background: The study aimed to evaluate whether a new OhtoFix plate reduced stress around the D-hole compared with an old OhtoFix and TomoFix plate. The study also assessed whether the new OhtoFix plate had biomechanical stability in a lateral hinge fracture (LHF).

Methods: A finite element model of the proximal tibia was developed using cross-sectional images from a 62-year-old Asian woman.

Intraoperative estimation of natural femoral anteversion from proximal femoral osseous orientation during total hip arthroplasty.

Background: The purpose of this study was to elucidate the relationship between the orientation of the osseous structure of the proximal femur encountered during total hip arthroplasty (THA) and preoperative femoral anteversion (FA).

Methods: Three-dimensional models were constructed using full-length lower extremity computed tomography images from a total of 80 participants. Femoral neck cutting was performed at heights of 5, 10, and 15 mm relative to the lesser trochanter.

Application of a machine learning and optimization method to predict patellofemoral instability risk factors in children and adolescents.

Purpose: Conservative treatment remains the standard approach for first-time patellar dislocations. While risk factors for patellofemoral instability, a common paediatric injury, are well-established in adults, data concerning the progression of paediatric recurrent patellar dislocation remain scarce. A reproducible method was developed to quantitatively assess the patellofemoral morphology and anatomic risk factors in paediatric patients using magnetic resonance imaging (MRI) and machine learning analysis.

Biomechanical Effects of Stem Extension of Tibial Components for Medial Tibial Bone Defects in Total Knee Arthroplasty: A Finite Element Study.

The aim of this study was to investigate the biomechanical effects of stem extension with a medial tibial bone defect in primary total knee arthroplasty (TKA) on load distribution and stress in the proximal tibia using finite element (FE) analysis.FE simulations were performed on the tibia bone to evaluate the stress and strain on the tibia bone and bone cement. This was done to investigate the stress shielding effect, stability of the tibia plate, and the biomechanical effects in TKA models with various medial defects and different stem length models.

An Image-Based Augmented Reality System for Achieving Accurate Bone Resection in Total Knee Arthroplasty.

Background and objective With the steady advancement of computer-assisted surgical techniques, the importance of assessing and researching technology related to total knee arthroplasty (TKA) procedures has increased. Augmented reality (AR), a recently proposed next-generation technology, is expected to enhance the precision of orthopedic surgery by providing a more efficient and cost-effective approach. However, the accuracy of image-based AR in TKA surgery has not been established.

The Application of Virtual Reality in Shoulder Surgery Rehabilitation.

To achieve a positive functional prognosis in orthopedic surgery, particularly in shoulder surgeries, effective rehabilitation is essential. Recently, there has been growing interest in the use of virtual reality (VR) in the field of orthopedics, particularly for preoperative education and training, as well as clinical and home-based rehabilitation. This report describes the process of developing an application utilizing Meta Quest 2 VR technology (Meta, CA, USA) for rehabilitation after shoulder surgery.

Reliability and modality analysis of patellar height measurement in pediatric knee.

Introduction: Various measurement methods and imaging technique are in use to measure patellar height in pediatric patients. However, there is no gold standard as to which measurement method and modality are the most reliable for pediatric patients. Therefore, the aim of this study was to determine the inter-observer reliability, intra-observer reliability, and applicability of various patellar height measurement methods in pediatric knee.

Preoperative joint line obliquity, a newly identified factor for overcorrection, can be incorporated into a novel preoperative planning method to optimise alignment in high tibial osteotomy.

Purpose: The aim of this study was to analyse the factors associated with additional postoperative alignment changes after accurate bony correction by selecting only patients with well-performed bony correction as planned and develop a method of incorporating significant factors into preoperative planning.

Methods: Among 104 consecutive patients who underwent medial open wedge high tibial osteotomy (MOWHTO) between October 2019 and July 2022, 61 with well-performed bony corrections were retrospectively reviewed. The major criterion for well-performed bony correction was a difference of <1° between the simulated medial proximal tibial angle (MPTA) and the actual postoperative MPTA as measured in three dimensions.

