DVT Prophylaxis for Left Leg Surgery and Left Arm Fracture
Yes, this patient requires DVT prophylaxis based on the left leg surgery alone, regardless of the arm fracture. The arm fracture does not contribute to VTE risk and should not influence the decision.
Risk Assessment Based on Leg Surgery Type
The need for and type of prophylaxis depends entirely on what type of left leg surgery was performed:
Major Lower Extremity Orthopedic Surgery (Hip/Knee Replacement, Hip Fracture Surgery, Femur Nailing)
Pharmacologic prophylaxis is mandatory for these procedures, as they carry a 41-85% risk of DVT without prophylaxis 1.
- Preferred agent: Low-molecular-weight heparin (LMWH) started 12-24 hours postoperatively once hemostasis is achieved 2
- Minimum duration: 10-14 days for all major orthopedic procedures 3
- Extended prophylaxis (up to 35 days) should be strongly considered if the patient has additional risk factors including: previous VTE history, active cancer, known thrombophilia, multiple risk factors (Caprini score ≥5), or prolonged immobilization 2, 3
- Alternative agents include direct oral anticoagulants (apixaban, rivaroxaban, dabigatran) if compliance with injections is problematic 2
Lower Leg Injuries Requiring Immobilization (Plaster Cast, Brace)
The ACCP suggests no routine prophylaxis for isolated lower-leg injuries requiring immobilization (Grade 2C recommendation) 4. However, this recommendation applies only to patients without additional risk factors 5.
- Consider LMWH prophylaxis if the patient has: previous VTE, active cancer, known thrombophilia, multiple risk factors (Caprini score ≥5), or prolonged immobilization expected 4
- For low-risk patients without these factors, mechanical prophylaxis with early mobilization is sufficient 4
- Recent evidence shows LMWH reduces VTE from 17.1% to 9.6% in lower extremity immobilization, though bleeding risk must be weighed 5
Knee Arthroscopy
No thromboprophylaxis is recommended for simple knee arthroscopy without prior VTE history (Grade 2B recommendation) 5, 4.
- Knee arthroscopy carries only 3% risk of symptomatic proximal DVT 5
- Exception: Consider prophylaxis only if the patient has a history of prior VTE 4
Regarding the Arm Fracture
Upper extremity injuries do not require DVT prophylaxis and do not contribute to VTE risk assessment 5. The arm fracture is irrelevant to this decision.
Bleeding Risk Modifications
If the patient has increased bleeding risk from either injury:
- Use mechanical prophylaxis alone (intermittent pneumatic compression devices achieving 18 hours daily compliance) until bleeding risk decreases 4, 3
- Then add pharmacologic agents once hemostasis is secure 2
Critical Pitfalls to Avoid
- Do not stop prophylaxis at hospital discharge if major orthopedic surgery was performed—VTE risk persists for up to 3 months postoperatively 2
- Do not overprescribe anticoagulation for low-risk procedures like simple knee arthroscopy, as this increases bleeding without proven benefit 4
- Do not screen for asymptomatic DVT, as this leads to unnecessary anticoagulation and increased bleeding risk without improving outcomes 4, 2
- Do not assume mechanical prophylaxis alone is sufficient for major orthopedic surgery in standard-risk patients 3