***TASK*** the task is to summarize an input biomedical literature in six sentences 
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    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
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    Input: The purpose of our study is to estimate the effect of tourniquet release and cementing in perioperative blood loss associated with total knee arthroplasty . Eighty patients were r and omly allocated into two equal groups concerning the timing of tourniquet release .  Group A : patients with tourniquet release and haemostasis before wound closure and group B : patients with tourniquet release after skin closure and compressive b and aging .  These groups were further subdivided in two subgroups ( + and - ) depending on cementing or not of the tibial tray only . The total blood loss averaged 961 ml in group A and 692 ml in group B , while it was estimated 763 ml in the cemented group and 890 ml in the non-cemented group . The total blood loss within subgroups was Group A+ 904 ml , Group A- 1017 ml , Group B+ 622 ml and Group B- 762 ml . The mean number of blood units transfused per patient was 4.7 in Group A and 4.0 in Group B , while the mean operating time was 79 min and 66 min , respectively . Complications such as deep vein thrombosis , haematomata and minor wound complications occurred in patients of Group A and Group B , 0 and 2 , 0 and 2 , 8 and 11 , respectively . Intraoperative tourniquet release seems to be related with significantly greater blood loss ( P<0.001 ) and dem and s in blood transfusion P<0.05 as well as a longer operating time ( P<0.001 ) . Cementing of total knee replacements has a better haemostatic role compared to non-cemented prosthesis ( P<0.05 ) . Even though complications were more in postoperative tourniquet release group , no statistically significant difference was found between group A and B. Postoperative tourniquet release seems to offer better conditions of haemostasis probably due to the better controlled fibrolytic activity BACKGROUND Total knee arthroplasty ( TKA ) is commonly performed using a tourniquet . However , some studies have reported that several complications were associated with the use of a tourniquet in TKA . In this study we investigate whether the limited use of a tourniquet in TKA would reduce complications and facilitate postoperative recovery . METHODS Sixty patients were r and omly divided into two groups ( 30 cases/group ) : group A using the tourniquet throughout the surgical procedure , and group B using the tourniquet starting from the cementation to the completion of the procedure .  Operation time , total measured blood loss , and incidence of complications were all recorded . RESULTS There was no significant difference in operation time , total measured blood loss , and hemoglobin concentration between the two groups . Incidence of postoperative complications in group B was significantly decreased in comparison to that in group A. The limb circumference at 10 cm above the superior patellar pole or below the inferior patellar pole and the pain score in group B were significantly decreased compared with that in group A at any time point . Range of motion in group B was significantly increased at three and 5 days postoperatively in comparison to that in group A. CONCLUSIONS The limited use of a tourniquet in TKA provides the benefit of decreased limb swelling and knee joint pain while not compromising the operation time or blood loss and recovery . LEVEL OF EVIDENCE Level I ( Therapeutic ) . TRIAL REGISTRATION NUMBER NCT02102581 In surgical practice , hemostasis is used to minimize postoperative bleeding in total knee arthroplasty . We performed a prospect i ve r and omized study to determine the influence of tourniquet use and the timing of its release on amount of bleeding .  Eighty four patients ( 96 knees ) were scheduled for total knee arthroplasty and r and omly divided into three groups . Posterior cruciate retaining bicompartmental total knee prostheses  were used in all . In group I , no tourniquet was used . In group II , a tourniquet was used and was deflated for hemostasis once all components had been inserted . In group III , the tourniquet was deflated after wound closure and application of a compressive dressing .  