Lower function, quality of life, and survival rate after total knee arthroplasty for posttraumatic arthritis than for primary arthritis

International audienceBackground and purpose - Total knee arthroplasty (TKA) for treatment of end-stage posttraumatic arthritis (PTA) has specific technical difficulties and complications. We compared clinical outcome, postoperative quality of life (QOL), and survivorship after TKA done for PTA with those after TKA performed for primary arthritis (PA). Patients and methods - We retrospectively reviewed patients who were operated on at our institution for PTA between 1998 and 2005 (33 knees), and compared them to a matched group of patients who were operated on for PA during the same period (407 knees). Clinical outcomes and postoperative QOL were compared in the 2 groups using Knee Society score (KSS), range of motion (ROM) of the knee, and the knee osteoarthritis outcomes score (KOOS). Implant survival rate was calculated using Kaplan-Meier analysis. Results - At a mean follow-up of 11 (5-15) years, KSS knee increased from mean 39 (SD 18) to 87 (SD 16) in the PA group (p = 0.003), and from 31 (SD 11) to 77 (SD 15) in the PTA group (p = 0.003). KSS function increased from 55 (12) to 89 (25) in the PA group (p = 0.008) and from 44 (SD 14) to 81 (SD 10) in the PTA group (p = 0.008). Postoperative ROM also improved in both groups, from 83 degrees to 108 degrees in the PTA group (p < 0.001) as opposed to 116 degrees to 127 degrees in the PA group (p = 0.001), with lower results in the PTA group (p < 0.001). KOOS was lower in the PTA group (p < 0.001). The survival rate of TKA at 10 years with an endpoint defined as "any surgery on the operated knee" showed better results in the PA group (99%, CI: 98-100 vs. 79%, CI: 69-89; p < 0.001). Interpretation - Patients and surgeons should be aware that clinical outcome and implant survival after TKA for PTA are lower than after TKA done for P

Pull-out strength of four tibial fixation devices used in anterior cruciate ligament reconstruction

International audienceIntroduction: In reconstructions of the anterior cruciate ligament (ACL), tibial fixation can be the weak point in the assembly during the early postoperative period. The present study sought to compare pull-out strength between four tibial fixation systems used in ACL reconstruction.Hypothesis: The study hypothesis was that all four devices show ≥ 450 N pull-out strength with comparable biomechanical breakage characteristics. Material and methods: An experimental study used a mechanical model to perform axial traction on a synthetic ligament (polypropylene cord folded in four) implanted in an artificial tibia (Sawbones Proximal Tibia # 1116-2: model: normal anatomy; solid foam; size: medium) using four tibial fixation systems: Ligafix ® interference screw (SBM TM); Bio-Intrafix ® (Mitek TM); Translig ® (SBM TM); RIGIDfix ® (SBM TM). For each system, four models were tested using an Instron 5566 ® traction machine, allowing 100 mm/min stretching up to breakage. Study parameters comprised: pull-out strength, maximal whole assembly slippage, stiffness at breaking point, and type of break.Results: Mean pull-out strength was 450 ± 24 N (range, 421–488 N) for Ligafix ® , 415 ± 60 N (327–454 N) for Bio-Intrafix ® , 539 ± 66 N (449–636 N) for RigidFix and 1067 ± 211 N (736–1301 N) for Translig ® , and was significantly greater for Translig ® than for the other devices (p = 0.02), which did not significantly differ from one another. The expected maximal load of 450 N was reached in 100% of cases with Translig ® and RIGIDfix ® and in 50% of cases with Bio-Intrafix ® and Ligafix ®. There were no significant differences regarding stiffness. Ligafix ® showed significantly less slippage than the others (p = 0.006), with breakage caused by the ligament sliding between bone and implant.Discussion: In this in-vitro study, the Translig ® fixation device showed better pull-out strength than the other three devices tested. Type of study and level of evidence: Comparative laboratory study. Level II

The First Genomic and Proteomic Characterization of a Deep-Sea Sulfate Reducer: Insights into the Piezophilic Lifestyle of Desulfovibrio piezophilus

Desulfovibrio piezophilus strain C1TLV30T is a piezophilic anaerobe that was isolated from wood falls in the Mediterranean deep-sea. D. piezophilus represents a unique model for studying the adaptation of sulfate-reducing bacteria to hydrostatic pressure. Here, we report the 3.6 Mbp genome sequence of this piezophilic bacterium. An analysis of the genome revealed the presence of seven genomic islands as well as gene clusters that are most likely linked to life at a high hydrostatic pressure. Comparative genomics and differential proteomics identified the transport of solutes and amino acids as well as amino acid metabolism as major cellular processes for the adaptation of this bacterium to hydrostatic pressure. In addition, the proteome profiles showed that the abundance of key enzymes that are involved in sulfate reduction was dependent on hydrostatic pressure. A comparative analysis of orthologs from the non-piezophilic marine bacterium D. salexigens and D. piezophilus identified aspartic acid, glutamic acid, lysine, asparagine, serine and tyrosine as the amino acids preferentially replaced by arginine, histidine, alanine and threonine in the piezophilic strain. This work reveals the adaptation strategies developed by a sulfate reducer to a deep-sea lifestyle

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

Anterior Cruciate Ligament Reconstruction: The Long Road from Science to Clinical Relevance.

