Improvement of arthroscopic surgical performance using a new wide-angle arthroscope in the surgical training.

Background: We have developed a new arthroscope with a field of view of 150°. This arthroscope requires less motion to maneuver and exhibits reduced optical error. It also improves how novices learn arthroscopy.

Comparison of the biomechanics of radial head prostheses with dynamic loading in the radiocapitellar joint.

We used eight fresh cadaveric elbows to evaluate the biomechanical characteristics of the native radial head, an anatomic radial head prosthesis, and a non-anatomic radial head prosthesis using a dynamic model. The biceps, brachialis, and triceps were attached to pneumatic actuators loaded to mimic muscle force. The radiocapitellar contact pressure and area were measured in real time, and the associated curves were depicted simultaneously.

Contact Mechanics of Anatomic Radial Head Prosthesis: Comparison Between Native Radial Head and Anatomic Radial Head Prostheses in the Dynamic Mode.

Purpose: The biomechanical characteristics of anatomic radial head prostheses have not been completely investigated. We compared and analyzed the contact kinematic characteristics of the native radial head and radial head prostheses replicating the native head contour, using a real-time flexion simulation model.

Methods: Ten fresh-frozen cadavers were used in this pilot study.

The Dimensionless Squared Jerk: An Objective Parameter That Improves Assessment of Hand Motion Analysis during Simulated Shoulder Arthroscopy.

Purpose: Attempts to quantify hand movements of surgeons during arthroscopic surgery faced limited progress beyond motion analysis of hands and/or instruments. Surrogate markers such as procedure time have been used. The dimensionless squared jerk (DSJ) is a measure of deliberate hand movements.

Functional Classification of the Medial Ulnar Collateral Ligament: An In Vivo Kinematic Study With Computer-Aided Design.

Background: It has been widely accepted that the anterior and posterior bundles of the medial ulnar collateral ligament (MUCL) tighten at extension and flexion, respectively. However, this belief is based on anatomic data acquired from cadaveric studies. The advancement of 3-dimensional (3D) model technology has made possible the simulation of dynamic movement that includes each ligament bundle fiber to analyze its functional properties.

Mechanoreceptors distribution in the human medial collateral ligament of the elbow.

Background: The human elbow maintains its stability mainly through its bony structure. Stability is enhanced by ligamentous structures. To allow the ligamento-muscular reflex, which protects against strain and stress, mechanoreceptors are embedded in the ligament.

Isometric Tunnel Placement in Ulnar Collateral Ligament Reconstruction with Single CT Scan.

Background: Isometric tunnel placement for anterior bundle of the medial collateral ligament (MCL) reconstruction is mandatory for successful surgery.

Purpose: This study aimed to demonstrate a useful method for identifying isometric tunnel placement using a single computed tomography (CT) scan.

Study Design: Descriptive Laboratory Study.

The Effect of Split Nerve on Electromyography Signal Pattern in a Rat Model.

Background:  Recent developments of prosthetic arm are based on the use of electromyography (EMG) signals. To provide improvements, such as coordinated movement of multiple joints and greater control intuitiveness, higher variability of EMG signals is needed. By splitting a nerve lengthwise, connecting each half to new target muscles, and employing a program to assign each biosignal pattern to a specific movement, we hope to enrich the number of biosignal sites on amputees' stump.

Beveled posteromedial corner of the radial head: a three-dimensional micro-computed tomography modeling study.

The posteromedial quadrant of the radial head is known to be different from the other quadrants. However, the explanation of this unique anatomical feature remains elusive. Hence, this study was designed to address this unique anatomical variance using three-dimensional μCT (micro-computed tomography) analysis.

Digital data acquisition of shoulder range of motion and arm motion smoothness using Kinect v2.

Background: Range of motion (ROM) is a clinically important parameter in evaluating joint function. However, dynamic evaluation to determine the quality of the arm motion using digitized measurement is often overlooked during clinical assessment. We evaluated the accuracy of Kinect v2 (Microsoft, Redmond, WA, USA) as a digital tool for measuring shoulder ROM objectively and proposed a concept of motion smoothness reflecting the quality of arm motion.

Head-shaft angle changes during internal and external shoulder rotations: 2-D angulation in 3-D space.

Introduction: Restoration of native head-shaft angle (HSA) is critical for treatment of proximal humerus fracture. However, HSA has not been properly investigated according to the humeral rotation. This study was designed to analyze the relationship between the humeral rotation and the HSA at 1° increments, and clarify its serial changing pattern according to the humeral rotation.

