Evaluation and comparison of priori alignment techniques for transtibial prostheses in the developing world Field trial in Nicaragua

Purpose. The purpose of this study was to transfer three simplified alignment techniques to prosthetic technicians in a developing country through training materials and a hands-on training workshop, and to subsequently evaluate the efficacy of the alignment systems in producing acceptably aligned monolimb prostheses. Method. Prosthetists utilized the anatomically-based- alignment ABA-standing, ABA-supine and vertical alignment axis VAA alignment systems to produce three monolimbs for each of 30 healthy and active transtibial amputees. Prosthetists assessed all three monolimbs for each subject in both static and gait conditions to determine which monolimb had the best alignment and produced the best functional gait. Subjects also selected the monolimb which they believed had the best alignment; subjects utilized each monolimb for a 1-month home assessment. Results. Twenty-eight subjects completed the study. Eighty-four monolimbs were evaluated by the prosthetists and the subjects. A few monolimbs had minor socket fitting and alignment issues, but none prevented evaluation in the laboratory or during the 1-month home assessment. Only three monolimbs had poor alignment and could not be worn by the subjects. Conclusions. All three systems captured acceptable alignments, although the two systems that incorporate weight bearing, the ABA-standing and VAA alignment systems, produced slightly better outcomes. The alignment ratings between these two systems were statistically insignificant.