What is the recommended approach for deep vein thrombosis (DVT) prophylaxis in patients undergoing total hip arthroplasty (THA)?

DVT Prophylaxis for Total Hip Arthroplasty

Low molecular weight heparin (LMWH) or fondaparinux should be used as first-line pharmacological prophylaxis for all patients undergoing total hip arthroplasty, starting 12-24 hours postoperatively and continuing for a minimum of 10-14 days with strong consideration for extended prophylaxis up to 35 days. 1, 2

Preferred Pharmacological Agents

LMWH is the most intensively studied and preferred thromboprophylactic agent for hip replacement surgery. 1 The standard dosing regimen is enoxaparin 30 mg subcutaneously twice daily or 40 mg once daily, initiated 12-24 hours after surgery. 3, 2

Fondaparinux (2.5 mg subcutaneously once daily) is considered an equal alternative to LMWH and should be started 6-10 hours postoperatively. 3, 1 However, fondaparinux is contraindicated in severe renal insufficiency (CrCl <30 mL/min) and requires dose reduction to 1.5 mg once daily in moderate impairment (CrCl 30-50 mL/min). 3, 1

Direct oral anticoagulants offer the advantage of oral administration without INR monitoring. Rivaroxaban 10 mg once daily, started 6-10 hours postoperatively, is FDA-approved and demonstrated reduced DVT, PE, or death without increased bleeding compared to enoxaparin. 3, 1, 2 Apixaban 2.5 mg twice daily demonstrated superiority to enoxaparin in hip replacement (1.4% vs 3.9% VTE, RR 0.36, P<0.001). 1, 4

Adjusted-dose warfarin (target INR 2.0-3.0) is an acceptable but less preferred alternative due to logistic difficulties, higher bleeding risk (3.3% vs 5.3% with LMWH, P=0.002), and lower efficacy (20.7% DVT rate vs 13.7% with LMWH, P=0.0002). 3, 2

Duration of Prophylaxis

Extended prophylaxis up to 35 days is strongly recommended as the risk of VTE persists for 2-3 months following hip replacement. 1, 2 The minimum acceptable duration is 10-14 days, but this leaves patients vulnerable to postdischarge VTE events. 3, 1, 2

Extended prophylaxis (approximately 5 weeks total) significantly reduces the continuing DVT risk of 12-37% demonstrated in six randomized double-blind trials. 2 The RECORD 2 trial showed that extended rivaroxaban (31-39 days) was more effective than shorter-duration enoxaparin (10-14 days) without increased bleeding. 2

Mechanical Prophylaxis

Intermittent pneumatic compression (IPC) devices or graduated elastic compression stockings should be used as adjuncts to pharmacological prophylaxis. 3, 1, 2 Combined mechanical and pharmacological prophylaxis reduces DVT risk by 66% compared to either modality alone. 1

Mechanical prophylaxis alone is reserved only for patients with high bleeding risk until pharmacological agents can be safely initiated. 3, 1

High Bleeding Risk Patients

In patients with active bleeding, coagulopathy, or hemodynamic instability, use IPC devices alone until stabilization occurs. 3, 1 Once bleeding risk diminishes, transition to pharmacological prophylaxis. 3

The ACCP, ICS, SIGN, French, and Brazilian guidelines all support mechanical devices without pharmacological prophylaxis specifically for patients at high bleeding risk (Grade 2C). 3

Renal Impairment Considerations

For patients with severe renal impairment (CrCl <30 mL/min), avoid fondaparinux and rivaroxaban. 1 Switch to unfractionated heparin 5000 units subcutaneously every 8 hours instead of LMWH in patients with renal failure. 5 Apixaban does not require dose adjustment in renal impairment, including ESRD on dialysis. 4

Critical Contraindications and Pitfalls

Do not use aspirin as sole prophylaxis—it is explicitly recommended against by ACCP and French guidelines. 3, 1 While one recent study suggested aspirin efficacy in femoral neck fracture patients 6, this contradicts established guidelines for elective THA and should not be extrapolated to the elective arthroplasty population.

Do not stop prophylaxis at hospital discharge—extended prophylaxis significantly reduces postdischarge VTE, particularly after hip replacement. 1, 2 Many VTE events occur after discharge, leading surgeons to underestimate the true thrombosis rate in their practice. 3

Coordinate LMWH timing carefully with neuraxial anesthesia to minimize bleeding risk. 5 Administer the first postoperative dose at least 12 hours after epidural catheter removal.

Failure to adjust for renal function can lead to bleeding complications, particularly with renally-cleared agents like fondaparinux and rivaroxaban. 1, 5

Algorithm for Agent Selection

1. Standard risk patient with normal renal function: LMWH (enoxaparin 30 mg BID or 40 mg daily) or fondaparinux 2.5 mg daily for 10-35 days 1, 2

2. Patient preferring oral medication: Rivaroxaban 10 mg daily or apixaban 2.5 mg BID for 10-35 days 1, 2

3. Moderate renal impairment (CrCl 30-50 mL/min): Reduce fondaparinux to 1.5 mg daily, use caution with rivaroxaban, or use apixaban without dose adjustment 3, 1, 4

4. Severe renal impairment (CrCl <30 mL/min): Unfractionated heparin 5000 units TID or apixaban 5, 4

5. High bleeding risk: IPC devices alone until bleeding risk resolves, then initiate pharmacological prophylaxis 3, 1

6. History of VTE: Continue home anticoagulation postoperatively with multimodal prophylaxis including IPC devices 7