Influence of prosthesis alignment on the standing balance of below-knee amputees.

The effect of alignment of the prosthesis on the standing balance of below knee amputees was investigated in this work. Alignment variations consisted of varus and valgus tilt and plantar- and dorsiflexions. The foot-ground reaction forces measured in the anteroposterior, mediolateral, and vertical directions as well as global parameters describing the total sway activity, asymmetry, and weight-bearing imbalance were used to compare the various alignment positions studied. The results indicate the presence of a common standing pattern in below-knee amputees, where activity of the foot-ground reaction forces in the anteroposterior direction is significantly higher in the contralateral limb compared with the amputated limb. It was also found that the varus and valgus alignments were the least stable of all alignments.