scholarly journals Clinical outcomes and cost analysis of one- versus two-stage bilateral hip arthroplasty. A retrospective study of a single surgeon experience

2020 ◽  
pp. 221049172097183
Author(s):  
M Hefny ◽  
F Syed ◽  
A Ugwuoke ◽  
P Saunders ◽  
SK Young

Purpose: One in 10 patients presenting for total hip arthroplasty (THA) will have significant osteoarthritis in both hips. In appropriately selected individuals, one-stage bilateral THA is a treatment option. This study aims to compare outcomes of one-stage bilateral THA with two-stage procedure. Methods: A retrospective review of a single surgeon series was conducted comparing One-stage bilateral THA (n = 59) with two-stage bilateral THA (n = 50). The primary outcomes were post-operative complication and the Oxford Hip Score. The secondary outcome was a financial analysis. Results: Complications were infrequent and comparable between both groups. Oxford hip scores were slightly higher in the one-stage group. One-staged bilateral THA had a lower cost but hospital tariff is higher for two-stage bilateral THA. Conclusion: In appropriately selected patients with bilateral hip arthritis, one-stage bilateral THA gives good clinical outcomes. However, the current payment system in the NHS makes two-stage bilateral THA more financially viable to the hospital.

2019 ◽  
Vol 8 (4) ◽  
pp. 485 ◽  
Author(s):  
Svensson ◽  
Rolfson ◽  
Kärrholm ◽  
Mohaddes

Late chronic infection is a devastating complication after total hip arthroplasty (THA) and is often treated with surgery. The one-stage surgical procedure is believed to be the more advantageous from a patient and cost perspective, but there is no consensus on whether the one- or two-stage procedure is the better option. We analysed the risk for re-revision in infected primary THAs repaired with either the one- or two-stage method. Data was obtained from the Swedish Hip Arthroplasty Register and the study groups were patients who had undergone a one-stage (n = 404) or two-stage (n = 1250) revision due to infection. Risk of re-revision was analysed using Kaplan–Meier analysis with log-rank test and Cox regression analysis. The cumulative survival rate was similar in the two groups at 15 years after surgery (p = 0.1). Adjusting for covariates, the risk for re-revision due to all causes did not differ between patients who were operated on with the one- or two-stage procedure (Hazard Ratio (HR) = 0.9, 95% Confidence Interval (C.I.) = 0.7–1.2, p = 0.5). The risk for re-revision due to infection (HR = 0.7m, 95% C.I. = 0.4–1.1, p = 0.2) and aseptic loosening (HR = 1.2, 95% C.I. = 0.8–1.8, p = 0.5) was similar. This study could not determine whether the one-stage method was inferior in cases when the performing surgeons chose to use the one-stage method.


1967 ◽  
Vol 18 (01/02) ◽  
pp. 198-210 ◽  
Author(s):  
Ronald S Reno ◽  
Walter H Seegers

SummaryA two-stage assay procedure was developed for the determination of the autoprothrombin C titre which can be developed from prothrombin or autoprothrombin III containing solutions. The proenzyme is activated by Russell’s viper venom and the autoprothrombin C activity that appears is measured by its ability to shorten the partial thromboplastin time of bovine plasma.Using the assay, the autoprothrombin C titre was determined in the plasma of several species, as well as the percentage of it remaining in the serum from blood clotted in glass test tubes. Much autoprothrombin III remains in human serum. With sufficient thromboplastin it was completely utilized. Plasma from selected patients with coagulation disorders was assayed and only Stuart plasma was abnormal. In so-called factor VII, IX, and P.T.A. deficiency the autoprothrombin C titre and thrombin titre that could be developed was normal. In one case (prethrombin irregularity) practically no thrombin titre developed but the amount of autoprothrombin C which generated was in the normal range.Dogs were treated with Dicumarol and the autoprothrombin C titre that could be developed from their plasmas decreased until only traces could be detected. This coincided with a lowering of the thrombin titre that could be developed and a prolongation of the one-stage prothrombin time. While the Dicumarol was acting, the dogs were given an infusion of purified bovine prothrombin and the levels of autoprothrombin C, thrombin and one-stage prothrombin time were followed for several hours. The tests became normal immediately after the infusion and then went back to preinfusion levels over a period of 24 hrs.In other dogs the effect of Dicumarol was reversed by giving vitamin K1 intravenously. The effect of the vitamin was noticed as early as 20 min after administration.In response to vitamin K the most pronounced increase was with that portion of the prothrombin molecule which yields thrombin. The proportion of that protein with respect to the precursor of autoprothrombin C increased during the first hour and then started to go down and after 3 hrs was equal to the proportion normally found in plasma.


