***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: Trauma patients with fractures of the pelvis , acetabulum , or femur are at risk for deep venous thrombosis complicating the treatment of their injuries . This risk can be lessened with anticoagulant medications or with mechanical methods such as sequential pneumatic compression . However , many patients in this population group have contraindications to systemic anticoagulation and can not use sequential limb compression devices because of leg injuries or appliances . Intermittent pneumatic compression of the plantar venous plexus is able to provide prophylaxis against deep venous thrombosis in many of these patients . We performed a prospect i ve , r and omized , controlled comparison between plantar compression and leg compression for prevention of deep venous thrombosis in an orthopedic trauma population of 124 patients . Patients were evaluated with  duplex ultrasonagraphy  at intervals after surgery . Both methods proved protective in comparison with reported rates in patients not given prophylaxis , and although the numbers were too small to give statistically meaningful results , we observed no significant difference in the thrombosis rate ( 4 % for plantar compression versus 0 % for leg compression ) . We conclude that foot pumps are an effective alternative to calf compression for prevention of deep venous thrombosis after a lower extremity fracture We performed a prospect i ve , blinded study to assess and compare the values of preoperative contrast venography and magnetic resonance venography in the detection of deep venous thrombosis in the thigh and pelvis of forty-five consecutive patients who had a displaced acetabular fracture . The magnetic resonance venography and contrast venography were performed an average of seven days ( range , one to twenty-nine days ) after the injury . Twenty-four asymptomatic thrombi were identified with magnetic resonance venography in fifteen ( 33 percent ) of the patients . Four of the thrombi were in the superficial femoral vein , nine were in the common femoral vein , one was in the external iliac vein , seven were in the internal iliac vein , and three were in the common iliac vein . Ten ( 42 percent ) of the twenty-four thrombi were confirmed with contrast venography ; nine of them were located in the thigh . The remaining fourteen thrombi ( 58 percent ) that had been noted on magnetic resonance venography could not be seen with contrast venography because they were located either in the deep pelvic veins or in the uninjured extremity . The thrombi in the internal iliac vein were identified only with magnetic resonance venography . Twelve of the fifteen patients who had thrombi had a filter placed in the inferior vena cava preoperatively . In eight of these patients , the filter was placed because of the findings of magnetic resonance venography alone . Magnetic resonance venography result ed in a change in the therapeutic management of ten ( 22 per cent ) of the forty-five patients . There were no pulmonary emboli . We concluded that magnetic resonance venography is superior to contrast venography for the preoperative evaluation of proximal deep venous thrombosis in patients who have an acetabular fracture .  Magnetic resonance venography is non-invasive , does not require the use of contrast medium , images the proximal aspects of both lower extremities simultaneously , and , most importantly , allows for the identification of deep venous thrombosis in the pelvis The existing evidence on the effectiveness of thromboprophylaxis after trauma is conflicting . Although prophylaxis with heparin and /or sequential compression devices is practice d widely , many studies failed to document a clear benefit . A recent meta- analysis suggests that prophylaxis does not reduce posttraumatic deep venous thrombosis rates compared to no prophylaxis . The objective of this prospect i ve study is to examine if the use of thromboprophylaxis prevents posttraumatic pulmonary embolism ( PE ) .  Sixty-four critically injured patients with clinical evidence of PE were studied by computed tomographic pulmonary angiography and /or conventional pulmonary angiography . PE was diagnosed in 24 ( 37.5 % ) patients . Patients with PE were similar to patients without PE with regard to demographics , injury type and severity , operations , and mortality .  