Clinical and radiologic results after open-wedge high tibial osteotomy in haemophilic knee arthropathy with varus deformity.

INTRODUCTION: The previous studies have described only closed-wedge high tibial osteotomy (HTO) in haemophilic arthropathy (HA). AIM: The purpose of this study was to evaluate clinical and radiographic results after open-wedge HTO in HA with varus knee deformity. METHODS: We included 13 open-wedge HTOs in HA performed between 2005 and 2016. The mean age of patients was 28.9 years. Visual analogue scale (VAS), Western Ontario and McMaster Universities (WOMAC), and range of motion (ROM) indices were assessed. Any complications or requirements for total knee arthroplasty (TKA) were investigated. Mechanical axis (MA), minimal joint space width (mJSW) and Pettersson score were measured. Bone union rates at 3 and 6 months postoperative were evaluated. RESULTS: VAS improved from 5.1 to 2.4 (P < .001). WOMAC was 66.5 preoperatively, and 26.6 postoperatively (P < .001). Pre- and postoperative ROM did not differ significantly. There were no cases of HTO converted to TKA, but one case of HTO required TKA 152 months postoperative. No complications were observed. The MA was corrected from varus 5.1° to valgus 1.2° (P < .001). Pre- and postoperative mJSW did not significantly differ. Pettersson score improved from 3.84 to 2.47 (P < .001). The bone union rates at the osteotomy gap were 45.2% and 67.8% at 3 and 6 months postoperative. CONCLUSIONS: Open-wedge HTO should be considered in cases of HA with varus deformity in young haemophilic patients, even though inflammatory arthritis is not an optimal indication for this procedure. It can be an appropriate treatment with respect to the choice to postpone TKA.

Application of pseudo-parameter iteration method to nonlinear deflection analysis of an infinite beam with variable beam cross-sections on a nonlinear elastic foundation.

In this study, the nonlinear deflection of an infinite beam with variable beam cross-sections on a nonlinear elastic foundation was analyzed using the pseudo-parameter iteration method (PIM), which is a novel iterative semi-analytic method for solving ordinary/partial differential equations. To do this, we set six types of infinite beams with concave and convex shapes under static loading conditions. To calculate the nonlinear deflection of the infinite beam with variable cross-sections, the Bernoulli-Euler beam equation (fourth-order ordinary differential equation) considering changing beam flexural rigidity was introduced, and the PIM was adopted to this equation. Through the numerical experiment, it was confirmed that the nonlinear deflections calculated via the PIM are quite close to the exact solution within a few iterations. In addition, the graph of error quickly reaches the steady state error for all cases as the number of iterations increases.

Evolutionary consequences, constraints and potential of polyploidy in plants.

Polyploidy, the possession of more than 2 complete genomes, is a major force in plant evolution known to affect the genetic and genomic constitution and the phenotype of an organism, which will have consequences for its ecology and geography as well as for lineage diversification and speciation. In this review, we discuss phylogenetic patterns in the incidence of polyploidy including possible underlying causes, the role of polyploidy for diversification, the effects of polyploidy on geographical and ecological patterns, and putative underlying mechanisms as well as chromosome evolution and evolution of repetitive DNA following polyploidization. Spurred by technological advances, a lot has been learned about these aspects both in model and increasingly also in nonmodel species. Despite this enormous progress, long-standing questions about polyploidy still cannot be unambiguously answered, due to frequently idiosyncratic outcomes and insufficient integration of different organizational levels (from genes to ecology), but likely this will change in the near future. See also the sister article focusing on animals by Choleva and Janko in this themed issue.

Systematic methodology for the design of a flexible keel for energy-storing prosthetic feet.

An effective design method is suggested for a flexible keel design for energy-storing prosthetic feet (ESPF). The basic, two-dimensional shape of the keel is based on anthropometric data and normal gait analysis available in the literature. Cost function is defined for the performance evaluation of the keel. Five factors and five levels of their effect on the performance of the keel are established. By use of an orthogonal array table, 25 trials of dynamic simulations of prosthetic walking are designed, from among 3,125 possible combinations, dramatically reducing the number of total simulations needed to examine sufficiently the contribution of each factor to cost function. A prosthetic walking model is built, and a dynamic simulation of prosthetic walking is performed using the finite element method. The contribution of each factor to cost function is investigated by an analysis of variance (ANOVA), and the average main effects of factors for cost function are calculated. The optimum combination of factor levels is obtained by minimisation of cost function. To examine the structural safety of the keel, the deformation and stress distribution of the keel are investigated by static analysis, and failure indices are calculated by three failure criteria. Finally, the optimum flexible keel is designed with increased energy storage capacity, without failure, and suitable for more active prosthetic walking; the recoverable strain energy stored in the optimum ESPF keel is 25.8J.