Microprocessor vs Mechanical Prosthetic Knees: Which Gives Better Mobility and Value?
Reading Time: 4 minutes
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Summary:
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Microprocessor knees can feel smoother and more stable than mechanical knees
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Users report better daily mobility and confidence
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Quality-of-life gains are real but modest in the short term
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Long-term benefits, like fewer falls, may matter more than short-term cost data
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Choosing the appropriate prosthetic knee is crucial for individuals with above-knee amputations to regain mobility, confidence, and quality of life. Thanks to technological advancements, microprocessor-controlled prosthetic knees (MPKs) are becoming more common. However, they are significantly more expensive than traditional mechanical (non-microprocessor) knees (NMPKs). So, a health economic evaluation, published in the Canadian Prosthetics & Orthotics Journal, sought to answer a key question: Do the benefits of MPKs justify their higher price compared with mechanical knees?
Study Design and Participants
The study involved 111 prosthesis users, with 62 using an MPK and 49 using an NMPK. Participants varied in age and amputation level, including above-knee and through-knee amputations.
The researchers gathered cross-sectional data on health-related quality of life, prosthesis satisfaction, mobility, healthcare use, and costs. The results were evaluated from a societal perspective in the Netherlands, accounting for direct medical expenses, productivity, and quality-adjusted life years (QALYs).
QALYs are a common health economics measure that quantify both the length and quality of life, with one QALY representing one year of perfect health and zero QALYs indicating death. This measure helps compare the cost-effectiveness of different treatments across various diseases by showing the cost per QALY gained.
Quality of Life Gains: Real but Modest
A key finding was that MPK users reported better mobility and higher satisfaction with their prostheses than those using NMPKs. MPK users also generally felt more confident doing daily activities and faced fewer limitations. These results matter because they reflect what people experience in real life, not just clinical test scores.
While MPK users saw some improvements compared to NMPK users, the difference in QALYs is modest. Over six months, MPK users gained an average of 0.032 more QALYs than NMPK users.
Even small QALY gains can be important in health economics, especially if they lead to more independence or reduce the risk of falls. But because MPKs are much more expensive than NMPKs, the researchers concluded that these small improvements don’t justify the higher costs under usual cost-effectiveness standards.
Cost Differences
During initial purchase, MPKs averaged €21,018, compared to €4,417 for NMPKs. Even though other medical and productivity costs were included, the high upfront price was the biggest factor in the cost comparison.
When the researchers looked at the additional cost per QALY gained by using an MPK instead of an NMPK, they found it was €457,063 per QALY. This amount is far higher than what health systems usually consider acceptable, which is typically between €20,000 and €80,000 per QALY.
Short-Term vs Long-Term Perspectives
It’s important to note that this study focused on a six-month period, with the authors noting that a longer follow-up could alter the economic assessment. Previous research shows that MPK users often experience lasting benefits such as fewer fall-related healthcare visits, increased participation in daily activities, and extended prosthesis use—all of which could improve long-term value. However, these longer-term data were not included in this analysis.
The modest QALY improvement over six months, combined with high costs, indicates that, at least in the short term and within the studied conditions, MPKs do not meet typical cost-effectiveness standards.
Do you currently use MPKs or NMPKs? What do you think of the findings?
Related Reading:
Study Says Powered Lower-Limb Prostheses Promote Better Overall Health
Transforming Lives: The Impact of Microprocessor Knees on Amputees in Wales
Anthem Now Covers Microprocessor-Controlled Lower-Limb Prostheses
