RECORD3 was a multicentre, phase III study designed to investigate the efficacy and safety of rivaroxaban – a novel, oral, once-daily, direct Factor Xa inhibitor – compared with subcutaneous enoxaparin for thromboprophylaxis in patients undergoing total knee arthroplasty (TKA).

Patients scheduled to undergo TKA (N=2,531) were randomized to receive either rivaroxaban 10 mg once daily (initiated 6–8 hours after surgery) or enoxaparin 40 mg once daily (initiated the evening before surgery, then given 6–8 hours after surgery), and daily thereafter for 10–14 days.

The primary efficacy outcome was the composite of any deep vein thrombosis (DVT; symptomatic or asymptomatic detected by mandatory, bilateral venography), non-fatal pulmonary embolism (PE) and all-cause mortality within 13–17 days after surgery.

Rivaroxaban significantly reduced the incidence of the primary efficacy outcome compared with enoxaparin (9.6% vs 18.9%, respectively; p< 0.001; relative risk reduction [RRR] 49%). Rivaroxaban significantly reduced the incidence of major VTE (the composite of proximal DVT, non-fatal PE and VTE-related death) compared with enoxaparin (1.0% vs 2.6%, p=0.01; RRR 62%), and the incidence of symptomatic VTE (0.7% vs 2.0%, p=0.005; RRR 66%). The incidence of bleeding events was similar in both groups (major bleeding: 0.6% and 0.5% in the rivaroxaban and enoxaparin groups, respectively; any on-treatment bleeding: 4.9% and 4.8%, respectively; haemorrhagic wound complications [the composite of excessive wound haematoma and surgical-site bleeding]: 2.0% and 1.9%, respectively). There were no deaths or PEs in the rivaroxaban group during the treatment period, and two deaths and four PEs in the enoxaparin group.

Rivaroxaban was significantly more effective than enoxaparin for the prevention of VTE after TKA, with a similar rate of bleeding. The oral, direct Factor Xa inhibitor rivaroxaban, given once daily as a fixed, unmonitored dose of 10 mg, has the potential to change clinical practice for thromboprophylaxis after TKA.

Dabigatran etexilate (Pradaxa^®) is an oral anticoagulant licensed in multiple countries, Europe and Canada, for the prevention of venous thromboembolic events (VTE) in patients undergoing total hip replacement surgery (THR) or total knee replacement surgery (TKR). The label recommendation for therapy initiation of dabigatran etexilate is a half dose given 1–4 hours after surgery. If this is not possible, then dabigatran etexilate should be started the day following surgery with the full dose. In the European pivotal Phase III clinical trials, this initial dosing was delayed until the day after surgery in 14% of the cases. This prompted a post hoc study to analyze if these patients received adequate thromboprophylaxis. Pooled efficacy data of major VTE events (composite of proximal DVT, symptomatic DVT, pulmonary embolism and VTE-related death) from the two European pivotal trials (RE-MODEL; Eriksson BI et al. J Thromb Haemost2007;5:2178–2185, and RENOVATE; Eriksson BI et al. Lancet2007;370:949–956) where analyzed. The group with delayed dosing was compared to the group that received therapy initiation on the day of surgery to determine if there was any significant effect on clinical outcome. The final decision on the timing of the administration of the first dose required sometimes clinical judgment, and in particular good haemostasis had to be present. Therefore, the bleeding rate and the timing of the first dose are confounded and an analysis of bleeding events was not performed. The major VTE rate in the group with delayed treatment initiation compared with the 1–4 hour post surgery treatment initiation group were 2.2% (95% CI: 0.1–4.4) vs. 3.0% (95% CI: 2.0–3.9) for 220 mg dabigatran etexilate, 8.3% (95% CI: 4.3–12.4) vs. 3.5% (95% CI 2.5–4.5) for 150 mg dabigatran etexilate, and 4.3% (95% CI 1.2–7.4) vs. 3.7% (95% CI 2.7–4.8) for 40 mg enoxaparin. As the confidence intervals overlap markedly, no statistically significant differences where found. In conclusion, no difference in the rates of major VTE and VTE related mortality was seen when the doses of dabigatran etexilate were postponed to the first postoperative day. These data need to be interpreted carefully due to the low number of patients in the delayed treatment group. As recommended in the current labelling of dabigatran etexilate, treatment should be initiated 1–4 hours post-surgery.

