Lower extremity kinematics and kinetics during level walking and stair climbing in subjects with triple arthrodesis or subtalar fusion.

The purpose of this study was to identify the kinematic and kinetic strategies used by patients with unilateral triple arthrodesis or subtalar fusion during level walking, stair ascent, stair descent and to determine the influence of these different conditions on kinematics and kinetics. Nine subjects with unilateral triple or subtalar fusion and five normal control subjects were recruited for this experiment. Temporal distance, kinematic and kinetic data were collected using a six camera 3-D motion analysis system and a custom fabricated set of stairs with five steps; the second and third steps were each instrumented with one force platform. During level walking, affected limbs lost all of the plantarflexion at the ankle joint during push-off and showed greater knee flexion angle during the same period of stance. During stair ascent, affected limbs showed a different movement pattern at the knee, a greater knee flexion angle during the whole stance phase and a near zero degree of plantarflexion angle during the forward continuance (FCN) phase. During descent, affected limbs showed a greater knee flexion angle during the whole stance phase and less ankle dorsiflexion angle during the same period of stance phase. At the ankle, peak moment and power values were significantly different between the affected side and the limbs of the control subjects during level walking in the push-off phase, stair ascent in the FCN phase, and stair descent in the weight acceptance (WA) phase, where the affected limbs had a lower plantarflexion moment and power values.