Natural History
Insall 1984 / no prophylaxis
- DVT 70 - 80%
- asymptomatic PE 8 -17%
- symptomatic PE 0.5 -3%
- death 0.2%
- most commonly in calf / 85-90% below trifurcation
THR
- THR only 10-15% below trifurcation
Bilateral DVT in 10-15%
Prophylaxis
Mechanical prophylaxis
- TEDS
- compression stockings
- early mobilisation
Chemical prophylaxis
- LMWH / enoxaparin
- factor Xa (oral) / rivaroxaban
With appropriate prophylaxis
- symptomatic DVT 1/10 or less
- symptomatic PE 1 or 2 / 100
- fatal PE 1 / 1000
Results
Brookenthal et al J Arthroplasty 2001
- meta-analysis
- LMWH better than warfarin at preventing proximal DVT
- no significant difference in LMWH / warfarin / aspirin in reducing symptomatic or fatal PE
- no significant difference in bleeding rates
Edwards et al J Arthroplasty 2008
- RCT of LMWH v LMWH + compression stocking
- significant reduction in DVT rates
CRISTAL study group JAMA 2022
- RCT 100mg aspirin v 40 mg enoxeparin in 9711 THA and TKA patients
- symptomatic VTE in aspirin group was 3.5%
- symptomatic VTE in enoxeparin group was 1.8%
https://pubmed.ncbi.nlm.nih.gov/35997730/