Preoperative tibiofemoral contact point on standing lateral radiograph predicts anteroposterior knee kinematics in total knee arthroplasty.

Purpose: This study investigated the tibiofemoral contact point (CP) on standing lateral radiographs in knee osteoarthritis and assessed the relationship between CP and pre- and postoperative knee kinematics in total knee arthroplasty (TKA).

Methods: The intraoperative knee status of 46 knees with varus deformity that underwent bicruciate stabilized TKA using a navigation system was investigated. The intraoperative anteroposterior (AP) position of the femur relative to the tibia at maximum extension, 15°, 30°, 45°, 60° and 90° was evaluated by the navigation system before and after TKA.

Changes in the anteroposterior position of the femur relative to the tibia impact patient satisfaction in total knee arthroplasty.

Background: In this study, we aimed to investigate the preoperative and postoperative anteroposterior position (AP) of the femur relative to the tibia in total knee arthroplasty (TKA) and assess the influence of change in the AP position on clinical outcomes.

Methods: We evaluated 49 knees that underwent bi-cruciate-substituted TKA using a navigation system. The preoperative and postoperative AP position of the femur relative to the tibia at maximum extension, 15°, 30°, 45°, 60°, 90°, 105°, and 120° and maximum flexion angles were calculated.

Difference in implant design affects midflexion rotational laxity in cruciate-retaining total knee arthroplasty: a computer navigation study.

Purpose: This study aimed to compare midflexion rotational laxity between two different design concept models of cruciate-retaining total knee arthroplasty: symmetrical surface design of neutral joint line obliquity and asymmetrical surface design of varus joint line obliquity.

Methods: Sixty-three knees that underwent cruciate-retaining total knee arthroplasty were evaluated. Manual maximum passive rotational stress without acceleration was applied to the knees under navigation monitoring.

Feasibility of Bone Mineral Density and Bone Microarchitecture Assessment Using Deep Learning With a Convolutional Neural Network.

Objectives: We evaluated the feasibility of using deep learning with a convolutional neural network for predicting bone mineral density (BMD) and bone microarchitecture from conventional computed tomography (CT) images acquired by multivendor scanners.

Methods: We enrolled 402 patients who underwent noncontrast CT examinations, including L1-L4 vertebrae, and dual-energy x-ray absorptiometry (DXA) examination. Among these, 280 patients (3360 sagittal vertebral images), 70 patients (280 sagittal vertebral images), and 52 patients (208 sagittal vertebral images) were assigned to the training data set for deep learning model development, the validation, and the test data set, respectively.

Progression of varus deformity in osteoarthritic knees induces anterior paradoxical motion of the femur during early knee flexion.

Purpose: The purpose of this study was to investigate the position of the femur relative to the tibia throughout range of motion in the osteoarthritic knee to evaluate knee kinematics and assess its relationship with the degree of varus deformity.

Methods: In this study, 116 preoperative knees with varus deformity were evaluated using a navigation system. The internal-external, anteroposterior, and mediolateral positions of the femur relative to the tibia were measured at maximum extension, 15°, 30°, 45°, 60°, 90°, 105°, and 120°, and maximum flexion angles.

Psoriatic arthritis successfully treated with second-line anti-interleukin-6 treatment: a case report and review of the literature.

Background: Psoriatic arthritis treatment with antitumor necrosis factor has been shown to reduce disease activity. Nonetheless, more than 30% of patients do not achieve a sufficient response to tumor necrosis factor blockers. Currently, treatment with interleukin-6 inhibitors is expected to be effective and suppress the joint destruction in patients with psoriatic arthritis; however, evidence regarding their efficacy is limited to a few reports.

Epigenetic regulator UHRF1 orchestrates proinflammatory gene expression in rheumatoid arthritis in a suppressive manner.

Rheumatoid arthritis (RA) is characterized by chronic synovial inflammation with aberrant epigenetic alterations, eventually leading to joint destruction. However, the epigenetic regulatory mechanisms underlying RA pathogenesis remain largely unknown. Here, we showed that ubiquitin-like containing PHD and RING finger domains 1 (UHRF1) is a central epigenetic regulator that orchestrates multiple pathogeneses in RA in a suppressive manner.

Efficacy of posterior capsular release for flexion contracture in posterior-stabilized total knee arthroplasty.

