IntroductionAlthough total knee arthroplasty (TKA) in haemophilic arthropathy can reduce severe joint pain and improve functional disability, it is technically demanding. AimTo evaluate mid-term outcomes and complications of TKA in haemophilic arthropathy. MethodsThis study retrospectively reviewed 131 consecutive primary TKAs in a single institute. The mean age was 41.0years old, and the mean follow-up period was 6.8years. Clinical and radiographic results were evaluated. Complications were categorized according to the classification system of the Knee Society for TKA complications. ResultsThe average Western Ontario and McMaster Universities Arthritis Index (WOMAC) score improved from 66.0 to 24.2. The average flexion contracture significantly decreased from 17.3 degrees to 4.7 degrees, but the average pre- and postoperative maximum flexion did not differ (80.9 degrees vs 85.6 degrees, respectively). The average mechanical axis was varus 5.2 degrees preoperatively and valgus 0.3 degrees postoperatively. The coronal positions of the femoral and tibial components and the sagittal positions of these components were within 3 degrees in 83.2%, 89.3%, 63.4% and 73.3% of cases, respectively. Complications occurred in 17 knees (13.0%): hemarthrosis (n=7), medial collateral ligament injury (n=1), stiffness (n=2), deep periprosthetic joint infection (PJI) (n=3) and periprosthetic fracture (n=4). ConclusionsThe mid-term results of TKA in haemophilic arthropathy were satisfactory in pain relief, improved function and decreased flexion contracture. Bleeding and PJI continue to be major concerns for TKA in haemophilic arthropathy, and risk of periprosthetic fracture must be taken into account for patient education and appropriate prevention.

Cognizance of common reasons for failure in primary and revision TKA, together with their time course, facilitates prevention. However, there have been few reports specifically comparing modes of failure for primary vs. revision TKA using a single prosthesis. The goal of the study was to compare the survival rates, modes of failure, and time periods associated with each mode of failure, of primary vs. revision TKA. The survival rates, modes of failure, time period for each mode of failure, and risk factors would differ between primary and revision TKA. Data from a consecutive cohort comprising 1606 knees (1174 patients) of primary TKA patients, and 258 knees (224 patients) of revision TKA patients, in all of whom surgery involved a P.F.C® prosthesis (Depuy, Johnson & Johnson, Warsaw, IN), was retrospectively reviewed. The mean follow-up periods of primary and revision TKAs were 9.2 and 9.8 years, respectively. The average 10- and 15-year survival rates for primary TKA were 96.7% (CI 95, ± 0.7%) and 85.4% (CI 95%, ± 2.0%), and for revision TKA 91.4% (CI 95%, ± 2.5%) and 80.5% (CI 95%, ± 4.5%). Common modes of failure included polyethylene wear, loosening, and infection. The most common mode of failure was polyethylene wear in primary TKA, and infection in revision TKA. The mean periods (i.e., latencies) of polyethylene wear and loosening did not differ between primary and revision TKAs, but the mean period of infection was significantly longer for revision TKA (1.2 years vs. 4.8 years, P = 0.003). Survival rates decreased with time, particularly more than 10 years post-surgery, for both primary and revision TKAs. Continuous efforts are required to prevent and detect the various modes of failure during long-term follow-up. Greater attention is necessary to detect late infection-induced failure following revision TKA. Case-control study, Level III.

