A 65-year-old male with a history of obesity and osteoarthritis is scheduled for a total knee arthroplasty. He has no personal or family history of VTE. What is the most appropriate deep vein thrombosis (DVT) prophylaxis for this patient postoperatively?

The correct answer to the question "A 65-year-old male with a history of obesity and osteoarthritis is scheduled for a total knee arthroplasty. He has no personal or family history of VTE. What is the most appropriate deep vein thrombosis (DVT) prophylaxis for this patient postoperatively?" is Option C: Low molecular weight heparin (LMWH) or fondaparinux.

The other options — A) Aspirin monotherapy, B) Compression stockings only, D) No prophylaxis needed as risk is low — are incorrect for this USMLE Exam Prep question. As explained above: Major orthopedic surgery like total knee arthroplasty carries a high risk of VTE. Pharmacologic prophylaxis, such as LMWH or fondaparinux, is strongly recommended to prevent DVT and PE.