A recent literature review found that scientifically valid evidence on the performance of patients with microprocessor-controlled prosthetic knees in everyday life is limited and future research should focus on activities and participation to increase the understanding of their functional-added value.
“The effectiveness of microprocessor-controlled prosthetic knee joints has been assessed using a variety of outcome measures in a variety of health and health-related domains. However, if the patient is to receive a prosthetic knee joint that enables him to function optimally in daily life, it is vital that the clinician has adequate information about the effects of that particular component on all aspects of persons’ functioning,” the researchers wrote. “The present study aimed to review the outcome measures that have been utilized to assess the effects of microprocessor-controlled prosthetic knee joints, in comparison with mechanically controlled prosthetic knee joints, and aimed to classify these measures according to the components and categories of functioning defined by the International Classification of Functioning, Disability and Health. Subsequently, the gaps in the scientific evidence regarding the effectiveness of MPKs were determined.”
Effects of MPKs
Searching through six databases, researchers identified 37 studies comparing the effects of using microprocessor-controlled prosthetic knees (MPKs) with mechanically controlled prosthetic knee joints on patients’ functioning. Seventy-two outcome measures used in the studies were extracted and categorized according to the International Classification of Functioning (ICF) framework. Researchers also performed a descriptive analysis regarding all studies.
Overall, 67% of outcome measures that described the effects of using an MPK on actual performance with the prosthesis covered the ICF body functions component, according to study results. Researchers found 31% of the measures on actual performance investigated how an MPK may affect performance in everyday life. Overall, research primarily focused on young, fit and active patients.
“The scientific knowledge that is currently available regarding the effects of using an MPK on persons’ functional abilities is limited,” the researchers concluded. “Additional information is necessary about how the use of an MPK may affect persons’ actual ability to perform activities in everyday life and how using an MPK may influence people’s participation in society.”
Broadening future research
Although most comparative studies have investigated the effects of an MPK vs. a mechanically controlled prosthesis on walking, including quality, physical effort and cognitive effort, the researchers found little information available about other aspects of functioning with a prosthesis. Finding only one study that assessed individuals’ actual ability to perform activities of daily living, the researchers believe future research should focus on whether the effects measured in a motion lab can be found in an individual’s everyday life. To complement information on MPK performance available so far, future research should be aimed at older, less active amputees.
According to the researchers, future research also should focus on the development of objective tools that measure actual performance in transfemoral amputees, specifically those that measure activity and participation. A measurement tool that also includes parameters on self-perceived performance is also warranted.
“Prosthesis research should focus more on the effects of using an MPK in persons with a lower functional level (eg, amputees classified as MFCL-2),” the researchers wrote. “Given their limited physical capacity, these persons might not benefit from using the adaptive swing phase control that should enable them to walk at varying speeds. However, they may possibly benefit from the higher levels of stability of the knee due to the continuous adaptive stance phase control.” — by Casey Tingle
Disclosure: The researchers have no relevant financial disclosures.