What a Knee Should Be: A Pilot Study on the Perspectives of Highly Active Prosthetic Users

IntroductionIn recent years, microprocessor-controlled knees have become available to people with lower-limb amputation. Although they may be associated with greater economic benefits and improved clinical outcomes when compared with non-microprocessor-controlled knees, some individuals discontinue use or do not utilize all the functions they provide. Better understanding of how the relationship between human factors and prosthetic function influences peoples' experience is needed to make microprocessor-controlled knees and their functions more accessible to users.ObjectivesThe aims of this study were to explore the prosthetic history of highly active individuals with transfemoral amputation and identify the factors important for prosthetic satisfaction, use, and acceptance, as well as opportunities in advanced prosthetic development.Study DesignA qualitative study design was used.MethodsSemistructured interviews were conducted with five highly active people with transfemoral amputation using microprocessor-controlled knees.ResultsWe identified several factors important for prosthetic satisfaction, use, and acceptance: 1) feeling in control of prosthesis, 2) consistency in functions of prosthesis, 3) intuitive prosthesis, 4) feeling unrestricted by prosthesis, 5) spontaneity, 6) easy to walk and change speed, 7) quiet function, 8) easy to trigger and transition between modes, 9) individually relevant modes, 10) harmonious function with ankle, 11) shock absorption, 12) waterproof, 13) appearance, and 14) weight.ConclusionsFostering trust through consistent and intuitive functions that can be used during various activities is perceived as highly important for satisfaction with prosthetic devices. Furthermore, expected long-term benefits associated with advanced devices are, alone, not sufficient motivation for their use. More intuitive triggering methods coupled with active assistance are necessary to make advanced solutions and their functions more accessible and beneficial. Finally, a multitude of individual characteristics and needs influence use and acceptance, highlighting the necessity of taking human factors into account in prosthetics.Clinical RelevanceThe results shed light on opportunities in future development of prosthetic knees and importance of human factors for powered prosthetic design. They further provide insight into aspects meaningful to highly active end users, affecting prosthetic use and satisfaction.