OBJECTIVES: New Innovative Knee Implants (IKIs) have the potential to reduce patients' awareness of the artificial knee, increase their confidence in performing daily activities, and reduce problems leading to revisions compared with Contemporary Knee Implants (CKI). This study aimed to illustrate the expected economic value of a new IKI among osteoarthritis (OA) patients requiring total knee arthroplasty (TKA).
METHODS: A Markov model was developed to explore the cost-effectiveness of the IKI compared with CKIs among OA patients undergoing TKA from a United States payer perspective. The model design distinguished between the IKI and CKIs in terms of functional status and implant survivorship. CKI survivorship was estimated using patient-level survivorship data with SIGMA fixed bearing knees from the United Kingdom National Joint Registry. To estimate IKI survivorship, the approach used by Suter et al. (2011) was adopted. Adjustments were made to the risk of revision for causes addressed in the design of the IKI, specifically, wear, loosening, pain, instability, patella maltracking, and stiffness. Costs and utilities associated with various health states were literature based.
RESULTS: The model predicts that the IKI will reduce revisions by nearly 20% and that this improvement in survivorship will translate to economic savings. Additionally, independent of survivorship, improvements in patient functioning will result in economic value. The IKI is expected to be cost-neutral with improved health, when restricting the expected benefit to survivorship only, or to be a therapy that both improves health and reduces costs when functional improvements are also considered.
CONCLUSIONS: Although TKA can be a successful intervention, there is still potential for IKIs to provide clinical and economic value. Further investigation to quantify the link between improvement in IKI design features and clinical outcomes is necessary to improve the understanding of potential IKI clinical and economic benefits.
