Hidden costs of first choice alternatives: A financial model of thromboprophylaxis and prosthetic joint infection prophylaxis in total knee arthroplasty

Background: Aspirin has been shown to be equally or more effective than factor Xa inhibitors for thromboprophylaxis following total knee arthroplasty (TKA). Cefazolin has been proven more effective than vancomycin in preventing prosthetic joint infection (PJI) after TKA. This study aimed to compare costs between different drug combinations for prevention of venous thromboembolism (VTE) and PJI following TKA, focusing on costs associated with PJI management.

Methods: We used published PJI rates for TKA patients treated with aspirin or factor Xa inhibitors for thromboprophylaxis, as well as for those who received prophylactic cefazolin or vancomycin. Unit prices for each drug and labor costs associated with vancomycin administration were obtained from our hospital's pharmacy service. The PJI cost model included the price of 2-stage septic TKA revision and national projections of future TKA volume.

Results: The least expensive average per-patient cost resulted from the combination of aspirin and cefazolin, equating to $521.19 given a 0.8 % PJI rate. The most expensive average per-patient cost was the combination of a factor Xa inhibitor and vancomycin, equaling $5,714.96 given a 1.8 % PJI rate. This extrapolates to an annual cost burden of $19.5 billion by 2040.

Conclusion: The average per-patient cost of using a combination of a factor Xa inhibitor and vancomycin is 711 % greater than the combination of aspirin and cefazolin. In this era of value-based care, aspirin and cefazolin should be considered gold standards for TKA thromboprophylaxis and PJI prophylaxis, as they reduce costs and improve patient outcomes.