Could We Expect Postoperative Cup Anteversion after Total Hip Arthroplasty Using Postoperative Plain Anteroposterior and Lateral Radiograph? A Three-Dimensional Experimental Operation Study.

Background: A postoperative radiograph in total hip arthroplasty (THA) is usually obtained to evaluate the inclination and anteversion of the acetabular components. However, there is no gold-standard method for calculating the exact inclination and anteversion of the acetabular components on post-THA radiographs. We aimed to measure the actual anteversion of the acetabular component on postoperative radiographs by obtaining correlation data between the virtual and actual acetabular component positioning using virtual three-dimensional (3D) surgery.

Effect of surface matching mismatch of focal knee articular prosthetic on tibiofemoral contact stress using finite element analysis.

Aims: Focal knee arthroplasty is an attractive alternative to knee arthroplasty for young patients because it allows preservation of a large amount of bone for potential revisions. However, the mechanical behaviour of cartilage has not yet been investigated because it is challenging to evaluate in vivo contact areas, pressure, and deformations from metal implants. Therefore, this study aimed to determine the contact pressure in the tibiofemoral joint with a focal knee arthroplasty using a finite element model.

Evaluation of lateral and anterior center-edge angles according to sex and anterior pelvic plane tilt angle: a three-dimensional quantitative analysis.

Background: This study aimed to quantitatively evaluate lateral center-edge angle (LCEA) and anterior center-edge angle (ACEA) according to sex and the anterior pelvic plane (APP) tilt angle and analyze the correlation between these measurements and acetabular coverage.

Methods: Computed tomography scans of 71 adults (38 men and 33 women) with normal hip joints were obtained. LCEA, anterior ACEA, and acetabular coverage were measured with APP tilt every 5° from - 30° to + 30° and were compared between the sexes.

Evaluation of age group and sex differences in the measurement of patellar height of pediatric knee in a Korean population.

Introduction: Various methods based on bony landmarks are used to determine patellar height. This study analyzed five methods for patellar height measurement on lateral knee radiographs, namely, the Insall-Salvati, Koshino-Sugimoto, Blackburne-Peel, modified Insall-Salvati, and Caton-Deschamps methods.

Methods: Overall, 425 pediatric participants (221 males, 204 females; age range 5-18 years) were included and were divided equally into three age groups (A, 5-10 years; B, 11-13 years; and C, 13-18 years).

Computational analysis of tibial slope adjustment with fixed-bearing medial unicompartmental knee arthroplasty in ACL- and PCL-deficient models.

Aims: A functional anterior cruciate ligament (ACL) or posterior cruciate ligament (PCL) has been assumed to be required for patients undergoing unicompartmental knee arthroplasty (UKA). However, this assumption has not been thoroughly tested. Therefore, this study aimed to assess the biomechanical effects exerted by cruciate ligament-deficient knees with medial UKAs regarding different posterior tibial slopes.

Finite element analysis of femoral component sagittal alignment in mobile-bearing total knee arthroplasty.

Background: Recently, there has been an increasing interest in mobile-bearing total knee arthroplasty (TKA). However, changes in biomechanics for femoral component alignment in mobile-bearing TKA have not been explored in depth.

Objective: This study aims to evaluate the biomechanical effect of sagittal alignment of the femoral component in mobile-bearing TKA.

Biomechanical effect of anatomical tibial component design on load distribution of medial proximal tibial bone in total knee arthroplasty : finite element analysis indicating anatomical design prevents stress-shielding.

Aims: This study aimed to identify the effect of anatomical tibial component (ATC) design on load distribution in the periprosthetic tibial bone of Koreans using finite element analysis (FEA).

Methods: 3D finite element models of 30 tibiae in Korean women were created. A symmetric tibial component (STC, NexGen LPS-Flex) and an ATC (Persona) were used in surgical simulation.

Effects of the Anterolateral Ligament and Anterior Cruciate Ligament on Knee Joint Mechanics: A Biomechanical Study Using Computational Modeling.

Background: Recent studies on lateral knee anatomy have reported the presence of a true ligament structure, the anterolateral ligament (ALL), in the anterolateral region of the knee joint. However, its biomechanical effects have not been fully elucidated.

