Purpose. To evaluate outcome in 20 patients treated for periprosthetic fractures after total knee arthroplasty (TKA). Methods. Records of 14 women and 6 men aged 45 to 85 (mean, 67) years who underwent operative (n=18) or conservative (n=2) treatment for periprosthetic fractures of the supracondylar femur (n=15), patella (n=3), and tibia (n=2) following minor falls (n=18) or high-velocity injury (n=2) were reviewed. The mean time from TKA to fracture was 43 (range, 14-98) months. Of the 15 supracondylar femoral fractures, 2 were managed with immobilisation in a long leg cast, 11 with internal fixation using locked compression plating, and 2 with revision arthroplasty. All 3 patellar fractures were managed with tension band wiring. Both tibial fractures were managed with revision arthroplasty. Radiographic and functional outcomes (the Knee Society scores) were assessed. 15 (range, 12-38) weeks. One patient had delayed union. Postoperative alignment was satisfactory in all patients except one (with 5º varus). The mean tibiofemoral angle was 4º valgus. The mean range of motion was 98.5º. The mean Knee Society knee score was 85 (range, 75-89) and the functional score was 76 (range, 70-85). No patient had implant failure, loss of reduction, deep infection, deep vein thrombosis, or pulmonary embolism. Conclusion. The locked compression plate is effective in managing periprosthetic femoral fractures. Periprosthetic patellar and tibial fractures are uncommon. The latter often warrant revision arthroplasty owing to the loose implant.
We present an algorithm for the fast and accurate simulation of nanoscale devices. The idea underlying the algorithm is a divide-and-conquer method based on the nonequilibrium Green's function formalism. This formalism has provided a unifying conceptual framework for the analysis of quantum transport in nanodevices and the computations therein are of significant interest across many areas of research. We offer two applications, the atomistic level simulation of silicon nanowires and the two-dimensional simulation of nanotransistors, which highlight the benefits of the divide-and-conquer framework. The inherently parallel algorithm presented here allows for computing resources to be flexibly allocated toward either solving problems of larger sizes in comparable time or speeding up the solution of a problem for a given size. Our algorithm facilitates the solution of problems orders of magnitude larger and, in most cases, was able to achieve substantial speedup, as compared to the current state of the art algorithm. Thus, the method presented here allows for large-scale simulation problems that can now be realized without the use of special purpose hardware or approximation methods.
The progress in the development of composites with natural fibers for various applications in different sectors witnesses remarkable success worldwide in the last decade. Among the various natural fibers existing worldwide, pineapple leaf fibers (PALFs) possess remarkable mechanical properties because of the maximum content of cellulose (*80%) among all natural fibers. In spite of having few limitations such as hydrophilicity, its advantages such as low cost, low weight, and biodegradability overweigh their limitations. The PALFs are poorly reported in the literature as a reinforcement in epoxy material. Bagasse, wheat straw, and coir have been successfully reinforced with epoxy resin; but inspite of having highest tensile strength among all natural fibers, PALF's are seldom used. PALF has been characterized chemically, morphologically, and thermally. Using thermal analysis, the models were fitted to calculate its activation energies at different fraction levels using different heating rates. PALF epoxy composites have been prepared using the hand layup method. The effect of fiber loading has also been studied for morphological, chemical, mechanical, and thermal properties of composites. Composites with 10% fiber loading have better mechanical properties in comparison to composites with other fiber loading. Scanning electron microscopic micrographs of fractured surfaces have been analyzed for all fiber loading composites, and the results have been successfully studied linking the stated work of other distinguished researchers of this arena.
This paper introduces an efficient and accurate interconnect simulation technique. A new formulation for typical VLSI interconnect structures is proposed which, in addition to providing a compact set of modelling equations, also offers a potential for exploiting sparsity at the simulation level. Simulations show that our approach can achieve 50× improvement in computation time and memory over INDUCTWISE (which in turn has been shown to be 400× faster than SPICE) while preserving simulation accuracy.
Purpose The aim of this study was to evaluate the long-term results of arthroscopic excision of pigmented villonodular synovitis (PVNS) of the knee joint. Methods We retrospectively assessed the results of arthroscopic excision of PVNS done in 40 patients from 1987 to 2012 by the senior author (JVS). No radiotherapy was given to any patient. All patients were followed for a mean of seven years. At follow-up functional assessment was done using the Lysholm score. Recurrence-free survival and recurrence-free survival probability were calculated. Results No recurrence was noted in the localised variety. In the diffuse variety the five year recurrence-free survival probability was 57 %. Twelve patients developed recurrences between three months and two years. No recurrence was noted after two years. The mean recurrence interval was 6.25 months. Conclusions We concluded from this series that arthroscopic excision is an effective treatment for localised as well as diffuse PVNS. Recurrences can also be successfully dealt with by arthroscopic excision with excellent functional outcome.
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