What do systematic reviews say?

Heparin vs placebo

The review found no eligible studies for this question.

• Primary prophylaxis for venous thromboembolism in people undergoing major amputation of the lower extremity 2020 · Cochrane Headline outcomes only
  no estimate extracted
  Studies not reported
  No studies found

Low molecular weight heparin vs no prophylaxis

It is very uncertain whether low‐molecular‐weight heparin changes asymptomatic DVT: compared with no prophylaxis (very low certainty).

• Interventions for preventing venous thromboembolism in adults undergoing knee arthroscopy 2022 · Cochrane Headline outcomes only
  RR 0.14 [0.03, 0.61]
  2 studies · 369 participants
  Very low

Combined NMES and low‐dose heparin vs no prophylaxis

• Neuromuscular electrical stimulation for the prevention of venous thromboembolism 2017 · Cochrane Headline outcomes only
  no estimate extracted
  1 study · 32 participants
  GRADE not reported

Unfractionated heparin vs low molecular weight heparin

It is very uncertain whether unfractionated heparin changes DVT (symptomatic, asymptomatic, non‐fatal) (5 to 8 days after surgery) compared with low molecular weight heparin (very low certainty).

• Primary prophylaxis for venous thromboembolism in people undergoing major amputation of the lower extremity 2020 · Cochrane Headline outcomes only
  OR 1.23 [0.28, 5.35]
  1 study · 75 participants
  Very low