Prevention of venous thromboembolism after knee arthroscopy with low-molecular weight heparin (reviparin): Results of a randomized controlled trial. Prevention of deep-vein thrombosis in ambulatory arthroscopic knee surgery: A randomized trial of prophylaxis with low--molecular weight heparin. Randomized clinical trial of low molecular weight heparin with thigh-length or knee-length antiembolism stockings for patients undergoing surgery. Prevention of postoperative deep venous thrombosis and pulmonary emboli with combined modalities. Electrostimulation for the prevention of deep venous thrombosis in patients with major trauma: a prospective randomized study. Prevention of deep-vein thrombosis after total hip and knee replacement. Low-molecular-weight heparin in combination with intermittent pneumatic compression. Incidence and prevention of deep venous thrombosis occurring late after general surgery: randomised controlled study of prolonged thromboprophylaxis. Randomized clinical trial of intermittent pneumatic compression and low molecular weight heparin in trauma. Continuous passive motion in the prevention of deep-vein thrombosis: a randomised comparison in trauma patients.
Deep venous thrombosis (DVT) is a common, important complication of major orthopaedic surgery, particularly knee arthroplasty. Knee arthroscopy is increasingly performed on an outpatient basis. Few reports have elucidated the incidence of venous thromboembolism (VTE) in patients undergoing arthroscopic surgery receiving no prophylaxis. The objective of the present trial was to evaluate the risk of VTE in those patients and to determine efficacy and safety of a low-molecular weight heparin (LMWH) in preventing VTE.
                This is the first controlled randomized trial using objective diagnostic methods with blinded outcome assessment to reveal the incidence of VTE in outpatient arthroscopy and determine efficacy and safety of a LMWH (reviparin sodium) in preventing VTE in these patients.
                There were 262 patients undergoing elective knee arthroscopy prospectively randomized to receive either no treatment or reviparin once daily subcutaneously for 7 to 10 days. The blindly assessed primary outcome measure was the incidence of DVT detected by compression color-coded sonography. Both groups were comparable with regard to demographics and baseline characteristics.
                239 patients were evaluable (122 no treatment, 117 receiving LMWH). 6 DVT were detected - 5 in the control group (5/117 - 4.1%) and only one in the active treatment group (1/116 - 0.85%). This particular patient had a low level of protein C and a subnormal level of protein S. The odds ratio of 4.95 approximates a relative risk reduction of about 80%. Treatment with reviparin was safe and well tolerated. There was no major bleeding, four patients with minor bleedings. One patient had a transitory fall in platelet count below 100 giga-particles/L without any clinical symptoms.
                Patients undergoing knee arthroscopy have a moderate risk of VTE and effective prophylaxis can be achieved with LMWH (reviparin). The risk of deep vein thrombosis (DVT) in patients undergoing arthroscopic knee surgery is not well known. The purpose of this study was to determine the incidence of DVT, to demonstrate the efficacy of a perioperative and postoperative prophylaxis against thromboembolism with use of low--molecular weight heparin (LMWH), and to show the safety and feasibility of LMWH administration.
                Prospective, single-blind, randomized clinical trial.
                There were 218 consecutive outpatients scheduled for ambulatory arthroscopic knee surgery eligible. Of these, 130 patients were randomized to a treatment group with LMWH (dalteparin: 2,500 IU less-than-or-equal70 kg and 5,000 IU >70 kg, started perioperatively and given once daily for 4 weeks; n = 66) and a control group (n = 64) with no prophylaxis. To detect DVT, all patients underwent bilateral compression ultrasonography before and 12 and 31 days after surgery.
                Among the 130 patients studied, thromboembolism was significantly lower in the treatment than in the control group: 1 of 66 (1.5%) versus 10 of 64 (15.6%); 95% confidence interval, 7.8% to 26.8%; P =.004. Eighty percent of DVT occurred within the first 14 postoperative days. No severe side effects of LMWH were observed. Only 5% of patients refused continued subcutaneous LMWH injections.
                In patients undergoing ambulatory arthroscopic knee surgery without antithrombotic prophylaxis, the risk of DVT is high. Perioperative and postoperative prophylaxis with dalteparin is an effective and safe means of reducing this risk. This was a randomized clinical trial to determine the efficacy and safety of a 'blanket' protocol of low molecular weight heparin (LMWH) and the best length of antiembolism stocking, for every patient requiring surgery under general anaesthesia.
                Of 426 patients interviewed, 376 agreed to be randomized to receive one of three types of stocking: thigh-length Medi thrombexin climax (Medi UK, Hereford, UK), knee-length thrombexin climax and thigh-length Kendall T.E.D. (Tyco Healthcare UK, Redruth, UK). All patients received LMWH thromboprophylaxis. Duplex ultrasonography was used to assess the incidence of postoperative deep vein thrombosis (DVT).
