High-order simulation scheme for active particles driven by stress boundary conditions.

We study the dynamics and interactions of elliptic active particles in a two dimensional solvent. The particles are self-propelled through prescribing a fluid stress at one half of the fluid-particle boundary. The fluid is treated explicitly solving the Stokes equation through a discontinuous Galerkin scheme, which allows to simulate strictly incompressible fluids.

A Multi-Method Approach to Assess the Self-Interaction Behavior of Infliximab.

Attractive self-interaction processes in antibody formulations increase the risk of aggregation and extraordinarily elevated viscosity at high protein concentrations. These challenges affect manufacturing and application. This study aimed to understand the self-interaction process of Infliximab as a model system with pronounced attractive self-interaction.

Generation of mAb Variants with Less Attractive Self-Interaction but Preserved Target Binding by Well-Directed Mutation.

Strongly attractive self-interaction of therapeutic protein candidates can impose challenges for manufacturing, filling, stability, and administration due to elevated viscosity or aggregation propensity. Suitable formulations can mitigate these issues to a certain extent. Understanding the self-interaction mechanism on a molecular basis and rational protein engineering provides a more fundamental approach, and it can save costs and efforts as well as alleviate risks at later stages of development.

Axial-Plane Biomechanical Evaluation of 2 Suspensory Cortical Button Fixation Constructs for Acromioclavicular Joint Reconstruction.

Background: Although numerous suture-button fixation techniques for acromioclavicular (AC) joint reconstruction have been validated with biomechanical testing in the superior direction, clinical reports continue to demonstrate high rates of construct slippage and breakage.

Purpose: To compare the stability of a novel closed-loop double Endobutton construct with a commercially available cortical button system in both the axial and superior directions.

Study Design: Controlled laboratory study.

Distal femoral varus osteotomy for unloading valgus knee malalignment: a biomechanical analysis.

Purpose: To investigate the biomechanical properties of the load shifting following opening-wedge distal femoral varus osteotomies (DFVOs) and determine the osteotomy correction needed to unload the lateral compartment.

Methods: Five human cadaveric knees were tested with a load of 500 N of axial compression. Medial and lateral tibiofemoral compartment contact area and pressure were assessed utilizing a modified F-scan pressure-sensitive sensor.

Partial subscapularis release for total shoulder arthroplasty: a biomechanical comparison of two techniques.

Background: Glenohumeral joint exposure during total shoulder arthroplasty (TSA) is obtained by releasing the subscapularis (SSC) with either an osteotomy or a tenotomy. Recently, concerns regarding SSC dysfunction after TSA have been raised. In order to avoid this complication, alternative surgical approaches that release the inferior 50% or 10% of the tendon have been described.

The effect of two different trochanteric nail lag-screw designs on fixation stability of four-part intertrochanteric fractures: a clinical and biomechanical study.

Objectives: To compare lag-screw sliding characteristics and fixation stability of two cephalomedullary nails (CMN) with different lag-screw designs (solid and telescopic), we conducted a biomechanical study and an analysis of clinical results.

Methods: Six pairs of cadaver femurs with simulated intertrochanteric fractures were randomly assigned to one of two CMN fixations. Femur constructs were statically then cyclically loaded on an MTS machine.

Mechanical effects of defect closure following BPTB graft harvest for ACL reconstruction.

Anterior cruciate ligament injury affects roughly 120,000 athletes in the United States every year. One of the most common techniques is the use of a bone-patellar tendon-bone graft. Graft harvest creates a sizeable defect in the remaining patellar tendon.

A laboratory comparison of a new arthroscopic transosseous rotator cuff repair to a double row transosseous equivalent rotator cuff repair using suture anchors.

Background: Because current instrumentation makes it possible to perform an arthroscopic transosseous rotator cuff repair, we performed a biomechanical comparison of a double-row transosseous equivalent rotator cuff repair using suture anchors to an arthroscopic, transosseous rotator cuff repair to determine if they provided similar fixation stability.

Methods: Six pairs of shoulders were used. One of each pair had a standard double row, transosseous equivalent arthroscopic rotator cuff repair using a suture-bridge technique with suture anchors, and the other had an arthroscopic transosseous repair using an Xbox technique.

Relationship between cancer-related fatigue and physical activity in inpatient cancer rehabilitation.

Background: Fatigue is a serious problem for the majority of patients with cancer. In this context, several studies have shown benefits of physical activity during and following treatment. However, uncertainties remain regarding the optimal type and duration of physical activity.

Ventilation/perfusion lung scintigraphy. Multiple applications besides pulmonary embolism.