1983 ◽  
Vol 50 (03) ◽  
pp. 697-702 ◽  
Author(s):  
T W Barrowcliffe ◽  
A D Curtis ◽  
D P Thomas

SummaryAn international collaborative study was carried out to establish a replacement for the current (2nd) international standard for Factor VIII: C, concentrate. Twenty-six laboratories took part, of which 17 performed one-stage assays, three performed two-stage assays and six used both methods. The proposed new standard, an intermediate purity concentrate, was assayed against the current standard, against a high-purity concentrate and against an International Reference Plasma, coded 80/511, previously calibrated against fresh normal plasma.Assays of the proposed new standard against the current standard gave a mean potency of 3.89 iu/ampoule, with good agreement between laboratories and between one-stage and two- stage assays. There was also no difference between assay methods in the comparison of high-purity and intermediate purity concentrates. In the comparison of the proposed standard with the plasma reference preparation, the overall mean potency was 4.03 iu/ampoule, but there were substantial differences between laboratories, and the two-stage method gave significantly higher results than the one stage method. Of the technical variables in the one-stage method, only the activation time with one reagent appeared to have any influence on the results of this comparison of concentrate against plasma.Accelerated degradation studies showed that the proposed standard is very stable. With the agreement of the participants, the material, in ampoules coded 80/556, has been established by the World Health Organization as the 3rd International Standard for Factor VIII :C, Concentrate, with an assigned potency of 3.9 iu/ampoule.


2021 ◽  
Vol 11 (5) ◽  
pp. 2239
Author(s):  
Hailin Zhao ◽  
Hua Su ◽  
Guoding Chen ◽  
Yanchao Zhang

To solve the high leakage and high wear problems faced by sealing devices in aeroengines under the condition of high axial pressure difference, the two-stage finger seal is proposed in this paper. The finite element method and computational fluid dynamics (FEM/CFD) coupling iterative algorithm of the two-stage finger seal is developed and validated. Then the performance advantages of two-stage finger seal compared to the one-stage finger seal are studied, as well as the leakage and the inter-stage pressure drop characteristics of two-stage finger seal are investigated. Finally, the measure to improve the inter-stage imbalance of pressure drop of two-stage finger seal is proposed. The results show that the two-stage finger seal has lower leakage and lower contact pressure than the one-stage finger seal at high axial pressure difference, but there exists an inter-stage imbalance of pressure drop. Increasing the axial pressure difference and the root mean square (RMS) roughness of finger element can aggravate the imbalance of pressure drop, while the radial displacement excitation of rotor has little influence on it. The results also indicate that the inter-stage imbalance of pressure drop of the two-stage finger seal can be improved by increasing the number of finger elements of the 1st finger seal and decreasing the number of finger elements of the 2nd finger seal.


2021 ◽  
pp. 23-40
Author(s):  
Ricardo Fernández-Fernández ◽  
Ana Cruz-Pardos ◽  
Eduardo García-Rey

1977 ◽  
Author(s):  
T.B.L. Kirkwood ◽  
C.R. Rizza ◽  
T.J. Snape ◽  
I. Rhymes ◽  
D.E.G. Austen

A repeated finding of national and international collaborative studies of standard Factor VIII preparations has been that systematic differences exist between laboratories in their measurement of the relative activities of the same pairs of Factor VIII preparations.A workshop meeting was held at the Oxford Haemophilia Centre (England) during 23rd-26th November 1976 to investigate which of the possible sources of variation between laboratories were responsible. Participants from 16 British laboratories (9 one-stage, 7 two-stage) performed a total of 273 assays using three freeze-dried preparations of differing purity (a plasma, an intermediate and a high purity concentrate). The results of assays with each participant using their normal system established that, if the participants were a representative cross-section, approximately one-third of one-stage laboratories would show a systematic difference from the overall mean of at least 16%, with a similar figure for the two-stage laboratories of 9%. Various features of the assay systems were then modified in a controlled series of experiments. The results showed conclusively that i) differences between reagents accounted for most of the variation between laboratories and, ii) the two-stage assays were, on average, detecting relatively more activity in the more purified preparations than the one-stage assays. The results also suggested that the use of buffer as opposed to haemophilic plasma for the initial dilution of concentrates did not affect the assay results.