Mean blood drainage , mean volume of blood transfusion , hemoglobin ( Hb ) and hematocrit ( Hct ) values and operative time were compared between the three groups . Mean blood drainage was 810 mL ( 300 - 1300 ) in groups I 720 mL ( 240 - 1200 ) in group II and 705 mL ( 250 - 1150 ) in group III ( p = 0.062 ) . The Hb and Hct values , tourniquet time ( for groups II and III ) and volume of blood transfusion were similar . The operative time was significantly longer for first group ( p = 0.012 ) . Using tourniquet and its intraoperative release with hemostasis , does not reduce blood loss in total knee arthroplasty , but using tourniquet reduces operation time significantly Background Total knee arthroplasty with the use of a tourniquet during the entire operation has not been shown to improve the performance of the operation and may increase the risk of complications . Questions / purpose sWe asked whether the limited use of a tourniquet for cementation only would affect ( 1 ) surgical time ; ( 2 ) postoperative pain and motion of the knee ; ( 3 ) blood loss ; or ( 4 ) complications such as risk of nerve injuries , quadriceps dysfunction , and drainage compared with use of a tourniquet throughout the procedure . Methods Seventy-one patients ( 79 knees ) were r and omized to either use of a tourniquet from the incision through cementation of the implants and deflated for closure ( operative tourniquet group ) or tourniquet use only during cementation ( cementation tourniquet group ) . The initial study population was a minimum of 30 knees in each group as suggested for r and omized studies by American Society for Testing and Material s st and ards ; termination of the study was determined by power analysis performed after 40 knees in each group showed any statistical solution to our questions would require a minimum of 260 more cases . Patients were excluded who were considered in previous r and omized studies as high risk for complications , which might be attributed to the tourniquet . Results There were no differences in terms of surgical time , pain scores , pain medicine requirements , range of motion , hemoglobin change , or total blood loss . One major complication ( compartmental syndrome ) occurred in a patient with tourniquet inflation until closure . No other complications were attributed to the use of a tourniquet . Conclusions With the numbers available , our results suggest that there are no important clinical differences between patients who had a tourniquet inflated throughout the procedure compared with those who had it inflated only during cementation . Tourniquet inflation for cementation only provides the benefit of bloodless bone for fixation and may eliminate the risks associated with prolonged tourniquet use . Level of Evidence Level I , therapeutic study . See Guidelines for Authors for a complete description of levels of evidence Background Blood management is critical in total knee arthroplasty ( TKA ) . In bilateral , single stage TKA , blood loss seems more prominent . We believe it is important to control all potential bleeding within the wound tissue . Purpose The purpose of the study was to evaluate a series of topical procedures used to reduce blood loss and transfusion in single-stage bilateral cemented total knee arthroplasty : antifibrinolysis with tranexamic acid , vasoconstriction with epinephrine , sealing of the bone section intraoperatively , and closure of the drainage tube within the first 4 h postoperatively . Material s and methods Patients with osteoarthritis of the knees were r and omly divided into two groups . In group A , 5 ml ( 25 mg/ml ) tranexamic acid ( TXA ) and 5 ml analgesic containing epinephrine ( 3 μg/ml ) solution were injected at several points into the posterior capsule before installation of the prosthesis . The femoral medullar canal was closed with autograft bone and then sealed compressively with cement . Before the tourniquet was released , 10 ml TXA solution and 10 ml analgesic containing epinephrine were injected at several points into the periosteum , synovium , joint capsule , tendons , and deep fascia tissue ( injection of analgesic containing epinephrine into subcutaneous fat and dermis was avoided ) . The residual nail holes in the bone and the uncovered bone section were covered with bone wax . The tourniquet was then removed , and active bleeding points were stanched . TXA solution ( 20 ml ) was injected into the articular cavity after wound closure . The drainage tube was clamped for 4 h , then opened . In group B , injection of analgesic containing epinephrine into soft tissue , control of active bleeding , and clamping of the drainage tube for 4-h , only , were performed . Results Ninety patients were enrolled in the study . Compared with those in group B , intraoperative blood loss , drainage volume , total postoperative blood loss , and number of patients requiring allogenic blood transfusion were significantly reduced in group A. There was no significant difference between the incidence of complications in the groups . Conclusions Our topical procedures enable effective and safe reduction of blood loss and the number of patients requiring transfusion in single-stage bilateral osteoarthritic TKA Purpose Pneumatic tourniquets are frequently used in knee arthroplasty surgery . However , there is a lack of evidence to define safe tourniquet time in lower