Manipulation of expressions in a relational algebra

This paper describes a syntax for expressions based on the relational algebra. A tree representation is generated when an expression is analyzed. Transformations on the tree representations of expressions are applied in order to obtain improvements with respect to the speed of evaluation in a data base environment

Forget the flâneur

This paper discusses the connections between the ‘flâneur’, Baudelaire's symbol of modernity, the anonymous man on the streets of nineteenth century Paris, and his contemporary digital incarnation, the ‘cyberflâneur’. It is argued that, although the fl neur could be successfully re-imagined as the cyberfl neur in the early days of the web, this nineteenth century model of male privilege no longer fits the purpose. It is suggested that it is time to forget the flâneur and search for a new model to consider the peripatetic nature of location-aware networked devices in the digitally augmented city

Medium-term follow-up of 92 femoral component revisions using a third-generation cementing technique

Background and purpose - Very little has been published on the outcome of femoral cemented revisions using a third-generation cementing technique. We report the medium-term outcome of a consecutive series of patients treated in this way. Patients and methods - This study included 92 consecutive cemented femoral revisions performed in our department with a third-generation cementing technique and without instrumented bone impaction grafting between 1996 and 2007. The average age of the patients at revision was 66 (25-92) years. None of the patients were lost to follow-up. At review in December 2013, 55 patients were still alive and had a non-re-revised femoral revision component in situ after a mean follow-up of 11 (5-17) years. Results - The mean preoperative Harris hip score was 50, and improved to 73 at final follow-up. 2 patients died shortly after the revision surgery. 1 stem was re-revised for aseptic loosening; this was also the only case with radiolucent lines in all 7 Gruen zones. A femoral reoperation was performed in 19 hips during follow-up, and in 14 of these 19 reoperations the femoral component was re-revised. Survivorship at 10 years, with femoral re-revision for any reason as the endpoint, was 86% (95% CI: 77-92). However, excluding 8 patients with reinfections after septic index revisions and 1 with hematogenous spread of infection from the survival analysis, the adjusted survival for re-revision for any reason at 10 years was 92% (95% CI: 83-96). With re-revision for aseptic loosening as endpoint, the survival at 10 years was 99% (CI: 90-100). Interpretation - Femoral component revision with a third-generation cemented stem results in acceptable survival after medium-term follow-up. We recommend the use of this technique in femoral revisions with limited loss of bone stock

Femoral component revision with use of impaction bone-grafting and a cemented polished stem: A concise follow-up, at fifteen to twenty years, of a previous report

Contains fulltext : 107906.pdf (publisher's version ) (Open Access)We previously reported our results for thirty-three consecutive femoral component revisions with impaction bone-grafting, performed with the X-change femoral revision system and a cemented polished Exeter stem, at a minimum of eight years of follow-up. The present updated study shows the results after fifteen to twenty years. One stem was revised again for mechanical reasons during a rerevision of an acetabular cup. The probability of survival at seventeen years was 96% (95% confidence interval [CI], 72% to 99%) with a femoral rerevision for any reason as the end point and 100% (95% one-sided CI, 69% to 100%) with rerevision for aseptic loosening as the end point. The average subsidence was 3 mm and stable relative to our previous report. Although three early femoral fractures occurred after this surgery, in this update no additional fractures were seen. In conclusion, the probability of survival of femoral component revisions with impaction bone-grafting and a cemented polished stem was excellent at a mean of seventeen years. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence

Les atteintes du LCA en 2003 : le MacIntosh est-il encore justifiable ?

Chirurgie par arthroscopie du ligament croisé antérieur : point de vue sur le recours actuel à la technique de MacIntosh, comparée à d'autres techniques, comme le Jones, selon l'importance de la laxité