INTRODUCTION:Cognizance of common reasons for failure in primary and revision TKA, together with their time course, facilitates prevention. However, there have been few reports specifically comparing modes of failure for primary vs. revision TKA using a single prosthesis. The goal of the study was to compare the survival rates, modes of failure, and time periods associated with each mode of failure, of primary vs. revision TKA. HYPOTHESIS:The survival rates, modes of failure, time period for each mode of failure, and risk factors would differ between primary and revision TKA. MATERIAL AND METHODS:Data from a consecutive cohort comprising 1606 knees (1174 patients) of primary TKA patients, and 258 knees (224 patients) of revision TKA patients, in all of whom surgery involved a P.F.C® prosthesis (Depuy, Johnson & Johnson, Warsaw, IN), was retrospectively reviewed. The mean follow-up periods of primary and revision TKAs were 9.2 and 9.8 years, respectively. RESULTS:The average 10- and 15-year survival rates for primary TKA were 96.7% (CI 95%,±0.7%) and 85.4% (CI 95%,±2.0%), and for revision TKA 91.4% (CI 95%,±2.5%) and 80.5% (CI 95%,±4.5%). Common modes of failure included polyethylene wear, loosening, and infection. The most common mode of failure was polyethylene wear in primary TKA, and infection in revision TKA. The mean periods (i.e., latencies) of polyethylene wear and loosening did not differ between primary and revision TKAs, but the mean period of infection was significantly longer for revision TKA (1.2 vs. 4.8 years, P=0.003). DISCUSSION:Survival rates decreased with time, particularly more than 10 years post-surgery, for both primary and revision TKAs. Continuous efforts are required to prevent and detect the various modes of failure during long-term follow-up. Greater attention is necessary to detect late infection-induced failure following revision TKA. LEVEL OF EVIDENCE:Case-control study, Level III.

In this paper, numerical ductile tearing simulation results are compared with six circumferential through-wall and surface cracked pipes made of two materials (SA-333 Gr. 6 and A106 Gr. B carbon steels), performed at Battelle. For simulation, a model using a simplified fracture strain model is employed, by analysing tensile data of the material. By comparing experimental J-R data with FE simulation results, the damage model dependent on the element size is determined based on the ductility exhaustion concept. The model is used to simulate ductile tearing behaviour of six circumferential through-wall and surface cracked pipes. In all cases, simulated results agree well with experimental load, crack length and crack mouth opening displacement versus load line displacement data.

An Elbow is one of the major component that make up the piping system of a nuclear power plant and chemical plant facilities. In general, the elbow is made by welding a straight pipe and bend part. So, periodic welding inspection is required due to the potential defects in weld zone. Recently, the application of induction heating pipe bend is increasing in order to reduce this problem. Pipe bend made by induction heating band is not necessary welding process because it is made by bending a straight pipe but the intrados thickness and the extrados thickness are different. On the other hand, J-integral is widely used to evaluate a structural integrity (to check crack stability) but the J estimation of pipe bend with un-uniform thickness is very difficult because of the thickness differences in each locations.This paper proposes a reference stress based J estimation scheme of circumferential through-wall cracked pipe bend with un-uniform thickness under in-plane opening bending loading condition. The pipe bend with un-uniform thickness is assumed to have different thickness between intrados and extrados and the crack to be located in the entre of the pipe bend, either at the intrados or extrados. (C) 2015 Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility of the organizing committee of ICPVT-14

This paper describes ductile fracture simulation for Battelle fracture toughness and full-scale pipe tests (1). Materials in this research are low carbon steel and TP304 stainless steel. Tensile and Compact tension (CT) specimens are simulated to determine the fracture criteria with finite element (FE) method. Then, pipes containing through wall crack and surface crack are predicted by proposed damage method. The results from simulations are compared with test data for verification of proposed method and to check the applicability on industrial field. It is shown that predicted simulation results are compared with experimentally measured values, showing overall good agreements.

A high speed electromagnetic suspension (EMS) maglev has emerged as the solution to speed limit problem that conventional high-speed railroad has. In the EMS maglev, small levitation gap needs uniform guide-way which leads to increase the construction cost. The large levitation gap can reduce the construction cost. However it is hard for normal conducting electromagnet to produce larger magneto-motive force (MMF) for generating levitation force as increased levitation gap. This is because normal conductors have limited rating current to their specific volume. Therefore, the superconducting electromagnet can be one of the solutions for producing both large levitation gap and sufficient MMF. The superconducting electromagnets have incomparably high allowable current density than what normal conductors have. In this paper, the prototype of high temperature superconducting (HTS) electromagnets were designed and manufactured applicable to hybrid electromagnetic suspension system (H-EMS). The H-EMS consists of control coils for levitation control and superconducting coils for producing MMF for levitation. The required MMF for generating given levitation force was calculated by both equations of ideal U-core magnet and magnetic field analysis using the finite element method (FEM). The HTS electromagnets were designed as double pancakes with Bi-2223/Ag tapes. Experiments to confirm its operating performance were performed in liquid nitrogen (LN2).

