***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
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    Input: A prospect i ve study involving 120 consecutive patients undergoing total hip replacement was performed to compare the effectiveness of aspirin ( high and low dose ) or a combination of heparin plus dihydroergotamine ( heparin-DHE ) in preventing isotopic and phlebographic deep vein thrombosis ( DVT ) , and to evaluate their effect on postoperative platelet changes . Phlebographic DVT was demonstrated in 9 cases ( 30 % ) in control group , in 1 ( 3.3 % ) in aspirin ( high-dose ) group ( p less than 0.01 ) , in 1 ( 3.3 % ) in aspirin ( low-dose ) group ( p less than 0.01 ) and in 5 ( 16.6 % ) in heparin-DHE group ( p = NS ) . Aspirin was able to reduce the postoperative increase in circulating platelet aggregates , platelet factor 4 and beta-thromboglobulin observed in control group . This study shows that aspirin is effective in the prevention of DVT for patients undergoing total hip replacement . Small aspirin dose ( 250 mg/day ) represents an effective form of prophylaxis in these patients A r and omized trial was carried out with 194 patients to compare the effectiveness of sodium warfarin or aspirin with that of placebo in the prevention of  venous thromboembolism after surgery for fractured hip . Prophylaxis was commenced postoperatively and continued for 21 days or until patient discharge , whichever was earlier . All patients underwent surveillance with iodine 125-fibrinogen leg scanning and impedance plethysmography , with subsequent venography .  Venous thromboembolism occurred in 13 patients ( 20.0 % ) in the warfarin group , 27 patients ( 40.9 % ) in the aspirin group , and 29 patients ( 46.0 % ) in the placebo group . Proximal vein thrombosis or pulmonary embolism occurred in 6 patients ( 9.2 % ) in the warfarin group , 7 patients ( 10.6 % ) in the aspirin group , and 19 patients ( 30.2 % ) in the placebo group . The results of this study show that sodium warfarin therapy is safe and effective in preventing thromboembolic complications in patients undergoing surgery for fractured hip , and that aspirin therapy is an equally safe and effective method for preventing proximal vein thrombosis or pulmonary embolism Flaws in the design , conduct , analysis , and reporting of r and omised trials can cause the effect of an intervention to be underestimated or overestimated . The Cochrane Collaboration ’s tool for assessing risk of bias aims to make the process clearer and more This study compares the benefits of aspirin and warfarin prophylactic agents for patients with thromboembolic disease after total joint arthroplasty . It is a prospect i ve r and omized study of 388 patients having total hip or total knee surgery . All consecutive patients having total hip or total knee surgery were entered into this study and evaluated with preoperative and postoperative ventilation perfusion scans and a postoperative venogram  . The aspirin and warfarin treatment groups were compared by size and location of venographically revealed clots and changes in ventilation perfusion scans . The results showed that there was no difference in the size or location of deep venous thrombosis in the aspirin or warfarin treatment groups . The venogram was negative in 44.5 % of patients ; 28.8 % had small calf clots , 16 % had large calf clots , 3.9 % had popliteal clots , and 6.7 % had femoral clots . Patients with total knee replacement had a 2.6 times greater incidence of calf deep venous thrombosis than patients with total hip replacement . There was no difference between the aspirin and warfarin groups in the incidence of changes in ventilation perfusion scans ( 18.9 % ) . There was no difference between the 2 groups in bleeding complications . The results suggest that aspirin and warfarin are equivalent in prophylaxis against thromboembolic disease , as determined by prevention of venographic changes or changes in ventilation perfusion scans We have evaluated the quality of life and functional outcome after  unilateral primary total hip replacement ( THR ) . Between 5 January 1998 and 31 July 2000 , we recruited a consecutive series of 627 patients undergoing this procedure and investigated them prospect ively . Each was assessed before operation and review ed after six months , 18 months , three years and five years . The  Short Form-36 Health Survey ( SF-36 ) and Harris Hip scores  were evaluated at each appointment . All dimensions of the