Biomechanics and Motion Analysis

Logic Controlled Electromechanical Free Knee Orthosis

Principal Investigator: Kenton R. Kaufman, Ph.D.
Project Coordinator: Kathie Bernhardt — bernhardt.kathie@mayo.edu

Figure 1: Bilateral 3-D motion analysis is conducted at selfselected walking speeds over level ground.

The goal of this project is to design, develop, and test an electronically controlled knee joint that can be installed on a conventional KAFO. This knee brace system falls into a specialized family of braces called 'Stance Control Orthoses' or SCO. The brace developed here is called the Dynamic Knee Brace System (DKBS). It is comprised of a novel wrap spring clutch and electric motor drive, sensors at the foot and knee, electronic control circuitry, and a rechargeable battery pack. Two United States patents have been awarded to the designers and Mayo Foundation (6,500,138 and 6,834,752). The knee joint will unlock during the swing phase of gait and lock during the stance phase of gait. The clinical result of this project is expected to be improved efficiency of gait in patients with poliomyelitis, spinal cord injuries, myopathic disorders, congenital spinal defects, and acquired paralysis due to infections or vascular insults. Twenty-one participants have completed a 6-month field trial using the DKBS. Field tests also included periodic comprehensive 3-D motion analysis (Fig. 1). Engineering development continues to improve reliability and reduce weight. A second field trial is underway to compare the DKBS to commercially available SCO's.