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

Abstract

Objective: 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.

Design: Single-subject crossover design.

Setting: Tertiary rehabilitation facility with a motion analysis laboratory.

Participant: A 61-year-old ambulatory male volunteer with postpoliomyelitis walking with a stance-control KAFO.

Interventions: Instrumented gait analysis and Physiological Cost Index in the locked knee and stance-control modes.

Main outcome measure: Differences in gait parameters.

Results: 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.

Conclusions: Use of a stance-control knee joint in a KAFO appears to improve gait biomechanics and improve energy efficiency compared with a locked knee.