Background: Total knee arthroplasty is one of the most clinically successful and cost-effective interventions in medicine. However, implant malalignment, especially in the coronal plane, is a common cause of early failure following total knee arthroplasty. Computer-assisted surgery has been employed during total knee arthroplasty to improve the precision of component alignment. The purpose of the present study was to evaluate the cost-effectiveness of computer-assisted surgery to determine whether the improved alignment achieved with computer navigation provides a sufficient decrease in failure rates and revisions to justify the added cost.
Methods: A decision-analysis model was used to estimate the cost-effectiveness of computer-assisted surgery in total knee arthroplasty. Model inputs, including costs, effectiveness, and clinical outcome probabilities, were obtained from a review of the literature. Sensitivity analyses were performed to evaluate the impact of component-alignment precision with use of computer-assisted and mechanical alignment guides, total knee arthroplasty failure rates secondary to malalignment, and costs of computer-assisted surgery systems on the cost-effectiveness of computer navigation in total knee arthroplasty.
Results: Computer-assisted surgery is both more effective and more expensive than mechanical alignment systems. Given an additional cost of $1500 per operation, a 14% improvement in coronal alignment precision (within 3 degrees of neutral mechanical axis), and an elevenfold increase in revision rates at fifteen years with coronal malalignment (54% compared with 4.7%), the incremental cost of using computer-assisted surgery is $45,554 per quality-adjusted life-year gained. Cost-savings is achieved if the added cost of computer-assisted surgery is $629 or less per operation. Variability in published clinical outcomes, however, introduces uncertainty in determining the cost-effectiveness.
Conclusions: Computer-assisted surgery is potentially a cost-effective or cost-saving addition to total knee arthroplasty. However, the cost-effectiveness is sensitive to variability in the costs of computer navigation systems, the accuracy of alignment achieved with computer navigation, and the probability of revision total knee arthroplasty with malalignment.