Traumatic lesions at the thumb base: Treatment options.

Traumatic lesions around the base of the thumb have special features due to the location and structure of the joint and its inherent potential instability. This causes different fracture patterns, which are mostly isolated around the metacarpal base but can also involve just the trapezium or both. Exceptionally, there may be isolated dislocation. Fracture patterns are variable and influence the type of surgery. The most common fracture is Bennett's fracture accounting for 4% of all hand fractures and sometimes associated with trapezium fracture, usually in male subjects. Different fracture mechanisms have been proposed. Apart from intra-articular fractures of the metacarpal base and the trapezium, proximal metaphyseal fractures can exceptionally be treated conservatively by immobilization. All other fractures require open or closed reduction combined with different types of temporary pinning or open reduction and internal fixation with screws or locking plate in case of comminution. Immobilization depends on the type of surgical treatment and can be removable or non-removable. Close follow-up is mandatory to avoid the inconveniences of secondary swelling with non-removable plaster and resin casts. Extra-articular malunion may be tolerated, but articular malunion must be corrected surgically by intra-articular osteotomy to restore the joint. In case of posttraumatic joint degeneration, treatment will focus on a case-by-case basis on the patient's complaints. Arthrodesis or prosthetic surgery can be proposed in case of severe problems caused by osteoarthritis.

Volar plate fixation in intra-articular distal radius fractures with a volar lunate facet fragment.

The aims of the study were to determine whether a volar lunate facet fragment is present in 67 displaced intra-articular distal radius fractures and to investigate which factors are associated with reduction loss after treatment with a volar plate and locking screws. The fractures were analyzed preoperatively with three-dimensional computed tomography. The volar lunate facet fragment was present in 42 fractures. Reduction loss occurred in five wrists and in two of those, the carpus was subluxated. Loss of reduction was associated with a short palmar cortex (9mm or less) of the volar lunate facet fragment. This study has shown that measuring the length of the palmar cortex of a volar lunate facet fracture fragment may be useful for identifying distal radius fractures that have a higher risk of displacement after treatment with a standard volar plate and locking screws.

Accelerated nonlinear interactions in graded-index multimode fibers.

Multimode optical fibers have recently reemerged as a viable platform for addressing a number of long-standing issues associated with information bandwidth requirements and power-handling capabilities. As shown in recent studies, the complex nature of such heavily multimoded systems can be effectively exploited to observe altogether novel physical effects arising from spatiotemporal and intermodal linear and nonlinear processes. Here, we study for the first time, accelerated nonlinear intermodal interactions in core-diameter decreasing multimode fibers. We demonstrate that in the anomalous dispersion region, this spatiotemporal acceleration can lead to relatively blue-shifted multimode solitons and blue-drifting dispersive wave combs, while in the normal domain, to a notably flat and uniform supercontinuum, extending over 2.5 octaves. Our results pave the way towards a deeper understanding of the physics and complexity of nonlinear, heavily multimoded optical systems, and could lead to highly tunable optical sources with very high spectral densities.

Vascularization of the trapeziometacarpal joint and its clinical importance: anatomical study.

Few studies have investigated the vascular anatomy of the trapeziometacarpal (TM) joint of the thumb. The aim of our study was to describe the supplying arteries of the trapezium and the TM joint since this knowledge is essential for trapezium osteotomies. Ten anatomical dissections in ten different cadavers using two different techniques (four macerations, six classic dissections) were performed. The arteries of the TM joint originated from the radial artery and the princeps pollicis artery. Four important branches were identified. The arteries formed a vascular network around the joint. The dorsoradial surface of the joint contained the richest arterial network. These findings present an important consideration when performing an osteotomy of the trapezium.

Comparison of two mathematical models for correlating the organic matter removal efficiency with hydraulic retention time in a hybrid anaerobic baffled reactor treating molasses.

A modelling of the anaerobic digestion process of molasses was conducted in a 70-L multistage anaerobic biofilm reactor or hybrid anaerobic baffled reactor with six compartments at an operating temperature of 26 °C. Five hydraulic retention times (6, 16, 24, 72 and 120 h) were studied at a constant influent COD concentration of 10,000 mg/L. Two different kinetic models (one was based on a dispersion model with first-order kinetics for substrate consumption and the other based on a modification of the Young equation) were evaluated and compared to predict the organic matter removal efficiency or fractional conversion. The first-order kinetic constant obtained with the dispersion model was 0.28 h(-1), the Peclet dispersion number being 45, with a mean relative error of 2%. The model based on the Young equation predicted the behaviour of the reactor more accurately showing deviations lower than 10% between the theoretical and experimental values of the fractional conversion, the mean relative error being 0.9% in this case.

Anaerobic treatment of synthetic medium-strength wastewater using a multistage biofilm reactor.

A laboratory-scale multistage anaerobic biofilm reactor of three compartments with a working volume of 54-L was used for treating a synthetic medium-strength wastewater containing molasses as a carbon source at different influent conditions. The start-up period, stability and performance of this reactor were assessed at mesophilic temperature (35 degrees C). During the start-up period, pH fluctuations were observed because there was no microbial selection or zoning, but as the experiment progressed, results showed that phase separation had occurred inside the reactor. COD removal percentages of 91.6, 91.6, 90.0 and 88.3 were achieved at organic loading rates of 3.0, 4.5, 6.75 and 9.0 kg COD/m(3) day, respectively. A decrease in HRT from 24 to 16 h had no effect on COD removal efficiency. When HRT decreased to 8h, COD removal efficiency was still 84.9%. Recirculation ratios of 0.5 and 1.0 had no effect on COD removal but other factors such as the volatile fatty acid (VFA) content were affected. The effect of toxic shock was also investigated and results showed that the main advantage of using this bioreactor lies in its compartmentalized structure.