Is total ankle arthroplasty a cost-effective alternative to ankle fusion?

Abstract

Background: Total ankle arthroplasty (TAA) implantation is increasing, as the potential for pain relief and restoration of function and risks are compared with those for ankle fusion. A previous analysis with a simple decision tree suggested TAA was cost-effective compared with ankle fusion. However, reevaluation is warranted with the availability of newer, more costly implants and longer-term patient followup data.

Questions/purposes: Considering all direct medical costs regardless of the payer, we determined if TAA remains a cost-effective alternative to ankle fusion when updated evidence is considered.

Patients and methods: Using a Markov model, we evaluated expected costs and quality-adjusted life years (QALY) for a 60-year-old hypothetical cohort with end-stage ankle arthritis treated with either TAA or ankle fusion. Costs were estimated from 2007 diagnosis-related group (DRG) and current procedural terminology (CPT) codes for each procedure. Rates were extracted from the literature. The incremental cost-effectiveness ratio (ICER), a measure of added cost divided by QALY gained for TAA relative to ankle fusion, was estimated. To identify factors affecting the value of TAA, sensitivity analyses were performed on all variables.

Results: TAA costs $20,200 more than ankle fusion and resulted in 1.7 additional QALY, with an ICER of $11,800/QALY gained. Few variables in the sensitivity analyses resulted in TAA no longer being cost-effective.

Conclusion: Despite more costly implants and longer followup, TAA remains a cost-effective alternative to ankle fusion in a 60-year-old cohort with end-stage ankle arthritis.

Fig. 1

Individuals initially undergo either TAA or ankle fusion. As the model progresses patients enter different health states, represented by the ovals in the diagram, based on reported rates in the literature. A certain percentage of patients will die after the initial surgery, represented by the dashed arrow to the Dead state. Individuals who survive the initial surgery begin in either the Well Post-TAA or Well Post-Fusion health state. Patients may remain in either of these two health states for several years, represented by the larger curved arrows. Eventually patients either will die and move to the Dead state, or need a revision surgery or have arthritis develop and transition to Revision Surgery or Develop Arthritis. After revision surgery, patients either will enter the Well Post-Revision TAA or Well Post-Revision Fusion health state. A small percentage of patients having revision TAA and revision ankle fusions also will undergo a BKA and enter the Well BKA health state. Patients who have additional areas of arthritis develop either will enter the Ipsilateral Arthritis health state or undergo revision surgery. Patients might remain in each of the health states (ie, Well Post-TAA, Well Post-Fusion, Well Post-Revision TAA, Well BKA) for several years, again represented by the large curved arrows. The dashed lines show age-specific transitions from each health state to death based on US life-table mortality rates.