In general, the current leads of high voltage superconducting apparatuses cooled by liquid nitrogen are exposed to gaseous insulation media. Therefore, the investigation on the electrical breakdown characteristics of gaseous insulation media should be performed to develop electrically reliable high voltage superconducting power apparatuses. In this study, the lightning impulse breakdown tests on gaseous insulation media are conducted by using sphere-to-plane electrode systems made of stainless steel. Also, the lightning impulse breakdown voltage tests on gaseous insulation media according to various pressures are performed. The experimental results show that the electrical breakdown characteristics under lightning impulse voltage are affected by the gap length between electrode systems, the size of electrodes, and the field utilization factors. From these results, the electrical insulation design criteria to estimate the electrical breakdown voltage are established. The results are expected to be applicable to the design of current leads for high voltage superconducting apparatuses.

We assessed the reliability, accuracy and variability of closed-wedge high tibial osteotomy (HTO) using computer-assisted surgery compared to the conventional technique. A total of 50 closed-wedge HTO procedures were performed using the navigation system, and compared with 50 HTOs that had been performed with the conventional technique. In the navigation group, the mean mechanical axis prior to osteotomy was varus 8.2 degrees, and the mean mechanical axis following fixation was valgus 3.6 degrees. On the radiographs the mean preoperative mechanical axis was varus 7.3 degrees, and the mean post-operative mechanical axis was valgus 2.1 degrees. There was a positive correlation between the measured data taken under navigation and by radiographs (r > 0.3, p < 0.05). The mean correction angle was significantly more accurate in the navigation group (p < 0.002). The variability of the correction was significantly lower in the navigation group (2.3 degrees vs 3.7 degrees, p = 0,012).We conclude that navigation provides reliable real-time intra-operative information, may increase accuracy, and improves the precision of a closed-wedge HTO.

High-Tc superconducting (HTSC) electrodynamic suspension (EDS) system basically consists of the HTSC levitation magnet and the ground conductor. The levitation force of EDS system is forms by the interaction between the moving magnetic field produced by the onboard levitation magnet and the induced magnetic field produced by eddy current in the ground conductor. This paper deals with the characteristics of the EDS simulators with high-Tc superconducting (HTS) levitation magnet. Two EDS simulator systems, rotating type EDS simulator and static type EDS simulator, were studied in this paper. The rotating type EDS simulator consists of a HTS levitation magnet and a 1.5 m diameter rotating ground conductor, a motor, the supporting structure and force measuring devices. In the static type EDS simulator, instead of moving magnetic field, AC current was applied to the fixed HTS levitation magnet to induce the eddy current. The static type EDS simulator consists of a HTS levitation magnet, a ground conductor, force measuring devices and supporting structure. The double-pancake type HTSC levitation magnet was designed, manufactured and tested in the EDS simulator.

AIMS:This research aims to investigate the efficiency of two lipolytic enzymes--fungal cutinase and yeast esterase--upon the biodegradation of dihexyl phthalate (DHP).METHOD AND RESULTS:During the enzymatic degradation of DHP dissolved in methanol, several degradation products were detected and their time-course changes were monitored using GC/MS. The DHP-degradation rate of cutinase was surprisingly high; i.e. almost 70% of the initial DHP (500 mg l(-1)) was decomposed within 4.5 h. Although the same amount of esterase was employed, more than 85% of the DHP remained after 3 days. Almost all the DHP was converted by cutinase into 1,3-isobenzofurandione (IBF), whereas hexyl methyl phthalate and IBF were abundantly produced by esterase. In addition, the toxicities of the DHP-degraded products by esterase were evaluated using various recombinant bioluminescent bacteria, which caused oxidative and protein damage, whereas the hydrolysis products from cutinase never caused any cellular damage in the methanol-containing reaction system.CONCLUSIONS:Cutinase starts to act as a DHP-degrader much earlier and faster than esterase, with high stability in ester-hydrolytic activity, therefore a plausible approach to the practical application of cutinase for DHP degradation in the DHP-contaminated environments may be possible.SIGNIFICANCE AND IMPACT OF THE STUDY:This study describes the enhanced degradation and detoxification of DHP using Fusarium oxysporum f. sp. pisi cutinase.

