3,566 research outputs found
Improving tibial component alignment in total knee arthroplasty
No full textPurpose
Tibia torsion may influence the accuracy of extramedullary instrumentations in total knee arthroplasty (TKA). This study assessed whether the effect of tibial torsion may be overcome using a surgical technique in which the extramedullary rod is aligned to reference points at the proximal tibia only.
Methods
A consecutive series of 94 knees that underwent TKA were analyzed. In the first 47 knees (group 1), a standard procedure for tibial component alignment was performed while in the second group of 47 knees, a modified surgical technique was used including the alignment of the extramedullary rod to the reference points at the proximal tibia only (group 2). Lower limb, femoral, and tibial component alignment were measured on postoperative long-leg radiographs.
Results
Femorotibial mechanical axes angles were similar in the two groups. Femoral component alignment also did not differ between the groups. A neutral alignment of the tibial component was achieved in 17 and 34 % of the knees in group 1 and group 2, respectively (p = 0.04). A malalignment of the tibial component >3° was found in 34 % of knees in group 1 compared with 4 % of those in group 2 (p = 0.0001).
Conclusions
Coronal alignment of the tibial component may improve by setting the extramedullary rod in line with anatomical references in the proximal tibia only. This technique appears to bypass the influence of tibial torsion on the alignment of the extramedullary guide at the distal tibia. The clinical relevance of the study is that using this technique, the rate of malalignment of the tibial component may be reduced compared to a standard technique in which a fixed reference is used at the ankle jointAbstract
PURPOSE:
Tibia torsion may influence the accuracy of extramedullary instrumentations in total knee arthroplasty (TKA). This study assessed whether the effect of tibial torsion may be overcome using a surgical technique in which the extramedullary rod is aligned to reference points at the proximal tibia only.
METHODS:
A consecutive series of 94 knees that underwent TKA were analyzed. In the first 47 knees (group 1), a standard procedure for tibial component alignment was performed while in the second group of 47 knees, a modified surgical technique was used including the alignment of the extramedullary rod to the reference points at the proximal tibia only (group 2). Lower limb, femoral, and tibial component alignment were measured on postoperative long-leg radiographs.
RESULTS:
Femorotibial mechanical axes angles were similar in the two groups. Femoral component alignment also did not differ between the groups. A neutral alignment of the tibial component was achieved in 1
Effects of tibial torsion on distal alignment of extramedullary instrumentation in total knee arthroplasty.
No full textBackground and purpose Whether tibial torsion affects the positioning of extramedullary instrumentation and is a possible factor in malalignment of the tibial component in total knee arthroplasty (TKA) is unknown. We assessed the influence of tibial torsion on distal alignment of extramedullary systems for TKA, using the center of the intermalleolar distance as anatomical reference at the ankle joint.
Patients and methods We analyzed CT scans of knee and ankle joints of 50 patients with knee osteoarthritis (mean age 73 years, 52 legs). The tibial mechanical axis was identified and translated anteriorly at the level of the medial one-third (proximal AP axis 1), at the medial border of the tibial tuberosity (proximal AP axis 2), and at the level of the talar dome (distal AP axis). The center of the intermalleolar distance and the width of the medial and lateral malleolus were calculated. The proximal AP axes 1 and 2 were translated at the level of the ankle joint and any difference between their alignment and the distal AP axis was calculated as angular and linear values.
Results The center of the ankle joint was located, on average 2 mm medial to that of the intermalleolar distance. The distal AP axis was externally rotated by 18 degrees and 27 degrees compared to the proximal AP axes 1 and 2, respectively. Overall, the center of the ankle joint was shifted laterally by 9-11 mm with respect to the proximal AP tibial axes.
Interpretation To avoid a varus tibial cut in TKA, extramedullary alignment systems should be aligned more medially at the ankle joint than previously thought, due to the effect of tibial torsion and-to a lesser extent-to the different malleolar width
Combining different rotational alignment axes with navigation may reduce the need for lateral retinacular release in total knee arthroplasty.
No full textPURPOSE: The aim of the study was to compare femoropatellar alignment and the incidence of lateral retinacular release (LRR) in total knee arthroplasty (TKA) in which the rotational alignment of the femoral component was determined using a combination of different rotational alignment axes and navigation or a single reference axis in the standard procedure.
METHODS: We assessed 66 patients undergoing TKA in whom the rotation of the femoral component was determined on the posterior condylar axis in standard procedures (group A) and 65 patients in whom it was determined by combining the posterior condylar axis, anteroposterior axis and epicondylar axis in navigated procedures (group B). The mean age was 68 and 69 years in groups A and B, respectively. Patellar tracking was assessed after deflation of the tourniquet and LRR performed in the presence of maltracking. Visual analogue scale (VAS), Knee Society Score (KSS), Lonner patellar score and patellar tilt were recorded.