The oral direct thrombin inhibitor dabigatran etexilate (Pradaxa^®) was recently approved in Europe for the prevention of venous thromboembolism (VTE) in patients undergoing elective total knee or total hip replacement surgery. In the Phase III RE-MODEL (Eriksson BI et al. J Thromb Haemost2007; 5: 2178–2185) and RENOVATE (Eriksson BI et al. Lancet2007; 370: 949–956) clinical trials the safety and efficacy of 220 mg and 150 mg dabigatran etexilate once daily were studied. In both trials these doses were compared with 40 mg subcutaneous enoxaparin. A post hoc pooled analysis was performed in patients with moderate renal impairment (glomerular filtration rate ≥ 30 and < 50 ml/min) who participated in these two trials. The primary efficacy endpoint in both studies and the post hoc analysis was total VTE and all cause mortality; the key pre-specified secondary efficacy endpoint was major VTE and VTE-related mortality. Bleeding events (the primary safety endpoint) were blindly adjudicated and categorised as major bleeding events (MBE), which includes surgical site bleedings. A total of 1825 patients were treated with 220 mg dabigatran etexilate, 1866 with 150 mg dabigatran etexilate and 1848 with 40 mg enoxaparin. Of these, 337 patients had moderate renal impairment. 68% of these patients could be evaluated for the primary efficacy endpoint, 72% for the secondary efficacy endpoint, and all patients were included in the safety and bleeding analyses. The incidence of total VTE and all cause mortality was 17.7% (14/79), 23.5% (16/68) and 27.8% (25/90) in the 220 mg dabigatran etexilate, 150 mg dabigatran etexilate and enoxaparin groups, respectively. When the secondary efficacy endpoint was analysed a similar trend was seen, with a descriptive statistical significance for a lower event rate in the 220 mg group: 1.2% (1/83; p=0.04 vs enoxaparin using Fisher’s exact test), 4.3% (3/70) with 150 mg dabigatran etexilate; and 9.0% (8/89) in the enoxaparin group. MBE occurred in 6/113 patients (5.3%) in the 220 mg dabigatran etexilate-treated group, in none of the patients in the 150 mg dabigatran etexilate-treated group (0/96; p=0.04 vs enoxaparin using Fisher’s exact test), and in 6/128 patients (4.7%) receiving enoxaparin. Of note, 3/6 MBE in the 220 mg group started before oral dabigatran etexilate treatment was initiated. In conclusion, oral 150 mg dabigatran etexilate showed similar efficacy compared with subcutaneous enoxaparin in patients with moderate renal impairment undergoing hip or knee replacement surgery, with an apparently lower rate of major bleeding. As bleeding is a major concern, especially in this population, the 150 mg once daily dose of dabigatran etexilate is currently recommended by EMEA for this group.

Dabigatran etexilate (Pradaxa^®) is an oral direct thrombin inhibitor that was recently approved in Europe and Canada for the prevention of venous thromboembolism (VTE) in patients undergoing elective total knee replacement or total hip replacement surgery. Two pivotal clinical trials, RE-MODEL (Eriksson BI et al. J Thromb Haemost2007; 5: 2178–2185) and RENOVATE (Eriksson BI et al. Lancet2007; 370: 949–956), studied the efficacy and safety of 220 mg and 150 mg dabigatran etexilate once daily compared with 40 mg subcutaneous enoxaparin. A post hoc pooled analysis was performed in elderly patients (> 75 years) since renal function gradually declines with age. The primary efficacy endpoint was total VTE and all cause mortality and the secondary efficacy endpoint was major VTE and VTE-related mortality. The primary safety endpoint was major bleeding events (MBE), including those occurring at the surgical site. All bleeding events were blindly adjudicated. Of the patients treated with 220 mg dabigatran etexilate (n=1825), 150 mg dabigatran etexilate (n=1866) and enoxaparin (n=1848), 883 patients (16%) were over 75 years. 73% of these elderly patients were evaluable for the primary efficacy endpoint and 75% were evaluable for the secondary efficacy endpoint. All patients > 75 years were evaluable for safety outcomes, including bleeding. The incidence of total VTE and all cause mortality was 20.8% (44/212), 22.6% (49/217), and 27.2% (58/213), respectively, in the three groups. A similar trend was observed for major VTE and VTE-related mortality: 220 mg dabigatran etexilate, 1.9% (4/216, p=0.045 vs enoxaparin using Fisher’s exact test); 150 mg dabigatran etexilate, 4.5% (10/221); enoxaparin, 6.0% (13/218). MBE occurred in 11 of the 295 elderly patients receiving 220 mg dabigatran etexilate (3.7%), 4 of the 282 elderly patients receiving 150 mg dabigatran etexilate (1.4%) and in 9 of the 306 elderly patients taking enoxaparin (2.9%). Notably, 6/11 MBE in the dabigatran 220 mg group and 2/4 MBE in the 150 mg group started before the first dose of treatment. We conclude that in elderly patients (> 75 years) undergoing hip or knee replacement surgery, oral 150 mg dabigatran etexilate exhibited a numerically favourable bleeding profile with no difference in efficacy compared with 40 mg enoxaparin. Because safety, particularly bleeding, is of paramount importance in the elderly, the 150 mg once daily dose of dabigatran etexilate is currently recommended by EMEA for this group.

