# Higher cost, comparable outcomes: A health economic evaluation of patient‐specific instrumentation vs. conventional instrumentation for total knee arthroplasty in a Dutch aging population

## TL;DR

A study compared the cost and outcomes of two knee surgery techniques in older patients and found that the newer method was more expensive but no better in improving quality of life.

## Contribution

The study provides a long-term economic evaluation of patient-specific instrumentation versus conventional instrumentation for total knee arthroplasty in an aging population.

## Key findings

- Patient-specific instrumentation (PSI) had higher costs (€658.69 more per patient) than conventional instrumentation (CI) without significant differences in quality of life outcomes.
- Both PSI and CI improved quality of life over 10 years, but PSI was not cost-effective from a hospital perspective.
- Incremental cost-effectiveness ratios for PSI were €14,856.07/QALY after 5 years and €12,836.66/QALY after 10 years.

## Abstract

The demand for treatment of knee osteoarthritis is rising as the population ages. To optimise outcomes of total knee arthroplasty (TKA), several innovative techniques have been introduced, including patient‐specific instrumentation (PSI). While these developments may improve clinical outcomes, they are often associated with higher healthcare costs. The present study aimed to evaluate the long‐term cost‐utility of PSI compared to conventional instrumentation (CI) for TKA, from a hospital perspective.

A multicenter randomised controlled trial including 180 patients was conducted in 2010, with 45 patients in each treatment arm per center. For the current economic evaluation, data from one participating center (n = 90) were analysed. Patients were assigned to receive either PSI or CI TKA and completed EQ‐5D‐5L questionnaires preoperatively and at 5‐ and 10‐year follow‐up. Utility scores and Quality‐Adjusted Life Years (QALYs) were derived from these questionnaires. Hospital records provided cost data, which were indexed to 2023 values. Incremental cost‐effectiveness ratios (ICERs) were calculated as cost per QALY gained.

At final follow‐up, 23 patients (26%) were lost due to death (n = 15, 17%) or withdrawal (n = 8, 9%). The cohort included 58% females with a mean age of 67 years. QALY gains did not differ significantly between groups at either follow‐up point. Mean total costs were €10,722.58 per patient for PSI and €10,063.89 for CI, with PSI exceeding CI by €658.69. This translated into an ICER of €14,856.07/QALY after 5 years and €12,836.66/QALY after 10 years for PSI, compared to €13,932.24/QALY and €12,550.40/QALY, respectively, for CI.

Both PSI and CI TKA improved quality of life at 5 and 10 years postoperatively. However, PSI incurred higher costs without demonstrating additional clinical benefit. From a hospital perspective, CI remains the more cost‐effective approach.

Level II, retrospective study of an RCT.