SF-36 except for mental health and general health perception , improved significantly after operation and this was maintained throughout the follow-up . The greatest improvement was seen at the six-month assessment . On average , women reported lower SF-36 scores pre-operatively , but the gender difference did not continue post-operatively . The Harris Hip scores improved significantly after operation , reaching a plateau after 18 months . The improved quality of life was sustained five years after THR OBJECTIVE To compare the health-related quality of life of people with osteoarthritis before and after primary total hip and knee replacement surgery  with that of the general Australian population . DESIGN A prospect i ve cohort study . SETTING Three Sydney hospitals , public and private . PARTICIPANTS Patients with osteoarthritis undergoing primary total hip ( n = 59 ) and knee ( n = 92 ) joint replacement surgery .  MAIN OUTCOME MEASURE Medical Outcomes Study Short Form ( SF-36 ) scores before and 12 months after joint replacement surgery ( compared with population norms ) . RESULTS Patients in each age group showed a significant improvement in health-related quality of life after joint replacement surgery in most scales of the SF-36 , particularly physical function , role physical and bodily pain . SF-36 scores for the 42 hip-replacement patients aged 55 - 74 years improved to equal or exceed the population norm on all scales . SF-36 scores of the 52 knee replacement patients aged 55 - 74 years improved , but physical function and bodily pain scores remained significantly worse than the population norm . SF-36 scores for both hip ( n = 17 ) and knee ( n = 40 ) replacement patients aged 75 years and over improved significantly , becoming similar to population norms for this age group . CONCLUSIONS Total hip or knee replacement for osteoarthritis significantly improves patient health and well-being at 12 months after surgery . Age alone should not be a barrier to surgery Aspirin has been demonstrated to be an effective prophylactic agent against postoperative venous thromboembolic disease , but the optimum dosage is unknown . We compared the efficacy of daily doses of 3.6 grams of aspirin ( high dose ) with that of 1.2 grams ( low dose ) in 182 patients . All patients were more than forty years old and all underwent a total hip replacement . This r and omized , prospect i ve , double-blind study was done using only objective dta for diagnosis . Twenty-three ( 44 per cent ) of fifty-two women who were treated with the low dose had thrombi , compared with eighteen ( 34 per cent ) of fifty-three women who were given the high dose . Thrombi developed in thirteen ( 32 per cent ) and in eighteen ( 49 per cent ) of thirty-seven men who were given the high dose . There were no statistically significant differences among the four groups , nor was there a significant difference among the subgroups that were determined according to prior history of venous thromboembolic disease . Therefore , the higher dose of aspirin was neither more nor less effective than the lower dose . Our data continue to support the use of 1.2 grams in men In a prospect i ve and controlled study , we compared the prophylactic effect of high-dose acetylsalicylic acid ( ASA ) and dihydroergotamine-heparin ( DHEH ) in 82 patients over 50 years of age undergoing total hip replacement . The patients were screened by pulmonary scan and 125I fibrinogen uptake . Phlebography was done if the 125 I fibrinogen test was positive . According to our criteria , thromboembolism developed in 9 of 40 receiving ASA and in 5 of 42 patients receiving DHEH . The effect of ASA was limited to men ; in 16 men on this therapy , none had thromboembolism versus 9 of 24 women . Twenty-two patients showed wound hematomas , but none needed surgical intervention A prospect i ve , r and omized study of the effectiveness of intraoperative and postoperative use of intermittent pneumatic compression , alone or in combination with oral administration of either aspirin or low-dose warfarin , was done of a consecutive series of patients who had a total hip replacement and were more than thirty-nine years old . All patients began walking by the third postoperative day . One hundred and ninety-six patients who had 217 total hip arthroplasties were included . Twenty-eight per cent of the procedures were revisions of a previous total hip replacement or of an endoprosthesis , and the remainder were primary arthroplasties . Patients