Contribution of a distal radioulnar joint stabilizer on forearm stability: A modeling study.

Instability of the forearm is a complex problem that leads to pain and limited motions. Up to this time, no universal consensus has yet been reached as regards the optimal treatment for forearm instability. In some cases, conservative treatments are recommended for forearm instability injuries.

Kinematic determinants of performance parameters during golf swing.

In golf, the trunk and pelvis kinematic variables are often related to measures of performance due to the highly complex and multi-joint movements involved in swings. However, it is unclear how specific body segments or joints contributed to the golf performance parameters. Therefore, the purpose of this study was to identify the key joints, including those of the upper and lower trunk, that are associated with golf performance parameters, such as X-Factor and pelvis motion.

New method to evaluate three-dimensional push-off angle during short-track speed skating using wearable inertial measurement unit sensors.

The push-off mechanism to generate forward movement in skating has been analyzed by using high-speed cameras and specially designed skates because it is closely related to skater performance. However, using high-speed cameras for such an investigation, it is hard to measure the three-dimensional push-off force, and a skate with strain gauges is difficult to implement in the real competitions. In this study, we provided a new method to evaluate the three-dimensional push-off angle in short-track speed skating based on motion analysis using a wearable motion analysis system with inertial measurement unit sensors to avoid using a special skate or specific equipment insert into the skate for measurement of push-off force.

Effects of medial collateral ligament release, limb correction, and soft tissue laxity on knee joint contact force distribution after medial opening wedge high tibial osteotomy: a computational study.

In this study, the effects of medial collateral ligament (MCL) release and the limb correction strategies with pre-existing MCL laxity on tibiofemoral contact force distribution after high tibial osteotomy (HTO) were investigated. The medial and lateral contact forces of the knee were quantified during simulated standing using computational modeling techniques. MCL slackness had a primary influence on contact force distribution of the knee, while there was little effect of simulated limb correction.

Biomechanical Effects on Cervical Spinal Cord and Nerve Root Following Laminoplasty for Ossification of the Posterior Longitudinal Ligament in the Cervical Spine: A Comparison Between Open-Door and Double-Door Laminoplasty Using Finite Element Analysis.

Many clinical case series have reported the predisposing factors for C5 palsy and have presented comparisons of the two types of laminoplasty. However, there have been no biomechanical studies focusing on cervical spinal cord and nerve root following laminoplasty. The purpose of this study is to investigate biomechanical changes in the spinal cord and nerve roots following the two most common types of laminoplasty, open-door and double-door laminoplasty, for cervical ossification of the posterior longitudinal ligament (OPLL).

Comparative Evaluation Between Anatomic and Nonanatomic Lateral Ligament Reconstruction Techniques in the Ankle Joint: A Computational Study.

Biomechanical studies have indicated that the conventional nonanatomic reconstruction techniques for lateral ankle sprain (LAS) tend to restrict subtalar joint motion compared to intact ankle joints. Excessive restriction in subtalar motion may lead to chronic pain, functional difficulties, and development of osteoarthritis (OA). Therefore, various anatomic surgical techniques to reconstruct both the anterior talofibular and calcaneofibular ligaments (CaFL) have been introduced.

Interjoint coordination of the lower extremities in short-track speed skating.

In short-track speed skating, the three-dimensional kinematics of the lower extremities during the whole skating cycle have not been studied. Kinematic parameters of the lower extremities during skating are presented as joint angles versus time. However, the angle-time presentation is not sufficient to describe the relationship between multi-joint movement patterns.

Increased stress and strain on the spinal cord due to ossification of the posterior longitudinal ligament in the cervical spine under flexion after laminectomy.

Myelopathy in the cervical spine due to cervical ossification of the posterior longitudinal ligament could be induced by static compression and/or dynamic factors. It has been suggested that dynamic factors need to be considered when planning and performing the decompression surgery on patients with the ossification of the posterior longitudinal ligament. A finite element model of the C2-C7 cervical spine in the neutral position was developed and used to generate flexion and extension of the cervical spine.

