A study published online November 27 in the journal BMC Musculoskeletal Disorders found that there is little scientific evidence available about how microprocessor knees (MPKs) affect users’ performance in activities of daily living (ADLs) and participation in society when compared to mechanically controlled prosthetic knees. They said determining what characteristics an individual with a transfemoral amputation should have for an MPK to be a more suitable prosthetic solution than a mechanically controlled prosthetic knee joint to function optimally in daily life is an important step in streamlining the current prescription guidelines and reimbursement policies regarding MPKs.
The research team performed a systematic literature search in six databases (PubMed, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Cochrane Library, Embase, Medline, and PsychINFO) to identify studies that compared the functional effects of using MPKs with mechanically controlled prosthetic knee joints among the device users. Within the 37 studies identified in the literature, they reviewed 72 outcome measures that could be used to determine the necessary characteristics to prescribe an MPK and classified the measures within the International Classification of Functioning, Disability and Health (ICF). The ICF defines two categories of health: functioning and disability, and contextual factors. Functioning and disability is further categorized into the components called body functions, body structures, and activities and participation. Contextual factors is divided into environmental factors and personal factors. Additionally, individuals with amputations can be classified into K-levels based on their ability or potential ability to function with their prosthesis.
According to the researchers, the majority of the evidence (67 percent) that is available regarding the effectiveness of MPK use is primarily based on measures covering the ICF body functions component. Yet, only few studies (31 percent) have investigated the effects of MPK use on the activities and participation component of the ICF. The former is valuable to understand the principles behind how MPK use may contribute to optimizing a person’s performance with a prosthesis; the latter is more closely related to the problems experienced by amputees in daily life. “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 prosthetic device on all ICF components that comprise persons’ level of functioning,” they said.
These finding led to the study’s conclusion that the currently available scientific knowledge regarding the effects of MPK use on functional abilities is limited. Future studies, the authors said, should focus on outcome measures that focus more on whether the effects measured in a human movement lab also apply to situations in a person’s everyday life; the development of tools that are able to objectively measure actual performance in persons with a transfemoral amputation; and on the effects of MPK use in persons with a lower functional level, such as older, less active persons with an amputation.