were r and omized as to the type of prophylaxis that they received : intermittent pneumatic compression alone , seventy-six hips ; intermittent pneumatic compression and aspirin , seventy-two hips ; or intermittent pneumatic compression and low-dose warfarin , sixty-nine hips . Before discharge from the hospital , and at an average of seven days after the operation , all patients were evaluated for the presence of proximal deep-vein thrombosis with either venography on the side of the operation or with bilateral venous ultrasonography . The relative frequency with which thrombosis occurred in a proximal vein was not significantly different in the three groups ; the over-all relative frequency was 10 per cent . Intermittent compression during and after the operation effectively reduces the rate of proximal-vein thrombosis after total hip replacement . With the number of patients in our study , the effectiveness of this technique could not be shown to be augmented by oral administration of either aspirin or low-dose warfarin Two hundred seventy-five patients undergoing unilateral total knee arthroplasty were prospect ively r and omized to receive spinal epidural anesthesia ( SEA ) , a VenaFlow calf compression device , and enoxaparin ( group A ) or SEA , VenaFlow , and aspirin ( group B ) . Aspirin was started on the day of surgery , whereas enoxaparin was started 48 hours after surgery . Anticoagulants were continued for 4 weeks after surgery . All patients had an in-hospital ultrasound screening test on postoperative days 3 to 5 and a second follow-up ultrasound 4 to 6 weeks after surgery . The overall deep venous thrombosis rates in groups A and B were 14.1 % and 17.8 % ( P = not significant ) , respectively . When used in combination with pneumatic compression devices and SEA , enoxaparin was not superior to aspirin in preventing deep venous thrombosis after total knee arthroplasty BACKGROUND The study objective was to determine the relative efficacy and safety of a low-molecular-weight heparinoid ( Orgaran ) compared with aspirin for the prevention of postoperative venous thromboembolism in patients undergoing surgery for fractured hips . A double-blind , r and omized , controlled trial was used to study 251 consecutive eligible and consenting patients undergoing surgery for hip fracture in seven participating hospitals . METHODS AND RESULTS Patients received either fixed-dose Orgaran by subcutaneous injection every 12 hours in a dose of 750 anti-Factor Xa units or aspirin 100 mg orally twice daily ; both regimens were started 12 to 24 hours after surgery and continued for 14 days or until discharge , if sooner . All patients had postoperative 125I-fibrinogen leg scanning and impedance plethysmography . If the results of one or both tests were positive , then venography was performed . Otherwise , venography was done at day 14 , or sooner if the patient was ready for discharge . Pulmonary embolism in symptomatic patients was diagnosed on the basis of a high probability perfusion/ventilation lung scan , a positive angiogram , or a clinical ly significant embolism detected at autopsy . Evaluable venograms were obtained in 90 of the 125 patients r and omly assigned to receive Orgaran and in 87 of the 126 patients assigned to receive aspirin .  Venous thromboembolism was detected in 25 ( 27.8 % ) patients in the Orgaran group and in 39 ( 44.3 % ) patients in the aspirin group . Thus , there was a relative risk reduction of 37 % with Orgaran ( P=.028 ; 95 % confidence interval , 3.7 % to 59.7 % ) . Six ( 6.8 % ) of 88 patients in the Orgaran group and 12 ( 14.3 % ) of 84 patients in the aspirin group developed proximal deep vein thrombosis or pulmonary embolism , a relative risk reduction of 52 % with Orgaran ( P=.137 ; 95 % confidence interval , -30.7 % to 84.6 % ) . Hemorrhagic complications occurred in 2 ( 1.6 % ) patients given Orgaran and 8 ( 6.4 % ) patients given aspirin ( P=.10 ) . There was one major bleed in the Orgaran group compared with four in the aspirin group . CONCLUSIONS This study demonstrates that Orgaran is significantly more efficacious than aspirin in preventing postoperative venous thromboembolism in patients undergoing surgery 
    Output:
    
Compared with anticoagulation , aspirin may be associated with higher risk of DVT following hip fracture repair , although bleeding rates were substantially lower .
Aspirin was similarly effective after lower extremity arthroplasty and may be associated with lower bleeding risk .