Introduction: Rivaroxaban is a novel, oral, direct Factor Xa inhibitor in advanced clinical development for the prevention and treatment of thromboembolic disorders. In this phase III trial, the efficacy and safety of thromboprophylaxis with rivaroxaban was compared with enoxaparin in patients undergoing total knee replacement (TKR).

Methods: In RECORD3 – a randomized, double-blind trial – patients received rivaroxaban 10 mg 6–8 hours after surgery and once daily (od) thereafter, or enoxaparin 40 mg od beginning the evening before surgery; both were continued for 10–14 days. The primary efficacy outcome was the composite of any deep vein thrombosis (DVT), non-fatal pulmonary embolism (PE) and all-cause mortality. Secondary efficacy outcomes included major venous thromboembolism (VTE; the composite of proximal DVT, PE and VTE -related death) and symptomatic VTE. The primary safety outcome was major bleeding, and other safety outcomes included any on-treatment bleeding and haemorrhagic wound complications (the composite of excessive wound haematoma and surgical-site bleeding).

Results: A total of 2531 patients were randomized; 2459 were eligible for inclusion in the safety population and 1702 for the modified intention-to-treat population. The primary efficacy outcome was reported in 9.6% of patients receiving rivaroxaban and 18.9% of patients receiving enoxaparin. This equated to a relative risk reduction of 49% (p< 0.001) with rivaroxaban compared with enoxaparin. The incidence of major VTE was also significantly reduced with rivaroxaban compared with enoxaparin (relative risk reduction 62%, p=0.016). The incidence of symptomatic VTE was significantly lower in the rivaroxaban group than in the enoxaparin group (p=0.005). Major bleeding rates were 0.6% and 0.5% in the rivaroxaban and enoxaparin groups, respectively, and rates of any on-treatment bleeding were 4.9% and 4.8%, respectively. The incidence of haemorrhagic wound complications was 2.1% in the rivaroxaban group and 1.9% in the enoxaparin group.

Conclusions: Rivaroxaban was significantly more effective than enoxaparin for the prevention of VTE after TKR, with a similar safety profile. The oral, direct Factor Xa inhibitor rivaroxaban, given as a fixed, unmonitored dose, may have the potential to change clinical practice for thromboprophylaxis after TKR.

Purpose: Rivaroxaban is a novel, oral, direct Factor Xa inhibitor in advanced clinical development for the prevention and treatment of thromboembolic disorders. RECORD3 was a phase III trial conducted to compare the efficacy and safety of oral rivaroxaban with subcutaneous enoxaparin for the prevention of venous thromboembolism (VTE) in patients undergoing total knee replacement (TKR).

Method: In this randomized, double-blind trial, patients received rivaroxaban 10 mg once daily (od), or enoxaparin 40 mg od. Enoxaparin was initiated the evening before surgery, and rivaroxaban 6–8 hours after surgery; therapy continued for 10–14 days. The primary efficacy outcome was the composite of any deep vein thrombosis (DVT), pulmonary embolism (PE), and all-cause mortality. Secondary efficacy outcomes included major VTE (the composite of proximal DVT, PE, and VTE-related death) and symptomatic VTE. Major bleeding was the primary safety outcome. Other safety outcomes included any on-treatment bleeding and hemorrhagic wound complications (the composite of excessive wound hematoma and surgical-site bleeding).

