A randomized trial investigating the cost-utility of patient specific instrumentation in total knee arthroplasty in an obese population

Abstract Background Patient specific instrumentation (PSI) has been introduced in total knee arthroplasty (TKA) with the goal of increased accuracy of component positioning by custom fitting cutting guides to the patient’s bony anatomy. A criticism of this technology is the associated cost. The purpose of this randomized-controlled trial was to determine the cost-utility of PSI compared to standard of care (SOC) instrumentation for TKA in an obese population. Methods Patients with body mass index greater than 30 with osteoarthritis and undergoing primary TKA were randomized to SOC or PSI. Patients completed a healthcare resource use diary and the EuroQol-5D at three-, six-, nine- and 12-months and the WOMAC at three- and 12-months post-surgery. We performed cost-utility and cost-effectiveness analyses from public healthcare payer (HCP) and societal perspectives. Results One hundred and seventy-three patients were included in the analysis with 86 patients randomized to PSI and 87 to SOC. PSI was dominated (more costly and less effective) by SOC from an HCP perspective. From a societal perspective, an incremental cost-utility ratio was calculated at $11,230.00 per quality-adjusted life year gained, which is cost-effective at a willingness-to-pay (WTP) threshold of $50,000. Net benefit analyses found PSI was not significantly cost-effective at any WTP value from either perspective. Conclusion Our results suggest that widespread adoption of PSI may not be economically attractive or clinically indicated. Future considerations are to compare long-term clinical outcomes and radiographic alignment between the groups.