Factors associated with a risk of prosthetic knee buckling during walking in unilateral transfemoral amputees

Background: Walking and mobility are essential for a satisfactory quality of life. However, individuals with transfemoral amputations have difficulties in preventing falls due to prosthetic knee buckling, defined as the sudden loss of postural support during weight-bearing activities. The risk of prosthetic knee buckling can be evaluated by determining the prosthetic knee angular impulse (PKAI) during the early stance phase. However, little is known about the factors associated with PKAI in individuals with unilateral transfemoral amputations. Research question: What are the demographic factors that can be associated with the risk of prosthetic knee buckling, quantified by PKAI, during walking in individuals with unilateral transfemoral amputations? Methods: Thirteen individuals with unilateral transfemoral amputations were instructed to perform level walking at a comfortable, self-selected speed on a straight, 10-m walkway. PKAI was calculated as the time integral of the prosthetic knee external flexion–extension moment during the initial 40 % of the prosthetic gait cycle. We used Pearson's correlation coefficients to examine the relationship of PKAI with the following variables: the subject's body height, body mass, and age; the time since amputation; and the current prosthesis use history. Furthermore, an independentt-test was used to compare PKAI according to the sex (male vs. female) and etiology (trauma vs. nontrauma). Results: PKAI exhibited a significant negative linear relationship with the subject's body height and body mass. However, it showed no significant correlation with age, the time since amputation, and the current prosthesis use history. It was also significantly greater in women than in men and was not significantly influenced by the etiology. Significance: Awareness about demographic factors associated with PKAI during walking can contribute to fall assessments in gait rehabilitation programs for individuals with unilateral transfemoral amputations.