Original Article
Extended-Duration Thromboprophylaxis With Enoxaparin After Arthroscopic Surgery of the Anterior Cruciate Ligament: A Prospective, Randomized, Placebo-Controlled Study

https://doi.org/10.1016/j.arthro.2007.02.001Get rights and content

Purpose: To compare the efficacy of extended-duration thromboprophylaxis with enoxaparin for 20 days in the outpatient setting with in-hospital thromboprophylaxis with enoxaparin (3 to 8 days) only in patients who had undergone arthroscopic surgery of the anterior cruciate ligament (ACL). Methods: This was a single-center, randomized, double-blind, prospective trial investigating 175 ACL surgery patients. All patients received subcutaneous enoxaparin 40 mg once daily 12 to 18 hours presurgery and 3 to 8 days postsurgery during hospitalization. After discharge, patients were randomized to 40 mg enoxaparin (n = 87) or placebo (n = 88) self-administered once daily subcutaneously for 20 days. The primary efficacy end-points were the incidences of symptomatic and asymptomatic deep vein thrombosis (DVT) and pulmonary embolism (PE). Primary safety endpoints were the incidences of major and minor bleeding. Results: Thirty-five patients were excluded because of noncompliance with the predefined protocol. No patient had DVT confirmed by magnetic resonance venography (MRV) at discharge. Of 140 patients in the intention-to-treat population, 2 (2.8%) who received postdischarge enoxaparin (n = 72) and 28 (41.2%) who received placebo (n = 68) had DVT confirmed by MRV (P < .001). No patients were diagnosed with PE. No major bleeds occurred. Minor bleeding occurred in 13 (2.5%) out of 513 postdischarge enoxaparin injections and 10 (2.0%) out of 492 placebo injections (P = .595). Risk factors for DVT during the 20 days postdischarge were age >30 years (odds ratio [OR]: 3.241; 95% confidence interval [CI], 1.015 to 10.349) and immobilization before surgery (OR 18.195; 95% CI, 2.046 to 161.837). Conclusions: Extended-duration postdischarge thromboprophylaxis for 20 days with enoxaparin in the outpatient setting significantly reduced the incidence of DVT in ACL surgery patients compared with enoxaparin limited to in-hospital thromboprophylaxis without increasing major or minor bleeding. Level of Evidence: Level I, high-quality randomized controlled trial.

Section snippets

Methods

This was a randomized, double-blind, prospective trial performed in a university teaching hospital in patients undergoing arthroscopic ACL surgery. The study was approved by the local ethics committee, and all participating patients provided written informed consent before enrollment.

Patients aged 19 to 55 years, with a maximum weight of 100 kg, who were admitted to the hospital for arthroscopic ACL surgery were included in this study. Patients were excluded if they had participated in another

Results

A total of 175 patients were enrolled in the study, and all patients received enoxaparin during the inpatient phase (Fig 1). At hospital discharge, no patient had MRV-confirmed DVT. Postdischarge, 87 patients were randomized to the enoxaparin treatment group and 88 patients to the placebo group.

Thirty-five patients were not included in the ITT population (Fig 1) on either medical grounds (they underwent arthroscopy but not ACL surgery, n = 16), because of noncompliance with the study protocol

Discussion

Results from this study show that, in patients who have undergone arthroscopic ACL surgery, the incidence of DVT is significantly reduced (P < .001) with extended-duration postdischarge thromboprophylaxis with enoxaparin (40 mg SC OD) for an additional 20 days compared with enoxaparin limited to in-hospital thromboprophylaxis (3 to 8 days), without an associated increase in major or minor bleeding.

The rates of DVT found in this study (extended-duration thromboprophylaxis, 2.8%; in-hospital

Conclusions

Extending the duration of thromboprophylaxis with enoxaparin by an additional 20 days postoperatively resulted in a statistically significant reduction (P < .001) in venographically detected DVT without an associated increase in major or minor bleeding compared with enoxaparin limited to in-hospital thromboprophylaxis for 3 to 8 days.

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    Supported by an unrestricted educational grant from Sanofi-Aventis, Paris, France.

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