Purpose: To investigate, by using computer simulation, the association between the ALL and anterior cruciate ligament (ACL) under dynamic loading conditions.

Correlation of Femoral Trochlear Dysplasia With Anterior Cruciate Ligament Injury in Skeletally Immature Patients.

Background: Reports of anterior cruciate ligament (ACL) injury in patients with skeletal immaturity have been increasing. Variations in knee joint anatomy have been linked to ACL injury risk factors.

Purpose: To identify associations between ACL injury, patella alta, and femoral trochlear dysplasia in patients with skeletal immaturity by using magnetic resonance imaging (MRI).

Existence of Gender-Based Difference in Morphology of Convex Lateral Tibial Plateau in Korean Population Primary Knee Joint Osteoarthritis.

Purpose: Morphological differences in the knee joints of females and males have been reported in a previous study. These differences have realized the need of developing a gender-specific prosthesis. However, anatomical studies on gender-based differences in the proximal tibial plateau's sagittal curvature have rarely been conducted.

Analysis of Gender Differences in the Rotational Alignment of the Distal Femur in Kinematically Aligned and Mechanically Aligned Total Knee Arthroplasty.

To compare the angle between the external rotation references of the femoral components in the axial plane by gender and lower limb alignment in Korean patients with osteoarthritis (OA). Magnetic resonance (MR) images of 1273 patients were imported into a modeling software and segmented to develop three-dimensional femoral bony and cartilaginous models. The surgical transepicondylar axis (sTEA), posterior condylar axis (PCA), the kinematically aligned axis (KAA), and anteroposterior axis were used as rotational references in the axial plane for mechanically aligned (MA) TKA.

Gender-Based Quantitative Analysis of the Grand Piano Sign in Mechanically Aligned Total Knee Arthroplasty in Asians.

In mechanically aligned (MA) total knee arthroplasty (TKA), the grand piano sign helps surgeons to further ensure the proper external rotation of the femoral component. The goal of this study was to determine the sex-related differences in the shape of the anterior resection surface using 3D magnetic resonance imaging (MRI) models. MRI scans were performed on 267 consecutive patients (202 women and 65 men) with osteoarthritis who underwent TKA in order to reconstruct a 3D model.

Effect of post-cam design on the kinematics and contact stress of posterior-stabilized total knee arthroplasty.

Background: The post-cam mechanism in the posterior-stabilized (PS) implant plays an important role, such as durability and kinematic performances, in total knee arthroplasty (TKA).

Objective: The purpose of this study was to evaluate the difference in the kinematics and contact stress of five post-cam designs, which are flat-and-flat, curve-and-curve (concave), curve-and-curve (concave and convex), helical, and asymmetrical post-cam designs, using three-dimensional finite element models.

Methods: We designed the post-cam model with five different geometries.

Biomechanical Difference between Conventional Transtibial Single-Bundle and Anatomical Transportal Double-Bundle Anterior Cruciate Ligament Reconstruction Using Three-Dimensional Finite Element Model Analysis.

The purpose of our study was to analyze the graft contact stress at the tunnel after transtibial single-bundle (SB) and transportal double-bundle (DB) anterior cruciate ligament (ACL) reconstruction. After transtibial SB (20 cases) and transportal DB (29 cases) ACL reconstruction, the three-dimensional image of each patient made by postoperative computed tomography was adjusted to the validation model of a normal knee and simulated SB and DB ACL reconstructions were created based on the average tunnel position and direction of each group. We also measured graft and contact stresses at the tunnel after a 134 N anterior load from 0° to 90° flexion.

Anatomic Differences in the Sagittal Knee Joint Are Associated With ACL Injury: Results From a Skeletally Immature Korean Population.

Background: Differences in tibiofemoral articular morphology are associated with risks of anterior cruciate ligament (ACL) injury.

Purpose: To determine whether bony and cartilaginous morphological characteristics are related to ACL injury in pediatric patients and to investigate any differences according to sex.

Study Design: Cohort study; Level of evidence, 3.