Biomechanical Effects of Kneeling With Posterior Cruciate Retaining and Posterior Cruciate Substituting Total Knee Arthroplasty

Kneeling is an activity that is important in certain occupations and recreational activities. Culturally, kneeling plays a large role in Middle Eastern and Asian countries, where activities of daily living require the ability to kneel and achieve deep knee flexion.

Development of a Novel Micro-Manipulation Device and Its Simulation Using COMSOL

The manipulation of particles in fluids using microfluidic devices is a fundamental task in Lab-on-a-Chip applications. Grooved structures have been widely studied in particle handling and fluid mixing in microfluidic channel systems. In this study, we report use of patterning flows produced by a series of grooved surfaces with different geometrical setups integrated into a microfluidic device, to continuously manipulate the flowing particles, ranging from 6 to 20 μm in diameters, of comparable sizes to the depth of the channel. COMSOL, a multiphysics modeling software that can help predict engineering trends, is used to systematically quantify the following parameters: 1) channel depth, 2) groove width, 3) groove depth, 4) groove angle, and 5) flow speed, which may affect the performance of separation for flowing particles inside the channel. The device is fabricated using softlithographic techniques and is composed of inlets, microfluidic channels, and outlets for loading, manipulating and retrieving cell suspensions, respectively. Experimental results indicated that the particles were evenly distributed in the entrance of the microchannel and illustrate patterns of enriching, focusing, or size-selective profiles after passing through the grooved area. The preliminary simulation results also demonstrated that particles tend to bias towards the sidewall after flowing through the grooves.

Segmental Stiffness Achieved by Three Types of Instrumented Fixation for Unstable Lumbar Spondylolytic Motion Segments

Spondylolysis is a defect in the vertebral pars interarticularis. Its cause may be developmental or due to mechanical etiologies such as trauma. Most childhood and adolescent spondylolisthesis (defined as a slip of one vertebrae relative to another) is associated with spondylolysis of the pars interarticularis at the L5–S1 motion segment.

Self-Expandable Thin Film Nitinol Endografts for Vascular Repair: Manufacturing and Short-Term Results in Swine

A thin film nitinol covered endograft for vessel treatment was manufactured and in vivo swine testing was performed. Thin film nitinol graft material was fabricated by DC sputter deposition and stress-strain behavior and DSC characteristics were investigated. Micro size patterns were fabricated by MEMS technology in order to promote endothelial layer growth. In-vivo studies in swine were conducted to evaluate deployment, placement and patency of the implanted stent device.

Shoulder Arthroplasty: Current State of Affairs and Future Directions

Shoulder arthroplasty is a reliable procedure used to treat glenohumeral arthritis thanks to the efforts of many orthopaedic surgeons and design engineers over the past thirty years. Surgeons such Drs. Charles Neer and Robert Cofield were instrumental to making clinical observations that were effectively translated into improving implant design and clinical outcomes. Yet, there remains much room for further growth and development. With the increase numbers of shoulder arthroplasties performed, new observations and problems have been recognized that remain unanswered.

Arthroscopic Challenges in Treating Rotator Cuff Tears of the Shoulder

Rotator cuff tears can be the source of significant morbidity. Impingement syndrome involving repetitive and prolonged mechanical irritation of the rotator cuff against the roof of the shoulder creates a progression of disease. Chronic tendon inflammation can lead to structural loss of integrity, leading to partial tears, and if left unchecked, full-thickness tears. Currently, the surgeon has the ability to repair full-thickness tears using minimally invasive techniques. However, the persistent tear rate after repair is remarkably high, more than 50% in some studies. One surgical goal is to alter progression of disease, and repair partial-thickness tears, for example. Another goal is to optimize the healing environment with the repair construct itself, accounting for biomechanical considerations. When using an arthroscopic approach, the challenges for treating partial- versus full-thickness tears varies significantly given anatomic restrictions—particularly, during repair of partial-thickness tears, the surgeon is “blind” for portions of the procedure as the arthroscope is typically placed intra-articularly, while instruments are passed from above the tendon, extra-articularly. Ideally, new technologies can be developed to optimize rotator cuff repair and healing in this setting.

External Fixation of Distal Radius Fractures

External fixation has been used for the treatment of distal radius fractures for more than 50 years. Although the fixator configurations have undergone considerable modification over time, the type of fixator itself is not as important as the underlying principles that provide the foundation of external fixation. Although volar plate fixation is currently in vogue, the indications for external fixation remain largely unchanged. New fixator designs have also expanded hrte traditional usage to include nonbridging applications that allow early wrist motion. The following discussion focuses on the myriad uses for external fixation as well as the shortcomings and potential pitfalls.

Analysis of Electrode Degradation Through the Use of Synthetic Tissue Analog

RF Ablation Efficacy Testing: Modern surgical techniques utilize radio frequency ablation tools in minimally invasive procedures around the world today. The safety and efficacy of these tools must be verified before being used in human trials. This verification is typically performed on bovine, ovine, or porcine tissues which simulate clinical use.

Volumetric Image Alignment Utilizing Particle Swarm Optimization

In some cases an object can not be completely imaged with a single image. These cases call for taking multiple images and stitching the images together to form a complete view of the object. The images that are dealt with are taken with a confocal laser-scanning microscope. This produces a stack of two-dimensional images that represent the volume in the microscope’s field of view. While the microscope automatically creates a z stack, the positioning of the tiles in x and y is done manually. Therefore, the slices within each stack are assumed to be already aligned. Our technique will take multiple stacks of images and stitch them together to form a single volume. We will use a particle swarm optimization technique to calculate the proper transformations required to produce the final volume.

Periprosthetic of the Femur and Acetabulum: An Emerging Problem

Presentation will review the epidemiology, risk factors and treatments of fractures of the pelvis and femur associated with total hip arthroplasty. The attendee will be exposed to classification systems and treatment rationale base on accepted criteria. Additionally the at risk patient will be clarified in respect to types of implants, duration of service and pathologic comorbidities.