Gait evaluation of an automatic stance-control knee orthosis in a patient with postpoliomyelitis.

Abstract

To determine gait differences in a subject ambulating with a knee-ankle-foot orthosis (KAFO) with a locked knee joint versus an automatic stance-control knee joint. Single-subject crossover design. Tertiary rehabilitation facility with a motion analysis laboratory. A 61-year-old ambulatory male volunteer with postpoliomyelitis walking with a stance-control KAFO. Instrumented gait analysis and Physiological Cost Index in the locked knee and stance-control modes. Differences in gait parameters. On the braced limb, stance-control mode showed a near-normal knee flexion wave in swing, reduced pelvic retraction and rotational excursion, and improved hip power generation. On the nonbraced limb, the stance-control mode allowed elimination of vaulting, reduction in abnormal ankle and hip power generation, increased knee power absorption, and more typical quadriceps activation. There was a trend toward improved energy efficiency in the stance-control mode. Use of a stance-control knee joint in a KAFO appears to improve gait biomechanics and improve energy efficiency compared with a locked knee.