Results: A total of 2531 patients were randomized; 2459 were eligible for inclusion in the safety population and 1702 for the modified intention-to-treat population. The incidence of the primary efficacy outcome was significantly reduced with rivaroxaban compared with enoxaparin (relative risk reduction 49%, p< 0.001). Major VTE occurred in 1.0% and 2.6% of patients receiving rivaroxaban and enoxaparin, respectively (relative risk reduction 62%, p=0.016). The incidence of symptomatic VTE was significantly lower in the rivaroxaban group than in the enoxaparin group (p=0.005). Major bleeding rates were 0.6% and 0.5% in the rivaroxaban and enoxaparin groups, respectively, and rates of any on-treatment bleeding were 4.9% and 4.8%, respectively. The incidence of hemorrhagic wound complications was 2.1% in the rivaroxaban group and 1.9% in the enoxaparin group.

Conclusion: Rivaroxaban was significantly more effective than enoxaparin for thromboprophylaxis after TKR. Importantly, the incidence of bleeding was low and similar in both groups. This is the first trial to demonstrate the efficacy and safety of a fixed, unmonitored regimen of an oral, direct Factor Xa inhibitor – rivaroxaban – for thromboprophylaxis after TKR.

Continuous neuraxial or deep peripheral nerve blockade used to provide postoperative analgesia after major orthopaedic surgery is associated with a risk of spinal or perineural haematoma, especially in patients concomitantly receiving anticoagulants. Limited data on the use of fondaparinux in surgical patients in whom this procedure is performed are available. The EXPERT trial was an observational international study in patients undergoing major orthopaedic surgery designed to evaluate the overall efficacy and safety of once-daily 2.5 mg fondaparinux initiated 6 to 12 hours post-operatively and administered for 4±1 weeks after surgery. A 48-hour “therapeutic window” was applied in patients in whom a neuraxial/deep peripheral indwelling catheter was placed: one of the planned doses of fondaparinux was omitted, the catheter was removed 36 hours after the previous fondaparinux dose, and the next fondaparinux dose administered 12 hours after catheter removal. The primary endpoints were symptomatic venous thromboembolism (VTE) and major bleeding 5±1 weeks after surgery. These events were validated by an independent adjudication committee. Overall, 5704 patients (mean age ± SD: 66 ± 12 years) were recruited between July 2003 and October 2004. They underwent surgery for total hip replacement (52%, n=2941), knee replacement (40%, n=2263), hip fracture (6%, n=353), or other indications (3%, n=148). Fondaparinux was given for a median of 35 (range: 1–105) days. Many operations (62%) were performed under regional anaesthesia only. A neuraxial or deep peripheral nerve block catheter was placed in 29% (n=1630) of patients. It was removed between one and two days after surgery in 43% (706/1626), and between three and six days after surgery in 57% (920/1626). Overall, the rate of symptomatic VTE was 1.0% (54/5387); it was 0.8% (13/1535) in patients with catheter and 1.1% (41/3852) in patients without catheter, giving an odds ratio of 0.79 (95% CI: 0.42 to 1.49) in favour of patients with a catheter. The upper limit of the 95% CI being below the predetermined non-inferiority margin of 1.75, the efficacy of fondaparinux in patients with a catheter was therefore not inferior to that observed in patients without a catheter. The rate of major bleeding was 0.8% (42/5382) overall, 0.5% (7/1532) in patients with catheter and 0.9% (35/3850) in patients without catheter. No spinal or perineural hematomas or nerve damage were reported. At 5±1 weeks, 23 (0.4%) patients had died. In conclusion, 2.5 mg fondaparinux given daily for 4±1 weeks after major orthopaedic surgery was both effective and safe in routine practice. This benefit-risk ratio was similar in 1630 patients with a neuraxial/ deep peripheral indwelling catheter in whom a 48-hour “therapeutic window” was applied.

BACKGROUND: Oral DVT prophylaxis not requiring monitoring is an advantage in orthopaedic patients. Dabigatran etexilate is an oral direct thrombin inhibitor undergoing evaluation for the prevention of venous thromboembolic events (VTE) following orthopaedic surgery.

METHODS: In a phase III, multicenter, non-inferiority, double-blind study, patients undergoing total knee replacement were randomized to 3 treatments. The patients received 8±2 days of oral dabigatran etexilate, 150 or 220 mg once daily starting with a half dose (i.e.75 or 110 mg) 1–4 hours after surgery, or subcutaneous enoxaparin 40 mg once daily starting 12 hours prior to surgery. The primary efficacy outcome was the composite of total VTE and all causes of mortality during the treatment period. All efficacy and safety outcome events were adjudicated by blinded independent committees.

