Treatment of Bilateral Recurrent Dislocation of Hip Prosthesis with Malpositioned Well-Fixed Shell: A Case Report

Dislocations of total hip prostheses cause pain and patient dissatisfaction. Recurrent dislocations are difficult to treat mainly when the acetabular metal shell is well-fixed. The purpose of this article was to describe the surgical technique used for the treatment of a bilateral recurrent posterior dislocation after a cementless total hip prosthesis, caused by ex- cessive inclination of acetabular components, in a 72-year-old patient. On both sides, acetabular metal shell, porous- coated, was well-fixed. Revision of the entire acetabular component could be an appropriate therapeutic option because it was malpositioned. Nevertheless, a conservative operation was performed. The metal shell was left in situ and the preexisting polyethylene liner was removed and replaced by a new undersized cross-linked polyethylene liner, then, cemented into the shell and properly oriented. An acetabular cemented augmentation reinforced by 3 cortical screws was associated with the reconstruction. This report suggests that cementation of new liner into a malpositioned well- fixed metal shell associated with an acetabular cemented augmentation is a simple and safe technique for the manage- ment of recurrent hip dislocation, for elderly patients in which it is advisable to avoid a major revision hip surgery by medical comorbidities. Nonetheless, further studies with medium-and long-term follow-up are needed to validate this technique

Complicações da via transfemoral no tratamento do descolamento assético de artroplastias da anca

A via transfemoral é um procedimento com reconhecido valor na cirurgia de recolocações de artroplastias da anca. Todavia, poucas são as publicações que estudam as complicações que podem surgir a médio ou longo prazo. O objetivo central deste trabalho inclui a análise do tipo e frequência de complicações relacionadas com a via transfemoral, usada no tratamento de 61 descolamentos asséticos de artroplastias da anca com um recuo médio de 39 meses (min. 12 meses, max. 132 meses), implantando em todos os casos uma haste de revisão cónica Conelock®. Entre janeiro de 2006 e Março de 2011 foram realizadas no Serviço 445 revisões de artroplastias da anca: 181 recolocações acetabulares, 8 recolocações de hastes femorais, 230 recolocações bipolares, 15 recolocações da cabeça/colo da haste e 11 artroplastias de ressecção. A via transfemoral foi usada em 108 situações . Neste período e respeitando os critérios acima referidos identificou‐se de modo aleatório uma série de 61 recolocações de hastes femorais, implantadas em 22 doentes do género feminino e 38 do masculino, com idade média 71 anos (máx. 87; min 45 ). Em 94% dos casos houve uma consolidação da osteotomia. Como complicações relacionadas com a via transfemoral registou‐se: Não‐união trocantérica (2); migração proximal do fragmento ósseo femoral (1); fraturas tardias do fragmento trocantérico-femoral (3); infeção superficial (1); infeção periprotética (4), osteólises relacionadas com cabos metálicos (1), descolamento assético precoce (1); afundamento da haste femoral (1); No total obteve‐se uma taxa de complicação de 23%, que está em consonância os resultados obtidos na literatura internacional que ronda os 24%. Em 8 casos foi necessária uma ou mais revisões motivadas pelas complicações acima descritas. A complicação maior foi a infeção periprotética que levou à excisão artroplástica em uma situação. Os casos de fraturas do fragmento trocantérico-femoral foram tratadas de forma conservadora. Contrariamente à situação que acontecia quando o fragmento trocantérico-femoral era fixado, de forma não rígida, com fios de sutura não reabsorvíveis, a baixa frequência de migrações proximais do fragmento ósseo janela pode ser explicada pelo uso, para a sua estabilização mecânica, de pelo menos 2 cabos metálicos. Por sua vez, as osteólises relacionadas com os cabos metálicos não tiveram repercussões funcionais significativas. Os aloenxertos esponjosos desempenharam o seu papel biológico no processo de consolidação da osteotomia. De salientar a idade elevada dos pacientes, assim como a incontornável frequência de co-morbilidades. Apesar de facilitar a técnica de recolocação das hastes femorais, a via transfemoral pode estar na origem de uma frequência significativa de complicações e, por isso, deve ser indicada em casos seleccionados de recolocações das artroplastias da anca por descolamento assético

Quantitative cross-species extrapolation between humans and fish: The case of the anti-depressant fluoxetine

This article has been made available through the Brunel Open Access Publishing Fund.Fish are an important model for the pharmacological and toxicological characterization of human pharmaceuticals in drug discovery, drug safety assessment and environmental toxicology. However, do fish respond to pharmaceuticals as humans do? To address this question, we provide a novel quantitative cross-species extrapolation approach (qCSE) based on the hypothesis that similar plasma concentrations of pharmaceuticals cause comparable target-mediated effects in both humans and fish at similar level of biological organization (Read-Across Hypothesis). To validate this hypothesis, the behavioural effects of the anti-depressant drug fluoxetine on the fish model fathead minnow (Pimephales promelas) were used as test case. Fish were exposed for 28 days to a range of measured water concentrations of fluoxetine (0.1, 1.0, 8.0, 16, 32, 64 μg/L) to produce plasma concentrations below, equal and above the range of Human Therapeutic Plasma Concentrations (HTPCs). Fluoxetine and its metabolite, norfluoxetine, were quantified in the plasma of individual fish and linked to behavioural anxiety-related endpoints. The minimum drug plasma concentrations that elicited anxiolytic responses in fish were above the upper value of the HTPC range, whereas no effects were observed at plasma concentrations below the HTPCs. In vivo metabolism of fluoxetine in humans and fish was similar, and displayed bi-phasic concentration-dependent kinetics driven by the auto-inhibitory dynamics and saturation of the enzymes that convert fluoxetine into norfluoxetine. The sensitivity of fish to fluoxetine was not so dissimilar from that of patients affected by general anxiety disorders. These results represent the first direct evidence of measured internal dose response effect of a pharmaceutical in fish, hence validating the Read-Across hypothesis applied to fluoxetine. Overall, this study demonstrates that the qCSE approach, anchored to internal drug concentrations, is a powerful tool to guide the assessment of the sensitivity of fish to pharmaceuticals, and strengthens the translational power of the cross-species extrapolation

Three-Dimensional Neurophenotyping of Adult Zebrafish Behavior

The use of adult zebrafish (Danio rerio) in neurobehavioral research is rapidly expanding. The present large-scale study applied the newest video-tracking and data-mining technologies to further examine zebrafish anxiety-like phenotypes. Here, we generated temporal and spatial three-dimensional (3D) reconstructions of zebrafish locomotion, globally assessed behavioral profiles evoked by several anxiogenic and anxiolytic manipulations, mapped individual endpoints to 3D reconstructions, and performed cluster analysis to reconfirm behavioral correlates of high- and low-anxiety states. The application of 3D swim path reconstructions consolidates behavioral data (while increasing data density) and provides a novel way to examine and represent zebrafish behavior. It also enables rapid optimization of video tracking settings to improve quantification of automated parameters, and suggests that spatiotemporal organization of zebrafish swimming activity can be affected by various experimental manipulations in a manner predicted by their anxiolytic or anxiogenic nature. Our approach markedly enhances the power of zebrafish behavioral analyses, providing innovative framework for high-throughput 3D phenotyping of adult zebrafish behavior