Recent development of CC, usually called second generation (2G) HTS, is actively in progress. Because of its higher critical current density as well as higher n-value, 2G HTS is feasible for the applications such as superconducting fault current limiter and superconducting cable. For operating the HTS equipment stably, it needs to investigate the characteristics of normal zone propagation occurred by quench. Investigations on the fundamental characteristics can be one of the indispensable foundations for research and development of power equipments.In this paper, normal zone propagation (NZP) characteristics according to various insulation materials are researched. By heating with NiCr heater and insulating with epoxy, we applied the operating current with respect to the critical current for calculation of minimum quench energy (MQE) and measurement of NZP. (C) 2007 Elsevier B.V. All rights reserved.

PURPOSE:To evaluate the clinical and radiologic results, second-look arthroscopic findings, histologic evaluation, and results of immunohistochemical staining and the Western blotting test for type II collagen after microfracture for full-thickness chondral defects in patients with osteoarthritic knee.METHODS:Between October 1997 and December 1998, 49 knees in 46 patients who had moderate osteoarthritic changes underwent microfracture; 44 patients (47 cases) had second-look arthroscopy and biopsy performed 1 year after surgery. The clinical outcomes were assessed by use of Baumgaertner's 9-point scale and joint space changes were measured radiographically; 18 knees underwent immunohistochemical study and 21 knees underwent Western blotting tests to identify formation of type II collagen.RESULTS:Significant improvements were noted for the parameters of daily living activity and pain (P < .05). The joint spaces were widened by 1.06 mm on standing anteroposterior and by 1.37 mm on standing lateral radiographs, which showed statistical significance (P < .05). Individual defects were filled with white tissue resembling cartilage on second-look arthroscopy, and the cartilage healing was found by histologic evaluation. Type II collagen formation was identified qualitatively by immunohistochemical staining. Quantitative collagen formation by Western blotting showed 44% growth compared with the normal control. This healed tissue is a combination, or hybrid, of fibrocartilage and hyaline-like cartilage, and it is shown to contain type II collagen on immunohistochemical staining and the Western blotting test.CONCLUSIONS:Patients with full-thickness chondral defects in the osteoarthritic knee can have improved function and see an increase in joint space after microfracture. Cartilaginous tissue containing type II collagen is formed after the microfracture procedure in the osteoarthritic knee.LEVEL OF EVIDENCE:Level IV, retrospective case series.

Purpose: We describe an anatomic reconstructive surgical procedure that simultaneously reconstructs the fibular collateral ligament, popliteal tendon, and popliteofibular ligament using split Achilles allograft, and compare the clinical results of this technique with those of the posterolateral corner sling procedure for posterolateral instability of the knee. Type of Study: Case series. Methods: Forty-six patients were treated for posterolateral instability of the knee between 1998 and 2002. The posterolateral corner sling procedure was performed in 25 patients (group A) and anatomic reconstructive surgery in 21 patients (group B). The minimum follow-up was 12 months. In all cases, arthroscopic evaluation was performed. Clinical review included the Lysholm knee scores and varus laxity and tibial external rotation assessment. Results: The mean Lysholm knee scores were 54.8 points in group A and 54.4 points in group B before surgery, and 86.9 and 93.6 points at the time of the latest follow-up, respectively (P < .05). Tibial external rotation of 5 degrees more than the contralateral uninjured knee was present in 12% of group A and in 5% of group B (P < .05). Varus laxity of 5 mm greater than the contralateral knee was observed in 28% of group A and in 14% of group B (P < .05). Conclusions: Anatomic reconstruction of the posterolateral corner resulted in less varus laxity and tibial external rotation than did the posterolateral corner sling procedure. Level of Evidence: Type IV, case series, no or historical control group.