RESULTS: Efficacy could be evaluated for 1541 (75%) treated and operated patients. Total VTE and death occurred in 40.5%, 36.4% and 37.7% of patients assigned to dabigatran etexilate 150 or 220mg once daily or enoxaparin, respectively. Proximal DVT and/ or PE occurred in 3.8%, 2.6% and 3.5% of patients receiving dabigatran 150 or 220mg or enoxaparin, respectively. Three deaths occurred during the treatment period, one in each of the treatment groups. Safety was evaluated for all 2076 patients receiving study treatment. The rate of major bleeding was 1.3%, 1.5% and 1.3% of patients receiving dabigatran 150 or 220mg or enoxaparin. Elevated LFTs (ALT > 3xULN) occurred in 3.7%, 2.8% and 4.0% of the patients treated with 150 and 220 mg dabigatran or enoxaparin during the study. A temporary rise in LFTs was observed during the follow-up period in 0.5% of the patients who had received dabigatran and in 0.4% of the patients who had received enoxaparin.

CONCLUSIONS: Non-inferiority for the primary efficacy endpoint was met for both doses of dabigatran etexilate compared to enoxaparin. There was no difference in bleeding rates between the treatment groups. Oral administration of dabigatran etexilate once daily, given early in the postoperative period, was effective and safe for the prevention of total VTE in patients undergoing total knee replacement surgery.

Introduction Recent changes in the management of hip fracture surgery patients may have resulted in changes in the epidemiology of venous thromboembolism (VTE). We aimed to determine the incidence of and predictive risk factors for symptomatic VTE and mortality, and the use of VTE prophylaxis, in hip fracture surgery patients.

Methods Hip fracture surgery patients were enrolled in 525 hospitals in France between October 1 and November 30, 2002 in this prospective, multicenter, epidemiological study. VTE was assessed by a critical events committee at 3 months. Risk factors were identified using logistic regression.

Results Data were from 6860 (97%) of 7019 enrolled patients. Median age was 82 years and 76% were women. 47% were femoral neck and 53% trochanteric or subtrochanteric fractures. All were operated on (osteosynthesis 57%, half prosthesis 35% and THR 8%).

Prophylaxis with a low-molecular-weight heparin (LMWH) was administered perioperatively in 97.6% and for at least four weeks in 69.5% (median prophylaxis duration: 6 weeks). The rate of symptomatic VTE at 3 months was 1.34% (95% CI: 1.04– 1.64). There were 16 PE (rate 0.25%) and 3 were fatal. The rate of major bleeding was 1.2%. At 6 months, 1006 patients (14.7%) were dead. Significant risk factors for symptomatic VTE were: history of VTE (OR 2.9), induction of anesthesia until arrival in the recovery room > 2 hrs (OR 2.5), and varicose veins/post-thrombotic syndrome (OR 2.2). LMWH prophylaxis significantly reduced the risk of symptomatic VTE (OR 0.2).

Significant predictive factors for mortality were: cancer (OR 2.3), surgical complications requiring re-intervention (OR 1.8), confusion before fracture (OR 1.8), ASA score ≥3 (OR 1.7), BMI ≤18 kg/m2 (OR 1.6), congestive heart failure (OR 1.6), atrial fibrillation (OR 1.6) and age > 80 years (OR 1.1).

Conclusions Extended LMWH prophylaxis is applied widely after hip fracture surgery in France. The current rate of postoperative VTE is low. However, a major change in the care of these patients is needed because of the high mortality rate.

Purpose: Periprosthetic ossification is a frequent complication of total hip arthroplasty and can have a major functional impact. Non-steroidal anti-inflammatory drugs (NSAID) can provide effective prevention but with a risk of morbidity. The purpose of this work was to evaluate the efficacy of an anti-Cox2 agent, cele-coxib, for this indication.

Material and methods: Total hip arthroplasty was performed in 42 patients with a relative (gastrointestinal) contraindication for the use of NSAID. These patients were given celecoxib (Celebrxy(r)) 200 mg bid starting the day before the operation and continuing for at least five days. A control group of 42 age- (±3 yr) and sex-matched patients who underwent surgery for the same indication performed by a surgeon with equivalent experience was also established. The control patients were given ketoprofen (Profénidy(r)) 50 mg qid for two days then 150 mg bid for five days. The approach, implant, and other adjuvant treatments were equivalent between the two groups. Ossifications were analysed on the follow-up films taken at least three months after surgery. The Brooker classification was used. The exact Fisher test was used for the statistical analysis.