Reinnervated Split-Muscle Technique for Creating Additional Myoelectric Sites in an Animal Model.

Background: This study proposes a novel reinnervated split-muscle operation to create additional myoelectric sites as sources of command signals of myoelectric prostheses for enhanced dexterous hand-to-wrist motions. The aim of this study was to investigate the postprocedure electromyographic properties of the muscles as distinct myoelectric sites in a rat model.

Methods: The reinnervated split-muscle group (n = 6) had the gastrocnemius muscle separated along its longitudinal axis and nerves transferred to each new muscle (peroneal nerve to lateral muscle head and tibial to medial one); the non-split-muscle group (n = 6) only had nerve transfers with its muscle intact.

A hands-free region-of-interest selection interface for solo surgery with a wide-angle endoscope: preclinical proof of concept.

Background: A hands-free region-of-interest (ROI) selection interface is proposed for solo surgery using a wide-angle endoscope. A wide-angle endoscope provides images with a larger field of view than a conventional endoscope. With an appropriate selection interface for a ROI, surgeons can also obtain a detailed local view as if they moved a conventional endoscope in a specific position and direction.

The use of continuous negative pressure after open debridement for septic arthritis of the shoulder.

Aims: The treatment of septic arthritis of the shoulder is challenging. The infection frequently recurs and the clinical outcome can be very poor. We aimed to review the outcomes following the use of continuous negative pressure after open debridement with a large diameter drain in patients with septic arthritis of the shoulder.

Dorsal apex curve of the proximal ulna.

Objective: To analyze the apexes and angulations along the curvature in the posterior border of the proximal ulna-termed the "dorsal apex curve" (DAC)-using the computer-aided design software.

Methods: Eight pairs of normal cadaveric ulnae were analyzed. The ulnar Cartesian coordinate system was standardized using a user-defined coordinate systems feature.

A new wide-angle arthroscopic system: a comparative study with a conventional 30° arthroscopic system.

Purpose: To compare users' hand movements in performing validated shoulder arthroscopic tasks between a 30° and a wide-angle arthroscopic system, using phantom models with an optical motion analysis system.

Methods: Twelve orthopaedic residents were enrolled and randomly allocated into two groups. In order to compensate for any learning effect, a Latin square counterbalancing technique was used.

Decellularized Nerves for Upper Limb Nerve Reconstruction: A Systematic Review of Functional Outcomes.

Background: This is a systematic review for evaluating the evidence for functional outcomes after decellularized nerve use in clinical setting. Decellularized nerves are allografts whose antigenic components have been removed, leaving only a scaffold that promotes the full regeneration of axons.

Methods: Literature research was performed using the PubMed/MEDLINE database for English language studies with the keywords "decellularized nerve" and "processed nerve allograft.

Comparative analysis of visual field and image distortion in 30° and 70° arthroscopes.

Purpose: There have been very few attempts to compare the visual fields and image distortion in arthroscopes. To better understand the images generated using existing arthroscopes, we performed image-mapping experiments to assess field of view and image distortion. The purpose of this study was to quantify and compare the visual fields obtained using 30° and 70° arthroscopes and assess image distortion in each arthroscope.

Vortical flow in human elbow joints: a three-dimensional computed tomography modeling study.

The human elbow joint has been regarded as a loose hinge joint, with a unique helical motion of the axis during extension-flexion. This study was designed to identify the helical axis in the ulnohumeral joint during elbow extension-flexion by tracking the midpoint between the coronoid tip and the olecranon tip of the proximal ulna in a three-dimensional (3D) computed tomography (CT) image model. The elbows of four volunteers were CT-scanned at four flexion angles (0°, 45°, 90°, and 130°) at neutral rotation with a custom-made holding device to control any motion during scanning.

Morphometric analysis of the proximal ulna using three-dimensional computed tomography and computer-aided design: varus, dorsal, and torsion angulation.

Purpose: The proximal ulna, particularly the course of the posterior border, has a complex three-dimensional (3D) morphology which has been highlighted recently due to its clinical relevance in relation to surgical treatments. 3D computed tomography (CT) reconstruction and computer-aided design (CAD) based software can help to visualize the complex anatomy and thus aid the investigation of the more detailed morphology of the proximal ulna.

Methods: In our current study, 3D CT reconstruction images of 20 cadavers were imported into the 3D CAD program.