Purpose: Posterior capsular contracture causes stiffness during knee extension in knee osteoarthritis. Furthermore, in posterior-stabilized total knee arthroplasty (PS-TKA), a unique design such as the cam mechanism could conflict with the posterior capsule (PC) causing flexion contracture (FC). However, few studies have focused on the anatomical aspects of the PC.

Gender-specific difference in the recurrence of flexion contracture after total knee arthroplasty.

Background: Range of motion after total knee arthroplasty (TKA) can impact patients' daily lives. Nevertheless, flexion contracture (FC) often recurs after TKA, even upon achieving full extension intraoperatively. This study aimed to evaluate the relationship among preoperative, intraoperative, and postoperative knee extension angles, and clarify the risk factor for postoperative FC.

Rotational Soft-Tissue Balance Is Highly Correlated with Rotational Kinematics in Total Knee Arthroplasty.

Recovery of normal knee kinematics is critical for improving functional outcomes and patient satisfaction after total knee arthroplasty (TKA). The kinematics pattern after TKA varies from case to case, and it remains unclear how to reproduce normal knee kinematics. The present study aimed to evaluate rotational knee kinematics and soft-tissue balance using a navigation system and to assess the influence of intraoperative soft-tissue balance on the rotational knee kinematics.

In vivo anterior cruciate ligament length pattern assessment secondary to differences in the femoral attachment under loading condition using image-matching techniques.

Background: The anterior cruciate ligament is composed of two functional bundles and is crucial for knee function. There is limited understanding of the role of each individual bundle and the influence on length pattern due to difference in bone tunnel position under loading conditions throughout the range of motion. We measured point to point length between the femoral and tibial footprints of the ligament throughout the range of motion in normal knees, under normal loading conditions, and investigated length pattern changes secondary to differences in the femoral footprint.

Bi-cruciate substituting total knee arthroplasty provides varus-valgus stability throughout the midflexion range.

Background: Proper soft tissue balance is crucial for a successful clinical outcome after total knee arthroplasty (TKA). Bi-cruciate substituting (BCS)-TKA has been developed to more closely approximate normal knee characteristics. The purpose of the present study was to evaluate midflexion laxity before and after BCS-TKA using a navigation system, and assess the correlation between intraoperative laxity and the maximum flexion angle after surgery.

Varus-valgus stability at 90° flexion correlates with the stability at midflexion range more widely than that at 0° extension in posterior-stabilized total knee arthroplasty.

Introduction: Midflexion stability can potentially improve the outcome of total knee arthroplasty (TKA). The purpose of this study was to evaluate the correlation between varus-valgus stability at 0° of extension and 90° of flexion and that at the midflexion range in posterior-stabilized (PS)-TKA.

Materials And Methods: Forty-three knees that underwent PS-TKA were evaluated.

The influence of tibial resection on the PCL in PCL-retaining total knee arthroplasty: A clinical and cadaveric study.

Background: The influence of tibial resection on the joint gap and on stability against posterior laxity in posterior cruciate ligament-retaining total knee arthroplasty (CR-TKA) remains unclear. In addition, there are no detailed reports regarding how much of the tibial attachment of the posterior cruciate ligament (PCL) is preserved during tibial resection. Our goals were to evaluate the influence of tibial resection on the intraoperative joint gap and on postoperative anteroposterior stability in a clinical population, and to assess the preserved area of the tibial PCL attachment using cadaveric knees.

Assessment of the midflexion rotational laxity in posterior-stabilized total knee arthroplasty.

Purpose: To evaluate changes in midflexion rotational laxity before and after posterior-stabilized (PS)-total knee arthroplasty (TKA).

Methods: Twenty-nine knees that underwent PS-TKA were evaluated. Manual mild passive rotational stress was applied to the knees, and the internal-external rotational angle was measured automatically by a navigation system at 30°, 45°, 60°, and 90° of knee flexion.

Preoperative varus-valgus kinematic pattern throughout flexion persists more strongly after cruciate-retaining than after posterior-stabilized total knee arthroplasty.

Background: Restoration of normal knee kinematics is key to improving patient satisfaction and functional outcomes after total knee arthroplasty (TKA). However, the effect of preoperative varus-valgus kinematics due to knee osteoarthritis on the postoperative kinematics is unclear. The function of the knee ligament contributes to both knee stability and kinematics.