Biomechanical investigation of post-operative C5 palsy due to ossification of the posterior longitudinal ligament in different types of cervical spinal alignment.

Post-operative C5palsies are among the most common complications seen after cervical surgery for ossification of the posterior longitudinal ligament (OPLL). Although C5 palsy is a well-known complication of cervical spine surgery, its pathogenesis is poorly understood and depends on many other factors. In this study, a finite element model of the cervical spine and spinal cord-nerve roots complex structures was developed.

Biomechanical Behaviors in Three Types of Spinal Cord Injury Mechanisms.

Clinically, spinal cord injuries (SCIs) are radiographically evaluated and diagnosed from plain radiographs, computed tomography (CT), and magnetic resonance imaging. However, it is difficult to conclude that radiographic evaluation of SCI can directly explain the fundamental mechanism of spinal cord damage. The von-Mises stress and maximum principal strain are directly associated with neurological damage in the spinal cord from a biomechanical viewpoint.

Effect of posterior decompression extent on biomechanical parameters of the spinal cord in cervical ossification of the posterior longitudinal ligament.

Ossification of the posterior longitudinal ligament is a common cause of the cervical myelopathy due to compression of the spinal cord. Patients with ossification of the posterior longitudinal ligament usually require the decompression surgery, and there is a need to better understand the optimal surgical extent with which sufficient decompression without excessive posterior shifting can be achieved. However, few quantitative studies have clarified this optimal extent for decompression of cervical ossification of the posterior longitudinal ligament.

Influence of sagittal and axial types of ossification of posterior longitudinal ligament on mechanical stress in cervical spinal cord: A finite element analysis.

Background: There are few studies focusing on the prediction of stress distribution according to the types of ossification of the posterior longitudinal ligament, which can be fundamental information associated with clinical aspects such as the relationship between stress level and neurological symptom severity. In this study, the influence of sagittal and axial types of ossification of the posterior longitudinal ligament on mechanical stress in the cervical spinal cord was investigated.

Methods: A three-dimensional finite element model of the cervical spine with spinal cord was developed and validated.

Conversion Equation between the Drop Height in the New York University Impactor and the Impact Force in the Infinite Horizon Impactor in the Contusion Spinal Cord Injury Model.

There are several widely used devices for controlled contusion of the spinal cord, including the Ohio State University device, the University of British Columbia multi-mechanisms injury device, the New York University (NYU) impactor, and the Infinite Horizon (IH) impactor. Although various devices and protocols have been used to generate consistent injury severities, further investigation of the relationship between the key parameters of different spinal cord injury (SCI) contusion devices (e.g.

Effect of bone fragment impact velocity on biomechanical parameters related to spinal cord injury: a finite element study.

Several experimental and computational studies have investigated the effect of bone fragment impact on the spinal cord during trauma. However, the effect of the impact velocity of a fragment generated by a burst fracture on the stress and strain inside the spinal cord has not been computationally investigated, even though spinal canal occlusion and peak pressure at various impact velocities were provided in experimental studies. These stresses and strains are known factors related to clinical symptoms or injuries.

Biomechanical effects of spinal cord compression due to ossification of posterior longitudinal ligament and ligamentum flavum: a finite element analysis.

Ossification of the posterior longitudinal ligament (OPLL) and ossification of the ligamentum flavum (OLF) have been recognized as causes of myelopathy due to thickening of the ligaments resulting in narrowing of the spinal canal and compression of the spinal cord. However, few studies have focused on predicting stress distribution under conditions of OPLL and OLF based on clinical aspects such as the relationship between level of stress and severity of neurologic symptoms because direct in vivo measurement of stress is very restrictive. In this study, a three-dimensional finite element model of the spinal cord in T12-L1 was developed based on MR images.