OBJECTIVES: Total knee arthroplasty (TKA) is a common, cost-effective orthopaedic procedure which has demonstrated highly successful clinical outcomes. However, revision procedures are sometimes necessary and are associated with significant patient morbidity and high costs. Registries have shown that revision rates can vary significantly by implant selection. The purpose of this study was to conduct an economic analysis to calculate and compare the net present value (NPV) of revision total knee procedures by prosthesis, using a well performing implant system as an illustrative example.

METHODS: This analysis uses cumulative percent revision from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR). The cost of a revision is based on the Australian Refined Diagnosis-Related Group (AR-DRG) code. A one-way deterministic sensitivity analysis was performed to calculate the NPV of revision TKA costs arising from various implant usage. NPV of revision TKA costs was caluculted using constant parameters (i.e cumulative percent revision, patient cohort size, time horizon, discount rate and national reimbursement rate) for revision knee procedures, and a varying parameter (i.e implant system usage mix).

RESULTS: There was a statistically significant difference in cumulative percent revision of the well performing implant system and that of other implant systems at 6 years. The NPV (inflation adjusted) of revision TKA cost for a 6 year time horizon was as high as 5,302,709 AUD (with 0% well performing implant system usage) and as low as 3,304,866 AUD (with 100% well performing implant system usage).

CONCLUSIONS: This analysis may be utilized by healthcare decision-makers to evaluate the economic impact of implant choice in primary TKA. With a potential savings of 1,997,843 AUD in revision TKA costs over a 6 year period for a cohort size of 1000 patients, this analysis highlights the impact of implant choice on a healthcare system.