                No postoperative DVT occurred in 85 patients at low or moderate risk. Nineteen DVTs occurred, all in the 291 high-risk patients: two with the Medi thigh-length stockings, 11 with the Medi knee-length stockings (odds ratio 0.18 (95 per cent confidence interval 0.04 to 0.82); P = 0.026) and six with the Kendall T.E.D. thigh-length stockings. No patient developed a pulmonary embolism. Stocking groups were similar for age, sex, thromboembolic risk, type of operation and compliance. One significant bleeding complication occurred.
                A single protocol comprising LMWH and thigh-length stockings abolished DVT in low- and moderate-risk patients, and reduced the rate of DVT to 2 per cent in high-risk patients.
                Copyright 2004 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd. Worldwide statistics reveal that 25 to 40 per cent of patients who are over the age of 40 years and operated on for 1 or more hours will develop a deep venous thrombosis (DVT). The studies reviewed in this paper were performed to evaluate several modalities and compare their effectiveness in preventing DVT in postoperative patients. In the first study, five modalities plus a control group were evaluated in 562 patients from five surgical specialties. The incidence of DVT in the control group was 35 per cent. Though most of the pharmacologic agents were effective in reducing the incidence of DVT, the antistasis devices (gradient elastic stockings and intermittent pneumatic compression) were most effective. The purpose of the second study was to evaluate the effectiveness of combining a pharmacologic drug with an antistasis modality. Deep venous thrombosis was virtually eliminated in this group of 328 patients. There was only a 1.5 per cent incidence of DVT in the treated population as compared to a 26.8 per cent incidence in the control group. Thus, it seems that combining one antistasis and one pharmacologic agent greatly reduces the incidence of lower extremity thrombi. I-125 fibrinogen scanning was the most sensitive test in detecting DVT and had an accuracy of 97 per cent. 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.
                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 randomized 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.
                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.
                MEST was not effective in decreasing DVT rates in major trauma patients. After total hip (THR) or knee replacement (TKR), there is still an appreciable risk of developing deep-vein thrombosis despite prophylaxis with low-molecular-weight heparin (LMWH). In a prospective, randomised study we examined the efficacy of LMWH in combination with intermittent pneumatic compression in patients undergoing primary unilateral THR or TKR. We administered 40 mg of enoxaparin daily to 131 patients combined with either the use of intermittent pneumatic compression or the wearing of graduated compression stockings. Compression ultrasonography showed no evidence of thrombosis after LMWH and intermittent pneumatic compression. In the group with LMWH and compression stockings the prevalence of thrombosis was 28.6% (40% after TKR, 14% after THR). This difference was significant (p < 0.0001). In the early post-operative phase after THR and TKR, combined prophylaxis with LMWH and intermittent pneumatic compression is more effective than LMWH used with graduated compression stockings. To study the incidence of late deep venous thrombosis (DVT), and to evaluate a regimen of prolonged thromboprophylaxis after general surgery.
                Randomised, controlled, open trial, with blinded evaluation.
                University hospital, Denmark.
                176 consecutive patients undergoing major elective abdominal or non-cardiac thoracic operations, of whom 118 were eligible for evaluation.
                Thromboprophylaxis with a low-molecular-weight heparin, tinzaparin, given for four weeks (n = 58), compared with one week (control group, n = 60).
                Presence of DVT established by bilateral venography four weeks after the operation.
                The incidence of late DVT in the control group was 6/60 (10%, 95% confidence interval (CI) 4% to 21%). In the prophylaxis group it was 3/58 (5.2%, 95% CI 1% to 14%) (p = 0.49).
                Prolonged thromboprophylaxis had no significant effect on the incidence of DVT occurring late after general surgery. After trauma, up to 60 per cent of immobilized patients have been reported to develop a silent deep vein thrombosis (DVT). No large, prospective randomized trials have tested the efficacy of intermittent pneumatic compression (IPC) devices in these patients.
                A prospective randomized trial was performed of 442 patients who received thromboprophylaxis using either an IPC device or low molecular weight heparin (LMWH). Duplex imaging was performed on both legs on admission, and was repeated weekly thereafter until discharge, at 30 days or when there was a thrombotic event, whichever occurred first.
                There were no significant differences in time spent in intensive care, or the proportion of patients with pelvic fractures, spinal cord or head injuries between the two groups. Six patients (2.7 per cent) developed a DVT in the IPC group and one (0.5 per cent) in the LMWH group (P = 0.122). Pulmonary embolism occurred in one patient in each group. There were 13 minor bleeding episodes (four in the IPC group and nine in the LMWH group) and eight major bleeding episodes (four in each group), none of which required operative intervention.
                The low rate of thromboembolic complications and the cost savings suggest that IPC might be used safely and effectively for thromboprophylaxis in trauma patients.
                Copyright 2003 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd. 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 randomised 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 randomisation. 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).
This meta-analysis suggests that LMWH reduces the incidence of distal DVT diagnosed by sonogram. The clinical benefit of this is uncertain. No strong evidence was found to conclude thromboprophylaxis is effective to prevent thromboembolic events and safe, in people with unknown risk factors for thrombosis, undergoing knee arthroscopy.