Thromboprophylaxis  was used with equal frequency between PE and no-PE patients ( 71 % vs 80 % , P = 0.4 ) . The type of prophylaxis used was similar between patients with PE ( 17 % heparin , 71 % sequential compression devices , 17 % combination ) and patients without PE ( 32 % , 57 % , and 10 % , respectively ; P = 0.16 , 0.28 , 0.69 , respectively ) . Current methods of posttraumatic thromboprophylaxis may be inadequate . Practice s from nontrauma population s have been erroneously extrapolated to the unique trauma population . To reduce the rate of PE after trauma , new methods of thromboprophylaxis should be considered There is a high risk of venous thromboembolism when patients are immobilised following trauma . The combination of low-molecular-weight heparin ( LMWH ) with graduated compression stockings is frequently used in orthopaedic surgery to try and prevent this , but a relatively high incidence of thromboembolic events remains . Mechanical devices which perform continuous passive motion imitate contractions and increase the volume and velocity of venous flow . In this study 227 trauma patients were r and omised to receive either treatment with the  Arthroflow device and LMWH or only with the latter . The Arthroflow device passively extends and plantarflexes the feet . Patients were assessed initially by  venous-occlusion plethysmography , compression ultrasonography and continuous wave Doppler  , which were repeated weekly without knowledge of the category of r and omisation . Those who showed evidence of deep-vein thrombosis underwent  venography  for confirmation . The incidence of deep-vein thrombosis was 25 % in the LMWH group compared with 3.6 % in those who had additional treatment with the Arthroflow device ( p < 0.001 ) . There were no substantial complications or problems of non-compliance with the Arthroflow device . Logistic regression analysis of the risk factors of deep-vein thrombosis showed high odds ratios for operation ( 4.1 ) , immobilisation ( 4.3 ) , older than 40 years of age ( 2.8 ) and obesity ( 2.2 ) Objective To determine the cost-effectiveness of enoxaparin compared with low-dose-heparin ( LDH ) for thromboprophylaxis after major trauma and to assess the economic significance of major bleeding as a complication of the use of low-molecular-weight heparin ( LMWH ) . Design Decision model analysis of the cost and efficacy of enoxaparin at preventing venous thromboembolism ( VTE ) and the risk and costs of major hemorrhage related to LMWH . The primary outcome was deep vein thromboses ( DVTs ) averted . Model estimates were based on data from prospect i ve trials of LMWH and other studies of the financial ramifications of DVT and pulmonary embolism . Setting and Patients Hypothetical cohort of 1,000 critically ill trauma patients requiring thromboprophylaxis . Interventions In the model , patients were managed with either LMWH or LDH . Measurements and Main Results The marginal cost-effectiveness of enoxaparin was calculated as the savings result ing from cases of DVT averted less the additional costs of both 1 ) LMWH and 2 ) major bleeding . This result is expressed as cost ( or savings ) per DVT prevented . Sensitivity analysis of the impact of the major clinical inputs on the cost-effectiveness was performed . The base case assumed that the incidence of DVT with LDH was 14.7 % , that LMWH result ed in a relative risk reduction of DVT of 50 % , but that enoxaparin nearly quadrupled the risk of bleeding . Despite the higher costs of enoxaparin , this tactic yielded a net savings of $ 391.23 per DVT prevented . For sensitivity analysis , model inputs were adjusted by 25 % individually and then simultaneously . This demonstrated the model to be most sensitive to the calculated cost of a DVT . With the efficacy of LMWH reduced by 25 % of the base-case estimate , enoxaparin result ed in a cost of $ 311.77 per DVT avoided . When all variables were skewed against LMWH , total outlays were trivial ( approximately $ 85 per patient in the cohort ) . Neither the rate of increased bleeding with LMWH nor the costs incurred as a result of bleeding significantly altered the model ’s financial outcomes . Conclusions Reliance on enoxaparin represents a strategy for the prevention of VTE after trauma that may result in savings . Neither concerns about the higher cost of enoxaprin relative to LDH nor the financial implication s of major bleeding should preclude the use of LWMH for thromboprophylaxis in trauma patients . Further studies are warranted to confirm the efficacy of enoxaparin We prospect ively studied the outcome of a protocol of prophylaxis for deep vein thrombosis ( DVT ) in 103 consecutive patients undergoing surgical stabilisation of pelvic and acetabular fractures .  