limb surgery . The primary aim of this study was to investigate whether tourniquet time influences the risk of postoperative complications after primary and secondary knee arthroplasty . Methods This study was a prospect i ve register study . Since we wanted dispersion in tourniquet time , we included a consecutive series of 577 primary knee arthroplasties , 46 revision knee arthroplasties , and 18 patellar supplementing knee arthroplasties from a clinical audit data base over a period of five years . The following postoperative complications were recorded : superficial wound infections , deep wound infections , deep vein thrombosis , pulmonary embolism , nerve injuries , compartment syndrome , cuff pressure injuries , and b and age injuries . Results Tourniquet time over 100 minutes was associated with an increased risk of complications after knee arthroplasty surgery ( OR 2.2 , CI 1.5–3.1 ) . This increase in risk remained after adjusting for cuff pressure , sex , age , American Society of Anesthesiologists ( ASA ) classification , smoking , diabetes , and surgery indication ( OR 2.4 , CI 1.6–3.6 ) . Conclusions Tourniquet time over 100 minutes increases the risk of complications after knee arthroplasty surgery and special attention is advocated to reduce the tourniquet time AIM To reduce blood loss in total knee arthroplasty various physical measures including the use of a tourniquet are recommended . The question of an early tourniquet release is still unsettled . PATIENTS AND METHOD To confirm our theory that blood loss and need of blood transfusions might be reduced while removing the tourniquet for meticulous hemostasis before wound closure we analysed 70 ( 41 male , 29 female ) consecutive patients with total knee arthroplasty for osteoarthritis performed by a single surgeon in a prospect ive-r and omized study between 1/1996 to 6/1998 . In group I the tourniquet was released before , in group II after wound closure . RESULTS We could n't find any significant differences in the estimated blood loss , the decrease of hemoglobin and hematocrit level , and the transfusion need . In Group II we observed two cases of deep vein thrombosis . This difference was not significant . CONCLUSION We conclude that tourniquet release for hemostasis is not an effective tool in reducing blood loss or transfusion need in total knee arthroplasty Today the use of pneumatic tourniquet is commonly accepted in total knee arthroplasty ( TKA ) to reduce perioperative blood loss . There are a few prospect i ve r and omised and nonr and omised studies that compare the effect of tourniquet release timing in cementless or cemented unilateral TKA . However , many of these studies show an inadequate reporting and methodology . This r and omized prospect i ve study was design ed to investigate the efficiency of tourniquet release timing in preventing perioperative blood loss in a simultaneous bilateral TKA study design . To our knowledge , this is the first study of its kind , in which the effect of tourniquet release timing on perioperative blood loss was investigated in simultaneous bilateral cemented TKA to compare both techniques intraindividually . In 20 patients ( 40 knees ) one knee was operated with tourniquet release and hemostasis before wound closure , and the other knee with tourniquet release after wound closure and pressure dressing . We found no significant difference in total blood loss between both techniques ( p=0.930 ) , but a significant difference in operating time ( p=0.035 ) . There were no postoperative complications at a follow-up of 6 month . Other studies report an increase the blood loss in early tourniquet release and an increase the risk of early postoperative complications in deflation of tourniquet after wound closure . In this study we found no significant difference in perioperative blood loss and no increase of postoperative complications . Therefore , we recommend a tourniquet release after wound closure to reduce the duration of TKA procedure and to avoid possible risks of extended anaesthesia We included 46 total knee arthroplasties ( 43 patients ) in a prospect i ve , r and omised study , dividing them into two groups : group A ( 23 knees , 21 patients ) in which the ischaemia was released prior to wound 
    Output:
    
The results showed that there were no significant differences in overt blood loss , hemoglobin drop , and blood transfusions , whereas the tourniquet release after wound closure might increase the risks of overall complications and major complications .
Conclusions Tourniquet release before wound closure for hemostasis might reduce the rate of complications , but it could not limit overall blood loss .
The current evidence s are not enough to indicate that tourniquet release before wound closure is superior to its release after wound closure in cemented TKA