The Kenevo microprocessor-controlled prosthetic knee compared with non-microprocessor-controlled knees in individuals older than 65 years in Sweden: A cost-effectiveness and budget-impact analysis.
Alexander Kuhlmann, Kerstin Hagberg, Ilka Kamrad and 3 others
PMID 35511441WHAT IT FOUND
For people over 65 needing a first leg prosthesis, a microprocessor knee cost €6,576 more per patient but gained 0.58 quality-adjusted life years, yielding a cost-effectiveness ratio of €11,369 per QALY.
This fell below Sweden’s higher willingness-to-pay threshold of €40,000 but exceeded the lower €8,000 threshold.
Key findings
01The microprocessor knee had an incremental cost-effectiveness ratio of €11,369 per QALY gained, which is below the €40,000 threshold but above the €8,000 threshold.
02Cost-effectiveness was driven by a simulated 63% reduction in fall rate and lower fall-related medical costs, despite higher upfront prosthesis costs.
03The model’s budget impact was €1.76 million over five years, but results were highly uncertain with the ICER ranging from €2,551 to €33,780 in sensitivity analyses.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
The study is a model-based simulation, not a direct clinical trial, so results depend entirely on the accuracy of input parameters from other sources. Key input data on fall rates and utilities came from studies with small sample sizes and short follow-ups, contributing to high uncertainty in the cost-effectiveness ratio. The model assumed that patients were wearing their prosthesis when they fell, which is unlikely for many elderly users with low prosthetic use rates, potentially inflating the estimated benefit of the MPK. Long-term health-related quality-of-life reductions from falls were not included, which may underestimate the total benefit of the MPK. Results cannot be generalized to other microprocessor knees, only the Kenevo. Mortality rates were based on all patients with amputation, not just prosthesis users, which may misrepresent the survival of the simulated population.
Declared interests
The manufacturer of the Kenevo knee, Ottobock, provided the prosthesis prices and warranty package costs used in the model. No other specific funding sources or author conflicts were detailed in the provided text beyond this data contribution.
The easy way to misread this
Do not interpret the positive cost-effectiveness ratio as direct clinical evidence that the Kenevo knee improves patient outcomes. This is a simulation model based on aggregated data from other studies, not a trial measuring real-world patient results. The uncertainty in the cost-effectiveness ratio was very high, ranging from €2,551 to €33,780 per QALY, and the model’s assumptions about prosthesis use during falls may overestimate the benefit.