Results: The two groups each included 31 women and eleven men, mean age being the same in the two groups (67.12 yrs). Mean follow-up was very similar (8.44 vs 8.6 months). Aetiologies were: primary degenerative hip (n=30), degenerative hip disease after dysplasia (n=9), sequela of infantile arthritis (n=1), revision total hip prosthesis (n=2). Two patients in each group interrupted their treatment between day 2 and 4 because of intolerance. There were no cases of significant haematoma in either group. No ossification > grade 2 was observed. The overall rate of ossification was 42.5% in the control group versus 48.6% in the celecoxib group. The rate of grade 2 ossifications was 8% in the cele-coxib group versus 12% in the control group. These rates were not significantly different (Fisher’s exact test= 0.6).

Discussion: In this study, celecoxib and ketoprofen were found to have equivalent efficacy for the prevention periprosthetic ossification. This is an interesting perspective in the probable hypothesis of less morbidity with anti-Cox 2 antiinflammatory drugs used in combination with an antalgesia protocol.

Aims: To investigate the efficacy and safety of a new dosage regimen of the oral direct thrombin inhibitor ximelagatran, and its subcutaneous (sc) form melagatran, started in close proximity to surgery. Methods: In a randomised, double-blind, parallel-group study, duration 8–11 days, patients undergoing total hip or knee replacement (THR, n= 1856; TKR, n= 908) received either sc melagatran 2 mg immediately before surgery followed by sc 3 mg in the evening after surgery, and then by oral ximelagatran 24 mg bid as a fixed dose (the ximelagatran group), or sc enoxaparin 40 mg od, started the evening before surgery. Bilateral venography was performed on the final day of treatment. Results: The rate of proximal deep vein thrombosis plus pulmonary embolism was 2.3% in the ximelagatran group vs. 6.3% in the enoxaparin group (p< 0.000002; RRR 63.2%). The total rates of venous thromboembolism (VTE) were 20.3% vs. 26.6%, respectively (p< 0.0003; RRR 23.6%). Cases with symptomatic VTE were rare: 8 in the ximelagatran group and 12 in the enoxaparin group. Bleeding events were more common in the ximelagatran group compared with the enoxaparin group (3.3% vs. 1.2%) as were the transfusion rates (66.8% vs. 61.7%). Importantly, there were no differences in fatal bleeding, critical organ bleeding or bleeding requiring re-operation. Conclusion: Pre-operatively initiated sc melagatran followed by oral ximelagatran was superior in efficacy to enoxaparin in preventing VTE in patients undergoing THR or TKR.

Ximelagatran is an oral direct thrombin inhibitor intended for the prophylaxis and treatment of thrombo-embolic complications. Purpose: The efficacy and safety of ximelagatran, and its subcutaneous (sc) form melagatran, were evaluated in patients undergoing total hip or knee replacement (THR, TKR). Study 1 was a randomised, double-blind, controlled, dose–response study in which patients received 2-6 doses of sc melagatran (1, 1.5, 2.25, or 3 mg bid) followed by oral ximelagatran (8, 12, 18, or 24 mg bid), or sc dalteparin (5000 IU od). Melagatran treatment was initiated immediately before surgery. Study 2 was a randomized, double-blind, controlled study in which patients received 1–5 doses of sc melagatran (3 mg bid) initiated 4–12 h after surgery followed by oral ximelagatran (24 mg bid), or sc enoxaparin (40 mg od). In both studies, low-molecular-weight heparin (LMWH) was started the evening before surgery, and all treatment regimens were continued for 8–11 days. Bilateral venography was performed on the final day of treatment.

Results: In Study 1, 1876 patients underwent THR (n=1270) or TKR (n=606). A significant dose-dependent reduction in venous thromboembolism (VTE) was seen with melagatran + ximelagatran for both THR (P< 0.0001) and TKR (P=0.0014). The rate of VTE was significantly lower with the highest dose of melagatran + ximelagatran (15.1%) when compared with dalteparin (28.2%) (P< 0.0001). In Study 2, 2788 patients underwent THR (n=1923) or TKR (n=865). The VTE rate was 31% in the melagatran + ximelagatran group and 27% in the enoxaparin group (P=0.053). Total bleeding volume was not significantly different between treatment groups. Conclusion: Fixed-dose sc melagatran followed by oral ximelagatran are efficacious and well tolerated for the prophylaxis of VTE following THR or TKR.