With the successful commercialization of Bi-2223 powder-in-tube wire, various attempts in the R&D of the high-Tc superconducting (HTS) magnets for high magnetic field applications are being implemented actively. Operating temperature of HTS magnet has to be maintained at the designed level but the magnetic energy and mechanical disturbance can cause unstable operational temperature of HTS magnet. Especially, the generated heat energy of inner HTS winding is apt to be accumulated, so the normal region appears in HTS winding. This paper deals with the quenching characteristics of three kinds of selected Bi-2223 wires: the high current density wire (HC-A) and the high strength wire (HS-A) made by AMSC and HTS wire (HW-I) made by Innost. The Innost wire has the highest minimum quench energy (MQE). The high current density wire has the highest normal zone propagation velocity (NZPV).

The resistive type high temperature superconducting fault current limiter (HTSFCL) limits the fault current with the resistance that generated by fault current. The generated resistance by fault current makes large pulse power which makes the operation of HTSFCL unstable. So, the cryogenic cooling system of the resistive type HTSFCL must diffuse and eliminate the pulse energy very quickly. Although the best way is to make wide direct contact area between HTS winding and coolant as much as possible, HTS winding also need the impregnation layer which fixes and protects it from electromagnetic force. This paper deals with thermal conductivity and dielectric strength of some epoxy compounds for the impregnation of high temperature superconducting (HTS) winding at 77K. The measured data can be used in the optimal design of impregnation for HTS winding. Aluminar filling increased the thermal conductivity of epoxy compounds. Hardener also affected the thermal conductivity and the dielectric strength of epoxy compounds.

Purpose: The purpose of this study was to assess the outcome of arthroscopic double-bundle posterior cruciate ligament (PCL) augmentation using split Achilles allograft. Type of Study: Prospective case series. Methods: We analyzed 27 knees in 26 patients whose PCL had been augmented by the arthroscopic double-bundle technique using split Achilles allograft. There were 19 male and 7 female patients with a mean age of 27.9 years. Follow-up averaged 25 months (range, 12 to 48 months). The clinical results were evaluated according to the Lysholm knee scores. The posterior laxity was radiographically measured with differences of posterior tibial translation between the injured and the uninjured knee. Results: The Lysholm knee scores improved from 59.5 to 91.8 points (P < .05). The average radiographic side-to-side difference of the posterior tibial translation was 12.7 mm (range, 10 to 26 mm) preoperatively and 2.4 mm (range, 0 to 8 mm) at the time of the latest follow-up (P < .05). Eighteen knees (67%) had 0 to 2 mm translation, 6 knees (22%) had 3 to 5 mm, and 3 knees (11%) had 6 to 10 mm. Conclusions: PCL injuries can be successfully treated with arthroscopic double-bundle augmentation using split Achilles allograft. This technique can preserve remnant fibers and restore both anterolateral and posteromedial bundles of the PCL. Level of Evidence: Level IV, case series.

Twenty-five total knee arthroplasties were performed in 21 patients with hemophilia. The mean patient age was 35.8 years and mean follow-up time was 6.2 years. The average preoperative knee score increased from 18.6 points (range, 3-29) to 82.8 points (range, 44-99). The average preoperative knee function score increased from 41.4 points (range, 20-60 points) to 75.8 points (range, 45-95 points). The average preoperative range of motion was 73.4 degrees with an average flexion contracture of 22.6 degrees, whereas the average postoperative range of motion increased to 92.2 degrees with an average flexion contracture of 5.6 degrees. Median consumption of coagulation factor concentrate decreased from 4837 U/month before operation to 1500 U/month 1 year after surgery. The total knee arthroplasty is a useful treatment in severe hemophilic arthropathy to obtain pain relief and functional improvement, and to reduce the need for ongoing treatment using coagulation factor concentrate.