RESULTS: LRR was carried out in 18 cases (27 %) in group A and in four (6 %) in group B (p = 0.003). The KSS and VAS were improved significantly compared to the preoperative status, but with no significant differences between the two groups. The patellar score showed a greater improvement in the navigated compared to the standard group at the four week follow-up. Patella tilt improved significantly in both groups. The complication rate was similar in the two groups.
CONCLUSIONS: Combining different rotational alignment axes with navigation significantly reduces patellar maltracking and the need for LRR compared to the standard procedure in which the posterior condylar axis is used as single anatomical reference
Cyberbase Gradignan (documents)
No full textDocuments et travaux portant sur le corpus “Cyberbase Gradignan
Cyberbase Gradignan
No full textLe corpus 'Cyberbase Gradignan' a été recueilli de juillet 2010 à juin 2012 dans le cadre de l'expérimentation Cyber-base®Justice mise en œuvre la Maison d'Arrêt de Gradignan et finalisée à l'accès à l'information, à l'apprentissage de l'informatique et à l'enseignement. Il est constitué d'enregistrements audiovisuels portant, d'une part, sur les activités dans l'espace informatique de la Maison d'Arrêt et, d'autre part, sur des entretiens avec les différents acteurs. L'ensemble du corpus a d'abord été segmenté et indexé (l'indexation, à la fois contextuelle et thématique, a été reportée dans les noms de fichiers). Une partie des séquences a ensuite été transcrite et annotée
THIGH PAIN, SUBSIDENCE AND SURVIVAL USING A SHORT CEMENTLESS FEMORAL STEM WITH PURE METAPHYSEAL FIXATION AT MINIMUIM 9-YEAR FOLLOW-UP
No full textBackground: Short femoral stems designed to spare bone stock and improve load transfer at the proximal femur have been introduced in the last years. However, little is known on the long-term results of these stems.
Hypothesis: short cementless stems have low rate of revision at mid term follow up with limited bone remodelling in relation to the physiological loading in the proximal femur.
Materials and Methods: We prospectively followed 64 patients (72 hips) undergoing total hip arthroplasty with a femoral stem designed to achieve a pure metaphyseal fixation. Patients with hip fracture, femoral neck deformity and osteoporotic bone were excluded. Clinical evaluations were performed annually until the last follow-up, a minimum of nine years after surgery. At each follow-up, implant positioning was assessed on conventional plain films with a computed radiographic evaluation.
Results: Harris hip score, Womac and SF-36 were significantly improved compared to preoperative status. Computed radiographic analysis showed a neutral alignment of the stem in 56% of cases, a varus-valgus alignment < 5° in 36% and ≥ 5° in 8%. Stem subsidence was observed in 12 hips but was less than 4mm in all cases. Calcar height remained unchanged over time. Adaptive bone remodelling, including proximal bone resorption and distal cortical hypertrophy were not observed at follow-up. No patients had aseptic loosening of the stem nor were radiolucent lines detectable at the level of the porous coating. Survivorship analysis showed a 100% survival rate of the stem at nine years.
Discussion: The results of this study showed that a femoral stem designed to achieve a pure metaphyseal fixation may obtain satisfactory clinical outcomes in high rates of patients without compromise implant stability. The limited periprosthetic bone remodelling observed after a minimum of 9 years follow-up suggest that this type of implant my improve mechanical stresses on host bone compared with standard stems with diaphyseal fixation. Level of evidence: IV.
Key words: total hip arthroplasty; femoral stem; proximal fixation; bone remodeling; thigh pai
Collecting Cures in an Artisanal Manuscript: Practical Therapeutics and Disease in Ms. Fr. 640
No full textScattered throughout Ms. Fr. 640, the forty medical recipes form a small percentage of its over 900 entries. A consideration of the ailments, ingredients, and making processes described in the manuscript, as well as the author-practitioner’s process of collecting information, reveals a variety of connections between Ms. Fr. 640’s medical recipes and early modern artisanal work
Chemiluminescent methods for explosives (TNT, TATP, HMTD) detection
No full textLuciferase from Indian firefly Luciola praeusta (Coleoptera: Lampyridae: Luciolinae) was isolated and the properties compared with that of the North American firefly, Photinus pyralis. Luciola praeusta luciferase was purified using acetone extraction, gel-filtration column chromatography, ammonium sulfate precipitation and anion exchange chromatography. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicates a homogeneous preparation and the molecular mass was slightly higher than that of Photinus pyralis. The effect of pH, buffer composition and metal ions on the spectral characteristics was studied. The maximum bioluminescence activity of luciferase was observed in ACES buffer at pH 6.5. The emission maximum of 562 nm (in crude extract) was red shifted to 570 nm in Tricine buffer at pH 7.8. In addition, the effect of bovine serum albumin on the storage stability of the protein was investigated. Based on the unique spectral characteristics observed, we propose that Luciola praeusta luciferase in the native form is suitable for the assay of biochemical metabolites in acidic pH
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