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VOLUME 8, ISSUE 2 

 2025 
 

LETTER TO THE EDITOR 

 

Bosman C.E, van der Sluis C.K, Vrieling A.H, Geertzen J.H.B, Seves B.L, Groen H. Response to the 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. 7. 

Https://doi.org/10.33137/cpoj.v8i2.46486 

 

  

 

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1 

Bosman C.E, van der Sluis C.K, Vrieling A.H, Geertzen J.H.B, Seves B.L, Groen H. Response to the 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. 7. 
Https://doi.org/10.33137/cpoj.v8i2.46486 

 

 

LETTER TO THE EDITOR 

 

RESPONSE TO THE LETTER TO THE EDITOR REGARDING “HEALTH ECONOMIC 

EVALUATION OF MICROPROCESSOR AND NON-MICROPROCESSOR-CONTROLLED 

PROSTHETIC KNEES” 

Bosman C.E1*, van der Sluis C.K1, Vrieling A.H1, Geertzen J.H.B1, Seves B.L1, Groen H2 

1. Department of Rehabilitation Medicine, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands. 
2. Department of Epidemiology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands. 
 

  

Dear Editor,  

 

We thank colleagues Brüggenjürgen, Riemer and Gapp for their detailed consideration and for 

recognizing the quality of our study.1 

We appreciate that when comparing two lower-limb prosthetic devices across a range of prices, 

such as microprocessor-controlled and non-microprocessor-controlled prosthetic knees, the 

average reader would not expect an incremental cost-effectiveness ratio that exceeds values 

observed for expensive drugs such as monoclonal antibodies. However, it should be noted that 

the ratio not only reflects the difference in costs, but also the difference in effects. As the 

difference in effects becomes very small, the ratio will increase very sharply. In our case, the 

small QALY difference explains the high cost-effectiveness ratio, even though the cost 

difference is not excessive. 

With respect to the costs of prosthesis, we would like to clarify the design of our study to avoid 

misunderstanding. It is true that we included participants who had their first prosthesis fitted, 

as well as those who received a replacement. However, we treated both groups as if they were 

new fittings, in our comparison of prosthesis types. This was a deliberate choice to ensure a 

consistent cross-sectional comparison of prosthesis types. Consequently, we assigned full 

costs of their respective prosthesis to all participants. We acknowledge that this approach 

influences ICUR estimates and agree that assumptions about replacement cycles warrant 

further investigation. 

We regret that the impression was given that a very short replacement cycle would be required. In fact, in the first paragraph 

of our discussion, we refer to a previous study that suggests that cost-effectiveness of the MPK may improve in the long term 

due to lower healthcare costs related to falls. Thus, the higher initial costs of MPK could be at least partially compensated. 

We appreciate your recalculations of ICUR,2 but we feel that the proposed corrections to our ICUR are based on assumptions 

beyond our dataset; they illustrate the sensitivity of ICUR to prosthesis life-cycle assumptions. The calculations show the 

importance of the parameters such as prosthesis life-cycle and stress the importance of future studies evaluating long-term 

outcomes. Also, development of a quality-of-life measurement instrument that is more sensitive to prosthesis-specific 

outcomes, to be translated into a utility value, would be a big step forward in evaluating the cost-effectiveness of prostheses. 

 

DECLARATION OF CONFLICTING INTERESTS 

The authors have no conflicts of interest to declare. 

 

 

 

 

 

 

 
 

REFERENCES 

1.Bosman C.E, van der Sluis C.K, Vrieling A.H, Geertzen J.H.B, Seves 

B.L, Groen H. Health economic evaluation of microprocessor and non-

microprocessor controlled prosthetic knees. Can Prosthet Orthot J. 

2025; Volume 8, Issue 2, No. 3. https://doi.org/10.33137/cpoj.v8i2.4582 

2.Brüggenjürgen B, Riemer A, Gapp M. Letter to the editor regarding 

"Health economic evaluation of microprocessor and non-

microprocessor-controlled prosthetic knees". Can Prosthet Orthot J. 

2025; Volume 8, Issue 2, No. 6. 

https://doi.org/10.33137/cpoj.v8i2.46339 

 
* CORRESPONDING AUTHOR: 
Professor Henk Groen, 

Affiliation: Department of Epidemiology, University of Groningen, 
University Medical Center Groningen, Groningen, The Netherlands. 

E-Mail: h.groen01@umcg.nl 

ORCID ID: https://orcid.org/0000-0002-6629-318X 

 

 

 
OPEN  ACCESS 

CITATION 

Bosman C.E, van der Sluis C.K, 

Vrieling A.H, Geertzen J.H.B, 

Seves B.L, Groen H. Response to 

the 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. 7. 

Https://doi.org/10.33137/cpoj.v8i2

.46486 

KEYWORDS 

Lower Limb; Amputation; 

Prostheses; Cost Analysis; 

Quality of Life; Questionnaire; 

Mobility; Microprocessor Knee; 

Cost-effectiveness.  
 

Journal Homepage: https://jps.library.utoronto.ca/index.php/cpoj/index 

Volume 8, Issue 2, Article No. 7. 2025 

 

 

https://doi.org/10.33137/cpoj.v8i2.46486
https://doi.org/10.33137/cpoj.v8i2.4582
https://doi.org/10.33137/cpoj.v8i2.46339
https://orcid.org/0000-0002-6629-318X
https://doi.org/10.33137/cpoj.v8i2.46486
https://doi.org/10.33137/cpoj.v8i2.46486
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