Bernd Brüggenjürgen, Annika Riemer, Matthias Gapp

LETTER TO THE EDITOR REGARDING "HEALTH ECONOMIC EVALUATION OF MICROPROCESSOR AND NON-MICROPROCESSOR-CONTROLLED PROSTHETIC KNEES"

Introduction

Letter to the editor regarding "health economic evaluation of microprocessor and non-microprocessor-controlled prosthetic knees". This letter critiques a health economic evaluation of microprocessor vs. non-microprocessor prosthetic knees, recalculating cost per QALY to a more plausible €19,603.

Abstract

This Letter to the Editor responds to the article by Bosman et al. ( https://doi.org/10.33137/cpoj.v8i2.45823 ). Real-world Dutch resource use data from Bosman et al. demonstrated lower non-prosthesis healthcare costs for microprocessor-controlled knee users compared with non-microprocessor-controlled knees, although the reported incremental cost per QALY (€457,063) appears unexpectedly high. This estimate likely overstates cost per QALY because prosthesis-related expenses were inconsistently prorated and implicitly assumed a 6-month replacement cycle, which is not clinically plausible. Recalculation assuming a conservative 5-year prosthesis replacement cycle resulted in an ICUR of €19,603 per QALY, consistent with accepted health technology assessment thresholds. Article PDF Link: https://jps.library.utoronto.ca/index.php/cpoj/article/view/46339/34632 How To Cite: Brüggenjürgen B, Riemer A, Gapp M. Letter to the editor regarding "Health economic evaluation of microprocessor and non-microprocessor-controlled prosthetic knees". Canadian Prosthetics & Orthotics Journal. 2025; Volume 8, Issue 2, No. 6. https://doi.org/10.33137/cpoj.v8i2.46339 Corresponding Author: Prof. Dr. med. Bernd Brüggenjürgen, MPHAffiliation: Institute for Health Services Research and Technical Orthopedics, Orthopedic Department, Medical School Hannover (MHH) at DIAKOVERE Annastift Hospital, Germany.E-Mail: Brueggenjuergen.Bernd@mh-hannover.deORCID ID: https://orcid.org/0000-0002-8866-0809

Review

This Letter to the Editor serves as a critical re-evaluation of the health economic analysis presented by Bosman et al. regarding microprocessor-controlled (MPK) versus non-microprocessor-controlled prosthetic knees. The authors acknowledge Bosman et al.'s valuable finding that real-world Dutch data demonstrated lower non-prosthesis healthcare costs for MPK users. However, the primary catalyst for this letter is the original study's reported incremental cost per QALY (ICUR) of €457,063, which the present authors correctly identify as unexpectedly and implausibly high, necessitating further scrutiny. The core of the critique lies in identifying two significant methodological flaws in the original analysis: the inconsistent prorating of prosthesis-related expenses and the implicit assumption of an unrealistic 6-month replacement cycle for prosthetic knees. To address these issues, Brüggenjürgen et al. undertake a crucial recalculation. By applying a more clinically sound and conservative 5-year prosthesis replacement cycle, they derive a substantially different and more plausible ICUR of €19,603 per QALY. This revised figure directly challenges the original study's conclusion regarding the cost-effectiveness. The significance of this Letter to the Editor cannot be overstated. By correcting a critical methodological assumption, Brüggenjürgen et al. have successfully transformed an outlier ICUR into a figure that aligns well within accepted health technology assessment thresholds. This correction is vital for clinicians, policymakers, and health economists making decisions about prosthetic technologies, as it provides a far more accurate and actionable understanding of the economic value of microprocessor-controlled knees. It underscores the critical importance of rigorous methodological considerations in health economic evaluations to ensure reliable and clinically relevant conclusions.

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