A computed tomography based study on rotational alignment accuracy of the femoral component in total knee arthroplasty using computer-assisted orthopaedic surgery

Rotation of the femoral component in total knee arthroplasty (TKA) is of high importance in respect of the balancing of the knee and the patellofemoral joint. Though it is shown that computer assisted surgery (CAOS) improves the anteroposterior (AP) alignment in TKA, it is still unknown whether navigation helps in finding the accurate rotation or even improving rotation. Therefore the aim of our study was to evaluate the postoperative femoral component rotation on computed tomography (CT) with the intraoperative data of the navigation system. In 20 navigated TKAs the difference between the intraoperative stored rotation data of the femoral component and the postoperative rotation on CT was measured using the condylar twist angle (CTA). This is the angle between the epicondylar axis and the posterior condylar axis. Statistical analysis consisted of the intraclass correlation coefficient (ICC) and Bland-Altman plot. The mean intraoperative rotation CTA based on CAOS was 3.5° (range 2.4–8.6°). The postoperative CT scan showed a mean CTA of 4.0° (1.7–7.2). The ICC between the two observers was 0.81, and within observers this was 0.84 and 0.82, respectively. However, the ICC of the CAOS CTA versus the postoperative CT CTA was only 0.38. Though CAOS is being used for optimising the position of a TKA, this study shows that the (virtual) individual rotational position of the femoral component using a CAOS system is significantly different from the position on a postoperative CT scan

Vibrational dynamics in molecular condensed phases with the CLIO free electron laser

International audienc

PRR2, a pseudo-response regulator, promotes salicylic acid and camalexin accumulation during plant immunity

Calcium signalling mediated by Calmodulin (CaM) and calmodulin-like (CML) proteins is critical to plant immunity. CaM and CML regulate a wide range of target proteins and cellular responses. While many CaM-binding proteins have been identified, few have been characterized for their specific role in plant immunity. Here, we report new data on the biological function of a CML-interacting partner, PRR2 (PSEUDO-RESPONSE REGULATOR 2), a plant specific transcription factor. Until now, the physiological relevance of PRR2 remained largely unknown. Using a reverse genetic strategy in A. thaliana, we identified PRR2 as a positive regulator of plant immunity. We propose that PRR2 contributes to salicylic acid (SA)-dependent responses when challenged with the phytopathogenic bacterium Pseudomonas syringae. PRR2 is transcriptionally upregulated by SA and P. syringae, enhances SA biosynthesis and SA signalling responses; e.g. in response to P. syringae, PRR2 induces the production of SA and the accumulation of the defence-related protein PR1. Moreover, PRR2 overexpressing lines exhibit an enhanced production of camalexin, a phytoalexin that confers enhanced resistance against pathogens. Together, these data reveal the importance of PRR2 in plant immune responses against P. syringae and suggest a novel function for this particular plant specific transcription factor in plant physiology

Pertinence et reproductibilité de l’interprétation de l’IRM dans les luxations et les lésions ligamentaires bicroisées du genou

International audienceIntroductionAprès luxations et lésions ligamentaires bicroisées du genou, l’évaluation clinique des lésions des parties molles est difficile et une IRM est généralement réalisée.HypothèseL’IRM est un examen fiable permettant un bilan précis et reproductible des lésions des parties molles après luxation ou lésion ligamentaire bicroisée du genou.Patients et méthodeQuarante patients présentant des lésions ligamentaires bicroisées du genou ont été inclus dans cette étude prospective multicentrique. Tous ont eu une IRM du genou dans les 48 heures suivant l’accident. Trente-quatre patients ont été traités chirurgicalement. Une fiche d’interprétation standardisée de l’IRM a été créée. Cette fiche comprenait 17 items. La reproductibilité intra-observateur a été évaluée en comparant les résultats des interprétations de cinq chirurgiens réalisées à deux reprises à trois semaines d’intervalle. La reproductibilité inter-observateurss a été évaluée en comparant les résultats des interprétations de 40 IRM réalisées par trois binômes de chirurgiens. La pertinence des interprétations IRM était réalisée en comparant les résultats des chirurgiens à ceux d’un radiologue et avec les données des comptes rendus opératoires.RésultatsLa concordance globale intra-observateur et inter-observateurss était faible. En comparant les résultats du chirurgien à ceux du radiologue et des données opératoires, la concordance était faible.DiscussionAprès luxation ou lésion ligamentaire bicroisée du genou, un diagnostic précis est nécessaire. Notre étude met en évidence le manque de précision et de reproductibilité des interprétations par IRM de façon isolée pour le diagnostic lésionnel topographique. L’IRM doit être intégrée dans une évaluation complète avec un examen clinique précis et des radiographies de stress

Relevancy and reproducibility of magnetic resonance imaging (MRI) interpretation in multiple-ligament injuries and dislocations of the knee

International audienceIntroduction: After multiple-ligament injuries and dislocations of the knee, clinical assessment of the soft tissues is difficult and MRI is generally performed. Hypothesis: MRI is a reliable examination, providing a precise and reproducible assessment of soft-tissue lesions after multiple-ligament injuries or dislocations of the knee. Materials and methods: Forty patients presenting multiple-ligament lesions of the knee were included in this multicenter prospective study. All had an MRI of the knee in the 48. h following their accident. Thirty-four patients were treated surgically. A 17-item standardized interpretation guide was created. Intraobserver reproducibility was assessed by comparing the interpretations of five surgeons at two different times 3 weeks apart. Interobserver reproducibility was evaluated by comparing the results of the interpretations of 40 MRIs performed by three pairs of surgeons. The relevance of the MRI interpretations was determined by comparing the results of the surgeons to those of a radiologist and with the data from the surgical reports. Results: The overall intraobserver and interobserver agreement was low. Comparing the surgeon's results with the radiologist's results and the surgical data, the agreement was low. Discussion: After multiple-ligament injuries and dislocations of the knee, a precise diagnosis is necessary. This study provides an isolated demonstration of the lack of precision and reproducibility of MRI interpretations for the diagnosis of the lesion's topography. MRI should be integrated into a complete assessment with a precise clinical exam and stress X-rays. Level of evidence: Level IV, prospective case-control study