Ventilation/perfusion scintigraphy is the diagnostic tool of choice for detection and monitoring of pulmonary embolism. However, the knowledge on its value for other or concurrent pathologies is poor. In this review scintigraphic characteristics of the main pathologies, interpretation and artefacts are described.

Case report: analysis of an ultra-high-molecular-weight polyethylene acetabular cup retrieval at 41 years.

A polyethylene cup explanted after 41 years was examined using several analytical techniques to determine whether there was a material cause for the extremely low wear observed. Neither the amount of polyethylene oxidation nor crystallinity appeared to be a factor.

Midfoot fusion: a biomechanical comparison of plantar planting vs intramedullary screws.

Background: Numerous reconstructive techniques for midfoot collapse secondary to Charcot neuroarthropathy have been described, but few have been studied biomechanically. The purpose of this study was to biomechanically compare 2 of the most common techniques.

Methods: Seven paired below-knee specimens were amputated through the talonavicular and calcaneocuboid joints.

Effects of suture tension on the footprint of rotator cuff repairs--technical note.

The footprint is thought to be an important fact in rotator cuff repairs and has been used to compare various cuff fixation techniques. The following experiment used two different measurement sensors to evaluate the footprint as it is affected by suture tensions in a transosseous equivalent suture bridge repair. It was found that suture tension has a direct effect on footprint contact area and pressure and thus could affect healing and fixation stability and should be characterized in any study of comparative fixation techniques.

The effects of locked and unlocked neutralization plates on load bearing of fractures fixed with a lag screw.

Objectives: Because locked plates as a neutralization device for lag screw fracture fixation have different biomechanics than that of unlocked plates, we investigated how this would affect lag screw load at the fracture site. The purpose of this study was to assess the load at a fracture site compressed with a lag screw when both locked and unlocked plates are used as neutralization devices.

Materials And Methods: Nine cadaver femurs had a mid-shaft oblique fracture created and were fixed with a lag screw, incorporating load transducers at the fracture site and lag screw.

Biomechanical comparison of translaminar screw versus pedicle screw supplementation of anterior femoral ring allografts in one-level lumbar spine fusion.

Pedicle screws (PS) can provide initial stabilization of anterior interbody femoral ring allograft (FRA) lumbar constructs. Translaminar screws (TLS) have also been advocated for this procedure. The objective of this study was to use an in vitro human cadaveric model to compare the stability of one-level anterior interbody lumbar constructs stabilized with PS and those stabilized with TLS.

Sliding of two lag screw designs in a highly comminuted fracture model.

A fracture construct, representing a worst-case model of a comminuted intertrochanteric fracture, was created in order to compare the fixation stability of two different cephalomedullary nails: one where the lag screw can telescope within itself to achieve displacement of the head-neck fragment, and the other where the solid lag screw slides only. After nail fixation, the models were loaded and then cycled, and positions of the head-neck fragment and lag screw were determined. Both nails similarly acted to limit motion of the head-neck fragment by the sliding of their lag screws, causing impingement of the fragment against the nail.

Helical blade vs telescoping lag screw for intertrochanteric fracture fixation.

The purpose of this study was to compare fixation stability and lag screw sliding characteristics between 2 different hip-nail lag screw designs, a telescoping screwbarrel and a solid helical blade. Simulated, unstable, 4-part intertrochanteric hip fractures were created in 6 pairs of cadaveric femurs. Each nail type was randomly assigned within each femur pair.

Acoustic emission studies of posterior stabilized and cruciate retaining knee arthroplasties.

Different acoustic frequencies have been used to diagnose progression of osteoarthritis, gross pathology, and wear in knee prostheses. It is possible that detailed analysis of higher frequencies could detect and quantify the smaller geometric changes (asperities) that develop in articular prosthetic wear. In this study we evaluated the feasibility of using ultrasonic emission to determine total knee arthroplasty (TKA) type and time from implantation using a simple, handheld measurement system.

Suture loosening and its effect on tendon fixation in knotless double-row rotator cuff repairs.

Purpose: We have occasionally observed suture loosening in initial suture legs after final fixation of adjacent suture legs in the lateral row of rotator cuff repairs during arthroscopic rotator cuff repair with transosseous-equivalent suture-bridge constructs. We sought to determine how this occurred and what effects it had on tendon fixation stability.

Methods: Six pairs of fresh-frozen human shoulders were prepared with a simulated cuff defect.

Feasibility of using ultrasonic emission for clinical evaluation of prosthetic hips.

Background: Previous acoustic emission (AE) studies of the hip have proposed using AE for the diagnosis of musculoskeletal conditions and assessing the clinical status (loosening, wear, etc.) of prostheses. However, these investigations have had problems with spurious signal noises or complicated measurement techniques, or both.