International audienc

Key role of strains' transmission abnormality as an origin of femoro-acetabular diseases

Dans le cadre de ce travail de thèse nous nous sommes intéressés à deux pathologies fémoro-acétabulaires dont la pathogénie semble liée aux « conditions biomécaniques » locales. La première partie de cette thèse était consacrée à l’analyse de l’influence de l’anatomie osseuse sur l’apparition de l’ostéonécrose aseptique de la tête fémorale. Nous avons réalisé des analyses analytique de l’anatomie des patients souffrant d’ONA (notre hypothèse était que nous retrouverions un profil anatomique particulier chez les patients souffrant d’ONA par rapport à la population générale.Nos résultats démontrent que les patients souffrant d’ONA présentent fréquemment une anatomie particulière. Notre modèle en éléments finis de la hanche de dix patients souffrant d’ONAi, a permis de valider notre hypothèse puisqu’il existe un recouvrement quasi-parfait, entre la zone de nécrose osseuse et celle supportant les contraintes fémoro-acétabulaires. L’hypothèse selon laquelle une pathogénie mécanique puisse être responsable du développement l’ostéonécrose aseptique de la tête fémorale est vérifiée par nos travaux.Dans la seconde partie de cette thèse nous avons décrit le rôle mécanique du LA par une évaluation multimodale combinant analyse cinématique,de contraintes fémoro-labrales et enfin analyse en éléments finis. Les résultats de ces études ont permis de constater que le LA se déforme lors du mouvement reflétant une transmission de contraintes fémoro-labrales lors du mouvement d’abduction. Ces contraintes ont pu être enregistrées à l’aide de capteurs piezo-resistifs, elles augmentent lors du mouvement d’abduction. Ces éléments ont été confirmés par notre modèle en éléments finis.As parts of this thesis we focused on two femoro-acetabular diseases whose pathogenesis appears to be related to "biomechanical local conditions". The first part of this thesis was devoted to analyze the influence of bony anatomy on the development of aseptic osteonecrosis of the femoral head. We thus aimed to analyze ONA patients’ anatomy in a matched-controlled fashioned study. Our results demonstrate that patients with ONA often present a particular anatomy. A finite element model of ten iONA hips validated our hypothesis since we found an overlap between bone necrosis area and femoro-acetabular strains bearing area. The assumption that a mechanical pathogenesis may be responsible for ONA development has been confirmed by our results.If the relationship between bony anatomy and bone disease is quite intuitive, acetabular labrum involvement (AL) in the regulation of femoro-acetabular mechanical conditions is unclear. The mechanical role of the AL is widely controversial, though some authors attributed, AL, a key role in hip joint’s mechanics, others advocated its complete resection in case of painful traumatic tears. We tried to demonstrate AL’s mechanical role in a multimodal analysis combining kinematic, strains and finite element analysis. The AL deforms during abduction movement reflecting femoro-labral strains’ transmission. Those strains have been recorded using piezo-resistive sensors, they increase during adduction to abduction movement. These elements were confirmed by our finite element model: labral resection changed the Femoro-acetabular strains to the detriment of cartilage surfaces

Estimation de directivités acoustiques à l'aide d'antennes non-sphériques de microphones

International audienceEstimation de directivités acoustiques à l'aide d'antennes non-sphériques de microphone

Anterior Closing-Wedge High Tibial Osteotomy Using Patient-Specific Cutting Guide in Chronic Anterior Cruciate LigamenteDeficient Knees

An increased posterior tibial slope has been identified as an independent risk factor for anterior cruciate lig-ament (ACL) graft rupture, with a critical threshold of 12 degrees. Surgical slope correction by anterior closing wedge (ACW)-high tibial osteotomy (HTO) can reduce ACL force and anterior tibial translation with good clinical outcomes when combined with revision ACL reconstruction. Performing ACW-HTO preserving the tibial tubercule can be challenging for inexperienced surgeons. Patient-specific cutting guides have been shown to be effective in facilitating the surgeon's learning curve in medial opening wedge-HTO by reducing operative time and the use of fluoroscopy as well as decreasing anxiety. The present technique describes a retro-tibial tubercule ACW-HTO using a patient-specific cutting guide