1975 ◽  
Author(s):  
B. M. Bas ◽  
A. D. Muller ◽  
H. G. Hemker

Five different ways of estimating prothrombin are applied to the plasma of persons receiving vitamin K antagonists, to know: the one-stage assay, the two-stage assay, the Echis Carinatus Venom assay, the coagulase-reacting factor assay and the immunological assay. The Protein Induced by Vitamin K Absence analogous to prothrombin (PIVKA-II) can be shown to be co-estimated in all but the one-stage assay. There are minor differences, however, between the other four tests. The most practical way to assess both prothrombin and PIVKA-II seems to be the coagulase-reacting factor assay. The difference between the one-stage assay and the others can be explained on basis of the new data on the role of vitamin K in prothrombin biosynthesis. The differences between the other tests are smaller and remain to be explained.


Blood ◽  
1952 ◽  
Vol 7 (7) ◽  
pp. 710-720 ◽  
Author(s):  
S. VAN CREVELD ◽  
M. M. P. PAULSSEN

Abstract Transfusions of heparinized plasma have a greater and more lasting effect on the coagulation time of hemophiliacs than transfusions of citrated plasma. Both in vitro and in vivo, heparinized plasma causes in hemophiliacs a far greater consumption of prothrombin as determined with the two-stage method than citrated plasma. In using the one-stage method no important differences in prothrombin activity are found after transfusions of heparinized and of citrated plasma respectively. This fact was thought to be connected with the more or less rapid appearance of an accelerator. Its a hemophiliac with a circulating anticoagulant, transfusions of heparinized plasma were unable to shorten the coagulation time to any important degree, nor did these transfusions cause an important decrease of serum prothrombin as determined by the two-stage method.


1987 ◽  
Author(s):  
M J Seghatchian ◽  
M J Dembinski

Two stage Coatest assay of F. VIII is reportedly insensitive to pretreatment of F. VIII with thrombin. Since thrombin is formed rapidly, during the incubation step, a one stage method was tried by incorporating S2222, containing thrombin inhibitor (1-2581) in the incubation system, thus making the assay highly specific to F. Xa-induced activation of F. VIII and allowing to monitor directly the formation of paranitroaniline in microtray plate at 2-5 min. intervals. Initial comparative analyses performed on cold activated and/or adsorbed/non-adsorbed samples (FFP, cryoprecipitate and hypo- or hypercoagulable state) revealed that in all cases the lag phase was prolonged (2-3 fold) in the one stage method. Cold activation had little effect on the lag phase/reaction rate, whereas AL(0E)3 decreased up to 50% F. VIII like activity, prolonged the lag phase and dose-response curves become non-parallel. Substituting phospholipid (pL) by tissue factor (TF) or addition of diluted TF (1/500) to reaction mixture increased synergistically the rate of F. Xa generation in both adsorbed and non-adsorbed system. In contrast washed platelets (PLT), up to 3000 x 109/1, were less effective on both TF or PL-induced F. Xa generation. The presence of 1-2581 in this system prolonged the lag phase to Ih. Substitution of the conventional O. D. reading by the time required to achieve a fixed absorbancy (O. D. =0.5) make the one stage coatest F. VIII equivalent to the APPT-type assay. Based on these results it is concluded that thrombin is involved in increasing F. VIII catalytic activity. TF and F. VII contribute to the shortening of the lag phase and increased F.a generation. The Kinetic property of cell surface-bound F. VIII is not the same in the presence or absence of thrombin. The reported insensitivity coatest F. VIII to thrombin is probably due to the fact that thrombin activated F. VIII is a good substrate for F. Xa and is cleaved by F. Xa which is produced in abundance in the two-stage chromogenic assays. A new procedure for monitoring various pathways of F. Xa generation, based on the coatest reagent is provided, which is particularly suitable for large scale screening of blood donors and blood products.


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