Low-molecular-weight heparin ( LMWH ) was administered within 24 hours of injury or on achieving haemodynamic stability . Patients were screened for proximal DVT by duplex ultrasonography performed ten to 14 days after surgery . The incidence of proximal DVT was 10 % and of pulmonary embolus 5 % . Proximal DVT developed in two of 64 patients ( 3 % ) who had received LMWH within 24 hours of injury , but in eight of 36 patients ( 22 % ) who received LMWH more than 24 hours after the injury ( p < 0.01 ) . We conclude that LMWH , when begun without delay , is a safe and effective method of thromboprophylaxis in high-risk patients with major pelvic or acetabular fractures BACKGROUND Patients who have had major trauma are at very high risk for venous thromboembolism if they do not receive thromboprophylaxis . We compared low-dose heparin and a low-molecular-weight heparin with regard to efficacy and safety in a r and omized clinical trial in patients with trauma . METHODS Consecutive adult patients admitted to a trauma center who had Injury Severity Scores of at least 9 and no intracranial bleeding were r and omly assigned to heparin ( 5000 units ) or enoxaprin ( 30 mg ) , each given subcutaneously every 12 hours in a double-blind manner , beginning within 36 hours after the injury . The primary outcome was deep-vein thrombosis as assessed by contrast venography performed on or before day 14 after r and omization . RESULTS Among 344 r and omized patients , 136 who received low-dose heparin and 129 who received enoxaparin  had venograms adequate for analysis . Sixty patients given heparin ( 44 percent ) and 40 patients given enoxaparin ( 31 percent ) had deep-vein thrombosis ( P=0.014 ) . The rates of proximal-vein thrombosis were 15 percent and 6 percent , respectively ( P=0.012 ) . The reductions in risk with enoxaparin as compared with heparin were 30 percent ( 95 percent confidence interval , 4 to 50 percent ) for all deep-vein thrombosis and 58 percent ( 95 percent confidence interval , 12 to 87 percent ) for proximal-vein thrombosis . Only six patients ( 1.7 percent ) had major bleeding ( one in the heparin group and five in the enoxaparin group , P=0.12 ) . CONCLUSIONS Low-molecular-weight heparin was more effective than low-dose heparin in preventing venous thromboembolism after major trauma . Both interventions were safe BACKGROUND Current methods of posttraumatic thromboprophylaxis ( heparins and sequential compression devices ) are inadequate . New methods should be tested . Muscle electrostimulation ( MEST ) has been used over the years with mixed-but predominantly encouraging- results for a variety of conditions , including prevention of deep venous thrombosis ( DVT ) . It has not been tested in multiple trauma patients . METHODS Trauma patients with Injury Severity Score higher than 9 who were admitted to the intensive care unit and had a contraindication for prophylactic heparinization were r and omized to groups MEST and control .  MEST patients received 30-minute MEST sessions twice daily for 7 to 14 days . Venous flow velocity and venous diameter were measured by duplex venous scan . Venography-or , if not available , duplex-was used to evaluate the presence of proximal and peripheral DVT between days 7 and 15 . RESULTS After exclusions , 26 MEST and 21 control patients completed the study and received outcome evaluation by venography ( 25 ) or duplex ( 22 ) . Three patients in each group developed proximal DVT ( 11.5 % vs 14 % , P = .79 ) , and an additional 4 ( 15 % ) MEST group and 3 ( 14 % ) control group patients developed peripheral DVT ( P = .96 ) . There was no difference in venous flow velocity or venous diameter between the groups . CONCLUSIONS MEST was not effective in decreasing DVT rates in major trauma patients OBJECTIVE To investigate the safety and effectiveness of low molecular weight heparin ( LMWH ) in preventing deep venous thrombosis ( DVT ) in high-risk trauma patients , compared with mechanical methods of prophylaxis . DESIGN A prospect i ve r and omized trial conducted over a 19-month period in an urban , academic trauma center . MET 
    Output:
    
The findings of this study suggest that low molecular weight heparin ( LMWH ) may be superior to low dose heparin ( LDH ) , and that LMWH should be used in addition to mechanical prophylaxis measures in patients following major skeletal trauma .
There is limited evidence for the use of electrostimulation .
There appeared to be no significant difference between the use of LDH compared to  calf compression devices .
Conclusions There is currently insufficient research to be able to inform trauma surgeons as to the optimal method of thromboprophylaxis for patients following major skeletal trauma