Low-Molecular-Weight Heparin for the Prevention of Venous Thromboembolism in Patients Undergoing Knee Arthroscopic Surgery and Anterior Cruciate Ligament Reconstruction: A Meta-analysis of Randomized Controlled Trials

Am J Sports Med. 2019 Jul;47(8):1994-2002. doi: 10.1177/0363546518782705. Epub 2018 Aug 16.


Background: Low-molecular-weight heparin (LMWH) thromboprophylaxis is widely used for reducing the risk of thrombosis after major orthopaedic surgery. However, the effect and safety on knee arthroscopic surgery are still controversial.

Purpose: To assess the efficacy and safety of LMWH for the prevention of symptomatic venous thromboembolism (VTE) after knee arthroscopic surgery and anterior cruciate ligament reconstruction (ACLR) by conducting a meta-analysis of randomized controlled trials (RCTs).

Study design: Meta-analysis.

Methods: The authors searched the electronic databases of MEDLINE, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), ClinicalTrials.gov , and Web of Science for all studies from inception to June 30, 2017. All selected studies were categorized into 2 subgroups: simple knee arthroscopic surgery and ACLR. The primary effect and safety endpoint were the incidence of major VTE and major bleeding events (BEs), respectively. The secondary effect and safety endpoint were the incidence of all VTE and all BEs, respectively. Relative risks (RRs) with 95% CIs were calculated using Review Manager 5.3.

Results: Eight RCTs with 4113 patients were included. For patients undergoing simple knee arthroscopic surgery, LMWH prophylaxis did not bring a significant reduction in the risk of major VTE (RR, 1.00 [95% CI, 0.37-2.67]; P > .99) and all VTE (RR, 0.63 [95% CI, 0.31-1.29]; P = .21) and did not increase the risk of major BEs (RR, 0.98 [95% CI, 0.06-15.72]; P = .99) but did have a higher risk of all BEs (RR, 1.64 [95% CI, 1.18-2.28]; P = .003) in comparison with non-LMWH prophylaxis. For patients undergoing ACLR, LMWH prophylaxis was associated with a significantly lower rate of major VTE (RR, 0.23 [95% CI, 0.12-0.43]; P < .001) and all VTE (RR, 0.22 [95% CI, 0.06-0.73]; P = .01) but no increase in major BEs (RR, 1.80 [95% CI, 0.19-17.25]; P = .61) and all BEs (RR, 1.12 [95% CI, 0.72-1.74]; P = .61) in comparison with non-LMWH prophylaxis.

Conclusion: Compared with non-LMWH treatment, LMWH had no significant efficacy in preventing VTE in patients undergoing simple knee arthroscopic surgery but increased the risk of BEs. However, LMWH had significant efficacy in preventing VTE for patients mainly undergoing ACLR and did not increase the risk of BEs.

Keywords: arthroscopic surgery; knee; low-molecular-weight heparin; meta-analysis; venous thromboembolism.

Publication types

  • Meta-Analysis
  • Systematic Review

MeSH terms

  • Anterior Cruciate Ligament Reconstruction / adverse effects
  • Anticoagulants / administration & dosage*
  • Arthroscopy / adverse effects
  • Heparin, Low-Molecular-Weight / administration & dosage*
  • Humans
  • Randomized Controlled Trials as Topic
  • Venous Thromboembolism / epidemiology
  • Venous Thromboembolism / prevention & control*


  • Anticoagulants
  • Heparin, Low-Molecular-Weight